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Hi All,

Looking for some advice on cooling issues I'm having with my Turbo Mach 1. I have read the Simplified Cooling system thread but am wondering if there have been any other break throughs since that was written.

I have moved my thermostat to the upper rad hose. I capped off the bypass on the Coolant crossover. I have a 180F thermostat with no holes drilled in it but it does have a small bleeder hole. I still have the original expansion tank as well. I replaced the lower rad hose with one from a GT. I originally had a thermostat with 3 holes drilled in it but found the car ran too cool from what I remember. So I went from being too cool to too hot it seems.

I see that Modularspeed has done a lot of testing throughout that thread and has experimented with different sizes and amounts of drilled holes in his thermostat. I also found another thread where he had reintroduced a 1/2" bypass line from the inline thermostat housing at the engine side of the thermostat down to a Tee in the lower hose and just uses one 1/8" drilled hole in the thermostat.

I'm wondering on what everyone's thoughts are or might know to be the best solution for cooling? Is adding a bypass line the answer? drilling holes the answer? doing a mix of both. I do need to replace my radiator since it is leaking. I am looking at replacing it with a Mishimoto unit that is a direct bolt in and will be all aluminum. Will that be enough for added cooling? Are there better radiators than what I have mentioned.

I had some hotter than comfortable moments this summer with the AC on and want it resolved for when this summer rolls around.

The car is a On 3 Turbo car so it has a larger heat load than the cooling system was was designed for. It is mounted in between the radiator and engine so it is directly in the path of the airflow. It also has a A2A intercooler mounted out front of the rad support. All this adds up to airflow being somewhat hindered. I have wrapped all hot side piping with heat wrap when I first installed my turbo system.

My gut feeling is the bypass line with a small drilled hole in the thermostat is the answer but wanted to hear thoughts from others on the matter.

Shawn
 

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Hi All,

Looking for some advice on cooling issues I'm having with my Turbo Mach 1. I have read the Simplified Cooling system thread but am wondering if there have been any other break throughs since that was written.
The “standard” t-stat in the top and unrestricted lower block inlet is both the most simple and also the most effective in-car cooling model possible.


I have moved my thermostat to the upper rad hose. I capped off the bypass on the Coolant crossover.
This is good.

The coolant crossover bypass to the back of the water pump or to the radiator inlet, is more for the heater core if it is still plumbed in.


I have a 180F thermostat with no holes drilled in it but it does have a small bleeder hole.
This is not good!

The three bleeder holes fulfill the function of the coolant bypass in an OEM system. Eliminating these will not improve the operation of the cooling system. The purpose of the holes is to provide the coolant flow that the original bypass did. That coolant flow is how the t-stat reads engine operating temperature and decides to open.

Elimination of the holes causes the engine to overheat until enough heat has been transferred by convection through the block and head castings to the t-stat spring to open the t-stat. The lack of the three holes will consistently cause the engine to overheat to open the t-stat. Once open, the overheating phenomena will repeat as soon as the engine temp falls below the opening temp on the t-stat.

In a supercharged engine you run a much higher risk of damaging the engine from/by overheating because of not using the bypass holes.


I still have the original expansion tank as well.
This is good to keep.


I replaced the lower rad hose with one from a GT.
You want to use the largest coolant feed hose from the radiator outlet to the water pump inlet as possible. The less restriction you place on the inlet of a pump the more efficient the pump. This is why a throttle blade is used to control engine power.


I originally had a thermostat with 3 holes drilled in it but found the car ran too cool from what I remember. So I went from being too cool to too hot it seems.
This is because you have dead headed the cooling system. Your t-stat will not open until enough heat soaks through the block and heads to heat the t-stat spring and open the t-stat. Until that happens everything else in the engine will overheat potentially causing damage.

If the engine runs too cool with the t-stat you have selected, go to a t-stat rated at a higher opening temp. Do not reduce the number or size of the bypass holes, you will do yourself no favors.


