C5 Z06 Overheating Issue
Thread Starter
Heel & Toe
Joined: Mar 2018
Posts: 22
Likes: 9
From: Imperial Missouri
C5 Z06 Overheating Issue
Hey everyone. After searching, I haven't had a lot of luck with anyone else having this issue. When stop and go driving with the AC on, my car overheats all the time. If the AC is on when highway driving, I don't have this issue. I have H/C/I as my main mods and bought the car that way. I'm wondering if possibly one of the fans aren't kicking on. I can't see one of them by just popping the hood and haven't tore the car apart yet to look any further. Has anyone else had this issue?
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Please give the temps you are experiencing......b/c heating up in stop and go driving is normal. AND not having the problem when highway driving is also normal. What have you checked already (radiator cap, hoses, water pump, coolant, clogged space between the a/c and the radiator and both fans working).
Last edited by Vetteman Jack; Sep 4, 2018 at 09:12 AM.
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Thread Starter
Heel & Toe
Joined: Mar 2018
Posts: 22
Likes: 9
From: Imperial Missouri
The temperature will sit around 220 which is fine with me. When I turn the AC on, it shoots to about 235 fast. I put on a brand new water pump last year so that checks alot of things off the list. The last thing I haven't dug into is the passenger side fan.
Drifting
Joined: Mar 2013
Posts: 1,496
Likes: 353
From: Little Rock Arkansas
If you have confirmed that the passenger side fan comes on at proper operating speeds (remember that the fans don't kick on to high speed until something like 237 F), then I would do the following;
1) Attempt to alleviate any air in the system. A very good way to do this is "bleed" the cross over tube under the intake. This tube is at a very high point in the cooling system. You can find a few how-to's through Google.
2) Check condition of the coolant tank (sometimes referred to as the "surge" tank). As this tank houses your radiator cap it has to be under constant pressure to keep the system working properly. If it loses even the smallest amount of pressure anywhere on the tank, a crack up high, cap not holding pressure, etc, it will cause the car to over heat.
1) Attempt to alleviate any air in the system. A very good way to do this is "bleed" the cross over tube under the intake. This tube is at a very high point in the cooling system. You can find a few how-to's through Google.
2) Check condition of the coolant tank (sometimes referred to as the "surge" tank). As this tank houses your radiator cap it has to be under constant pressure to keep the system working properly. If it loses even the smallest amount of pressure anywhere on the tank, a crack up high, cap not holding pressure, etc, it will cause the car to over heat.
Drifting
Joined: Jul 2015
Posts: 1,844
Likes: 375
From: San Jose, CA
Start with the simplest thing: Clean the radiator out. Seriously. Get it in the air, use compressed air to blast from the back through the fans and rad, out to the front. Usually any shop will do this for free if you're already getting anything else done and it's on the lift.
You can drop temps 10, 20, sometimes as much as 50F if it's really bad. A very, very small amount of dirt can make a difference of 10F; it only takes a fist-full to make the difference between fine and too-hot on an already hot day.
You can drop temps 10, 20, sometimes as much as 50F if it's really bad. A very, very small amount of dirt can make a difference of 10F; it only takes a fist-full to make the difference between fine and too-hot on an already hot day.
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Tech Contributor
Joined: Oct 1999
Posts: 40,999
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From: Charlotte, NC (formerly Endicott, NY)
Have you checked the front of the AC Condenser to see if there is dirt and debris pushed into the top of the condenser? Get car high enough you can stick your head under the front fascia and look to the top of the condenser to see if there is a lot of debris up there. That could cause idle temps to run a little high.
I saw coolant temps reach 245 degrees on my C5 Z06 while waiting in line between autocross runs on 90+ degree days. AC was on to keep me cool while I waited. So far the temps you are talking about seem to fall into the normal range.
Bill