It Never Ends!!!
Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
It Never Ends!!!
Hey everyone. Well, just as I thought everything was running good, I got a check engine light. P0507 re: high idle. I'm going to clean the IAC and throttle body to see if it helps. The other thing is that now I noticed that my temperature was up to 236 degrees. When I got on the freeway, it dropped down to 228 even with the a/c on but I swear it should be cooler than that. Are these 2 problems related? Can a high idle cause the car to get too hot? The temperatures I saw were on the digital gauge and not the analog. Thanks in advance, Ed.
Melting Slicks
Joined: May 2014
Posts: 2,888
Likes: 590
From: New Port Richey FL
Hey everyone. Well, just as I thought everything was running good, I got a check engine light. P0507 re: high idle. I'm going to clean the IAC and throttle body to see if it helps. The other thing is that now I noticed that my temperature was up to 236 degrees. When I got on the freeway, it dropped down to 228 even with the a/c on but I swear it should be cooler than that. Are these 2 problems related? Can a high idle cause the car to get too hot? The temperatures I saw were on the digital gauge and not the analog. Thanks in advance, Ed.
now onto the high coolant temp. first off is the coolant full, in proper mixture and circulating? Does the fans operate correctly? is the Radiator clear? Corvettes have a nasty habit of sucking up every bit of debris off the road. so take a look under the car looking from the front were the radiator gets its air, also from the right front under the hood there is a spot were you can see between Radiator and A/C make sure all is clear.
Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
you have the starting point pretty much right for the idle, I would give a good look and listen for a vacuum leak and cracked Vac. lines (those hard plastic ones) give them a good look.
now onto the high coolant temp. first off is the coolant full, in proper mixture and circulating? Does the fans operate correctly? is the Radiator clear? Corvettes have a nasty habit of sucking up every bit of debris off the road. so take a look under the car looking from the front were the radiator gets its air, also from the right front under the hood there is a spot were you can see between Radiator and A/C make sure all is clear.
now onto the high coolant temp. first off is the coolant full, in proper mixture and circulating? Does the fans operate correctly? is the Radiator clear? Corvettes have a nasty habit of sucking up every bit of debris off the road. so take a look under the car looking from the front were the radiator gets its air, also from the right front under the hood there is a spot were you can see between Radiator and A/C make sure all is clear.
Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
Just started up the car and let it idle. 1 driver's side fan turned on at about 218. Checked after a few minutes and both fans were on but the temperature kept rising to 238. Took a pretty good look with a flashlight and there wasn't anything blocking the radiator or between the radiator and condenser. Maybe need to change the thermostat, flush radiator or replace radiator.
Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
I see that many on this board bought Dewitt radiators. Is this because the stock radiators aren't good enough to keep your car cool? I ask this because the stock radiators were considered capable by GM so what has changed that the stock radiators can't handle the heat? I do plan to buy a Dewitt also.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
In some cases, engines are heavily modified, and in those cases, increased cooling capacity is legitimately required.
The stock radiator is better than good enough for a stock or stockish engine...provided that it's clean inside and out.
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Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
One of the plastic tanks on my original radiator cracked. I replaced it with a DeWitts.
Things I like about the DeWitts:
I didn't have to cut the shroud around the radiator cap, which I have heard needs to be done with some aluminum radiators.
It came with new rubber mounts that were sized to fit the larger radiator. I have seen posts that described how to cut the stock mounts, but I didn't need to do that.
The cooling is definitely better than stock. I see temperatures typically about 15 to 20 degrees cooler than the stock radiator. Something unusual related to that: I have a 195° AC Delco thermostat in my car (verified by looking at the temperature stamped into the bottom). My car will run as low as 180° on cool days when cruising. I guess the thermostat is on the low side of the tolerance (just what is the tolerance anyway?).
Things I like about the DeWitts:
I didn't have to cut the shroud around the radiator cap, which I have heard needs to be done with some aluminum radiators.
It came with new rubber mounts that were sized to fit the larger radiator. I have seen posts that described how to cut the stock mounts, but I didn't need to do that.
The cooling is definitely better than stock. I see temperatures typically about 15 to 20 degrees cooler than the stock radiator. Something unusual related to that: I have a 195° AC Delco thermostat in my car (verified by looking at the temperature stamped into the bottom). My car will run as low as 180° on cool days when cruising. I guess the thermostat is on the low side of the tolerance (just what is the tolerance anyway?).