I see that Modularspeed has done a lot of testing throughout that thread and has experimented with different sizes and amounts of drilled holes in his thermostat. I also found another thread where he had reintroduced a 1/2" bypass line from the inline thermostat housing at the engine side of the thermostat down to a Tee in the lower hose and just uses one 1/8" drilled hole in the thermostat.
If you like what he did you should duplicate it. I recommend you follow the three hole model. If your engine runs too cool it means the opening temp on the t-stat is too low. If your engine runs too hot it means the opening temp on the t-stat is too high. Make t-stat open temp adjustments to get your operating temperature where you would like it to be, just as if you had a factory bypass and a t-stat w/o drilled holes.


I'm wondering on what everyone's thoughts are or might know to be the best solution for cooling? Is adding a bypass line the answer? drilling holes the answer? doing a mix of both.
I highly recommend the three hole t-stat model and adjust your t-stat opening temperature to get the engine operating temperature where you want it.


I do need to replace my radiator since it is leaking. I am looking at replacing it with a Mishimoto unit that is a direct bolt in and will be all aluminum. Will that be enough for added cooling? Are there better radiators than what I have mentioned.
Virtually all of the aluminum radiator suppliers have good product. Select one that fits, is designed to cool an engine of your power level, and fits your budget. During the shopping process I would also look for one with a 2” diameter lower water outlet on the driverside. When Ford offered their combination water inlet and remote oil filter adapter, the size inlet they chose for the design was a 2” OD entry.

I am sure there is some sort of pecking order for radiator manufacturers. Check what Summit and Jegs offer and ask them who is the most popular and who has the most returns. They may or may not provide an answer, but if they do it will give you considerable insight into what you want to select.


I had some hotter than comfortable moments this summer with the AC on and want it resolved for when this summer rolls around.
Use the three hole design with a properly selected t-stat opening temperature. If the engine overheats with an early opening t-stat you either have an undersized radiator, a choked down coolant flow path somewhere or your tune is running the engine excessively hot — possibly more than one whoops could be occurring.


The car is a On 3 Turbo car so it has a larger heat load than the cooling system was was designed for.
If you are certain this is the case then you need to up your game in the cooling system design department and most likely provide a larger more efficient radiator.


It is mounted in between the radiator and engine so it is directly in the path of the airflow. It also has a A2A intercooler mounted out front of the rad support. All this adds up to airflow being somewhat hindered.
All good points.

If that is the way you wish to have the design, then you need to build a cooling system that is capable of offsetting the additional heat being created / absorbed by the charge cooler and the engine.


I have wrapped all hot side piping with heat wrap when I first installed my turbo system.
This is a good first step. But it does not eliminate the additional heat it only somewhat reduces it.

If you are experiencing heating problems and have properly selected and installed your three hole t-stat cooling hardware then you either have too small a radiator, an obstructed an airflow path, too much heat being introduced into the air flow or an engine that may be need to be retuned. Depending on which situation (or combination) you are dealing with the fix will vary.


My gut feeling is the bypass line with a small drilled hole in the thermostat is the answer but wanted to hear thoughts from others on the matter.

Shawn
I still highly recommend the t-stat with the three drilled holes. If you like any one of the alternatives you should use what you like most. If it works you will know right away. If it doesn’t you will also know right away.
 

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Discussion Starter · #3 ·
Thanks for all of this insight Ed,

I didn't have any overheating issues when I had the T-stat drilled with 3 holes. I just thought the car ran too cool. I didn't understand the role the bypass played in the overall functioning of the cooling system so I removed the drilled T-stat and replaced it with a non-drilled T-stat. That was the wrong move as it seems!. What you say about adjusting heating and / or cooling temperatures by changing the T-stat and leaving the drilled holes in play makes good sense. Now that I know the principles of operation I should be able to tweak my temp to where I feel it is best.

