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Overheating Issues

6K views 38 replies 11 participants last post by  1slo5.0 
#1 ·
I'll start off with saying that the car sat for five years until I bought it about 2 weeks ago. Since then I've been slowly trying to fix any of the little problems that show themselves. One problem I've been having is it's over heating here and there. The previous owner replaced the stock fan with an electric fan and wiring out of a 3.8L V6 Mustang. Some things I've tried so far is that I replaced the old 160* T-stat it came with with a brand new Duralast 160* t-stat, and I replaced the old radiator cap with a new one. That woked for the last few days, with temps staying between 165-190*. Even on a recent 4 hour trip the temps stayed about 185*, reaching 210* at the most. Then all of the sudden tonight I was driving home from about 15 minutes away and I noticed the temp gauge was reading about 230*. So I got home, let it sit and cool down a bit, then when the temp gauge read 165* I went out for a quick drive to see if it'd do it again. Needless to say, it started getting hot, so I headed back home. Just before pulling in my driveway the temp needle was touching the 250* line. Got out of the car and noticed it was leaking water. So I popped the hood, to find the water in the overflow tank just boiling and steaming like crazy: (see video)



Any tips on what the first thing I should check or do tomorrow morning is? We have a club cruise tomorrow evening, so I'd love to get this situated if it's possible. Thanks in advance for any help someone can give me.
 
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#5 ·
Notice you have an oil residue in the overflow. My 87 done the exact same thing and it was a head gasket.

Its had a problemb overheating for the past few months while city driving. Turns out it was the cooling fan(this time), so I just bypassed everything and hooked it straight to the battery with a cheap toggle in the cab. I ran an inline fuse from toggle to the fan.

Using 16g wire I did...battery to toggle switch inside the cab, toggle switch to inline 15a fuse, fuse to hot on the fan, fan was grounded to the chasis.

Just make sure the fan is on when the car gets up to temp. Should cut on at about 190 I believe.
 
#9 ·
Thanks everyone! I'll keep this all in mind. Here's hoping for the best...reps to you guys for the help.

Notice you have an oil residue in the overflow. My 87 done the exact same thing and it was a head gasket...
I was thinking this too, but I'm hoping not.

Radiator could have a lot of crap in it, especially if it sat for a long time. Usually this crap will get trapped in the overflow bottle, but if the crap is really caked in the radiator, it won't break loose. Make sure you don't have too much antifreeze or too much water. You should have a 50/50 mix. Too much antifreeze will run hot.. pure water will boil about 212* if its not under pressure...
Yea I'm running straight water right now until the colder weather gets here. And there was a bunch of gunk in the radiator before, so I've been flushing out the cooling system everyso often. Gonna go try it again now.

...One thing to check (I did) take your thermostat and drop it into a metal coffee can with water in it. Heat it on a stove with a cooking thermometer, and see what temperature it opens. Just because it is new doesn't mean it is working properly.
I'll keep this in mind. Thanks.
 
#6 ·
Make sure the T-stat wasnt put in up side down. Flush your cooling system. And after refilling your system ,make sure you bleed out any air that may be traped.
 
#8 · (Edited)
Radiator could have a lot of crap in it, especially if it sat for a long time. Usually this crap will get trapped in the overflow bottle, but if the crap is really caked in the radiator, it won't break loose. Make sure you don't have too much antifreeze or too much water. You should have a 50/50 mix. Too much antifreeze will run hot.. pure water will boil about 212* if its not under pressure... I've never seen coolant boil in an overflow bottle like that before, even when my 454 was running at 240* with a bad fan clutch.

A stock fan will cool adequately if you have a good fan clutch, waterpump, and radiator, and stock pulleys. Mine, with a 160* thermostat in Texas heat will run about 180* on the highway with the AC running. Idling in town traffic with the AC, the highest it will get is 195*. This is using a manual temp gauge in the stock temp gauge location in the intake. Of course it even runs colder with the AC off. It would never run this cool with underdrives (I put stock pullies in the summer and underdrives in the winter).

One thing to check (I did) take your thermostat and drop it into a metal coffee can with water in it. Heat it on a stove with a cooking thermometer, and see what temperature it opens. Just because it is new doesn't mean it is working properly.
 