Drifting
Joined: Dec 2007
Posts: 1,672
Likes: 8
From: Sumter South Carolina
Keep an eye out on the coolant level and also oil level. I hate to jump to worst case scenario but it has happened to me twice (I track the car though and run temps sometimes 300* oil/250* coolant). Cracked head gasket. Air gets in the system and can't cool it. Check oil level cause sometimes it goes into the oil which can be really bad. If your coolant level is good and oil level is stable and no obvious white smoke, you are prob good. Good news is even if it is a cracked gasket they are simple job to replace.
I don't like the "replace radiator" thing. Sounds like you are treating the symptom and not the cause. The stock rad is capable of cooling an engine at highway speeds even if it is less than ideal condition. They are such simple devices. I would remove the rad and wash it out. I couldn't believe the crap in mine. Even after everyone told me there would be a bunch I still was absolutely shocked. Now I do it more often.
Another thing would be take the temp reading from somewhere else in the block. Like see what the computer temp sensor says since it is opposite side not just gauge sensor.
I don't like the "replace radiator" thing. Sounds like you are treating the symptom and not the cause. The stock rad is capable of cooling an engine at highway speeds even if it is less than ideal condition. They are such simple devices. I would remove the rad and wash it out. I couldn't believe the crap in mine. Even after everyone told me there would be a bunch I still was absolutely shocked. Now I do it more often.
Another thing would be take the temp reading from somewhere else in the block. Like see what the computer temp sensor says since it is opposite side not just gauge sensor.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
with the suggestions above.You don't need a Dewitt's radiator if the one in the car has worked all these years, "that is", if you haven't done modifications to the motor... Why not start with the cheapest and easiest to do, like replacing the thermostat...If you don't have junk in front of, or in between the radiator and condensor, and the fans are coming on when they're suppose to, then this is the most logical place to start..When thermostats stick closed the temps keeps going up even with fans on, just like yours is doing..If you want to test the thermostat, take it out and put it in a pan of boiling water to see if it opens...I always start with the easy stuff first, if it's not the thermostat , then flush the system and refill the radiator if it's got a few years on the coolant.Also check and make sure your coolant is circulating and the waterpumps not dead or dying...Also don't forget that having air in the cooling system will cause these same symtoms....
....WW
Last edited by WW7; Dec 11, 2014 at 11:38 AM.
Instructor
Joined: Nov 2011
Posts: 147
Likes: 0
From: Florida
We took old radiator out and there was junk between it and the a/c condensor. We replaced the radiator and replaced the thermostate. Cleaned everything and filled it back up and now it runs very nicely. Also installed a manual fan switch and turn it on most of the time in MAY,JUNE,JULY AND August and Sept.
Hot now is about 205.
Screwed around a long time before I did this change should of done it a lot sooner. It is not terribly expensive. Wish I would of done it a lot sooner.
Hot now is about 205.
Screwed around a long time before I did this change should of done it a lot sooner. It is not terribly expensive. Wish I would of done it a lot sooner.
Burning Brakes
Joined: Apr 2012
Posts: 888
Likes: 4
From: Ridgecrest Ca
The high idle could be a symptom of a vacuum leak as the computer will try to correct for a lean condition by richening the mixture. But you didn't get a code for lean bank 1 or lean bank 2 so maybe not a vacuum leak. A lean condition would also make the engine run hotter. Hit up the FSM and you'll solve it.
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
I see that many on this board bought Dewitt radiators. Is this because the stock radiators aren't good enough to keep your car cool? I ask this because the stock radiators were considered capable by GM so what has changed that the stock radiators can't handle the heat? I do plan to buy a Dewitt also.
Thread Starter
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
I think I'm going check the thermostat first. I do remember checking the upper radiator hose when the engine was hot and the hose was very hot and firm. I'm trying to remember if checking the upper and lower hoses can lead to a faulty thermostat. Sonething like if the upper hose is very hot and the lower hose is cool means that the thermostat is stuck. Also, if the thermostat is stuck closed, will the heater still blow hot air into the cabin or will the stuck thermostat only allow cool air in with the heater on?
Instructor
Joined: Nov 2011
Posts: 147
Likes: 0
From: Florida
Do it as a PM you will be glad you did. Replace your radiator and all hoses and thermostat and WP. It is not that expensive and you will be glad you did change them all. It would take less time to change all of them out than to do the research and thought process to figure out why it is running hot.
