Engine Engine Running hot. I cannot figure out why.

79pace · May 28, 2020

Ok, Car had the factory engine in it with the factory fan and shroud with a 195 thermostat and ran extremely cool. I put a rebuilt short block with ported cast iron heads, E303 cam and new intake and lots of bolt ons. The car has a 4 core aluminum radiator which it has had and now has two 12" 1550cfm electric fans on a temperature actuated switch and I tested that they are working. I had a 180 thermostat installed and the car would drive fine and act normal for 15 minutes or so of driving but then the temp would start to creep up a little at a time. It will get to 200, then 210, 220 and seems to settle in around 230 at its hottest. I replaced the water pump this past weekend with a nice looking heavy duty one. It has the solid impeller on it and I also threw in a brand new 195 thermostat and flushed the cooling system at the same time. Put in fresh antifreeze and drove it today and it is acting exactly the same. Oh I also installed a nice manual gauge set so I can see the real temps. I am honestly at a loss on this. If it were the fans then why is it hot while driving at speed? I have a working overflow bottle and the cooling system was working great before I replaced the engine.

txstang84 · May 29, 2020

I'm going to assume you burped the system, because air can cause some issues, but if the temps are steady that might not be your problem.

As far as the water pump, I'm going to assume here that you noted a difference between the diameter of the old and the new impellers? If by solid you mean one piece casting, they're usually adequate, but the diameter is usually a better indicator of how much water it can move...I had a flow kooler pump years ago and took it off because all it did was blow up heater cores and pop hoses...

2 12" fans should be adequate if they're truly moving 1550 cfm a piece, you'll forgive my cynicism here...factory fans are often the best way to go...whether its from a taurus, contour, mk 8...whatever...

Have you checked your lower hose? Does it collapse at all when operating at higher RPMs?

How much is this block bored?

General karthief · May 29, 2020

I would look, as was suggested above, at the lower hose as the rpms are increased, it is possible the flow can't keep up with the pull from the water pump and collapses the hose.
Also test the thermostat to make sure it is opening completely.

LILCBRA · May 29, 2020

I had a similar problem a while back. It would be fine while the car was moving, but the temps would creep if the car was stopped or creeping in traffic. I beat my head against a wall for quite a while. Finally went through my engine and found that when I initially set the timing it was wrong and set at damned near TDC. Timed it again and haven't had a problem since. Anyway, where I guess I'm going with this is it might not be your cooling system at all. How new is your engine? Where is the timing set and have you confirmed it? Sometimes something that we think is unrelated is actually the problem. It sounds like everything else should be up to snuff....

mikestang63 · May 29, 2020

FOUR core radiator? that is your problem. not enough air flow unless you are a NASCAR driver. Most 2 core radiators are more than enough to keep a 400+HP cool.

79pace · May 29, 2020

Ok, Has nothing to do with the radiator, It is all aluminum and the radiator kept the engine ice cold with the stock motor. Not going to buy that the radiator does not have enough airflow. Dont mean that to sound crappy but we have been putting 4 core radiators in cars for years and been keeping them cooler than the thin stock radiators.

I will check the lower hose. I cant remember if it has the spring inside it or not. It is the same hose that was on the old motor but getting sucked closed is the only thing that makes any sense. I have check everything else. Is there any chance that the heads have too much port work done? I have heard stories in the past of over ported heads being too thin however I have my doubts on that. The block is stock bore also. As far as the fan conversation the fans dont matter at all when the car is moving at speed. Fans are for when the car is stopped and there is no natural airflow. If I am driving it down the road the fans are useless honestly.

79pace · May 29, 2020

It may be a 3 row and not 4 on the radiator. It is the one from LMR that the PO bought. I just went and looked and they sell a 3 row. The center core is as wide as the tanks.

90sickfox · May 29, 2020

Do you have all the shrouding in place ? There should be a plastic air dam attached to the bottom of the core support and tar paper type flaps on either side between the radiator and the back of the bumper support. Air takes the path of least resistance. At more speed the air could be going around your radiator instead of through it causing it to overheat.

I've never had a 12in dual fan set up actually work on any of my customers cars or my own. I run Ford Contour fans now on my turbo 331. No issues.

79pace · May 30, 2020

Again, Yes the cooling system was working great with the other engine. Nothing in that system changed except for the fans themselves. I dont have a shroud on the back side of the radiator because its dual fans but that wont matter on the highway. I have seen too many other cars with the same fan setup and plenty of cars run without even a shroud and not have issues. Has to be something to do with the engine itself or something. I should be able to run no fan or shroud at all if I stay on the road with the car moving. That is why i am confused. Maybe heads ported too much and thin ports? Head gaskets in backwards? I dont want to just start ripping into it but I am about to. Here is the fan setup.

