C4 Eng Temp gets very high
Thread Starter
Cruising
Joined: Jun 2015
Posts: 11
Likes: 1
From: Sandy Hook CT
C4 Eng Temp gets very high
Hi. Sorry if this is redundant, I checked a lot of forums and didn't see any threads that address this issue I'm having.
I have a '93 LT1 6sp. Engine is great, lower miles, runs as it should. I have noticed over the last couple weeks the engine temp gets very high when idling at red lights, traffic, etc. Cooling system is 100% functional but, it seems to me, the fan comes on very late - around 230F. Once the fan is on, the temp is static but doesn't really go down until I get rolling again. Ambient temps have been mild during these times so it isn't the weather. I should also say the car doesn't experience any change in performance no matter what the temp is (engine or outside).
Anyone run into this and/or have advice or guidance on the issue? If this is normal I'll feel a lot better. Maybe 230F isn't that hot - I just don't want to unknowingly be doing any damage.
Thanks in advance for any help you all can offer.
I have a '93 LT1 6sp. Engine is great, lower miles, runs as it should. I have noticed over the last couple weeks the engine temp gets very high when idling at red lights, traffic, etc. Cooling system is 100% functional but, it seems to me, the fan comes on very late - around 230F. Once the fan is on, the temp is static but doesn't really go down until I get rolling again. Ambient temps have been mild during these times so it isn't the weather. I should also say the car doesn't experience any change in performance no matter what the temp is (engine or outside).
Anyone run into this and/or have advice or guidance on the issue? If this is normal I'll feel a lot better. Maybe 230F isn't that hot - I just don't want to unknowingly be doing any damage.
Thanks in advance for any help you all can offer.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Your fan is programmed to come on at 228.
You should remove the plastic cover over the top of the radiator and check the area between the radiator and the AC cooler. There is often a build up of debris in this area which restricts the air flow to the radiator.
A 160 thermostat would help a little. You could also do a good coolant system flush which could also help.
You should remove the plastic cover over the top of the radiator and check the area between the radiator and the AC cooler. There is often a build up of debris in this area which restricts the air flow to the radiator.
A 160 thermostat would help a little. You could also do a good coolant system flush which could also help.
Flatulent Dwarf
Joined: Nov 2009
Posts: 729
Likes: 84
From: Poverty Holler NC
Something to keep in mind with C4's is they seem to moonlight as vacuums, There must be one tremendous negative pressure area under these cars as they seem to suck up all kids of road funk. Mine seems to have an appetite for Mc'd cups and those plastic grocery bags....unless it's the fall of the year, then it's pine needles and oak leaves.
later, tiny
later, tiny
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Your fan is programmed to come on at 228.
You should remove the plastic cover over the top of the radiator and check the area between the radiator and the AC cooler. There is often a build up of debris in this area which restricts the air flow to the radiator.
A 160 thermostat would help a little. You could also do a good coolant system flush which could also help.
You should remove the plastic cover over the top of the radiator and check the area between the radiator and the AC cooler. There is often a build up of debris in this area which restricts the air flow to the radiator.
A 160 thermostat would help a little. You could also do a good coolant system flush which could also help.
Melting Slicks
Joined: Nov 2013
Posts: 3,451
Likes: 336
From: Greater Cincinnati Area.
This bothers me too. I have the AUX relay, but not the aux fan? It looks factory?
So, I'm going to parallel it. Lower temp switch in the head, with it's own relay and wiring. And comp control relay and sensor to back it up.
May add a second fan for redundancy. Mine had a bad PCM and got hot. Blew a head gasket at about 240. It had probably been overheating for a while before I got it. Had a toggle switch on the dash.
So, I'm going to parallel it. Lower temp switch in the head, with it's own relay and wiring. And comp control relay and sensor to back it up.
May add a second fan for redundancy. Mine had a bad PCM and got hot. Blew a head gasket at about 240. It had probably been overheating for a while before I got it. Had a toggle switch on the dash.
Le Mans Master
Joined: May 2005
Posts: 7,373
Likes: 2,288
From: Central Maryland
On your '93, you can program the ECM to set the fan on/off temps lower. This will make a huge difference at idle and low-speed. Just be careful to not set them so low that the fans will run all the time after warm-up. Installing a lower-temp thermostat will give you more room to work with in that regard.
As others have noted, C4s are bottom-feeders, and they will suck an astonishing assortment of things into the cooling stack. Leaves, birds, bugs, plastic bags, cigarette butts, and nearly anything else they can get into their mouths. Check the front of your condenser, and the radiator, and clean out what has accumulated. Then consider adding a debris screen to keep most of this sort of crap out of there. This thread includes how I fabricated mine:
https://www.corvetteforum.com/forums...en-shield.html
Live well,
SJW
As others have noted, C4s are bottom-feeders, and they will suck an astonishing assortment of things into the cooling stack. Leaves, birds, bugs, plastic bags, cigarette butts, and nearly anything else they can get into their mouths. Check the front of your condenser, and the radiator, and clean out what has accumulated. Then consider adding a debris screen to keep most of this sort of crap out of there. This thread includes how I fabricated mine:
https://www.corvetteforum.com/forums...en-shield.html
Live well,
SJW
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Race Director
Joined: Apr 2002
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From: Anaheim CA
The operating temperature is determined by the coolant flow, air flow, radiator efficiency, water pump, fan efficiency, engine load, etc.
