Help C3 Overheating!
Thread Starter
Heel & Toe
Joined: May 2012
Posts: 16
Likes: 0
From: Gold Coast Queensland
Help C3 Overheating!
Guys can you give me some advice on the best thermo fan setup to use on my stock radiator on my C3 350. The motor is new, running around 400hp manual Gear box.
On the open road she runs just under 200 but as soon as I hit traffic she overheats.
I have had the core cleaned and flushed, new water pump and 165 deg thermostat.
Any help would be great.
Cheers,
Paul
On the open road she runs just under 200 but as soon as I hit traffic she overheats.
I have had the core cleaned and flushed, new water pump and 165 deg thermostat.
Any help would be great.
Cheers,
Paul
Burning Brakes
Joined: Apr 2009
Posts: 807
Likes: 2
From: VIRGINIA BEACH VIRGINIA
I have heard that a bad radiator cap will cause problems. do you have the air dam under the front bumper? you really need that to get all the air pushed up into the radiator. May have air in you system also. once it is cool, pull the cap and run it for awhile, letting the water flow and you should be able to get all the air out of it.
Another possibility would be a bad fan clutch, if it is not working correctly, that would really effect heat in the stop and go traffic.
Another possibility would be a bad fan clutch, if it is not working correctly, that would really effect heat in the stop and go traffic.
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
Eliminating air leaks from around the radiator is essential. Also, check your hoses to see if they are weak and collapsing. I use a constant flow type thermostat - this allows any air to escape in your system. You also need to verify that your fan/fan clutch is working properly.
Good luck.
I solved all of my overheating issues by replacing the radiator with a Dewitts unit - a great decision!
Good luck.
I solved all of my overheating issues by replacing the radiator with a Dewitts unit - a great decision!
CF Community Team
Joined: Oct 2004
Posts: 19,341
Likes: 5,232
From: Cape Cod, Mass.
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The best setup that actually works is a Dewitt's aluminum radiator and a stock clutch fan. Have you confirmed your gauge accuracy with an IR gun? Is your timing and vacuum advance set up properly? How old is your radiator? I'm not a big fan of trying to clean and flush old radiators.
My cars run 180 in all conditions with stock clutch fans and Dewitt's radiators. Good luck
My cars run 180 in all conditions with stock clutch fans and Dewitt's radiators. Good luck
Thread Starter
Heel & Toe
Joined: May 2012
Posts: 16
Likes: 0
From: Gold Coast Queensland
Found out the main problem with the overheating was a damaged lower air dam. Replaced with new one and them now sits around 190 on the open road. Still having overheating issues when stuck in traffic on hot days.
Can you guys recommend the correct Spal fans to run on my stock radiator?
Cheers.
Paul
Can you guys recommend the correct Spal fans to run on my stock radiator?
Cheers.
Paul
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
The air dam and the seals are for highway driving. If I understand the op correctly his problem is at idle while not moving or moving slowly. This would seem to indicate that the problem is lack of air movement generated from the fan.
I would check the fan clutch. Has anything been changed lately that you can attribute to this or has it ran hot since new engine? Can you confirm good water circulation from the pump by looking in the radiator before it gets hot but after the thermostat opens? To do this remove the cap when the engine is cool then start it up. Your 165 thermostat only dictates the minimum temp that the engine will run at. Is the fan shroud still in place?
I would check the fan clutch. Has anything been changed lately that you can attribute to this or has it ran hot since new engine? Can you confirm good water circulation from the pump by looking in the radiator before it gets hot but after the thermostat opens? To do this remove the cap when the engine is cool then start it up. Your 165 thermostat only dictates the minimum temp that the engine will run at. Is the fan shroud still in place?
Last edited by REELAV8R; Dec 30, 2012 at 08:01 PM.
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Drifting
Joined: Sep 2005
Posts: 1,896
Likes: 143
From: Manalapan New Jersey
As silly as this sounds this actually helped my car ( it's a big block though). If your car is a non-A/C car try an A/C fan as it has an extra blade... I can't make up this stuff..my car runs as cool as ever!! I've since changed my radiator etc but did the blade change quite some time back. A friend of mine told me he used to do this years ago and it helped.
Drifting
Joined: Apr 2020
Posts: 1,779
Likes: 250
From: Ocean County NJ
The air dam and the seals are for highway driving. If I understand the op correctly his problem is at idle while not moving or moving slowly. This would seem to indicate that the problem is lack of air movement generated from the fan.
I would check the fan clutch. Has anything been changed lately that you can attribute to this or has it ran hot since new engine? Can you confirm good water circulation from the pump by looking in the radiator before it gets hot but after the thermostat opens? To do this remove the cap when the engine is cool then start it up. Your 165 thermostat only dictates the minimum temp that the engine will run at. Is the fan shroud still in place?
I would check the fan clutch. Has anything been changed lately that you can attribute to this or has it ran hot since new engine? Can you confirm good water circulation from the pump by looking in the radiator before it gets hot but after the thermostat opens? To do this remove the cap when the engine is cool then start it up. Your 165 thermostat only dictates the minimum temp that the engine will run at. Is the fan shroud still in place?
My car tended to run hot at idle and slow speeds and somewhat hot at higher speeds (have a 6 blade flex fan with a recently changed copper radiator from PO)
thanks to another forum post I realized ALL of the seals were missing on the fan shroud and I sealed them and its now running a good bit cooler.
That being said it still gets super hot in the cabin and I just saw the old thread about the C3 cabin heat fixes, this forum is full of great info!!
Pro
Joined: Mar 2000
Posts: 669
Likes: 80
From: NE USA
Eliminating air leaks from around the radiator is essential. Also, check your hoses to see if they are weak and collapsing. I use a constant flow type thermostat - this allows any air to escape in your system. You also need to verify that your fan/fan clutch is working properly.
Good luck.
I solved all of my overheating issues by replacing the radiator with a Dewitts unit - a great decision!
Good luck.
I solved all of my overheating issues by replacing the radiator with a Dewitts unit - a great decision!
essential.it's simple, air passing through the radiator removes heat from the coolent via the surface area of rad. Hence all the fins. Lack of good seals around the rad allow the forced air from the fan/shroud assy to short circuit going around instead of through. The best new parts available won't get it done if that's the case. That said, mass volume of air forced through the radiator will remove mass amounts of heat from the engine. Think of it, late models kick in the electric fans when your sitting in traffic. Takes more air to exchange the heat.
Pro
Joined: Mar 2000
Posts: 669
Likes: 80
From: NE USA
Eliminating air leaks from around the radiator is essential. Also, check your hoses to see if they are weak and collapsing. I use a constant flow type thermostat - this allows any air to escape in your system. You also need to verify that your fan/fan clutch is working properly.
Good luck.
I solved all of my overheating issues by replacing the radiator with a Dewitts unit - a great decision!
Good luck.
I solved all of my overheating issues by replacing the radiator with a Dewitts unit - a great decision!
essential.it's simple, air passing through the radiator removes heat from the coolent via the surface area of rad. Hence all the fins. Lack of good seals around the rad allow the forced air from the fan/shroud assy to short circuit going around instead of through. The best new parts available won't get it done if that's the case. That said, mass volume of air forced through the radiator will remove mass amounts of heat from the engine. Think of it, late models kick in the electric fans when your sitting in traffic. Takes more air to exchange the heat.
I just fell for the old thread thing. Geeeze
