Running Hot when Idle
Thread Starter
Advanced
Joined: Nov 2007
Posts: 75
Likes: 11
From: Morgan Hill CA
Running Hot when Idle
Hey folks,
So my Norcal C5 doesn't have too many miles on it (52K) but it's been having trouble over heating rather quickly when idling in traffic. Within several minutes, it will shoot up from 190 highway crusing temp to the first fan trigger (216 if I recall correctly) and then a few minutes later will go up to the next fan trigger (235?). It doesn't go above the 240 mark but it has me nervous as it slowly creeps around this high mark. It discourages me from driving it in commuter traffic.
I've flushed the radiator and replaced the coolant twice now. I've checked that both fans are operational and that the radiator is free of debris. I've checked the digital readout for comparison. I've exchanged the thermostat so what's next?
How can I check that the water pump is operating adequately? I am inclined to go after that next, followed by a radiator exchange.
Is this the right sequence or are there any other suggestions? Thanks.
So my Norcal C5 doesn't have too many miles on it (52K) but it's been having trouble over heating rather quickly when idling in traffic. Within several minutes, it will shoot up from 190 highway crusing temp to the first fan trigger (216 if I recall correctly) and then a few minutes later will go up to the next fan trigger (235?). It doesn't go above the 240 mark but it has me nervous as it slowly creeps around this high mark. It discourages me from driving it in commuter traffic.
I've flushed the radiator and replaced the coolant twice now. I've checked that both fans are operational and that the radiator is free of debris. I've checked the digital readout for comparison. I've exchanged the thermostat so what's next?
How can I check that the water pump is operating adequately? I am inclined to go after that next, followed by a radiator exchange.
Is this the right sequence or are there any other suggestions? Thanks.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
That's basically the designed high operating temperature. If you don't like it then get the fans programmed to turn on at say 205 low and 210 high.
Did you separate the rad and AC condenser to clean between them? Take the top rad shroud off and get right in there?
I think low fan is 226 degrees. If you have the AC on then I think the low fan is 185 degrees and below 35mph - basically always on when driving slow.
Peter
Did you separate the rad and AC condenser to clean between them? Take the top rad shroud off and get right in there?
I think low fan is 226 degrees. If you have the AC on then I think the low fan is 185 degrees and below 35mph - basically always on when driving slow.
Peter
Instructor
Joined: Nov 2003
Posts: 180
Likes: 0
From: Vallejo CA
You can also improve airflow through the radiator and engine compartment by removing the plastic panels inside the "cove" vents on the sides of the car. Some folks do not remove the passenger side piece because the PCM is just inside it and they are concerned about water intrusion.
But bottom line, resetting the fan trip points is the answer.
But bottom line, resetting the fan trip points is the answer.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Or you can just turn on the AC and let the fans do their job. Put a ton of miles on my '99 both in town, freeway and traffic with no problems as long as the AC was on. In traffic with the AC off, you are going to see the heat spikes frankly because there is no or little air flow through the condensor then radiator. You need either the car moving through the air or the fans pulling air.
Thread Starter
Advanced
Joined: Nov 2007
Posts: 75
Likes: 11
From: Morgan Hill CA
Thanks everyone. I get different answers from various vette owners on their idle temperature. Some say theirs never gets above 210 etc.. I don't recall it ever getting that hot before and I'm pretty good at scanning the gauges. I may reset the fan set points to give me a peace of mind. I'll check the other suggestions too.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