Living on the East Coast of Canada, our hot days are not all that hot or long in duration. I only had the one uncomfortable heating event in the dead of summer, shut my AC down and the temp came back down relatively quickly.. I'm trusting there was no damage done. I'm guessing scored pistons or walls might be the result? Warped heads? Cracked block?.

The more I type the more I'm thinking the cooling system is probably adequate, I just had it set up improperly

Thanks again,
Shawn
 

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I probably contributed more to everyone's confusion by not explaining the way the modified cooling system functions way back when we first began to talk about it, Shawn — so I own a good piece of the confusion.

The top hose t-stat and unobstructed lower hose feed to the water pump from the radiator are the most basic of all the cooling system models. Ford's original cooling system model was emissions driven and did a good job of satisfying the emissions requirements at that time while still providing adequate cooling for an OEM engine configuration.

As we begin to raise the bar power-wise (which is so easy to do on these engines) the corresponding heat energy that the higher power levels bring to the table needs to be managed down to proper levels for engine operation and longevity. The simplified cooling model with the t-stat in the top hose does an excellent job of this.

Although, at first glance, the three drilled holes would appear to be for additional cooling, in fact they are used to promote a reduced coolant flow through the closed system around the t-stat, adequate to open the t-stat for proper engine cooling. They are literally fulfilling the same function as the bypass that Detroit uses on all production vehicles. I just chose to do it in as compact and simple a configuration as possible.

Use the t-stat manufacturer rated opening temps to manage your engine's operating temperature. If the t-stat seems a little slow on the draw, so to speak, you can increase the cold coolant flow to the t-stat by opening up the three holes slightly. I found three 3/16" holes to be a pretty good compromise. If your power level is in the 650/700 hp and higher range you might want to go up 0.030" to 0.060" per hole. Don't forget you don't need to drill all three at once. You can try them one at a time until you get a t-stat opening as quickly or slowly as you wish.

Bottom line, the bypass holes are just that. They allow the bypass of the warming coolant to wash around the t-stat, opening it for business before you start getting hot spots in the heads.
 

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Discussion Starter · #5 ·
I probably contributed more to everyone's confusion by not explaining the way the modified cooling system functions way back when we first began to talk about it, Shawn — so I own a good piece of the confusion.

The top hose t-stat and unobstructed lower hose feed to the water pump from the radiator are the most basic of all the cooling system models. Ford's original cooling system model was emissions driven and did a good job of satisfying the emissions requirements at that time while still providing adequate cooling for an OEM engine configuration.

As we begin to raise the bar power-wise (which is so easy to do on these engines) the corresponding heat energy that the higher power levels bring to the table needs to be managed down to proper levels for engine operation and longevity. The simplified cooling model with the t-stat in the top hose does an excellent job of this.

Although, at first glance, the three drilled holes would appear to be for additional cooling, in fact they are used to promote a reduced coolant flow through the closed system around the t-stat, adequate to open the t-stat for proper engine cooling. They are literally fulfilling the same function as the bypass that Detroit uses on all production vehicles. I just chose to do it in as compact and simple a configuration as possible.

Use the t-stat manufacturer rated opening temps to manage your engine's operating temperature. If the t-stat seems a little slow on the draw, so to speak, you can increase the cold coolant flow to the t-stat by opening up the three holes slightly. I found three 3/16" holes to be a pretty good compromise. If your power level is in the 650/700 hp and higher range you might want to go up 0.030" to 0.060" per hole. Don't forget you don't need to drill all three at once. You can try them one at a time until you get a t-stat opening as quickly or slowly as you wish.

Bottom line, the bypass holes are just that. They allow the bypass of the warming coolant to wash around the t-stat, opening it for business before you start getting hot spots in the heads.
I appreciate the clarity you’ve provided on this subject Ed. I had originally thought that the drilled holes were making the thermostat pointless. My though was that if the holes are allowing coolant around the thermostat then why bother with a thermostat.

