When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have a AA supercharger on my base c5 along with a bunch of other mods, the car originally had a stock size radiator and was running warm so I ordered the Dewitt’s cut down rad and just installed it this weekend. Now my temps are getting up to almost 240 degrees when just cruising, at idle it will stay around 195-200 but as soon as I start moving it spikes really quick when im just cruising around, it was a hot day yesterday (around 85 degrees) but I don’t think it should be getting that hot ever, I’ve tried to burp the air 3 times now and I’m pretty sure I’ve gotten all the air out. I’m kinda lost as to what to do now, any ideas would be greatly appreciated
thanks!
and to add I put new fans in with the rad install and they are programmed to turn on way earlier than stock but it makes no difference
Last edited by Just Another C5; Jun 7, 2026 at 01:02 PM.
I also have an A&A kit. I have the stock radiator and fans ( my fans are tuned as well). I don't ever get above 230 even on 100° days. On a normal day I don't get above 210°. You definitely have an issue. How much thicker is the Dewitt's radiator? Maybe there's not enough room for airflow in the custom A&A air box. That's just a guess though. I assume you have everything installed correctly. My normal advice would be to check your coolant levels and clean out the radiator, but you just installed it. Good luck, sorry I couldn't help more.
Last edited by MWWarlord; Jun 7, 2026 at 08:12 PM.
It still has the stock front end and I put the little lip that AA provides back on but it still climbs to 240 degrees when cruising down the highway, I’m gonna drain the coolant again and put a 160 degree thermostat into it and then I’m also gonna try to do the front license plate grill to hopefully force more air into the front, my car is on coil springs and lowered pretty good so I’m not sure if now that the Dewitt’s is wider there’s not enough room between the condenser and the rad to scoop any air into it to cool it down, otherwise I’m not sure what I could do or what it could be
Last edited by Just Another C5; Jun 9, 2026 at 11:20 PM.
It still has the stock front end and I put the little lip that AA provides back on but it still climbs to 240 degrees when cruising down the highway, I’m gonna drain the coolant again and put a 160 degree thermostat into it and then I’m also gonna try to do the front license plate grill to hopefully force more air into the front, my car is on coil springs and lowered pretty good so I’m not sure if now that the Dewitt’s is wider there’s not enough room between the condenser and the rad to scoop any air into it to cool it down, otherwise I’m not sure what I could do or what it could be
Yeah, that was my guess that there wasn't enough room between the condenser and the radiator. I feel like others have run a Dewitt's with the A&A kit without issue. Unfortunately, assuming your current t-stat is functioning, I don't think the 160°t-stat is going to have any effect at all. The fans will still kick on at the same temp.
I have basically the same set up as you do, except it is a ECS. Dewitt's rad with their fans. I run ported heads and Long Tubes with 650 to the wheels. Mine stays right around 195 and rarely gets over 210, even in stop and go traffic. When you fill the rad, you might want to use a vacuum fill to make sure you aren't getting an air pocket somewhere. That would definitely cause the issue you are seeing and what about your rad cap? Is it new and correct? I do have a 160 thermostat in mine as well.
What about your water pump? You know for sure it is functioning correctly? I run a electric pump, that's one other difference.
Last edited by Missileboy; Jun 10, 2026 at 08:07 AM.
Its an airflow problem with the radiator if its staying cool at idle. Try cruise with and without fans on, try both ways. Check the fan for air leaking around the sides and seal it good to the radiator. When people change the radiator during fan install sometimes the seal of the fan gets overlooked and it is critical that it does not leak.
The fans had to get trimmed down for the trimmed down radiator so there’s a gap at the top of the radiator between the fans so that could maybe be something but not sure how I’d fix that, I’ll try a bunch of stuff this weekend and hopefully I can figure it out, hoping opening up the front end/license plate over will help force some air right into it, gonna make a new air damn sort of a thing so it directs it right into the intercooler and rad
Yeah cutting down the fans is likely what's causing your issue. Sounds like the front scoop piece isn't aimed correctly for your setup either. Good luck getting everything fabbed up correctly.
It still has the stock front end and I put the little lip that AA provides back on but it still climbs to 240 degrees when cruising down the highway, I’m gonna drain the coolant again and put a 160 degree thermostat into it and then I’m also gonna try to do the front license plate grill to hopefully force more air into the front, my car is on coil springs and lowered pretty good so I’m not sure if now that the Dewitt’s is wider there’s not enough room between the condenser and the rad to scoop any air into it to cool it down, otherwise I’m not sure what I could do or what it could be
Do not put in a 160 degree thermostat. Does absolutely nothing when the engine is at operating temperature.
Back to formula.
1) Restore the factory fan settings in the tune.
2) Explain how you did the fill procedure and air purge.
3) Did you confirm circulation and how?
4) Are the fans operating at high and low speed?
5) Are you taking temp measurements with an IR thermometer for a cross check?
6) Have you done a pressure test of the system?
Start this re-eval at idle/parked before trying to drive.
Everything checks out besides pulling the thermostat I haven’t done that yet, I have now even opened up the front bumper to force air into the cooling pack and it is still getting up to 235 just driving normally. is what I don’t understand stand is that it never would get this hot before with the stock radiator, how is installing a Dewitt’s rad making it so much worse?
Last edited by Just Another C5; Today at 05:53 PM.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
Hot coolant temps
