Temperture heating up
Thread Starter
Advanced
Joined: Nov 2006
Posts: 82
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From: Alpharetta Georgia
Temperture heating up
Hello,
I have noticed my 1990 L98 Vette goes up to 250 -260 degrees when I am sitting still in traffic. When I start to move again and continue to move the temp will drop quickly to around the 210 -220 mark. Does this sound like a problem with the thermastate or do I need to replace the coolant? Anyone ever had the same issue?
Thanks,
John
I have noticed my 1990 L98 Vette goes up to 250 -260 degrees when I am sitting still in traffic. When I start to move again and continue to move the temp will drop quickly to around the 210 -220 mark. Does this sound like a problem with the thermastate or do I need to replace the coolant? Anyone ever had the same issue?
Thanks,
John
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Common problem and change a t/stat is NOT the answer. First, at what temp are your fans coming on? Do they come on when you turn on the A/C? Have you checked carefully for debris sucked up against the front of the radiator? 240*F is tolerable, at 260*F it is time to shut the engine down and let it cool off or risk damage.
Melting Slicks
Joined: Sep 2006
Posts: 3,194
Likes: 27
From: Monroe Twp, NJ
Chevrolet recommends to shut off the engine at 260, I think your running to hot . Has the radiator even been boiled out, is there pressure in the system are the fans working? You have some trouble shooting to do.
Thread Starter
Advanced
Joined: Nov 2006
Posts: 82
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From: Alpharetta Georgia
Thanks for the advice so far. The car runs fine and the only reason I noticed the temp gauge is as I was sitting in traffic and just looked at it and saw it pushing 250. There is no red line anywhere on the temp gauge. I will double check for debris and possible flush my system and add new coolant. Thanks again.
CF JASOC Member
Joined: Feb 2006
Posts: 8,040
Likes: 34
From: Downtown Annapolis, MD. The Future is where we all have to live. Let's not screw it up.
St. Jude Donor '08-'09-'10-'11
Man, that's waaaay too hot. Start by checking the fuse first if you find that the fan isn't coming on around 228 +/-, then the relays. Simple stuff first.
Most of us have been there at one time or another.
Most of us have been there at one time or another.
Le Mans Master
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
You definately have a temp issue - she's running way to HOT... and it could definately cause engine damage:
1. Use search function to find info on: how to remove trash collected in front of radiator, these C4's are like a vacume cleaner.
2. agree with xccter: check your fan fuse and relays
3. start and let get to temp - fan should kick on about 228* if not, problem
4. 240* okay, 250* shutdown, 260* definate shut down
5. check thermostat and hose flow - pop rad cap, let come up to temp and look to see if water flowing -
6. Search on how to burp C4's - you could have bad air pockets
1. Use search function to find info on: how to remove trash collected in front of radiator, these C4's are like a vacume cleaner.
2. agree with xccter: check your fan fuse and relays
3. start and let get to temp - fan should kick on about 228* if not, problem
4. 240* okay, 250* shutdown, 260* definate shut down
5. check thermostat and hose flow - pop rad cap, let come up to temp and look to see if water flowing -
6. Search on how to burp C4's - you could have bad air pockets
Le Mans Master
Joined: Jun 2001
Posts: 6,694
Likes: 3
From: Less Talk, More WOT | Houston TX
Also, how long has it been since you flushed the coolant? It isn't ever a bad idea to start with fresh coolant and water While apart, check all your hoses for restrictions. Mine was overheating once because I accidentally left a shop towel in the upper radiator hose that I had jammed in there to keep it from dripping everywhere.
While apart, check all your hoses for restrictions. Mine was overheating once because I accidentally left a shop towel in the upper radiator hose that I had jammed in there to keep it from dripping everywhere.
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Instructor
Joined: Aug 2006
Posts: 144
Likes: 0
From: Watertown SD
You definately have a temp issue - she's running way to HOT... and it could definately cause engine damage:
1. Use search function to find info on: how to remove trash collected in front of radiator, these C4's are like a vacume cleaner.
2. agree with xccter: check your fan fuse and relays
3. start and let get to temp - fan should kick on about 228* if not, problem
4. 240* okay, 250* shutdown, 260* definate shut down
5. check thermostat and hose flow - pop rad cap, let come up to temp and look to see if water flowing -
6. Search on how to burp C4's - you could have bad air pockets
1. Use search function to find info on: how to remove trash collected in front of radiator, these C4's are like a vacume cleaner.
