Overheating problems

[Ppower]

Ok this is some messed up overheating problem I have.

when it idles the temp creaps up to the middle of the gauge to the 200 degree area (top of the M bottom of the R), but when I am driving around normal the temp goes back down. If I get on it hard in town or even on the highway the temp shoots way up! To the top of the R and the O range in "normal" on the gauge. What is causing this...

Just had new engine put in and a new fan clutch part# 77244 (frankly didn't think there was anything wrong with my old one, mechanic did this) this one is thermally controlled where as my old one was not, it used the fluid. I have a Flow Kooler water pump (same as with old engine) 3 core rad. (same as before) and had a new thermostat (180 degree part# 30208 cartech) put in. The car will boil over and when I got home it needed about 1/2 gallon of water, this is after driving it over 50 miles. I got on it hard about 1/4 from my house on the way home and the temp shot way up! It was normal before that.

I don't see any leaks, to me it seems the new fan clutch is junk for my setup and/or the thermostat is junk too. My old thermstat also had a small hole drilled in it( I did this). The new engine only has about 150miles on it and it has a powerdyne s/c with only about 7psi...

So, to sum it up it seems to want to get hot/overheat when idling and if you get on it hard. But crusing around it doesn't have a problem.

any ideas? This is pissing me off I just had all this work done and now this is happening.

1988GT
DSS 306 short block
GT-40p heads 2 angle valve job
powerdyne BD11a 7psi.

 

[Ppower]

Update I pulled top rad. hose and checked thermostat and it is facing the correct way so that can be ruled out...

I am thinking it's the new fan clutch, for one I have a cobra grill insert in my car so more air comes in through the front section right in front of the thermal coil on the fan.

 

[NKau]

If you're heating up at speed, I doubt it's fan clutch related. Possible head gasket? What does your oil look like?
Could also quick check your thermostat by dropping it in a pot of water on the stove heated to 180-190 degrees, just to eliminate the possibility.
Another thing to think about is air in the cooling system; do a search on the forum to see how to "burp" your cooling system.
Just giving you some ideas.

 

[Ppower]

Oil looks fine nice and clean no chocolate look to it. Plus, I don't have a loss of boost pressure which would normally happen if a gasket is gone.

My block is O-ringed too.

I just think the clutch might not be spinning fast enough at idle and slips way to much when you get on the car and run it hard. But, has no problems in the 1800-2500rpm range.

 

[95Cobra302]

Make sure your sending unit and water temp gauge are working right.

 

[HISSIN50]

with those mods, you are relying on the stock gauges? the FIRST thing i would do is get a real gauge on there so you know what is really going on.
good luck.

 

[Ppower]

Make sure your sending unit and water temp gauge are working right.

Well I know for sure it is getting to hot, the car boiled over....once I got home..

Has new sending unit in it when new engine was installed.

 

[HISSIN50]

Well I know for sure it is getting to hot, the car boiled over....once I got home..

Has new sending unit in it when new engine was installed.

ya sure the rad cap is holding pressure? do you have access to a cooling system pressure tester?
good luck.

 

[Ppower]

ya sure the rad cap is holding pressure? do you have access to a cooling system pressure tester?
good luck.

Yeah, the overflow was out the reservoir bottle.

 

[HISSIN50]

Yeah, the overflow was out the reservoir bottle.

this does not mean the cap is holding pressure (~16 PSI), it just means the connection is water tight. i could put a solid cap on the rad and it could hold 100 PSI or none. the spring in the cap is what matters.

each PSI of pressure raises the effective-boiling point a few degrees. a few degrees times 16 PSI is a decent amount of boil over difference (between 212-225 with no pressure (of course it depends on the mixture) to 260-280 ish.

good luck.

 

[liv2ride]

I had a similar problem recently with the exception of the boiling over. I think the issue was two fold (1) the stock gauge is a POS (2) I believe I had a flow problem because only half of my radiator would get hot and the other side was about 15+ degrees cooler or more.

I hope this helps. BTW, I believe my flow problem is clearing up. I went to Redline and picked up some cooling system cleaner that does not require flushing the system. After approximately 15 hours of driving the system should be nice and clean again. The guy at the counter recommended periodically cleaning out the over flow bottle to get rid of whatever debris is in there. I will probably replace the coolant in a month or so just to make sure it is nice and clean and no debris in there to create another obstruction.

Good luck.

