c5 temperature fluctuating
Thread Starter
Intermediate
Joined: May 2015
Posts: 37
Likes: 0
From: PALM BAY Florida
c5 temperature fluctuating
My 2002 C5 with 5.7L has a new water pump. The thermostat was replaced last year so I kept it when the bearings went out on the pump. The temp rises above 220 when at idle but when you give it some gas, it goes down immediately. No temp issues when the car is rolling and the more RPMs the better. What do you think?
Last edited by edbutler66; Feb 16, 2017 at 06:46 PM.
Melting Slicks
Joined: Sep 2006
Posts: 2,728
Likes: 142
From: Iowa
Not normal. My Vette sits at 198 coolant temp and never budges one single bit. This is with 100% factory cooling system. If it were 100F out, it might rise a little...but what you're describing seems excessive.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Very likely that you need to clean the debris from the cooling fins on the radiator. C5's are bottom feeders for air to cool the radiator and they suck up everything on the road and throw it against the cooling fins of the radiator. If you have never cleaned the radiator cooling fins it is LONG past due.......
If there is any plastic bags floating in the wind on the road, it seems to get sucked into and under the Vette. While changing the oil, some years ago, I pulled a large t-shirt from the #1 fan...it was wrapped around it. It took out the fan motor and a relay and a couple fuses.
Burning Brakes
Joined: Dec 2015
Posts: 995
Likes: 16
From: Houston Tx
Very likely that you need to clean the debris from the cooling fins on the radiator. C5's are bottom feeders for air to cool the radiator and they suck up everything on the road and throw it against the cooling fins of the radiator. If you have never cleaned the radiator cooling fins it is LONG past due.......
Race Director
Joined: May 2003
Posts: 14,136
Likes: 2,984
From: Iowa
St. Jude Donor '03 thru '26
I don't think that is abnormal. The stock fan set-up doesn't even kick on at 220 degrees.
Copied from a different post:
Copied from a different post:
Factory temp settings are low speed on at 226 degrees and off at 219 degrees. High speed on at 235 degrees and revert to low speed at 226 degrees. As stated both fans run at low speed and high speed and fans are commanded off by the PCM when the vehicle speed exceeds 35mph.
You can force low speed operation at 185 degrees by turning on the AC. High speed operation with AC on is still 235 degrees.
You can force low speed operation at 185 degrees by turning on the AC. High speed operation with AC on is still 235 degrees.
Melting Slicks
Joined: Sep 2011
Posts: 2,258
Likes: 543
From: Appleton WI
My 2002 C5 with 5.7L has a new water pump. The thermostat was replaced last year so I kept it when the bearings went out on the pump. The temp rises above 220 when at idle but when you give it some gas, it goes down immediately. No temp issues when the car is rolling and the more RPMs the better. What do you think?
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Thread Starter
Intermediate
Joined: May 2015
Posts: 37
Likes: 0
From: PALM BAY Florida
After driving it for a couple days, it has stabilized. It runs at about 198 when the car is moving and if I'm sitting in traffic for a while or just idling for more than 10 minutes, it gets up to about 212. Do you think the air pocket circulated out?
Thread Starter
Intermediate
Joined: May 2015
Posts: 37
Likes: 0
From: PALM BAY Florida
You have air in the system. If it was the thermostat or pump, the temp would not change when you rev the engine. Reving the engine proves you have fluid flow through T stat and pump. Repeat burping procedure. Temp should remain stable while sitting still and reving engine.
Burning Brakes
Joined: Dec 2015
Posts: 995
Likes: 16
From: Houston Tx
installed headers on my car this weekend and now the car idles around 190 and never went hotter than 200 driving around. Is this a typical change in temp seen after headers. FYI no tune was performed after install.
Burning Brakes
Joined: Jul 2013
Posts: 935
Likes: 103
Thanks for this! I hit 220 today sitting in a drive through... I'm planning to tune and set the fans to come on early and possibly throw in a cooler Tstat.
Last edited by Roddy13; Mar 29, 2017 at 04:37 PM.