Still overheating...
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Still overheating...
Hey guys I have a 1985 Corvette. This problem all started after I installed brand new AFR 195 Eliminator Heads.
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests. Also no coolant loss.
I'm out of ideas.
Thanks!
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests. Also no coolant loss.
I'm out of ideas.
Thanks!
Pro
Joined: Oct 2012
Posts: 613
Likes: 3
Hey guys I have a 1985 Corvette. This problem all started after I installed brand new AFR 195 Eliminator Heads.
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests. Also no coolant loss.
I'm out of ideas.
Thanks!
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests. Also no coolant loss.
I'm out of ideas.
Thanks!
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
How did you "burp" the cooling system?The best way is to raise the front of the car at least 12". Remove the radiator cap and start the engine. Let in run to allow the thermostat to open. You should see a drop in the coolant level at that point. Raise the RPM to about 1100-1200 and fill the radiator so that the coolant level is at the top of the filler neck. Reduce RPM's to idle and replace the cap.
Is the cap the correct pressure rating? Make sure the coolant in the overflow reservoir is at the correct line.
You also stated in another thread that you wanted the "best" AFR for your build. You need to get that done by your tuner. If the engine is too lean now, that would be a overheating issue. What's the base timing set at?
And as mentioned, do you have the lower airdam installed? That is needed to get air directed up to the radiator.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Yeah it's still there.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Cooling is basic... air flow and coolant flow.... interrupt one, or both,
and you will overheat. Since there is no loss of coolant, a head gasket leak is ruled out. Just a guess, but is the belt slipping on the pulley?
and you will overheat. Since there is no loss of coolant, a head gasket leak is ruled out. Just a guess, but is the belt slipping on the pulley?
Hey guys I have a 1985 Corvette. This problem all started after I installed brand new AFR 195 Eliminator Heads.
What are the temps?
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
Just the opposite of how it should work. At idle, the fans will operate when the programmed hot temp is reached. At speed, the air motion supplied by the dam should provide adequate cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests.
Also no coolant loss.
What are the temps?
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
Just the opposite of how it should work. At idle, the fans will operate when the programmed hot temp is reached. At speed, the air motion supplied by the dam should provide adequate cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests.
Also no coolant loss.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Another suggestion.... it is possible that the knock sensor has build-up around it, and slowing coolant motion.
If you haven't replaced the knock sensor (instructions in the link),
you might consider doing so, and use high pressure water injected
into the knock sensor hole to remove 'gunk'....
http://forums.corvetteforum.com/c4-t...ck-sensor.html
Just a normal flush will not remove the 'gunk' around the sensor.
If you haven't replaced the knock sensor (instructions in the link),
you might consider doing so, and use high pressure water injected
into the knock sensor hole to remove 'gunk'....
http://forums.corvetteforum.com/c4-t...ck-sensor.html
Just a normal flush will not remove the 'gunk' around the sensor.
Melting Slicks
Joined: May 2010
Posts: 2,082
Likes: 3
From: Conowingo Maryland
do you do the pressure test like I suggested before. You have a classic symtoms of combustion in the cooleant. You need to test for this and a pressure test is a good way of doing this
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Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
If exhaust gases were present in the coolant, it would be due to a head gasket leak, and there would be increased pressure in the cooling system forcing coolant out. Since there is no loss of coolant, that would preclude exhaust gases from being in the system.
Safety Car
Joined: Sep 2001
Posts: 4,154
Likes: 553
From: Glenbeulah Wi
Hey guys I have a 1985 Corvette. This problem all started after I installed brand new AFR 195 Eliminator Heads.
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests. Also no coolant loss.
I'm out of ideas.
Thanks!
The car overheats when you drive it but when you pull over and let it idle it cools down. It could be sitting idling all day and have no problem cooling.
I just replaced the radiator with a performance radiator and the problem still persists. New thermostat, CTS, water pump, cooling system passes all pressure and vacuum tests and the engine passes compression tests. Also no coolant loss.
I'm out of ideas.
Thanks!
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
But I have an update. I finally took it out on the highway, it doesn't happen at around 50 mph or higher. It cools fine. It seems to happen at around 30 mph or lower.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Well the thermostat is new and the belt is routed correctly. The previous owner had a shop install one before I got the car. A few people had suggested the water pump so far. But I should also add that when I rev the engine to about 2k - 3k RPMs, it sounds like someone put a baseball card in the spokes on a wheel of a bicycle. I thought it was coming from the AIR pump but I may be wrong.
Pro
Joined: Oct 2012
Posts: 613
Likes: 3
Did you check to see if your fans are working?
You mentioned CTS, but is this the one that activates the fans? there is one for the fans, one to tell the ecu what temp the eng is, and a sensor for the dash guage.
Silly questions i know BUT you never know.
You mentioned CTS, but is this the one that activates the fans? there is one for the fans, one to tell the ecu what temp the eng is, and a sensor for the dash guage.
Silly questions i know BUT you never know.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Yes the fans come on at about 194* F, the CTS reports about 10 degrees lower on the scanner compared to the digital dash going off the Temperature Sending Unit.
Pro
Joined: Oct 2012
Posts: 613
Likes: 3
This happened to me more than once, so now i go right to the dealer of any car i have and just buy the brand specific dealer thermostat, yeah i pay the 16.00 but it's worth it to save me the grief of being stranded.
Melting Slicks
Joined: May 2010
Posts: 2,082
Likes: 3
From: Conowingo Maryland
It is very possible to spit the cooleant into the recovery tank and not loose and noticabe amout of cooleant. Esp with the little amount he has driven the car. But now that he says it only happens at 30 mph that follows no real reason to me at this time
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
When sitting in my driveway it will go up to 220 and come down to like 185.
When driving under 30 mph it keeps going, (237 was the highest so far), until I pull over and it comes down to around 185.
On the highway at 50 mph or more it goes to around 215 - 220 and comes back down.
When driving under 30 mph it keeps going, (237 was the highest so far), until I pull over and it comes down to around 185.
On the highway at 50 mph or more it goes to around 215 - 220 and comes back down.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Yes. But if I come to a stop light it'll drop down. When I consistently have a load on it it climbs up.
Also someone I talked to said that my Temperature Sending Unit is placed in an area that is hotter than other areas. It's between Cylinder 1 and 3 on the drivers side in between the headers. Someone said I may get a hotter reading there than I would in a place next to the thermostat housing. Any input on that? Thanks!
Also someone I talked to said that my Temperature Sending Unit is placed in an area that is hotter than other areas. It's between Cylinder 1 and 3 on the drivers side in between the headers. Someone said I may get a hotter reading there than I would in a place next to the thermostat housing. Any input on that? Thanks!