Engine keeps over heating

Itz_a Stang_Thang

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Jun 13, 2019
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I have a 2012 GT. The reason why I'm posting in here is because I swapped the 1st gen for a 2nd gen Aluminator with a ProCharger.

I can't keep the engine at a safe temperature without the heater on full blast. She's full on coolant and I replaced the fan resistor. With the heater off she hits high 230s-low 240s. With the heater on she'll happily stay in the mid-low 220s.

Anyone have similar issues? If so how did you fix it? Any help/advice is GREATLY appreciated. On
 
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7991LXnSHO

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Sep 1, 2010
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The heater core and fan lowering the engine temp sounds like either the radiator is not big enough or is clogged to airflow or coolant. An old brass one might need boiled out, I hope yours in not that corroded from coolant failure.

Before you replace it, here are some basic questions that are not meant to be insulting.
Is your fan/fans actually working? What shape is the shroud in?
Is the belt wrapped so the water pump turns the right way? Is there enough belt wrap around the water pump pulley that it does not slip?
Is the lower hose collapsing?
 

MustangIIMatt

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I have a 2012 GT. The reason why I'm posting in here is because I swapped the 1st gen for a 2nd gen Aluminator with a ProCharger.

I can't keep the engine at a safe temperature without the heater on full blast. She's full on coolant and I replaced the fan resistor. With the heater off she hits high 230s-low 240s. With the heater on she'll happily stay in the mid-low 220s.

Anyone have similar issues? If so how did you fix it? Any help/advice is GREATLY appreciated. On
1. Did you vacuum-fill the cooling system? The Coyote is somewhat prone to air pockets forming in the cooling system if you don't. You'll need something like this:
Amazon productView: https://www.amazon.com/UView-550000-Airlift-Cooling-Checker/dp/B0002SRH5G/ref=sr_1_3?crid=3FMCWEQYD46MR&dchild=1&keywords=airlift+coolant+refill+tool&qid=1599088895&sprefix=airlift+coo%2Caps%2C184&sr=8-3


2. Have you verified that the temperature data you're getting is accurate? Use an infrared thermometer (the one at Harbor Freight is good enough, but if you want better Autozone and Advance sell such a thing reasonably cheap) to verify what the real temperature at the upper and lower hoses, as well as the water outlet and temp sensor itself are and compare. If you're not seeing a drop between the two hoses, you've got another problem altogether, like a blockage in the radiator, or an air pocket (see question 1).
 
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7991LXnSHO

10 Year Member
Sep 1, 2010
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Kearney, NE
Too bad Ford still makes it so you have to burp the baby, I mean baby the coolant system, or some combination of the two. They could have left that problem in the 302/5.0 and not included it in the new 5.0.
 

MustangIIMatt

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Too bad Ford still makes it so you have to burp the baby, I mean baby the coolant system, or some combination of the two. They could have left that problem in the 302/5.0 and not included it in the new 5.0.
Everyone else decided that was the way to go now.

Hell, on BMWs, you've got to vacuum fill it, and THEN engage the water pump (they're electric) with the engine off for 10 minutes to bleed the system, and possibly repeat the second part if it didn't succeed the first time.

The good thing about vacuum filling is, I can have 2 gallons of coolant into a cooling system in about 45 seconds!
 

Itz_a Stang_Thang

New Member
Jun 13, 2019
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Indiana
The heater core and fan lowering the engine temp sounds like either the radiator is not big enough or is clogged to airflow or coolant. An old brass one might need boiled out, I hope yours in not that corroded from coolant failure.

Before you replace it, here are some basic questions that are not meant to be insulting.
Is your fan/fans actually working? What shape is the shroud in?
Is the belt wrapped so the water pump turns the right way? Is there enough belt wrap around the water pump pulley that it does not slip?
Is the lower hose collapsing?

Everything is brand new. New radiator, fan/fan shroud, belts, pulleys etc. I just got the car finished last week. The only things that aren't new are the fuel rails, alternator, and intake manifold. Before I replaced the fan resistor the fan didn't run at all. It does now and comes on when it's supposed to.

There is nothing seemingly wrong with the installation which is why it's so frustrating.
 

Itz_a Stang_Thang

New Member
Jun 13, 2019
7
0
1
20
Indiana
1. Did you vacuum-fill the cooling system? The Coyote is somewhat prone to air pockets forming in the cooling system if you don't. You'll need something like this:
Amazon productView: https://www.amazon.com/UView-550000-Airlift-Cooling-Checker/dp/B0002SRH5G/ref=sr_1_3?crid=3FMCWEQYD46MR&dchild=1&keywords=airlift+coolant+refill+tool&qid=1599088895&sprefix=airlift+coo%2Caps%2C184&sr=8-3


2. Have you verified that the temperature data you're getting is accurate? Use an infrared thermometer (the one at Harbor Freight is good enough, but if you want better Autozone and Advance sell such a thing reasonably cheap) to verify what the real temperature at the upper and lower hoses, as well as the water outlet and temp sensor itself are and compare. If you're not seeing a drop between the two hoses, you've got another problem altogether, like a blockage in the radiator, or an air pocket (see question 1).

No I didn't vacuum the system. However I spent several hours filling then warming the engine up and letting it cool then repeating the process till the coolant level stopped going down. I'm 100% positive there is no air in the system.


As for accurately measuring engine temp. I'm using my tuner to monitor the realtime coolant temp. And then using an infrared thermometer to check if the readout is accurate. And it is.
 

MustangIIMatt

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Mar 7, 2002
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No I didn't vacuum the system. However I spent several hours filling then warming the engine up and letting it cool then repeating the process till the coolant level stopped going down. I'm 100% positive there is no air in the system.
That doesn't always work on Coyotes.