Overheated idling 2002 70k miles
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,355
Likes: 139
From: Surprise AZ
Overheated idling 2002 70k miles
So today was a first. I have only had the car a couple months. But today it overheated on me the first time ever. Granted, it was 115 out and this is by far the hottest day I have ever driven it in, but it really caught me off guard. It seemed ok as long as I kept moving but heated up quickly even just at a stop light. And by hot I mean like 260. Water and oil.
Once I started moving again it seemed to recover on the water side pretty quickly. And once on the freeway the oil got back down to about 234.
I am wondering if my fan has failed... anything else I should check? Or are these just so sensitive to the heat that you shouldn't drive them on a day that is as hot as today?
I checked and it doesn't seem to have lost any coolant. The level wasn't low or anything.
Once I started moving again it seemed to recover on the water side pretty quickly. And once on the freeway the oil got back down to about 234.
I am wondering if my fan has failed... anything else I should check? Or are these just so sensitive to the heat that you shouldn't drive them on a day that is as hot as today?
I checked and it doesn't seem to have lost any coolant. The level wasn't low or anything.
Racer
Joined: Apr 2014
Posts: 346
Likes: 7
From: Jacksonville N.C.
Start with cleaning all the crap out from in front of your ac condenser. Its a common c5 problem, the car breathes from the bottom and thus picks up a lot of debris that can block incoming air from cooling the radiators. I generally take care of my cars and avoid such situations and running things over in the road so it was a real surprise to me when I cleaned mine out last month. Didn't realize the amount of garbage it picks up.
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,355
Likes: 139
From: Surprise AZ
Overheated idling 2002 70k miles
Originally Posted by 8VETTE7
Start with getting the front end up in the air so you can check for debris blocking the cooling fins on the radiator. Even if the fans are working properly, if there is a lot of debris in the cooling fins the car is going to heat up.
You can check the fan operation on low speed easily. With the engine idling and the coolant temp just above 185 turn on the AC. BOTH fans should be running in low speed mode. If only one (or none) are running then you have a fan issue. If the coolant temp gets above 235 degrees then both fans should be running in high speed mode. If only one (or none) are running then you have a fan issue. There are 3 fuses and 3 relays that are part of the fan operation. Here is a diagram:
If there is a fan issue start by checking the fuses and relays shown in the above diagram.
One last piece of info on the C5 cooling system. The fans only run when the vehicle speed is below 35 MPH. Above 35 the fans are commanded off irrespective of coolant temp. GM felt that air flow through the radiator at speeds above 35 would be better without the fans spinning. You car seems to show this since at highway speeds the coolant temp does come down.
Melting Slicks
Joined: Jul 2013
Posts: 2,012
Likes: 23
From: Anaheim CA
The sudden onset of symptoms makes me think either the fans are dead or you sucked something solid (like a plastic trash bag) into the radiator/condenser.
The concerns about dirt etc in the radiator are real, but that's something that comes on much more gradually.
The concerns about dirt etc in the radiator are real, but that's something that comes on much more gradually.
Le Mans Master
Joined: Jun 2007
Posts: 7,423
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From: BEST Corn-Nation
2015 C5 of the Year Winner
I'm in Mesa and have not had my car get anywhere near that temp. I have a 160 stat and tuned the fans to come on sooner. Mine usually runs around the 195-210 range depending on what I'm doing. And that's with the air on to. I haven't had my car out yet this summer to see what it's going to do. I bet if you clean the radiator out that it will solve your issue. I cleaned mine right away when I got it to Arizona in '07 and it has never over heated yet. (knock on wood) Check your center air dam and make sure it's there as well.
Melting Slicks
Joined: Jul 2013
Posts: 2,012
Likes: 23
From: Anaheim CA
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Melting Slicks
Joined: Sep 2012
Posts: 2,217
Likes: 784
From: Fort Myers Beach Florida
Last year my 02 vert sucked up a plastic bag in the right side fan which stopped the fan and caused a fuse to blow. I cleared the fan, replaced the fuse and was good to go and perhaps lucky the fan motor still works
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,355
Likes: 139
From: Surprise AZ
Overheated idling 2002 70k miles
Did a very rudimentary cleaning of the radiator and condenser yesterday. It was about 112 outside so not quite the 117 of the other day. Even so the water never got above 208 -212 and the oil peaked at 225. And I road tested it good to make sure.
I was worried when I looked in there. No plastic bags. Didn't even look that dirty. But when I sprayed the radiator I got some stuff that looked like a cat coughed it up. Not loads and loads but enough I guess. Was very fibrous. Reminded me of car hair *****. Anyhow that improved things a great deal. I'm going to go full bore next weekend and pull the radiator and do it right. I think I will also switch to a 160 degree thermostat.
I was worried when I looked in there. No plastic bags. Didn't even look that dirty. But when I sprayed the radiator I got some stuff that looked like a cat coughed it up. Not loads and loads but enough I guess. Was very fibrous. Reminded me of car hair *****. Anyhow that improved things a great deal. I'm going to go full bore next weekend and pull the radiator and do it right. I think I will also switch to a 160 degree thermostat.
Thread Starter
Drifting
Joined: Apr 2008
Posts: 1,355
Likes: 139
From: Surprise AZ
Overheated idling 2002 70k miles
Originally Posted by Lee DeRaud
The sudden onset of symptoms makes me think either the fans are dead or you sucked something solid (like a plastic trash bag) into the radiator/condenser.
The concerns about dirt etc in the radiator are real, but that's something that comes on much more gradually.
The concerns about dirt etc in the radiator are real, but that's something that comes on much more gradually.