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#10 ·
if you do flush and refill hopefuly you havent already. or if your radiator is just low on coolent. Take the radator cap off.. when its cool lol. you will be able to see the first 5-7 fins wich the coolent runs through to cool off. Im sure you will find a bunch of white buildup on the ends of those fins. also when your car is hot, run your and across the radiator itself, you might find cold spots which indicates zero flow in that part of the radiator. good luck
 
#11 ·
Thanks for all the tips everyone. Ended up being my radiator fan itself. The motor was locked up, so obviously not doing its job. Like I said, my buddy previously swapped in an electric fan out of the 3.8L V6 Stang, so today we pulled out the fan and swapped the fan motor out and put in a new motor in out of a 94-95 GT. Then we played around with the temp setting for when the fan cuts on and off and now she's cooling like a champ. I'm so happy it wasn't more serious.
 
#13 ·
I was actually wondering this myself and have been contemplating switching to a 180* in the future. As of right now it seems to be doing pretty good though, so we'll see.
 
#16 ·
I get 29.9 on the highway with the 160*, in the Texas heat with underdrives and the AC on. That's with topping the tank all the way off each time, and dividing the miles driven by gallons used.

:dunno
 
#17 ·
what does your engine run temperature wise? here in michigan it temp stays around 165-180 with a 160 t stat. never lets the computer go into closed loop.
 
#18 ·
Mine, with a 160* thermostat in Texas heat will run about 165-180* on the highway with the AC running. Idling in town traffic with the AC, the highest it will get is 195*. This is using a manual temp gauge in the stock temp gauge location in the intake. Of course it even runs colder with the AC off. It would never run this cool with underdrives (I put stock pullies in the summer and underdrives in the winter).


As far as when the ECM switches into closed loop, nobody seems to agree. Some say its coolant temperature only, some say its time, some say its exhaust gas temperature (picked up by O2 sensors), some say it's a complex combination of these.
 
#24 ·
long story short, you have zero to gain by running a cooler stat. you can dream up all sorts of "what if's" but you will come to find iout in the end that a 165 stat hurts performance. yes a cooler temp may trick the computer into introducing more fuel but when you don't have anything to take up that fuel (reads more 02 from nitrous or fi) all it does is make you run rich and wash the oil of of your cyl walls.

cyl heads will crack from heat not from milage. the first thing i would expect from a head that is worn from milage is blue smoke from worn valve giudes and valve giude seals.
 
#25 ·
For starters you shouldn't have a 160 thermostat in a fuel injected car. However that will not cause your problems. Things to check: remove the radiator cap and start the car. Let it get to operating temperature and look to see if there are any bubbles in the radiator. Check to make sure the plastic flap is under the radiator support. If it is not there the car will get warmer when you are driving down the road due to lack of airflow to the radiator. Get rid of the V6 fan. I am not familiar with it so I wouldn't use it on my car. I have no idea what it flows or how it is installed on your car. Do a visual inspection of the radiator, especially the lower portion of it. I bet that thing is so full of **** from sitting and corroding for the past 5 years.
 
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#26 ·
I have plans of soon switching to a bigger radiator with a slimline fan. At the same time I'm thinking of bumping up to a 180* Thermostat. Since swapping in a e-fan motor out of a 94-95 GT the car seems to be cooling down fine, so I'm gonna see how it goes for a while and hope it lasts until I can get the upgraded fan and radiator. Thanks for the suggestions, and I'll go out and take a look at everything.
 
#37 ·
Darrell, have you had any experience with the Robert Shaw type thermostats and how they compare to a standard design thermostat? The Robert Shaw has a built in bypass.

Here are some pictures if you don't remember what they look like..



 
#39 ·
Darrell, have you had any experience with the Robert Shaw type thermostats and how they compare to a standard design thermostat? The Robert Shaw has a built in bypass.

Here are some pictures if you don't remember what they look like..
Yes. I have used them and sold them. The bypass doesn't really mean much to me but the high flow design does. If nothing else they look cooler than regular thermostats.
 
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