C4 Overheating
Thread Starter
3rd Gear
Joined: Jul 2014
Posts: 3
Likes: 0
C4 Overheating
I decided to take my Corvette up to the mountains in Big Bear. It was a hot day about 105 degrees. The car ran fine until we start climbing the mountain. The temperature start going up quickly and about half way up I had to pull off when the temperature reached 260 degrees.
I waited about an hour turnaround and went back down the mountain. Car stayed cool and was cool all the way home about 30 miles away. Highest the temp went on the way home was 205 and that was only for a minute before settling around 200.
I have been testing the car since to see if it will overheat and it hasn't since. stays between 190 and 200. I driven on the freeway and in traffic no problem. I let it idle in my garage and it stays about 205 - 210. Never gets hot.
Anybody have any idea whats the problem?
I waited about an hour turnaround and went back down the mountain. Car stayed cool and was cool all the way home about 30 miles away. Highest the temp went on the way home was 205 and that was only for a minute before settling around 200.
I have been testing the car since to see if it will overheat and it hasn't since. stays between 190 and 200. I driven on the freeway and in traffic no problem. I let it idle in my garage and it stays about 205 - 210. Never gets hot.
Anybody have any idea whats the problem?
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
If you let it get that hot you probably just toasted your rings - especially if you pulled over and just let it soak at that temperature. You'll know in a couple thousand more miles if you oil gets black much faster than normal and starts blowing out the dipstick - guess how I know.
The radiator should be pulled and the front cleaned. A better water pump (Stewart) won't hurt, and you might as well put in a new 195 thermostat in while you're in there.
Good luck and hopefully you won't be putting an engine into this winter.
The radiator should be pulled and the front cleaned. A better water pump (Stewart) won't hurt, and you might as well put in a new 195 thermostat in while you're in there.
Good luck and hopefully you won't be putting an engine into this winter.
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
Hi
As mentioned by MCM check the gap between the a/c condenser and radiator, you will need to remove the cover (heaps of bolts) to access the gap.
There will be leaves, twigs, small roadkill, plastic bags and so on trapped in there, once cleaned out fit some mesh to keep it clean.
http://www.ebay.com/itm/360251155164...84.m1438.l2649
http://www.ebay.com/itm/84-91-CORVETTE-C4-ALUMINUM-MESH-RADIATOR-SCREEN-NEW-/290401657970?pt=Motors_Car_Truck_Parts_Accessories&hash=item439d49a472
As mentioned by MCM check the gap between the a/c condenser and radiator, you will need to remove the cover (heaps of bolts) to access the gap.
There will be leaves, twigs, small roadkill, plastic bags and so on trapped in there, once cleaned out fit some mesh to keep it clean.
http://www.ebay.com/itm/360251155164...84.m1438.l2649
http://www.ebay.com/itm/84-91-CORVETTE-C4-ALUMINUM-MESH-RADIATOR-SCREEN-NEW-/290401657970?pt=Motors_Car_Truck_Parts_Accessories&hash=item439d49a472
Instructor
Joined: Nov 2003
Posts: 137
Likes: 5
From: Clifton NJ
Hi
As mentioned by MCM check the gap between the a/c condenser and radiator, you will need to remove the cover (heaps of bolts) to access the gap.
There will be leaves, twigs, small roadkill, plastic bags and so on trapped in there, once cleaned out fit some mesh to keep it clean.
http://www.ebay.com/itm/360251155164...84.m1438.l2649
84 91 Corvette C4 Aluminum Mesh Radiator Screen New | eBay
As mentioned by MCM check the gap between the a/c condenser and radiator, you will need to remove the cover (heaps of bolts) to access the gap.
There will be leaves, twigs, small roadkill, plastic bags and so on trapped in there, once cleaned out fit some mesh to keep it clean.
http://www.ebay.com/itm/360251155164...84.m1438.l2649
84 91 Corvette C4 Aluminum Mesh Radiator Screen New | eBay
Burning Brakes
Joined: Apr 2009
Posts: 1,185
Likes: 33
From: Charlotte Michigan
I bought two piece's of expanded metal at Lowe's to make one, but changed my mind, because it being expanded metal with a ruff surface that debris would stick to it and not fall off. I than bought some perforated stainless, but nosy afraid the holes are not big enough to let air to flow through, so going to leave it as it was. Hopeful the new DeWitt's will help and cleaning once in a while will suffice.