Besides making sure the fans are coming on when they are supposed to come on, little else could cause a really hot car. yes there are other things but probably not the problem.
Merry Christmas
Besides making sure the fans are coming on when they are supposed to come on, little else could cause a really hot car. yes there are other things but probably not the problem.
Merry Christmas
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Sonething like if the upper hose is very hot and the lower hose is cool means that the thermostat is stuck. Also, if the thermostat is stuck closed, will the heater still blow hot air into the cabin or will the stuck thermostat only allow cool air in with the heater on?
2. Heater works regardless of stat position.
Do it as a PM you will be glad you did. Replace your radiator and all hoses and thermostat and WP. It is not that expensive and you will be glad you did change them all. It would take less time to change all of them out than to do the research and thought process to figure out why it is running hot.
Besides making sure the fans are coming on when they are supposed to come on, little else could cause a really hot car. yes there are other things but probably not the problem.
Besides making sure the fans are coming on when they are supposed to come on, little else could cause a really hot car. yes there are other things but probably not the problem.
Instructor
Joined: Nov 2011
Posts: 147
Likes: 0
From: Florida
Time is money. he just needs to make sure the fans are working was the point.
Spending hours and hours lamenting and research a PM that will answer all the issues 98% chance and know everything in the cooling system is perfect is a major time savings.
He never said anything on the cooling system has been replaced.
Time is some serious money. PM on the cooling system on the C4 is a short amount of time a little money and in the long run will save a lot of both.
I've owned mine for 24 years and have a lot of experience.
Also Florida can get hot for a long period of time the last thing you want is a hot running car. Or worse yet an overheated car with aluminum heads along the side of the road waiting on a tow truck...lol..
Do the PM there will never be a day in the car in hot conditions you will be saying I wish I would not have done the cooling system.
Spending hours and hours lamenting and research a PM that will answer all the issues 98% chance and know everything in the cooling system is perfect is a major time savings.
He never said anything on the cooling system has been replaced.
Time is some serious money. PM on the cooling system on the C4 is a short amount of time a little money and in the long run will save a lot of both.
I've owned mine for 24 years and have a lot of experience.
Also Florida can get hot for a long period of time the last thing you want is a hot running car. Or worse yet an overheated car with aluminum heads along the side of the road waiting on a tow truck...lol..
Do the PM there will never be a day in the car in hot conditions you will be saying I wish I would not have done the cooling system.
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
Time is money. he just needs to make sure the fans are working was the point.
Spending hours and hours lamenting and research a PM that will answer all the issues 98% chance and know everything in the cooling system is perfect is a major time savings.
He never said anything on the cooling system has been replaced.
Time is some serious money. PM on the cooling system on the C4 is a short amount of time a little money and in the long run will save a lot of both.
I've owned mine for 24 years and have a lot of experience.
Also Florida can get hot for a long period of time the last thing you want is a hot running car. Or worse yet an overheated car with aluminum heads along the side of the road waiting on a tow truck...lol..
Do the PM there will never be a day in the car in hot conditions you will be saying I wish I would not have done the cooling system.
Spending hours and hours lamenting and research a PM that will answer all the issues 98% chance and know everything in the cooling system is perfect is a major time savings.
He never said anything on the cooling system has been replaced.
Time is some serious money. PM on the cooling system on the C4 is a short amount of time a little money and in the long run will save a lot of both.
I've owned mine for 24 years and have a lot of experience.
Also Florida can get hot for a long period of time the last thing you want is a hot running car. Or worse yet an overheated car with aluminum heads along the side of the road waiting on a tow truck...lol..
Do the PM there will never be a day in the car in hot conditions you will be saying I wish I would not have done the cooling system.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
I understand not spending money on replacing something unless it has failed..I also refuse to throw parts at a car without figureing out what is really wrong first, I really don't like throwing money away..... But, I also understand what "garys vette" is saying... When I first got my 89 and had trouble with the cooling system, I also replaced the radiator, hoses, thermostat , but not the water pump because it looked almost new and was working fine..What I was doing was replacing parts that were over 20 years old and probably near their (end of life). I considered this a part of normal long term maintainence and had no problem doing it.. Spending a few hundred dollars to renew the cooling system was way better then having a failure on the road...This is just my 2 cents, it's up to each individual to make their own choices about spending their money........WW
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....WW.
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Last edited by WW7; Dec 12, 2014 at 09:55 AM.