1994 5.0 OVERHEATING

[BANGERSTANGER76]

Guys,

Having a problem with over heating.
I changed the thermostat to a 180. No improvement.
The car idles 20-30 minutes and gets hot. The gauge is over by the L.
Fan kicks on. The top hose is very hard and to me seems restricted under pressure. It also seems to me like the coolant isnt flowing throught the engine. When I open the resovoir while running it is still at the top??? No leaks, no noises, no smoke. Are there anymore test, recommendations or anything I'm missing? Your help is most appreciated.

BY THE WAY THE CAR OVERHEATED BEFORE I CHANGED THE T STAT.
I changed the T stat in response to it overheating.

Thanks
Banger

 

[revhead347]

With those symptoms I would start with the radiator. You said the fan is kicking on, so most likely it's not flowing through the radiator properly.

Kurt

 

[VibrantRedGT]

These cars came with the thinnest radiator I've ever seen in a V-8. It's time to upgrade to a 3 row aluminum, run a 60/40 mix (60% water), 180 stat and two bottles of Water Wetter. You car will run around 185 degrees not matter how hot or cold its out. One of the best mods I've ever done on my car. It sure sounds like the Stat isn't opening but I'd still upgrade everything since it's 17+ years old. If you want to go farther change the water pump while you have the coolant drained. It's another $50 for a lifetime warranty unit.

 

[revhead347]

Even the stock radiator cools fine so long as it's not all clogged up.

Kurt

 

[BANGERSTANGER76]

Vibrant

Im going to do that. I was waiting for the spring but looks like Im going to speed it up. I hate a car that cant startup and drive away. already got one dont need 2. I put in a 180 degree stat. I have a brand new water pump ready for install. I'm going to grab a radiator this weekend. And do a major flush. Just my luck the weather is decent here this week.

@ kurt.
I really think your right. It just seems to me something is clogged up. maybe a air pocket as well. Im praying it isnt the head gaskets.

HAS ANYONE ELSE EXPERIENCED THIS PROBLEM & ACTUALLY CORRECTED IT? PLEASE CHIME IN> THANK YOU
BANGER

 

[VibrantRedGT]

Good call. Burp the system when it's time. Run the car at idle with the cap off the radiator, the coolant will bubble (getting rid of the air), wait until the stat opens, when it does it will suck in coolant and the level will drop in the radiator, fill it up and put the cap back on.

This is 100 degrees outside, 347 Stroker and on the freeway. My car never got over 200 ever. I also had the fan set to stay on HIGH all the time (key on).

 

[BANGERSTANGER76]

I need some of those guages. They are easy to read and look accurate.

 

[revhead347]

Like Vibrant said, if you are going to change the radiator, you might as well get a nice aluminum one. I've just recently heard a lot of talk from people about how well the stock radiator actually cools. It doesn't sound like a head gasket to me. Usually a head gasket causes bubbling in the radiator. The combustion gasses are either trying to escape, or cause real uneven heating of the cooling water. The head gasket also causes irratic water temps.

Kurt

 

[95ssn95]

The awnser is...... your fan!..........Maybe...... it's probably the wiring going into the fan or the fan motor is shooting craps the symptoms you described are the same as I had when I...... changed the T-stat......still not cooling right then, my radiator craked from the high heat, and in the process of changing that found that my fan was shorting out. That was an expensive weekend ps been on the site for some time, just bought a beater and the mustang is officially parked the garage, looking forward to a build thread!

 

[BANGERSTANGER76]

The awnser is...... your fan!..........Maybe...... it's probably the wiring going into the fan or the fan motor is shooting craps the symptoms you described are the same as I had when I...... changed the T-stat......still not cooling right then, my radiator craked from the high heat, and in the process of changing that found that my fan was shorting out. That was an expensive weekend ps been on the site for some time, just bought a beater and the mustang is officially parked the garage, looking forward to a build thread!

The fan kicks on but not until the gauge is in the L area.
And it comes on right to high speed.
To me it is coming on late.
Did yours do that or did it just not come on at all?

And where did you get those red gauges from i wants some LOL.