Aloha

 

[Michael Yount]

You say you just had a new engine installed. Tell us more about the engine - crate engine? Used engine? The mechanic that did the installation rebuilt the engine? Need more detail there.

 

[sgarlic]

Did you ever try burping it like the earlier post said?

 

[Ppower]

You say you just had a new engine installed. Tell us more about the engine - crate engine? Used engine? The mechanic that did the installation rebuilt the engine? Need more detail there.

The engine is a DSSRacing super pro bullet..crate short block.

Specs:
SPECIFICATIONS:
Block: 5.0 roller cam block, thermal cleaned, stress relieved, Magna Fluxed, threads chased, mains checked and corrected, oil galleys tapped for thread in plugs and the decks are CBN squared and equalized. The block is then precision bored .004” smaller than final bore size, torque plate honed in our Sunnen CV616 to proper size and RMS finish. The block is o-ringed , Deep seat freeze plugs and Federal Mogul seamless cam bearings are installed.

Crank: Production crankshaft, thermal cleaned, shot-peened, Magna Fluxed, precision ground, oil scooped and chamfered and balanced to racing tolerances.
Rods: 4340 Forged Steel rods balanced to racing tolerances.
Pistons: NEW! D.S.S. PRO LITE Forged 2 valve relief flat top, CNC fly-cut for most aftermarket race cams and heads. Balanced to racing tolerances.
Rings: Severe duty Speed-Pro ductile iron moly rings. Perfect for high boost or nitrous levels.
Bearings: Federal Mogul/ TRW rod and main bearings.
Assembly: All Super Pro Bullet short blocks are hand assembled by a professional engine builder. Clearances are checked with precision dial bore gages and micrometers (much more accurate than plasti-gage). The D.S.S. Main Support System including custom ARP main studs is key to high horsepower longevity. Also included are stainless steel o-rings installed on the deck surface of the block.

With Max Quench pistons, low compression.

I have GT-40P heads that got a 2-angle valve job. Run a Fel-pro graphite 260-1169 head gasket. One was put on in upside down fashion for the water holes.


Yes, the rad had been burped. You do this by running the car without a rad cap on and let it heat up some then fill rad after air works way back to rad and the top.

 

[Ppower]

this does not mean the cap is holding pressure (~16 PSI), it just means the connection is water tight. i could put a solid cap on the rad and it could hold 100 PSI or none. the spring in the cap is what matters.

each PSI of pressure raises the effective-boiling point a few degrees. a few degrees times 16 PSI is a decent amount of boil over difference (between 212-225 with no pressure (of course it depends on the mixture) to 260-280 ish.

good luck.

Hmm, that is interesting. The cap could not be holding enough psi and thus letting water out into the overflow bottle. I also have a flow kooler water pump which pumps about 30% more water. Need to look into that.

For example, if the cap was only holding about 8psi or lower that might be good for normal driving, but when I get on it hard and spin the water pump up it might be forcing water out the rad. And at idle the psi demands of the cap would be higher than just cruising down the road I would think. Also, when it overflowed after getting home it didn't do it as I was driving in, the over flow started about 15secs. after I shut the car off.

 

[10secgoal]

Sounds like maybe a combination of a lack of cooling power and airflow. You could try a 190-195 for test porposes. That will give your radiator more time to cool the water coming out of the motor. If that rad. is too small for that motor, the therm. will never close and it will over heat. I had the same problem when I was stationed in the desert. It was fine with a stock radiator, for the stock motor. Once I built the motor up, forget about it. I put in a 190 and it did better. But if I romped on it for only 2.5 secs, it wouldn't cool down even if I cruised for 20 miles. I would have to pull over and let the fan take a shot at it. Speaking of which, does it have a shroud ? That just seams like a lot of motor. It gonna neat heavy duty cooling. I put in the Summint brand radiator(It's a Northern,stamped on the side,all welded) and I didn't even need a shroud after that. And if I wanted a 160, I put in a 160, and I could romp on it all day long and the needle wouldn't budge. I hope you find it soon. Always worrying sux! Good luck.