2000xp8 · May 30, 2020

Before I tore into the engine i'd put the factory fan and shroud back on and see what happens.
It will at least eliminate one of the variables.
And it's not much work.

I too have never seen a foxbody work with that style fan setup without a shroud. Is it your problem here? Not really sure, but regardless it's certainly not how i would run it especially with summer approaching.

79pace · May 30, 2020

Its more work than you might think. I will have to remove the radiator, cut the tabs holding the fans and it will have the same results. Again if I am at speed doing 65 on the highway in 5th how would the fans have anything at all to do with airflow? I am not trying to argue but cars have ran with fans like this forever. Heck look at any any non v8 mustang fan setup. I am looking guesses of other things that could cause this. If it were the fans it would overheat sitting in the driveway idling or just at stoplights. This is a consistent climb while driving. I may rip it apart and put the factory fan back on and try to get the shroud back in there since it was not in great condition but it will require taking everything apart in the front to get all of the fan stuff back out.

nickyb · May 30, 2020

Just outta curiosity have you started it cold in driveway and watch fans kick in?Then see what temp it has after fifteen or twenty mins.?

79pace · May 30, 2020

Yea the fans are kicking on fine. I have a let it run for quite a long time in the driveway and it wont overheat in 15 or 20 minutes. Did it twice when I fushed the radiator.

General karthief · May 30, 2020

I agree if it sits and does not over heat the fans are not the problem. Airflow or fluid flow is the problem.

Blown88GT · May 31, 2020

Those fans won't keep it cool at idle or in traffic.
This one will.

Mustang Contour Electric Fan Assembly (79-93) - LMR

Convert your Fox Body cooling fan to electric with this 1979-1993 Mustang Contour electric fan assembly!

lmr.com

Running hot on the highway is a different issue.

Is the new water pump a reverse rotation unit, like all the 5.0's need to be?
You said it was a "nice looking heavy duty one. It has the solid impeller".

79pace · May 31, 2020

If that is the case then how do the SN95 cars get away with a single fan and no shroud? Yes the water pump is the correct reverse rotation pump and yes the belt is on the right direction. Why would I order a standard rotation for a fox car? They have not been used since V belts?

I will go out and spend a fortune and buy other fans just to prove a point but I am still trying to wrap my brain around how a fan has anything to do with your cooling system when the car is doing 65mph down the highway. This car is getting hot around town, not while sitting.

LX1993 · May 31, 2020

Just because your doing 65 mph doesn't mean the air is being evenly distributed over the entire surface area of the radiator. Which is the job of the fan/fans & shroud. Those look like the same crap fans I've seen anywhere from LMR to Ebay. They don't move anywhere near 1550 cfm. And no shroud. Not saying something else can't be wrong as well, but that ain't going to work.

General karthief · May 31, 2020

Lets recap some questions:
How hot is it getting and what are the circumstances: you said it climbs upward at speed. This is a fluid flow symptom
does it cool down when the fan comes on: this question was not asked
did you check to see if the lower hose is collapsing when the rpms are raised: not answered
What is your timing set at? Not asked previously.
If you think the fans are working correctly and are not the issue don't worry about what is said about the fans.
Oh, is the air dam under the radiator support there?

Monkeybutt2000 · May 31, 2020

So,clearly the problem began after the engine swap. Let's recant. The current radiator was in the car before the swap,correct? Have you changed the cap? Are you sure there isn't a coolant leak? Does the belt have enough tension? I'm just spitballin' here,I know you're frustrated. We've ALL been there.

79pace · Jun 1, 2020

I will order some of the Contour fans and give it a shot. I have nothing to lose. It does not seem to matter if its moving or stopped. It just starts getting hot and has trouble cooling back down but if you stay sitting it will cool back down. If you can keep the engine rpms down it helps it come down but it just wont come down very fast. If the fans dont help it will move on to something else. If they do then so be it. Maybe LX1993 is right and the fans dont move the air they are suppose to but from past experience this setup "should" be able to handle this. The car is not a daily driver, just a weekend car.

Engine Engine Running hot. I cannot figure out why.

79pace

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General karthief

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LILCBRA

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mikestang63

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Mustang Contour Electric Fan Assembly (79-93) - LMR

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