 

[Bullitt95]

The fan kicks on but not until the gauge is in the L area.
And it comes on right to high speed.

That means the low speed fan mode isn't working, and the reason is likely to be a blown low speed fan relay inside the CCRM. Locate the wire going to pin 14 of the CCRM and splice a wire between that and a 12v source to see if that turns the low speed fan on.

 

[Hef5.0weisen]

I had a similar problem a few years ago...and it was the head gasket. Think it was a steam passage, just deteriorated over time I suppose.....however mine would eventually piss out the overflow bottle. I did the Fluidyne rad, new stat, wire in a fan switch.....all of which is nice to have now, but didn't fix the overheating.

Don't fear the headgasket...it is not a bad job, just dirty and time consuming. Can be done in the driveway with basic handtools in a long day/weekend. If you don't have tools, you can buy all you'd need for the price of taking it to a garage.....

Good Luck......if you wanna throw parts at it, the temp sending unit is cheap.....

 

[95ssn95]

My fan would work on and off, overheating at idle due to the short, I wiggled the plug and that's how i found it. Hope you get it straightened out. Here is a pic of them gauges, home made of course.

 

[BANGERSTANGER76]

I had a similar problem a few years ago...and it was the head gasket. Think it was a steam passage, just deteriorated over time I suppose.....however mine would eventually **** out the overflow bottle. I did the Fluidyne rad, new stat, wire in a fan switch.....all of which is nice to have now, but didn't fix the overheating.

Don't fear the headgasket...it is not a bad job, just dirty and time consuming. Can be done in the driveway with basic handtools in a long day/weekend. If you don't have tools, you can buy all you'd need for the price of taking it to a garage.....

Good Luck......if you wanna throw parts at it, the temp sending unit is cheap.....

I'm really thinking it is the head gasket as well.
I just cant see anything else making the car run this way.
I wont get a good look until Saturday. It is not boiling out of the overflow.
Is there a headgasket test?

 

[BANGERSTANGER76]

Guys,
At what point on the gauge should the low fan kick in?

Thanks

 

[Hef5.0weisen]

I have my low speed fan set for 190-ish, via Tweecer.....that is around the O/R......but right at 190 on the Autometer gauge. Take it for what its worth.

Don't remeber off the top off my head, and my Tweecer stuff is on another laptop, but I think the LS fan is set for ~210 and HS ~225......ish.

Re-reading this, does it cool off with the fan? Or just keep heating up...when my HG went south, no amunt of fan would cool it off.....may be some hope of not being a HG vs LS fan issue.

Again, Good Luck...hope it all helps!

 

[VibrantRedGT]

The fan should come on at like 218*, it's a weird number.

Totally flush out the radiator until its extremely clean. Get as much coolant / water out of the engine as well. Remove the stat all together. Put everything back, fill the fluids up, burp the system, everything. See if it overheats now. If it does then it could be a head gasket. Do all this first before buying a new aluminum radiator, water pump, etc.

 

[revhead347]

There is a headgasket test kit you can rent from Autozone. They even rent the test fluid. It's a little dohicky that goes in in place of the radiator cap. Then there is a little pump ball on top. You suck gasses through the test tube with the ball. If the fluid changes color, that means that you have combustion gasses in the coolant and a blown head gasket.

Kurt

 

[Bullitt95]

Guys,
At what point on the gauge should the low fan kick in?

Low speed should kick on at 208*F (M on the stock gauge) and high speed should kick on at 224*F (just past L on the stock gauge).

 

[BANGERSTANGER76]

Low speed should kick on at 208*F (M on the stock gauge) and high speed should kick on at 224*F (just past L on the stock gauge).

I didnt get to do much with my car this weekend. I had to get my truck ready to go.
But from what I can see so far the fan is skipping the low speed. and kicks on right around the L in high speed just like you stated. But by then Im guessing its not enough to cool it down. It hasnt vomited the fluid out of the resovoir yet. I just cant see the head gasket blowing for no reason. So Im going to go ahead and throw a new motor in my fan shroud. ill start there and if that isnt it. then Ill replace the CCRM. If thats not it. Im thinking the worst. HG.