04 wrx overheated suddenly

[powder]

Hi everyone. 198k miles, and barely any problems later, i'm having an overheating issue. It went from nothing to overheating in a matter of a drive to work. I changed the oil about a week ago, and while it was draining did my routine check over all the fluids. I noticed the coolant reservoir was half full, which i didn't think anything of. Saturday morning on the way home from work, i notice that it's taking some time for the car to heat up, but it finally did and no temp gauge issue. 70 mile drive daily, and i have a specific spot that i know i'm warm by in the winter lol.

So i make a mental note to check the coolant level since i'd had an issue with the heater not heating at idle before. I forgot to check it cuz frankly 19 days in a row of work i was a bit tired. Went to bed, woke up and watched football. Hopped in the car to head to work at about 10.30pm and again, i notice car taking a while to heat up and i'm kicking my own a** for not checking the coolant like i made an obviously terrible mental note of. I get half way to work and i smell coolant. Hmm... weird, glance at the temp gauge, doesn't look different. No more than 3 minutes later, glance back at the temp gauge and it's at the H!! WTF, i was crossing a bridge so i had to keep going, but i pulled over as soon as i could and shut it off.

I get out and open the hood. Lots of steam, coolant all over the engine. I'm trying to trace the direction it came from based on the splatter (CSI taught me something) and it's looking like the radiator. The whole top of the rad was wet but there was just splatter on everything else and around the seams of the plastic part of the rad had puddles of coolant. So i let it cool down and made a stupid choice to turn it around and try to make it a ways before possibly calling a tow truck. Started it, and got half way across the bridge before it was at H again. Stupid stupid me. Pulled over on the other side and called a tow truck. Got it home and today i checked around all the hoses and no cracks that i could feel, so again, thinking it's the rad. I'm hoping i didn't damage anything by overheating it again like an idiot.

So i'm thinking how i can make sure it's the rad. Should i fill it up with water and idle it to see where coolant comes from when it gets hot? I can order a rad wednesday if it is indeed that. I'm sure i won't know if i damaged the engine until i get the leak fixed and drive it some. I'll do a compression test too while i'm at it and see what i come up with.

Suggestions and scathing remarks about my stupidity welcome.

[SD_GR]

Clean it up and look and see, or clean it up and do a pressure test with the car off. The advantage of the latter is that the car is off; however you'll need a tester and if you don't have one (I don't either) you can either pay a shop to do it or rent one maybe.

[powder]

For now i'm driving my truck to work, but i'm thinking to fill it up and take it for a short drive around the neighborhood and see what it does. Stick close to home and carry some water with me. If it's a slow leak, and i feel comfortable running to a nearby shop, i may get a test done.

[SD_GR]

I'd find it remarkable if the rad lasted this long, frankly; I'm on my third at this point and I've barely done 130K miles. However, other things can and do fail so you need to find out what/why/etc. first.

[powder]

Right. It's just kind of telling that it's coming from the exact area everyone else has problems. The seam right below the radiator cap. Tstat was changed with the timing belt/water pump at 110k, so it's not impossible that it's bad at 198k, but i did use the Subaru brand so it would go til the next change which is coming up.

And it is remarkable that it lasted this long by all reports.

[SD_GR]

A long time ago there was a TSB for a rare event, where the rad was actually "OK" but the connection to the top hose leaked only when the motor was running and the car was revving (vibration dependent) and that would generate the same pattern as a failed rad seam. I find this unlikely but mention it. My bet, from what you've said, is on the rad itself.

[powder]

Yeah i have Perrin hoses and clamps, so i doubt it. Well i'll still probably try to make sure it's the rad, but seems i'll be ordering one here pretty soon.

[oguitar]

REV the motor and watch the top of the radiator. If it is cracked it will start pouring out.

[powder]

Good deal i'll try it.

[powder]

Following oguitar's instruction, i filled it with water and it's definitely the radiator. Holding it at about 3k rpms on a cold start, water was pooling and dripping off the radiator right around the seam between the 2 materials. I'll be ordering an aluminum radiator on Wednesday. Probably get a mishimoto.