It never occurred to me that the system would be dead headed with no drilled holes. I just assumed the thermostat would open when it got warm enough. But as you pointed out earlier in this post, the opening does happen but takes much longer because the coolant isn’t moving and would need to warm the thermostat from convection.

So, from what I understand now is that I can tweak the opening by either adjusting the amount / size of holes or changing the thermostat to a cooler or hotter rating based on what I think the temp needs to be.

In any event, at least now I understand how it all works and can tweak it as needed.

thanks,
Shawn
 

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You are reading the tea leaves correctly Shawn.

Lets say you want to run the engine at 190 ˚F. Install a 190 ˚F t-stat and use three 0.1875" diameter holes. If you use a coolant crossover in the rear put a temp sensor in the line back there. The back of the engine will always be different by a couple of degrees than the front but you should be in the same ballpark. If the three holes you drill in the t-stat are a little big the difference between front and rear temps on the engine will be small. If the holes are a little too small you will see rear temps rising. You won't be able to get them identical because the engine has a natural temperature gradient back to front. You just want to be close and you don't want to be boiling water in the heads because the t-stat is closed waiting for hot coolant to arrive to signal it to open, when it should have already been open.

The three drilled holes only provide a bypass allowing the coolant in the engine to reach the t-stat spring and open it when temps are right.
 

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Discussion Starter · #7 ·
thanks Ed,

I do have the rear crossover installed. I’ve read in some instances where people have run a line from that up to the front and tied it into the upper hose before the thermostat. Am I remembering that correctly? If not should I leave it as is or do you have a suggestion on what to do in this instance?
 

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You want to get the hot coolant back to the radiator to cool it down. Ford sort of cheated. They ran it back from the heater core to the water pump nipple on the backside of the water pump cavity in the valley between the two cylinder banks. Ford was emission's compliance driven and a rapid warming of the engine was a positive for them. By plumbing the hot coolant into the water pump they shortened the time to bring the engine to operating temperature.

While you don't have to vent the crossover to the radiator, it is none the less a good idea. By dumping hot coolant from the driverside bank into the passenger side bank you simply export the problem to both banks. If is much more preferable to vent the hot coolant from both heads to the radiator inlet. When you do this don't get crazy with hose size.

Once you vent coolant from the back side of the head castings, the coolant pressure in each head drops. Because it is now lower pressure the coolant movement forward to the radiator slows, potentially creating a heating issue further forward in the casting. A small half inch hose is a lot of hose so be circumspect and tread lightly. If you start detecting knock on forward cylinders of either side, you need to back off a notch on your coolant bleed off.

If you use the most current generation head gaskets, Ford substantially re-did the hole sizes at the rear of each gasket to "encourage" proper coolant flow and cooling. If you have already purchased a head cooling mod and used the new gaskets in the engine assembly you might want to give Ford's cooling system engineering fix a try before going to mods.

I just checked the Fel-Pro website and they appear to have dropped the gaskets with the revised cooling passages. Knowing that, I would go to Ford and buy the gaskets from them. The gaskets they sell will reflect the latest Engineering Change Order (ECO) for head cooling and are every bit as good as aftermarket alternatives. I tend to put more emphasis (and faith) in the Ford solution because they were motivated to fix the problem. It represented both a reputational stain and a warranty services expense they did not want to own.
 

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Discussion Starter · #9 ·
Thanks Ed,
When the engine was assemble last winter I used Felpro gaskets. If for some reason I’ve gotta pull heads in the future I’ll install the revised gaskets from Ford.

The coolant mod is already installed so I guess my best bet is to vent both cylinder banks to the lower rad hose? I think that s the inlet you speak of.

Now having said all of this do I still go ahead with the T-Stat set up we discussed earlier? I’m assuming the head cooling mod does not affect the bypass function of the drilled holes in the T-stat.

