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Old 11-19-2022, 12:45 AM   #1
Scooby Newbie
Member#: 269617
Join Date: Jan 2011
Chapter/Region: RMIC
Location: Englewood, CO
2007 WRX

Default Good ol Over Heating - 2007 2.5 WRX 122k

Hey Everyone, I have a 2007 wrx with 122k on a totally stock motor. I bought it from a dealer that does salvage to rebuild sales. It was in a front end accident and rebuilt. I've had it for a week and drove it 20 miles from where I bought it without any issues, drove it to get the emissions done, to work, lunch and back, no issues. BUT I was stuck in a winter storm with stop and go traffic out here in CO and it started over heating.

The car has a koyo radiator but it looks like possibly after market fans (not sure how to tell). The koyo radiator may have been the one that was in the crash as it has two really good dents in it (unknown).

I had it towed to my house because I didn't know what was going on but here's what I've found out today -

What I do and don't know (the facts):
1. It has green 50/50 coolant in it, probably from AutoZone.
2. The upper rad hose def has a tear or hole in it and needs to be replaced. I could feel fresh coolant every time I ran my gloves around it and it was making a hissing noise.
3. The coolant was still clear after the over heat (not milky).
4. I don't have history on the water pump/timing belt so that's getting replaced (ordered a Gates kit that will be here this week).
5. As stated earlier, I don't know about the fans.
6. The radiator may have core damage from the dents, it isn't physically leaking.
7. I just retested in my garage and the fans came on for the first time while idling at 204F, stayed on until the car started over heating at 219F (repeated highway failure).
8. The heater works great in the car so I'm guessing the heater core is NOT plugged.

Steps in the incoming week(s)
1. Going to replace both upper and lower rad hoses and bleed air from system.
2. Going to get OEM fans
3. Going to test for hydrocarbon/combustion gas from the radiator/coolant.
3. I've heard the blue coolant long term is the way to go for corrosion protection, when I replace the water pump and timing belt, I'll use the genuine coolant after a flush.
4. I may also test compression but that might not tell the whole story.

I'm creating this post to be thorough, create a good historical walk through when I do solve the problem, and to crowdsource some feedback/opinions.

Thanks everyone!
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Old 11-23-2022, 10:22 PM   #2
Scooby Newbie
Member#: 532253
Join Date: Nov 2022

I have a 2005, and I had to replace the fans a couple years ago due to a bad fan motor. It's tricky troubleshooting those because they come on at different speeds (mph), a/c on or off, and Temps. Green antifreeze is okay if it had the subaru additive in it...hard to know. I think otherwise it's bad for the aluminum waterpump. If fluid is low, it may be a small rubber line somewhere that is hard to see.
Snowcat021 is offline   Reply With Quote
Old 11-28-2022, 03:56 AM   #3
Scooby Newbie
Member#: 27525
Join Date: Oct 2002
Chapter/Region: SCIC
Location: Orange County
03 wrx wagon


If it had a koyo radiator chances are it's thicker than stock, that's probably why the fan was replaced with thinner fans. The stock fans barely clear the hose with a thicker radiator. Over time as the hose weakens it'll bulge and lightly touch the fan. The hose shrinks when things cool down. Check closely for wear marks.
NickVu is offline   Reply With Quote
Old 11-28-2022, 05:34 PM   #4
Scooby Guru
Member#: 487
Join Date: Nov 1999
Chapter/Region: TXIC
Location: Greatwood/Sgrlnd
1998 /2005 STunIcorn
Acadia Green RS-T


are u having to re-fill coolant to proper level a few times?
AliBenn is offline   Reply With Quote
Old 12-08-2022, 04:56 PM   #5
Scooby Specialist
Member#: 50902
Join Date: Dec 2003
Chapter/Region: RMIC
Location: backroads
$$$ Green


Should definetely change out the T-stat while you're in there, just mentioned becuase I dont see it on your list. It's possible that with the hole in your rad hose you might have just trapped some air in there. Also, I'll be in Englewood to check progress on my build at HTC this coming Saturday, if you're interested in getting another set of eyes on it shoot me a pm.
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