[powder]

Also what kind of coolant do you guys use? I used regular green stuff when i did my timing belt, but it wasn't pre mix. Do people use pre diluted coolant in their wrx's and what kind?

[SD_GR]

I switched to the blue prediluted from Subaru.

Also, your experience is not unlike Sasquatch's. Please see:

2004 OEM radiator is failing. How long do I have to replace?

as I think you will find useful info in that thread too, including shopping tips and so on.

Since you already have swapped timing belts (and so coolant) you already know about burping the system so I won't bore you with that. Notice though Sasquatch had a bit of a fitment choice to make (that he addressed it seems, but just be aware of the potential) and also remember to check the threads on all the mounting bolt holes for the fans and brackets, to make sure they are OK and if not, buy correct bolts for the new rad, whatever brand you chose.

[powder]

Thanks for the heads up. I'm not familiar with the "burping the system" term but i just basically added radiator coolant to full, then filled the reservoir, then continued to add via the tank near the turbo, until i saw no drop in the reservoir level. It seemed to work well and i never saw a spike in the temps while driving. I did have the one incident shortly after, where at idle the heater wasn't heating, even with the car hot. But i just added coolant and it went away.

I think i've fully decided on the Mishimoto, kind of due to reading that post. That Koyo seems thicker than stock and i guess i'm hoping the Mishimoto isn't. We will see. I'm a machinist by trade so i can rig something up if the fitment is off. I'm kind of sad i have to do this right now because my next timing belt change isn't do for another 10k+ miles, but it will give me a good idea about whether i have to do the head gaskets at these same time, from overheating a high mileage engine. I may end up just doing them anyways depending on the results from the compression test i'll do next week. Hoping to get this done by next friday the 6th, cuz i'm Maui bound after that!

[SD_GR]

Thanks for the heads up. I'm not familiar with the "burping the system" term but i just basically added radiator coolant to full, then filled the reservoir, then continued to add via the tank near the turbo, until i saw no drop in the reservoir level. It seemed to work well and i never saw a spike in the temps while driving. I did have the one incident shortly after, where at idle the heater wasn't heating, even with the car hot. But i just added coolant and it went away.

It sounds like you had an air pocket but got lucky. I'd rather be lucky than good any day. However, in case you run out of luck this time round:

Overheating problem

Also! Is your car manual or automatic? If it's automatic, the replacement radiator may NOT include a cooler for the transmission fluid. If you have a manual, you don't care about this at all.


I think i've fully decided on the Mishimoto, kind of due to reading that post. That Koyo seems thicker than stock and i guess i'm hoping the Mishimoto isn't. We will see. I'm a machinist by trade so i can rig something up if the fitment is off. I'm kind of sad i have to do this right now because my next timing belt change isn't do for another 10k+ miles, but it will give me a good idea about whether i have to do the head gaskets at these same time, from overheating a high mileage engine. I may end up just doing them anyways depending on the results from the compression test i'll do next week. Hoping to get this done by next friday the 6th, cuz i'm Maui bound after that![/QUOTE]

[SD_GR]

Thanks for the heads up. I'm not familiar with the "burping the system" term but i just basically added radiator coolant to full, then filled the reservoir, then continued to add via the tank near the turbo, until i saw no drop in the reservoir level. It seemed to work well and i never saw a spike in the temps while driving. I did have the one incident shortly after, where at idle the heater wasn't heating, even with the car hot. But i just added coolant and it went away.

It sounds like you had an air pocket but got lucky. I'd rather be lucky than good any day. However, in case you run out of luck this time round:

Overheating problem

Also! Is your car manual or automatic? If it's automatic, the replacement radiator may NOT include a cooler for the transmission fluid. If you have a manual, you don't care about this at all.

Hoping to get this done by next friday the 6th, cuz i'm Maui bound after that!

Maui sounds absolutely tragic, hang in there...