Shawn
 

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Thanks Ed,
When the engine was assemble last winter I used Felpro gaskets. If for some reason I’ve gotta pull heads in the future I’ll install the revised gaskets from Ford.
The FelPro's with the revised cooling passages were numbered 26187 PT for the driverside. and 26222 PT for the passenger side, Shawn. The previous generation gaskets were four digit part numbers. If you cannot find the FelPro five digit part number gaskets in the distribution channel go to Ford for their gaskets.


The coolant mod is already installed so I guess my best bet is to vent both cylinder banks to the lower rad hose? I think that s the inlet you speak of.
The preferred return route is to the top radiator hose going back into the radiator for cooling. You want to plumb it into the top hose between the in line t-stat housing and the radiator. When you plumb it to the bottom radiator hose you are directing hot coolant back into the engine like Ford did for emissions purposes.


Now having said all of this do I still go ahead with the T-Stat set up we discussed earlier? I’m assuming the head cooling mod does not affect the bypass function of the drilled holes in the T-stat.

Shawn
Yes you still need the t-stat modification. The head cooling mod was intended to alleviate the overheating problem the engine displayed at the rear of the driverside head. The t-stat modification is used to control engine operating temperature across the entire engine. The two modifications are unrelated and address different issues.

The easiest way to plumb the t-stat modification is the use of an inline t-stat housing. One of the nicer and reasonably priced (whatever that means today) t-stat housings, is the Meziere inline T-stat housing. Here is a pic of it, off their site;
Font Auto part Household hardware Cylinder Metal


It was less expensive pre-covid but still is a good buy compared to making it. Additionally this part number matches your OEM radiator hose size on top and makes for a very easy and clean modification.

This is a housing only so you will still need to buy a t-stat and do the three hole, hole drilling. Check with Meziere but if I remember correctly, this housing uses a legacy (Chev 327 / 350) style t-stat.
 

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I just checked the Fel-Pro website and they appear to have dropped the gaskets with the revised cooling passages. Knowing that, I would go to Ford and buy the gaskets from them. The gaskets they sell will reflect the latest Engineering Change Order (ECO) for head cooling and are every bit as good as aftermarket alternatives. I tend to put more emphasis (and faith) in the Ford solution because they were motivated to fix the problem. It represented both a reputational stain and a warranty services expense they did not want to own.
The proper Fel-Pro head gaskets are not discontinued. P/N's 26187PT and 26222PT are the ones to use.


 

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The proper Fel-Pro head gaskets are not discontinued. P/N's 26187PT and 26222PT are the ones to use.



You are right, Tony. The first time I used FelPro's product search engine it repeatedly failed to pull up those numbers. When I checked distribution they seemed to have the gaskets in stock. I think FelPro may have multiple instances of their web based search engine. Some bring back the gaskets as available, some do not. The most important thing is whether or not you can find them in distribution. As long as they are available through distribution they are the preferred gasket. FWIW the current Cometic's also have the revised coolant holes. Ford is the obvious fall back whenever the distribution channel seems iffy or simply unavailable.
 

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Discussion Starter · #13 ·
The FelPro's with the revised cooling passages were numbered 26187 PT for the driverside. and 26222 PT for the passenger side, Shawn. The previous generation gaskets were four digit part numbers. If you cannot find the FelPro five digit part number gaskets in the distribution channel go to Ford for their gaskets.




The preferred return route is to the top radiator hose going back into the radiator for cooling. You want to plumb it into the top hose between the in line t-stat housing and the radiator. When you plumb it to the bottom radiator hose you are directing hot coolant back into the engine like Ford did for emissions purposes.




Yes you still need the t-stat modification. The head cooling mod was intended to alleviate the overheating problem the engine displayed at the rear of the driverside head. The t-stat modification is used to control engine operating temperature across the entire engine. The two modifications are unrelated and address different issues.

