Engine Help diagnose random overheating??

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7991LXnSHO

wanna catch the space herp
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+1 to everything in this post.


The other thing I would like to add for AeroNose guys specifically.......................dotdotdot

Do you know that little chin spoiler that comes on the car stock and almost everybody breaks and throws away? That damned thing is important. The monicker "AeroNose" has nothing at all to do with any wind tunnel test results. :rlaugh:
That important piece is called an air Dam.
And I can’t get banned for swearing this time. :jester:

The only thing really useful I have to add is that when thermostats fail, they are designed to fail open. When they do so, the car does not get up to operating temp. Unless there is a weird EFI glitch, it will not overheat. It will have a hard time getting warm enough to defrost the windshield or keep your toes from freezing.
In the same way, a vehicle that overheats with a 160 deg thermostat is not the thermostat allowing too much flow for too long.
 

General karthief

wonder how much it would cost to ship you a pair
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The OEM t-stat is 192*. I have not personally had an issue with the OEM t-stats, even when I was running in the high desert.

I swapped to a 180* t-stat when I installed the Kenne Bell because I [wanted] the t-stat to open earlier and remain open longer (even though the heat soak is [nothing] like interwebz wannabeez would have you believe but that is another topic).

Take that for what it's worth. You get diminishing returns on lower temp t-stats and it's also possible to prevent the oil from getting hot enough to boil off any water that it has accumulated.

With a 192* thermostat, your cooling system is generally more efficient overall. I mean, the warmer your cooling system is, the more heat will transfer to the fins and ambient air with the least amount of travel.

A 180* t-stat can help to combat heat-soak and set the cooing system up ahead of time, for heat spikes from boost.

I don't know if I explained that very well. karthief will probably tell me. :D
Huh??? Wat I do now??? :doh: I tell ya it wernt me!! I be innocent.........
 

7991LXnSHO

wanna catch the space herp
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I said, "damned thing" :jester:
:D I got the pun. But I do not think you are in high risk of banning yourself, are you? :D
On my list of projects is adding one to a 1960’s car that does not have one. I plan on putting it on the bottom of the radiator support. It’s the air dam from an S-10 (cheap, easy enough to cut and is still tough) that I’ve seen used on different vehicles with a little modification. If it helps highway cooling and lessens front end lift, it will be a win.
 

Noobz347

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:D I got the pun. But I do not think you are in high risk of banning yourself, are you? :D
On my list of projects is adding one to a 1960’s car that does not have one. I plan on putting it on the bottom of the radiator support. It’s the air dam from an S-10 (cheap, easy enough to cut and is still tough) that I’ve seen used on different vehicles with a little modification. If it helps highway cooling and lessens front end lift, it will be a win.
I explained this once before. It keeps telling me that I can't ban myself. :shrug:
 
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manicmechanic007

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If it has fuel injection the ECT wants to see 195 or better to idle down and run lean
With a 180 it will run rich and never slow down to 650 idle. Instead it will idle around 800 and fail I/M & Turn on the light
Looks like going racing anyway so maybe it matters not
 
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TomOsiris

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If it has fuel injection the ECT wants to see 195 or better to idle down and run lean
With a 180 it will run rich and never slow down to 650 idle. Instead it will idle around 800 and fail I/M & Turn on the light
Looks like going racing anyway so maybe it matters not
Idles real nice around 750 when warm, I had it lower for a bit but the choppy cam seems to like it better where it is.
Not racing, but it is a drifty boi/ daily drifter
 

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manicmechanic007

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It is mainly hotrods I am talking about that get the sheet ran out of them that will overheat
Like my Boss 302 or My old 302 Z28
Hemi Cudas and cars like that you could swap from 160 to 180 and or take them out and run a washer
Either way you blow a cap off you got trouble (my buddies 440 Charger R/T )(with the 12;1's and tunnel ram)
If I told you what radiator and fans I am running I'd have to kill you
 

manicmechanic007

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yea I will take a look if its written on the cap, however no mention of psi rating is on the item listing page

The car has never overheated under normal driving conditions so there is no issue with the fan setup, tstat rating, water pump, etc.
It had an air pocket trapped at the thermostat that caused it to close and overheat, I am just trying to determine the cause of that and how to eliminate it now.

I still have the air dam intact, and the overheating only happened once and at idle, I have determined due to an air pocket at the thermostat.

