View Full Version : Overheating prelude

11-06-2008, 08:21 AM
I'm looking for some help on troubleshooting my buddies overheating prelude. It has a h23a engine.

The gauge peaks out sometimes when the car is sitting at idle, going up a bar every few minutes, and other times will hold at halfway. We also cannot get hot air out of his blower.

When the enine is hot, upper rad hose is hot, lower rad hose is warm, valvecover is at 70*C, upper rad hose coolant neck at 100*C, lower rad hose coolant neck 70*C, rad 70*C.

Where would I start looking? At first I thought it might have been a bad ground for the sensor somewhere, but because he has no heat that should indicate either thermostat or heater core blockage right?

11-06-2008, 08:32 AM
No heat out of the vents?
check your water pump / coolant level
if no heat is coming out of the vents, its likely not circulating

11-06-2008, 09:07 AM

11-06-2008, 09:12 AM
Yeah the thermostat is done man that's why you're not getting any heat and since it's not opening the bottom rad hose is probably not that warm to the touch even when the car is overheating. It is fairly easy to change but you will need to flush your cooling system and rebleed it after.

Also make sure your rad fan is working properly.

11-06-2008, 06:11 PM
The lower rad hose does get warm to the touch, but I thought the lower one does not get at hot as the upper hose anyways..

Since the rad hose is getting warm, I would guess that my thermostat is opening, so I think his problem might be elsewhere. I haven't checked his heater core hoses yet though, so possibly this weekend I will check them and bleed his system.

One of the rad fans turns on, but can't figure out how to get the other to kick in. I am guessing it is a 2ndary fan and only kicks in when the engine is extremely hot...

11-06-2008, 06:15 PM
You have two fans because one is for cooling engine, and the other one is auxiliary for when AC is on.

11-07-2008, 08:22 AM
^ Well thats what I originally thought, but I wasn't able to get it to kick on when I had the AC/heater/blower on.

11-07-2008, 10:54 AM
good idea with breeding the system. I have been burned calling a thermostate due to DCT's that were pulled off the car. If you don't have air in your system and when you drive the car it just starts to over heat, sorry dude you got a water pump issue.

11-07-2008, 11:02 AM
I'd start with the thermostat. Its cheap and easy, and if its not that, then go from there.