The easiest way to plumb the t-stat modification is the use of an inline t-stat housing. One of the nicer and reasonably priced (whatever that means today) t-stat housings, is the Meziere inline T-stat housing. Here is a pic of it, off their site;
View attachment 175936

It was less expensive pre-covid but still is a good buy compared to making it. Additionally this part number matches your OEM radiator hose size on top and makes for a very easy and clean modification.

This is a housing only so you will still need to buy a t-stat and do the three hole, hole drilling. Check with Meziere but if I remember correctly, this housing uses a legacy (Chev 327 / 350) style t-stat.

That is the exact housing I have installed. It fits well and looks decent too. Thanks for all the info Ed. It’s much appreciated
 

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just an fyi but recently (november) i tried to get the oem ford head gaskets through my local dealer and was told they are now obsolete and that they were unable to get them (can't remember if they told me just one was obsolete or if it was both of them).

it looked like modular head shop in florida had them on their website, just with their sticker on them though.

but those fel pro 26187pt and 26222pt were available and reasonably priced at amazon
 

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just an fyi but recently (november) i tried to get the oem ford head gaskets through my local dealer and was told they are now obsolete and that they were unable to get them (can't remember if they told me just one was obsolete or if it was both of them).

it looked like modular head shop in florida had them on their website, just with their sticker on them though.

but those fel pro 26187pt and 26222pt were available and reasonably priced at amazon

Good info, Chris!

Ford has done everything possible to kill off the Modmotor so they don't have embarrassing Modmotor-Coyote confrontations to explain. This is just one more step. It is sort of surprising because there are a lot of Modmotor cars still on the road that potentially could need parts. It is fairly apparent Ford is looking at the aftermarket to supply them.

The Summit pricing on the FelPro's is $41 and $45 dollars a side. The Summit pricing on the Cometic's is $126 a side. My personal preference, price not withstanding, is the FelPro product.
 
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Good info, Chris!

Ford has done everything possible to kill off the Modmotor so they don't have embarrassing Modmotor-Coyote confrontations to explain. This is just one more step. It is sort of surprising because there are a lot of Modmotor cars still on the road that potentially could need parts. It is fairly apparent Ford is looking at the aftermarket to supply them.

The Summit pricing on the FelPro's is $41 and $45 dollars a side. The Summit pricing on the Cometic's is $126 a side. My personal preference, price not withstanding, is the FelPro product.

I agree. Although the Coyote platform is impressive up to a point, I have always subscribed to the notion that the Coyote is a good street engine while the Teksid 4V mod motor is a better race engine. Furthermore, I would never swap out the original Teksid Cobra engine in my 2001 cobra for a Coyote simply because I find such a swap unappealing do the weakness and added cost of the Coyote engine when compared to the Mod Motor.
 

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I just picked up a set of head gaskets from ford dealer for my 03 mercury marauder. Not sure if these are same ones you guys are talking about? The new ones have larger coolant passages at back of heads. 4C2Z-6051-AA /BA
Packaging dates are May and October 2021
 

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those might work but here are the numbers my guy gave me after asking for my vin:

- 2R3Z-6051-AA/BA (RH/LH)


edit: looking back at my notes from november he said that the RH side (AA) was still available, but that the LH side was obsolete (BA).

he is usually really good at letting me know if any number has been superceded or anything and even goes the extra mile looking up aftermaket options for me in case something is not available, so i'd be surprised if there were other ford part numbers in the system that would work
 

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I think that if Ford is winding down repair parts availability for this engine family in their efforts to kill it off (as I suspect), then we will see initially an inability to fulfill entire orders and soon thereafter the progressive disappearance of the part(s) from the OEM channel entirely. That's the bad news. The good news (so far) is the aftermarket will undoubtedly continue to offer replacement parts because, that is what they do.

Both the FelPros's and the Cometic's are excellent alternatives and Cometic is the premier supplier of the MLS generation of head gaskets so we have alternatives. That said the FelPro's are still the more cost effective.
 
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