 

[Ppower]

Sounds like maybe a combination of a lack of cooling power and airflow. You could try a 190-195 for test porposes. That will give your radiator more time to cool the water coming out of the motor. If that rad. is too small for that motor, the therm. will never close and it will over heat. I had the same problem when I was stationed in the desert. It was fine with a stock radiator, for the stock motor. Once I built the motor up, forget about it. I put in a 190 and it did better. But if I romped on it for only 2.5 secs, it wouldn't cool down even if I cruised for 20 miles. I would have to pull over and let the fan take a shot at it. Speaking of which, does it have a shroud ? That just seams like a lot of motor. It gonna neat heavy duty cooling. I put in the Summint brand radiator(It's a Northern,stamped on the side,all welded) and I didn't even need a shroud after that. And if I wanted a 160, I put in a 160, and I could romp on it all day long and the needle wouldn't budge. I hope you find it soon. Always worrying sux! Good luck.

This is what I am thinking. Don't think there is enough radiator for the new motor. When I first got the radiator used 3 years ago it worked fine, but the last year to six months that I had my old motor in the car I noticed the car start to run warmer and noticed some deposits in the radiator.


I would also like to note to that I do NOT have a heater core, it is by-passed. One in car went bad and I don't feel like ripping the dash out for it, plus I live in Florida so I don't really need one. This might contribute to the lack of cooling since there is less surface radiator surface area without it. Yes, I have a fan shroud in the car. The fan clutch is brand new too, it is a thermal activated one too. Do you run a fan clutch or do you have a flex fan in your car?

Ppower

 

[10secgoal]

This is what I am thinking. Don't think there is enough radiator for the new motor. When I first got the radiator used 3 years ago it worked fine, but the last year to six months that I had my old motor in the car I noticed the car start to run warmer and noticed some deposits in the radiator.


I would also like to note to that I do NOT have a heater core, it is by-passed. One in car went bad and I don't feel like ripping the dash out for it, plus I live in Florida so I don't really need one. This might contribute to the lack of cooling since there is less surface radiator surface area without it. Yes, I have a fan shroud in the car. The fan clutch is brand new too, it is a thermal activated one too. Do you run a fan clutch or do you have a flex fan in your car?

Ppower

Hmmm. It's hard to say if the old motor was giving you problems with this rad. Points to a pre-existing problem. Addind HP will only make it worse. I run a electric fan on a therm. control. What temp does it come on ? Does it ever shut off at idle ? I have the flex-a-lite and I can adjust the on-temp. Maybe yours is coming on too late. I also have no heater. But that won't really help too much, unless you are blowing air across that, too. The summit is kind of a pain to put in. It's universal fit. So I had to do some hacking and fabbing for the mounts. To start I would really try to figure out the rad. issue. Sounds like it may be to small. But it's an expensive trial and error. So try your best to find out what is going on with the rad itself. If it's clean, I would put on an electric fan first. If that doesn't fix it, you really haven't lost anything, but gained hp.

 

[Michael Yount]

The new motor throws off heat proportionally to how hard it's being used. At idle, and just puttering around (what it sounds like you've been doing mostly) you're not asking the motor/radiator to produce/reject much more heat than you were with the old motor.

Now if you've been hammering it for those 20 minutes/miles of run time - then I'd agree it's radiator. And it may yet be the radiator - but I don't think you've really tested it by asking the engine to put out the additional heat it's capable of compared to the old engine. Unless of course the radiator is much worse off than you thought. If the water is as hard in FL as it was in Houston, it could very well have mineral deposited itself into oblivion in 3 years. For the future - especially in FL - I run only distilled water in the cooling system to avoid those deposits. If you put a new radiator in - distilled and a bit of antifreeze.

 

[Ppower]

The new motor throws off heat proportionally to how hard it's being used. At idle, and just puttering around (what it sounds like you've been doing mostly) you're not asking the motor/radiator to produce/reject much more heat than you were with the old motor.

Now if you've been hammering it for those 20 minutes/miles of run time - then I'd agree it's radiator. And it may yet be the radiator - but I don't think you've really tested it by asking the engine to put out the additional heat it's capable of compared to the old engine. Unless of course the radiator is much worse off than you thought. If the water is as hard in FL as it was in Houston, it could very well have mineral deposited itself into oblivion in 3 years. For the future - especially in FL - I run only distilled water in the cooling system to avoid those deposits. If you put a new radiator in - distilled and a bit of antifreeze.

Yes, totally going with distilled water in new one. Only have to drive it hard for about 30secs to get the temp running up high after the engine is warmed up from idle/putting around. The temp will come back down if you put around or idle but when ever you get on it the temp goes right up.