Thanks all who replied for your help so far.
Posts like yours Tom allow us all to talk back and forth to see what works
 

CAMTWO1070

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I find that using the wrong antifreeze is bad....Using anything other than green isnt good,,

On a 351w I bought for a core on my 408 project the guy removed the engine and cleaned it up pretty good then reassembled it and put it back in he used Orange Antifreeze and only put a few thousand miles on the truck before letting it sit for 4 months due to issues with thetransmssion...When I took the engine apart to do my 408 I took the heads off and a couple of the lil steamholes were clogged with a thick orange gel..

Theres a huge difference between orange and green antifreeze...The orange stuff is acidic and doesnt mix with green well or like being in engines that have green antifreeze residue inside the block and radiator and starts a chemical reaction....

The seal between the timing cover and block develops places for air to enter and water to escape.I find proper torque,indianhead shellac and a retorque after a few heat cycles helps but I also have a fix for that ..

When you get antifreeze in the oil it gets filtered out and eventually clogs the oil filter fast and can be detrimental to your engine..

I took 3/4" copper couplers and epoxied them into the waterpump cover then when I installed the cover I used MotoSeal to seal the tubes where they go into the engine block

IMG_20220409_230657.jpg


The 4 long screws that attaches the waterpump to the engine needs thread sealer as this is another way for air to enter and antifreeze/water to escape..

Another thing I find is that intake manifolds need to be retorqued plus I put a lil Indian Head Shellac around the water ports on the intake gasket to prevent any possible leaks..

Another thing I find is if youre running MLS gaskets is the way you initially treat the engine..I do my initial startups on plain water and even though it says its not needed I do a retorque anyway as my 351w didnt come with aluminum heads from the factory.

Then theres the matter of buying the right headgaskets too...Some manufacturers list if the gasket is for a steel to steel,,aluminum to aluminum or an aluminum to steel application too..........

Usually renting a cooling system pressure tester helps find the leaks fast if there are any..I pump it up to the max pressure my radiator can produce and let it sit overnight with a sheet of cardboard underneath..

If you run the car with plain water or antifreeze thats less than the 50/50 mix and you didnt remove it all during the winter ice could of started a crack in a waterjacket too depending on how cold your winters get.............

I hope you get to the bottom of the problem..
 
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justa check list (some seem OK, problem develops @ idle, not all):
"...Cooling System Dx?..."

There are abt a doz things U can wrk with to effect running temps. The big one - proper tune.
Here's the areas:

  • leaks in system; air in system
  • correct shroud (fan 1/2 in/1/2 out unless 'flex', that = 3/4 in)
  • coolant - mix, additives, age, cleanliness;
  • water pump - operation, condition; cavitation;
  • heater core - leaks, condition, it’s fan on/off;
  • block - water passages;
  • hoses - collapse, leaks;
  • thermostat - condition, temp rating;
  • radiator (sz, # rows, clean?, construction, materials - I like ol style copper)
  • radiator cap - pressure rating, condition, design;
  • fan (blades, design, clutch)
  • flush system last yr. or 2?
 
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TomOsiris

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Hey guys, back again...

So after reading all the information I received here, I determined that my thermostat had closed due to an air pocket that had formed.
I believe this to be from incorrect routing I had on the overflow tank, it was spilling out onto the ground, and therefore would be recovering air instead of coolant when it cooled down and eventually formed an air pocket at the highest point, the tstat housing.

Well after a solid rip on the car today, the car started to SLOWLY creep up in heat at IDLE ONLY.
It was very slow, but eventually made its way to about 2/3 up on the stock gauge which is MUCH higher than I ever see it under normal circumstances.
Took the car around the block, and it cooled down instantly to roughly 190 deg, let it sit at idle and it slowly crept up again.
If I gave the engine a burst of rpm to speed up the water pump, the temp would drop almost immediately, but then continue to creep up.

I am going to replace the thermostat with a motorcraft, got a larger overflow bottle to ensure it has plenty to recover, and bleed the entire system.
Is it possible for a failing water pump to act like this? When I had it off a week or 2 ago it felt totally fine by hand, no issues..
The radiator is brand new also so I highly doubt it is corroded or jammed up.
Cooling fan was running the entire team it was overheating at idle also.
Ugh please help so I can get this sorted before peak driving season!
 

