ok well i have tried everything i can think of to cure the overheating that started a few months ago. i thought it was a clogged cat, so i got a new one. didnt help. new exhaust didnt help either, and ive replaced the old precat with a DP. still the overheating continues. i was convinced it was exhaust related as the first time it happend was when i switched cats (to unfortunatly a more clogged one than what was already on there). now i have a brand new HF and the problem still ramains.

i currently do not have an aftermarket water temp gauge, and am using the stock radiator. i have a replacement KOYO to go in, but i want to solve the overheating problem how it is so i dont mask some other problem which may be there.

the next thing i suppose i will replace is the thermostat. whats next to check after that? im puzzled because the very first time this happend was the day that i put on the bad cat.

 

1) Check thermostat - actually just replace it since you probably don't know how old it is and it's a cheap item

2) Check fans by applying direct power to them and make sure they spin with your hand.

3) Leave FD running for a while till the fans are supposed to kick on. If they don't kick on and you did the direct power test and you know they DO work, then you are going to have to start diagnosing the electrical system

4) Flush the entire system. Gunk might be clogged up somewhere.

5) You have any leaks?

6) Check if your water pump is working.

7) Is your foot TOO heavy?

 

Don't go cheap on the thermostat. Get an oem unit. Even a Cheap Bastard wouldn't use an aftermarket t-stat

 

I tried a cheap thermostat, needless to say the next weekend I was replacing it with the OEM unit.

Under what conditions does your car overheat? Touch the radiator, does it get hot?

 

How many miles on your stock setup and what were the mods on the car when the overheating started?

Before you put in the thermostat, go and rent a coolant system pressurizer and see if you have any leaks. Pressurize it to 14 psi. If the pressure goes down, look for a leak.

If the system stays pressurized, then the next likely culprit is the t-stat.

Good luck.

 

atihun: 90K mi on the stock setup w/ the ast being preventively replaced 6 months ago. when the car started overheating the mods were K&N filter (in the stock airbox), efini y-pipe, wrapped DP (which was getting so hot along w/ the turbos that it had burned off/disintegrated the DEI heat wrap after 2 weeks). those were all the mods + the bad cat and and a CB that i can not identify. the strange thing about the CB was that after a hard run if i were to look down the exhaust the packing would be glowing red.

i will presurize the system and check for leaks but i have a feeling the temps are just getting too hot and it is boiling over. i usually experience a low coolant buzzer along with the overheat, as well as the car spewing coolant, intense boiling in the radiator & AST, and the whistling sound of of the radiator cap trying to let off excess pressure.

Tom93R1: most of the time under idling i have no problems, driving down the highway without boost it is usually fine (but on a few occasions has just randomly overheated), under boost i normally get an overheat if i boost and then reduce speed (but sometimes it will overheat no matter what).

i am also having problems with my secondary not coming online sometimes (which i was thinking could have possibly been as a result of too much backpressure in the exhaust system? maybe not) i dont know if thats related but its another problem that im having.

FlyBye: im pretty sure both fans are coming on at the correct times (i can reduce my temps and likelyhood of overheating if i keep the AC constantly on. and the main fan does come on eventually if i just let the car idle)

somthing else that i have recently noticed is that my heater does not blow hot, or does not get nearly as hot as it used to.

i dont see any leaks untill its spewing coolant after an overheat.

how can i check if my waterpump is working properly? im assuming its working fine but it could be bad i suppose. i dont think the FD ones fail very often, but w/ my luck

is my foot too heavy? yes! but even when i take it easy i get the same overheating problems. before putting on this bad i rarely had overheating problems (well now that i think about it last summer i did have a few overheats after getting off the freeway when it was insanely hot outside, but i just attributed it to the heat... maybe it was a building problem that was masked by the winter)

 

You can pick up a lower temp thermostat from Petit cheap, I got one from there last summer. That, along with my Koyo and a replaced (working) fan assembly has helped my overheating problem, although with bad coolant seals there is only so much that can be done. The thermostat takes maybe 20-30 minutes to install (if I remember right) and is just easy to do (and cheap), so why not?

 

From what you described, it may be your t-stat or your waterpump. When you said that you turned on your heater and aren't getting really hot air, that tells me that your system is not circulating water correctly.

The t-stat should be about $25 from the dealer, and a waterpump about $120. Get these replaced before you do anything else, ie. driving.

You have some other issues going on as well. Your secondary isn't coming on, your downpipe is getting overly hot, and you see your exhaust internals red. Your turbo may controls may not be functioning correctly, or your secondary is on its way. As for the glowing exhaust, that sometimes can mean you have an issue with running lean.

 

I will bet $10.97 that one of your fans stopped working. Usually the one under the Intercooler is a good bet.

 

Funny how you don't think that replacing your radiator will help your problem. Maybe it is your problem. I can't think of a reason not to put in the radiator, especially since you already have it.

 

I don't think its his radiator. It may mask the problem, but will not solve it. A clogged radiator would cause the car to overheat all the time. A leak in the radiator would be visible, even if it's just a pinhole. I replaced my radiator because of the same reason.

But, he should put it in when he puts in the waterpump and t-stat anyways.