overheating problem
Pro
Joined: Nov 2008
Posts: 680
Likes: 5
From: Denham Springs LA
How do you check for a collapsing hose? Will you see it with the engine in neutral running at higher rpm, maybe 2000rpm or so?
Don't want to jack this thread, hopefully it will also help the OP.
Thanks,
Roger
Don't want to jack this thread, hopefully it will also help the OP.
Thanks,
Roger
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
with your engine running and completely warmed up, reach down a squeeze your lower radiaror hose 'with gloves on' if you can squeeze it flat , its probably sucking shut. the venders sell a lower hose with the correct spring in it for $18 bucks, while the one without the spring is $48 bucks. go figure.
Thread Starter
Instructor
Joined: Nov 2007
Posts: 185
Likes: 0
I will check the hose too. Can't get my hands on a timing light until this weekend but I will update at that point too. Everything under the front of the car is there and completely intact so I don't think that's it but good to know in case it ever goes missing or falls off lol
Drifting
Joined: Apr 2003
Posts: 1,323
Likes: 2
From: Castle Hills Texas
The thermostat is for setting the minimum operating temp. Once the temp rockets past 160, how would it keep the engine at 180-185? It opens at 160, coolant flows, temps keep rising. Unless his thermostat is failing somehow I am guessing airflow, radiator, water pump, timing, collpased hose, etc.
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Thread Starter
Instructor
Joined: Nov 2007
Posts: 185
Likes: 0
checked the timing, it was a little off but fixing it didnt help the problem. I will see if I can rev it up and have someone check if the hose is sucking shut. I can squeeze it pretty close to flat when nothing is running but at idle everything looks line.
Thread Starter
Instructor
Joined: Nov 2007
Posts: 185
Likes: 0
This is the fan I have. Do I need a higher flowing one?
http://www.summitracing.com/parts/SUM-G4904/
http://www.summitracing.com/parts/SUM-G4904/
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
I'd be more inclined to check the ares in between the condenser for built up trash, put a spring in the lower radiator hose, renew the foam seals, get the ir gun and double check the accuracy of your temp. gauge, if you have the stock radiator, time to upgrade. The most knowledgeable vender for cooling issues on here offered to help, I'd answer his questions and see what he has to say
Thread Starter
Instructor
Joined: Nov 2007
Posts: 185
Likes: 0
I have no AC so there is no condenser. My fans come on at 200 like they are set for and the gauge reading in the car reads 200 at the same time so I think its all accurate. I have a new dewitts radiator with the fan shown at the link above but I have not checked the hose yet.
Le Mans Master
Joined: Oct 2007
Posts: 7,410
Likes: 949
From: Tennessee/Rhode Island
Some good suggestions from all but I am wondering about the rebuilt 350 engine. Is it using the OEM heads? The 882 L-82 heads are notorious for running the motors really hot for emissions. My stock L-82 ran hot right from the factory-225 normal operating temperature and 230-240 with the A/C on, on the HIGHWAY. Years of trial and error solved the problem involving many of the suggestions above. The solution? A combination of many changes but in summary: Spoiler rubber extension on the stock spoiler from 79 L-82 with heavy duty cooling, no pollution control at all, headers dual exhaust, correct timing. Dewitts radiator, and Stewart Stage 2 aluminum water pump with 180 thermostat. Runs about 175 now and never over 185! I am convinced that the 882 heads are the main problem with the 78/79 L-82's, not the L-48's, because of the coolant restriction in the heads. They actually flow pretty well but are known for cracking-Jeez I wonder why with those high operating temperatures GM used to lower emissions???
Safety Car
Joined: Sep 2012
Posts: 4,688
Likes: 41
From: Palm Harbor, Florida
Some good suggestions from all but I am wondering about the rebuilt 350 engine. Is it using the OEM heads? The 882 L-82 heads are notorious for running the motors really hot for emissions. My stock L-82 ran hot right from the factory-225 normal operating temperature and 230-240 with the A/C on, on the HIGHWAY. Years of trial and error solved the problem involving many of the suggestions above. The solution? A combination of many changes but in summary: Spoiler rubber extension on the stock spoiler from 79 L-82 with heavy duty cooling, no pollution control at all, headers dual exhaust, correct timing. Dewitts radiator, and Stewart Stage 2 aluminum water pump with 180 thermostat. Runs about 175 now and never over 185! I am convinced that the 882 heads are the main problem with the 78/79 L-82's, not the L-48's, because of the coolant restriction in the heads. They actually flow pretty well but are known for cracking-Jeez I wonder why with those high operating temperatures GM used to lower emissions???
Thread Starter
Instructor
Joined: Nov 2007
Posts: 185
Likes: 0
I confirmed the timing on saturday, checked it three times just to be sure. I just put in a new 195 thermostat, I had a 160 in there and I checked the operation of the thermostat before installing with boiling water. The engine will cool with normal driving on the street but not with sustained speed on the freeway.
Melting Slicks
Joined: May 2002
Posts: 2,716
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
azguy; when you get the IR gun shoot the oil pan also with the engine up to temp. If the oil temps are 20* or more then the water temp you may need an engine oil cooler.
Have the temps ever held at the T-stat setting with this engine?
Do the temps come down after slowing down?
The airflow at 70 to 80 mph is more than adequate to cool the engine if everything is working correctly.
Once the T-stat and timing are checked I would take some temp readings to make sure the gauge is correct than move to the temp drop across the radiator and check the oil temps.
Neal
Have the temps ever held at the T-stat setting with this engine?
Do the temps come down after slowing down?
The airflow at 70 to 80 mph is more than adequate to cool the engine if everything is working correctly.
Once the T-stat and timing are checked I would take some temp readings to make sure the gauge is correct than move to the temp drop across the radiator and check the oil temps.
Neal
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
If you can squeeze the lower radiator hose "flat" with your hand, I have no doubt that it is collapsing when the pump is trying to suck more coolant into it when at speed. There should be a metal spring inside that hose to keep it from collapsing. I understand that some suppliers sell the spring separate from the hose, these days. 