Safety Car
Joined: Aug 2006
Posts: 4,147
Likes: 452
From: Port St. Lucie West Florida
All of the above or just turn on your A/C . That will turn on your fans. For me living in Florida my A/C is on all the time so changing my fan settings would be useless down here. I also have a Dewitt radiator which helps ( 95 Vette)
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
I checked a lot of forums and didn't see any threads that address this issue I'm having.
Anyone run into this and/or have advice or guidance on the issue? If this is normal I'll feel a lot better. Maybe 230F isn't that hot - I just don't want to unknowingly be doing any damage.
Anyone run into this and/or have advice or guidance on the issue? If this is normal I'll feel a lot better. Maybe 230F isn't that hot - I just don't want to unknowingly be doing any damage.
Your temp conditions are normal. The contributing factor is that GM used a less than adequate radiator for the C4's. A Dewitts or other chinese knock offs will help to reduce the temp a bit in traffic. They will assist greatly in keeping temps down to factory t-stat levels when rolling.
As for the AUX fan.... Worthless waste of money and time.
.
Last edited by JrRifleCoach; Sep 18, 2015 at 01:16 AM.
Melting Slicks
Joined: Jan 2008
Posts: 2,054
Likes: 120
From: AZ
Sounds like the system is operating as designed. The fan only operates at low driving speeds; driving faster, it shuts off as the airflow is sufficient w/o it.. as you see with yours.
The temp rating of a 'stat is when it starts to open, as Cliff said. Plenty of this/that on 160/180 degree choices on ANY Corvette forum; Mine runs great with a 180 with WAY above stock power.
Pro
Joined: Oct 2010
Posts: 603
Likes: 45
From: Baltimore County MD
Hi temp
Hi. Sorry if this is redundant, I checked a lot of forums and didn't see any threads that address this issue I'm having.
I have a '93 LT1 6sp. Engine is great, lower miles, runs as it should. I have noticed over the last couple weeks the engine temp gets very high when idling at red lights, traffic, etc. Cooling system is 100% functional but, it seems to me, the fan comes on very late - around 230F. Once the fan is on, the temp is static but doesn't really go down until I get rolling again. Ambient temps have been mild during these times so it isn't the weather. I should also say the car doesn't experience any change in performance no matter what the temp is (engine or outside).
Anyone run into this and/or have advice or guidance on the issue? If this is normal I'll feel a lot better. Maybe 230F isn't that hot - I just don't want to unknowingly be doing any damage.
Thanks in advance for any help you all can offer.
I have a '93 LT1 6sp. Engine is great, lower miles, runs as it should. I have noticed over the last couple weeks the engine temp gets very high when idling at red lights, traffic, etc. Cooling system is 100% functional but, it seems to me, the fan comes on very late - around 230F. Once the fan is on, the temp is static but doesn't really go down until I get rolling again. Ambient temps have been mild during these times so it isn't the weather. I should also say the car doesn't experience any change in performance no matter what the temp is (engine or outside).
Anyone run into this and/or have advice or guidance on the issue? If this is normal I'll feel a lot better. Maybe 230F isn't that hot - I just don't want to unknowingly be doing any damage.
Thanks in advance for any help you all can offer.
Thread Starter
Cruising
Joined: Jun 2015
Posts: 11
Likes: 1
From: Sandy Hook CT
Thanks to everyone who replied. I took it out today and clicked on the AC when necessary and began to lower. This is counter intuitive being a former long time owner of a '67 Firebird with no AC. Will also look into a DeWitt.
Safety Car
Joined: Aug 2006
Posts: 4,147
Likes: 452
From: Port St. Lucie West Florida
In Florida I have 180(stock) thermostat with the Dewitt's rad. Temps are good because the A/C is always on. I believe a 160 stat wouldn't make too much difference with the continuous high temperature days
Last edited by enventr; Sep 19, 2015 at 07:05 AM.
Melting Slicks
Joined: Jan 2008
Posts: 2,054
Likes: 120
From: AZ
I said the system was normal b/c the temp stopped increasing, rather modulating near the 'ON' temp; NORMAL for a stock setup.
An aftermarket radiator will not likely change any of that, as the temperature goals are programmed into the system, not resultant from a deficient radiator/airflow problem, as far as I can see.
Racer
Joined: Jun 2011
Posts: 283
Likes: 5
When I first bought my 96 coupe, I was worried about the temperature because it kept going up to 260 degrees. Found out that a lot of c4's (not sure which years but mine's included) analog engine temperature displays are not working correctly and you should use the digital temperature readout for more accuracy. Not sure how you were reading the temperature so just wanted to throw this out there.
Team Owner
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