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They call me Garrett
98 RBP V4 STi Swapped RS
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4,091 Posts
Discussion Starter #1,103 (Edited)
Had some more car troubles again. Here's the story:

Headed out to the Detroit Auto Show with some friends on Saturday morning bombing down the highway. We hit some traffic, turn around to take some back roads instead and do some long 1-2 pulls. Revving it out to 8k RPM and gas being pushed through the floorboards. Nothing I haven't done before, but defintely the first time I've been on it in a while.

After those pulls I lose heat (physical in cabin heat) and I knew the car was about to overheat and the gauge started to rise a bit. Pulled it over and checked under the hood. Figured I'd popped a hose as I was having issues with coolant a while ago and one popped off.

Not the case.

Only place that had leaked was from the overflow, which I had also filled up just trying to make sure it wasn't drawing in air before, because I had problems with hearing air bubbles going through the HVAC after I had the engine out last month. Never had any overheating problems though.

Anyways, we leave the car in the Eaton building parking lot for the weekend and come back to it tonight. I pop open the header tank assuming there would be no coolant left and surprisingly there was a tiny amount in the header tank. I fill it up and start the car and it warms up without issue. We burp it and I head home on the highway (maybe 30 minutes from my house) and it stayed cool the entire time. I had the heat blasting just to be safe, but turned the heat off and let it idle for a good 5 minutes in my garage once home and the gauge didn't move.

Now, it appears it MIGHT be fixed.. but my question is what went wrong, and how it went wrong?

It seems like the thermostat and a big air pocket is the thing to blame here, but I don't exactly know how to connect to dots to revving the car out and overheating. Maybe it's a genuine overheating case and the headgaskets are toast? I don't know. I'm lost here. It has overheated once before, genuinely when the bottom hose popped. I'm afraid there's been some permanent damage done.

I'm going to pick up an OEM thermostat tomorrow and see if that helps anything.
 

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Registered
'01 RS '06 WRX swapped
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297 Posts
I've seen it happen when a car pulls hard that the radiator hose will collapse and you could possibly run into issues like this.
 

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Registered
EJ205 1996 Brighton coupe
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663 Posts
Are you using a stock radiator? or a thicker JDm sti radiator?

A lot of pulls in low gears with little airflow, MAYBE it got hot enough to dump some coolant into the overflow tank, and creat a air pocket.
 

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They call me Garrett
98 RBP V4 STi Swapped RS
Joined
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4,091 Posts
Discussion Starter #1,107
JDM STi radiator

Filled the expansion up this morning after it cooled off from last night and ran it for about 25 minutes just sitting in my garage. Got the fans to cycle on and off twice.

Still hear (what seems to be) bubbling in the HVAC. Drove and got into it a bit and the temp gauge didn't move.

I'm still lost.
 

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I ❤ BOOBIES
99 Coupe
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17,008 Posts
If you hear bubbling in the dash, theres air in the heater core. Take the heater core hoses off and put a hose to it, hold the other with your thumb and push the air out, its just air thats trapped in there. If the temp gauge doesnt move at all, you have an issue between the sensor and your cluster because the ecu uses that to control the fans.

Or if it gets worse, hook up a hose and push the system backwards with pressure and push the air out.
 

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I ❤ BOOBIES
99 Coupe
Joined
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17,008 Posts
oh lol, well then its just a bit of air then. Just drive it around for a while, itll usually work itself out, ive only had to put a hose on cars that had clogged heater cores. Dont sweat it if its not running hot, just keep driving it.
 

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They call me Garrett
98 RBP V4 STi Swapped RS
Joined
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4,091 Posts
Discussion Starter #1,112
Odd but your core could have a tiny leak, but im sure you would have noticed your carpets a little wet
Yeah, that's the only thing that's holding me back from assuming it's that. Whenever they fail, they usually let you know. I haven't noticed a thing.

I dunno boys and girls. I dunno :\
 

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They call me Garrett
98 RBP V4 STi Swapped RS
Joined
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4,091 Posts
Discussion Starter #1,113

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Registered
2001 Coupe
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1,256 Posts
Sucks you're having trouble.
I've only been on a non OEM thermostat for one short stint and I'll never do it again. Doesn't sound connected to your issue but I believe the hype now. Good piece of mind sometime.

When you describe your gauge are you referring to the oem cluster one? Someone did the math on how ridiculous the temp has to go for that to register movement but it's only after I've run an oil temp gauge and a water/oil cooler that I'm convinced. I can move the oil temp 40-50 degrees and never see the factory water temp move. I know they are only loosely related now, but I'm more inclined than ever to find a suitable place to run the sensor for water temp that I've had in the engine bay for years now.

Just food for thought... i wouldn't trust the oem gauge as more than an idiot light when diagnosing an issue.
 

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They call me Garrett
98 RBP V4 STi Swapped RS
Joined
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4,091 Posts
Discussion Starter #1,116
Adding in more stuff isn't really the way to solve a problem. If a problem exists something is messed up, and just adding things in isn't going to solve it.

I trust the OEM temp gauge enough to either say "you're good" or "AHHHHH!". There isn't really a need for anything in between for the car as you're either cooling it just fine, or it's not cooling enough. It's not like a boost number that could be better or could be good enough.
 

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Impreza Actual
2001 RS-T
Joined
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1,270 Posts
I don't remember, but do you have the V4 STi radiator or an RS one?

Edit: lol nvm I see you have the STi one. I had weird issues with my l radiator and the spring on the rad cap, but that's obviously not your issue.

Are you going to try a new thermostat? Maybe the water pump could be upgraded to the one with the better wheel?
 
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