7991LXnSHO

wanna catch the space herp
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A Motorcraft 5.0 thermostat is not likely made by Ford or Motorcraft at this point. If you are going to get a stock style, get a Stant, and drill an air bleed hole in the flat part.
I like the full flow style like this.
Mr. Gasket - 4363 High Performance/High Flow Thermostat Gm-160 Amazon product
View: https://www.amazon.com/dp/B000CMD5M6/ref=cm_sw_r_cp_api_i_B1VGMVXTQVX57E2JPNJW?_encoding=UTF8&psc=1

Mr. Gasket is not the premium brand I’m used to selling, but these are likely reboxed anyway. The point of these is they do not shut from higher pressure at higher RPM.
 

KRUISR

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Apr 16, 2015
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The point of these is they do not shut from higher pressure at higher RPM.
Inaccurate statements like this is why people get so confused with their cooling system.

Shuts from higher pressure ??? If the t-stat is open, a pressure increase on either side will equalize as soon as it starts to increase and therefore you will never have higher pressure on either side. With equal pressure on both sides, the t-stat will move how it wants. As well at higher RPM you are likely generating more heat and t-stat will stay open. Best way to never have this problem is design the cooling system to keep the t-stat open once up to temperature.



The way to keep the t-stat open is have a lower rated t-stat (I have a 180 unit) and have your e-fan controller temp switch in the cold side of the rad (mine is in the lower rad hose) and have a temp switch that will allow coolant to get to 195-200 before turning on the e-fans. The shut off temp for my switch is about 185. This way the coolant going into the engine will be consistent and at the temp the ECM likes it, the t-stat will keep the coolant flowing so none of the pressure lock or other issues like that will occur.

My car will run ALL day with this scenario with temps between 185 and 200, only turning on low speed on my Contour fans periodically (when in stop and go traffic).

If you have the e-fans set to a lower temp, the fans will run more, your engine will be getting hot, then cold, then hot again and cold again (as the t-stat cycles and slugs of cold coolant go through the engine). In my opinion this scenario is not conducive for a consistent running engine.
 

7991LXnSHO

wanna catch the space herp
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Inaccurate statements like this is why people get so confused with their cooling system.

Shuts from higher pressure ??? If the t-stat is open, a pressure increase on either side will equalize as soon as it starts to increase and therefore you will never have higher pressure on either side. With equal pressure on both sides, the t-stat will move how it wants. As well at higher RPM you are likely generating more heat and t-stat will stay open. Best way to never have this problem is design the cooling system to keep the t-stat open once up to temperature.



The way to keep the t-stat open is have a lower rated t-stat (I have a 180 unit) and have your e-fan controller temp switch in the cold side of the rad (mine is in the lower rad hose) and have a temp switch that will allow coolant to get to 195-200 before turning on the e-fans. The shut off temp for my switch is about 185. This way the coolant going into the engine will be consistent and at the temp the ECM likes it, the t-stat will keep the coolant flowing so none of the pressure lock or other issues like that will occur.

My car will run ALL day with this scenario with temps between 185 and 200, only turning on low speed on my Contour fans periodically (when in stop and go traffic).

If you have the e-fans set to a lower temp, the fans will run more, your engine will be getting hot, then cold, then hot again and cold again (as the t-stat cycles and slugs of cold coolant go through the engine). In my opinion this scenario is not conducive for a consistent running engine.
That statement is straight from the company’s promo. “high flow pressure” presses against the spring in a standard type thermostat in systems that pump out through the upper radiator hose.
The full flow thermostats operate in a twist manner.
Misinterpret it as you wish.
 

manicmechanic007

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Sep 26, 2017
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Fords go thru thermostats and as long as you do not get a fail safe you should be okay with just about any brand
The autozone duralast has the floating barbell and the little hole. I run them all the time with no problems
Op sounds like you might be overfilling the sysstem and 220+ is overheating not 205 or 210
Those old GT's in stock trim got damn hot on the gauge before the fan came on
 
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General karthief

wonder how much it would cost to ship you a pair
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The stock gauge is a 'best guess' reading and will move a long way between 180 through 200, only 20 * is a small amount that looks big on the stock gauge, get an aftermarket gauge with a big number dial and monitor that.
What cooling fan are you using and where is the reading taken from (location). Appears to not be big enough or not mounted correctly or has no shroud.
 
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