2. agree with xccter: check your fan fuse and relays
3. start and let get to temp - fan should kick on about 228* if not, problem
4. 240* okay, 250* shutdown, 260* definate shut down
5. check thermostat and hose flow - pop rad cap, let come up to temp and look to see if water flowing -
6. Search on how to burp C4's - you could have bad air pockets
I had the same problem. Had to replace the fan relay, the fan wasn't kicking on. Once I replaced the relay, it ran just fine.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Actually you won't really know without scanning it and since you're looking at an analog gage with no signs of a boilover, that's the better place to start. The scan will show you the temp from the Engine Coolant Temp Sensor which is used to control fuel delivery and fan engagement (non a/c). You can also check out the signal from the a/c pressure sensor which the ECM uses to engage the fans when the compressor is running. What you're seeing on the analog gage is from a different device and it may not be accurate - especially since it isn't spewing coolant from the overflow tank. Along the way, you can observe the fans and see what they're doing. For a '90, the main should come at 226 and the secondary at 228 as indicated by the Engine Coolant Temp Signal - unless the a/c is on. With that cranking, you should be seeing the main fan turning with a high side pressure of 200 psi or so; and the secondary if it climbs another 20 psi, regardless of engine temp. Once you know these things, repost - everything else is just a guess.
Intermediate
Joined: Jan 2006
Posts: 25
Likes: 0
From: Boardman Ohio
Turn on fans when motor get too hot.
On my 95 LT1 I checked the top most relay next to the rad. I found that the small thin wire (I think it was blue in color) is the ground wire.
If you ground this wire both of the fans came on when the ignition is turned on. I taped into the blue wire and ran the wire to a toggle switch
inside the car. I then ran a wire from the other side of the two pole toggle switch to a ground on the frame. Now when the engine gets too
hot I turn the switch on, the fans come on and cools the engine down.
Nothing too fancy but it works.
If you ground this wire both of the fans came on when the ignition is turned on. I taped into the blue wire and ran the wire to a toggle switch
inside the car. I then ran a wire from the other side of the two pole toggle switch to a ground on the frame. Now when the engine gets too
hot I turn the switch on, the fans come on and cools the engine down.
Nothing too fancy but it works.
Racer
Joined: Aug 2002
Posts: 305
Likes: 0
From: Mo
Common problem and change a t/stat is NOT the answer. First, at what temp are your fans coming on? Do they come on when you turn on the A/C? Have you checked carefully for debris sucked up against the front of the radiator? 240*F is tolerable, at 260*F it is time to shut the engine down and let it cool off or risk damage.
Advanced
Joined: May 2006
Posts: 80
Likes: 1
From: Atlanta GA
Distance and other things
Wow, a thread I can contribute to.
I agree with the above. Check your fans. I found a Helms manual great at this. Check fluid levels.
Some additional things to consider.
1. Check for junk in the radiator cavity. You will need to get under the Vette at the front. Look up between the radiator and AC unit. Pull out all junk. Might be junk pasted to your radiator, pull it off. Look from the right side with a flashlight between them as well.
I got my first Vette about a year ago. Had super heat issues. Was told to do this on the site, did it, and it was a huge help.
Check for the fans. I now have a manual switch and I turn it on at 210. Big help.
One last thing. In rush hour traffic, watch your distance to cars in front of you. As a bottom breather, your vette needs lots of air. Being too close tp cars in front of you leaves only hot, poor air for your Vette to take in - via the exhast from car in front. Avoid getting behing 18 wheelers, they block your Vette's air.
Good luck
I agree with the above. Check your fans. I found a Helms manual great at this. Check fluid levels.
Some additional things to consider.
1. Check for junk in the radiator cavity. You will need to get under the Vette at the front. Look up between the radiator and AC unit. Pull out all junk. Might be junk pasted to your radiator, pull it off. Look from the right side with a flashlight between them as well.
I got my first Vette about a year ago. Had super heat issues. Was told to do this on the site, did it, and it was a huge help.
Check for the fans. I now have a manual switch and I turn it on at 210. Big help.
One last thing. In rush hour traffic, watch your distance to cars in front of you. As a bottom breather, your vette needs lots of air. Being too close tp cars in front of you leaves only hot, poor air for your Vette to take in - via the exhast from car in front. Avoid getting behing 18 wheelers, they block your Vette's air.
Good luck
Racer
Joined: Jan 2007
Posts: 416
Likes: 2
From: Aquilla TX
Common problem and change a t/stat is NOT the answer. First, at what temp are your fans coming on? Do they come on when you turn on the A/C? Have you checked carefully for debris sucked up against the front of the radiator? 240*F is tolerable, at 260*F it is time to shut the engine down and let it cool off or risk damage.