Team Owner
Joined: Sep 2003
Posts: 20,179
Likes: 673
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Mine has seen temps higher than that before I learned about burbing the cooling system. Still running fine after all these years.
The radiator should be pulled and the front cleaned. A better water pump (Stewart) won't hurt, and you might as well put in a new 195 thermostat in while you're in there.
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Melting Slicks
Joined: May 2007
Posts: 2,075
Likes: 109
From: Longmont Co
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
Instructor
Joined: Jan 2013
Posts: 128
Likes: 26
I'd make sure both fans turn on all the time. I had a primary fan that would turn on 90% of the time but not always. After being really confused why I was reaching 260, I finally figured it out by testing multiple times from the ALDL connector. Secondary fan was burning it's fuse all the time. Rotating the fans by hand, both felt fine. It was only after I had removed one fan motor and compared it with a new motor that I understood how bad the originals were.
Melting Slicks
Joined: May 2005
Posts: 2,152
Likes: 33
From: Folsom Ca
I have a `95 Auto with about 87k on it. My car isn`t overheating. It runs normal temp around town in stop and go traffic. Fans are coming on and it stays in normal parameters.
The concern I have is that it is running hotter than it should on the freeway. The temp {both gauges} goes up at speed. It had been running about 209-215 for awhile when I took it the freeway. Actually got as hot as 219 last week.
It seems to actually cool some when I get off and running at lower speeds. So the car isn`t technically overheating but something is off.
Any help would be appreciated.
The concern I have is that it is running hotter than it should on the freeway. The temp {both gauges} goes up at speed. It had been running about 209-215 for awhile when I took it the freeway. Actually got as hot as 219 last week.
It seems to actually cool some when I get off and running at lower speeds. So the car isn`t technically overheating but something is off.
Any help would be appreciated.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Since temps are running normal at low speeds (fans), it would follow that the reason the temp increases on the highway might be due to the blockage of air flow behind the radiator, or damage to the air dams preventing upward airflow. A t-stat that only opens partially will cause temps to rise at highway speeds.
Cooling is basic..... air flow, coolant flow.... block one, or both, and
you will overheat.
Melting Slicks
Joined: May 2005
Posts: 2,152
Likes: 33
From: Folsom Ca
That is what I was leaning towards. I have had the buildup of dirt, leaves etc blocking the radiator in the past. It looks pretty clear from what I can see. One other thing that I noticed is that the car seems to get up in temp{into the 200s} really fast from startup. Does that point to the TStat as well?
Last edited by ETM; Jan 10, 2015 at 08:24 PM.
Thread Starter
3rd Gear
Joined: Jul 2014
Posts: 3
Likes: 0
My problem turned about to be like everyone said, a lot of leaves and stuff blocking the airflow. I replaced the radiator since I had to take it apart and installed a new Thermostat and it runs fine. It stays in the mid to high 180's and never hits 200. I would say airflow blockage is your problem.
I have a `95 Auto with about 87k on it. My car isn`t overheating. It runs normal temp around town in stop and go traffic. Fans are coming on and it stays in normal parameters.
The concern I have is that it is running hotter than it should on the freeway. The temp {both gauges} goes up at speed. It had been running about 209-215 for awhile when I took it the freeway. Actually got as hot as 219 last week.
It seems to actually cool some when I get off and running at lower speeds. So the car isn`t technically overheating but something is off.
Any help would be appreciated.
The concern I have is that it is running hotter than it should on the freeway. The temp {both gauges} goes up at speed. It had been running about 209-215 for awhile when I took it the freeway. Actually got as hot as 219 last week.
It seems to actually cool some when I get off and running at lower speeds. So the car isn`t technically overheating but something is off.
Any help would be appreciated.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
and check for the opening temp. T-stats are relatively cheap, if it has not been changed for some time.
replace it, even if it checks out 'good'.
Last edited by don hall; Jan 10, 2015 at 09:14 PM.