overheating problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

method2mymadnes · 06-01-2003, 07:21 PM

This problem is actually on a car I own but I figured that you truck guys are the only ones who could figure out the problem. Its a cutlass with a 260 olds v-8. Around town it seems to be ok. When I drive it on a trip of about 30-40 miles or more it overheats. I t boils the water out through the overflow tank. I have tried a new radiator cap, checked the timing, I can see coolant flowing through the top flues of the radiator when I take the cap off. Any other ideas?

*rage'nrat638* · 06-01-2003, 07:27 PM

when you start it up does the fan blow hard

if not???its the fan clutch....when cold turn the fan by hand if its not hard to turn thats it,feel the little spring in front of the clutch if its oily?thats it..

**old Rusty C10** · 06-01-2003, 08:10 PM

also if the thermostat is over a couple years old might be weakening pressure of its spring may wanna change that

Grim Reaper · 06-02-2003, 05:21 PM

Clutch fan is fine because it isn't overheating at Idle. When going down the hwy they don't do anything.

Checkj and make sure the lower radiator hose has a spring in it to keep it from colapsing. put a 180-190 Degree thermostat in it.

If the above doesn't fix it pull the radiator and have it flow tested.

rockman20 · 06-03-2003, 04:32 PM

Not sure on that new of a model, but my 69 Cutlass did the same thing. I found that there is a piece of plastic that was suppose to mount under the core support. This piece of plastic actually helped to divert the air flow and actually helped the radiator cool on the interstate. I was also missing all of the rubber pieces that were suppose to help flow the air into the radiator rather then through the fenders.

How did I fix this? Aluminum radiator with dual electric fans.

Definitely overkill, but it works and I am glad that I dropped that extra weight and got rid of the engine driven fan.

PHOENIX · 06-03-2003, 04:56 PM

Along with what the others said:

In No Order:

What speeds are you driving at and what engine rpm when its getting hot?

How old is the water pump?
Has it leaked from the weap (?) hole at all?
Belt ok (tight and in good shape)?
It is possible that the pump is not flowing enough to keep the engine cool. Long periods of higher engine speeds will require a water pump in good condition. May be pumping enough around town, but not flowing enough for extended periods of higher engine heat.

Is the car carb. or injected?
When was the last time it was tuned and who did it?
Incorrect fuel to air ratio can cause higher engine temps.

What is your coolant to water mixture?
50/50?

Slonaker · 06-03-2003, 06:07 PM

I had a similar problem with a car. It turned out to be a plugged up catalytic converter. The faster I went, the harder it had to work to push the exhaust out, so it overheated. Around town it was fine because of the lower RPM.

BTW, I had a '79 Cutlass with the 260. I called it the "Gutless Supreme" because it had no power at all.

It was much better after I put a '73 350 Olds in it. It was a direct bolt-in, as is a 455.

06-01-2003, 07:21 PM	#1
method2mymadnes Registered User Join Date: Jun 2003 Location: Dyersburg, TN Posts: 327	overheating problem This problem is actually on a car I own but I figured that you truck guys are the only ones who could figure out the problem. Its a cutlass with a 260 olds v-8. Around town it seems to be ok. When I drive it on a trip of about 30-40 miles or more it overheats. I t boils the water out through the overflow tank. I have tried a new radiator cap, checked the timing, I can see coolant flowing through the top flues of the radiator when I take the cap off. Any other ideas? __________________ 87% of all statistics are made up on the spot.

06-01-2003, 08:10 PM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	also if the thermostat is over a couple years old might be weakening pressure of its spring may wanna change that __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

06-02-2003, 05:21 PM	#4
Grim Reaper Registered User Join Date: Jul 2001 Location: Atlanta GA Posts: 1,704	Clutch fan is fine because it isn't overheating at Idle. When going down the hwy they don't do anything. Checkj and make sure the lower radiator hose has a spring in it to keep it from colapsing. put a 180-190 Degree thermostat in it. If the above doesn't fix it pull the radiator and have it flow tested. __________________ Grim-Reaper 70 Pontiac LeMans Sport Convertible, worlds longest resto in progress Looking for 71-72 2wd Blazer or Jimmy Project

06-03-2003, 04:32 PM	#5
rockman20 "The dude abides" Join Date: Apr 2003 Location: North Dakota Posts: 472	Not sure on that new of a model, but my 69 Cutlass did the same thing. I found that there is a piece of plastic that was suppose to mount under the core support. This piece of plastic actually helped to divert the air flow and actually helped the radiator cool on the interstate. I was also missing all of the rubber pieces that were suppose to help flow the air into the radiator rather then through the fenders. How did I fix this? Aluminum radiator with dual electric fans. Definitely overkill, but it works and I am glad that I dropped that extra weight and got rid of the engine driven fan. __________________ RockMan 1993 Chevy Silverado C3500 1 ton dually 1994 Honda Civic 1969 Oldsmobile Cutlass S 1953 IH Farmall Super M New to the fleet: 1992 Subaru Loyal

06-03-2003, 04:56 PM	#6
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	Along with what the others said: In No Order: What speeds are you driving at and what engine rpm when its getting hot? How old is the water pump? Has it leaked from the weap (?) hole at all? Belt ok (tight and in good shape)? It is possible that the pump is not flowing enough to keep the engine cool. Long periods of higher engine speeds will require a water pump in good condition. May be pumping enough around town, but not flowing enough for extended periods of higher engine heat. Is the car carb. or injected? When was the last time it was tuned and who did it? Incorrect fuel to air ratio can cause higher engine temps. What is your coolant to water mixture? 50/50? __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION *

06-01-2003, 07:27 PM	#2
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	when you start it up does the fan blow hard if not???its the fan clutch....when cold turn the fan by hand if its not hard to turn thats it,feel the little spring in front of the clutch if its oily?thats it..

06-03-2003, 06:07 PM	#7
Slonaker Insert Witty Text Here Join Date: Oct 2002 Location: San Antonio, TX Posts: 3,415	I had a similar problem with a car. It turned out to be a plugged up catalytic converter. The faster I went, the harder it had to work to push the exhaust out, so it overheated. Around town it was fine because of the lower RPM. BTW, I had a '79 Cutlass with the 260. I called it the "Gutless Supreme" because it had no power at all. It was much better after I put a '73 350 Olds in it. It was a direct bolt-in, as is a 455. __________________ '86 Chevy C10 (Sold 04/19/13 ) Stock '01 Silverado



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