Overheating issues

[LDadrenaline]

really not sure where to post this, if it needs to be moved thats fine

2006 wrx wagon. vf39, 05 STI drivetrain swap.... plus much more of course

having major overheating issues on the track. Only able to run like 1-1.5 laps before the needle just soars to the red. I have upgraded to the mishimoto radiator and am running my heater already. thermostat has been drilled out, both caps are 1.3bar. I have a splitter/undertray on that extends back behind the oil pan, and I have the greddy air panel diffuser thing on the top that connects the bumper (http://forums.nasioc.com/forums/showthread.php?p=23777871#) to the radiator. Running probably 1/4 dexcool, 3/4 water/water wetter. fans work as well. removed the grilles and took off my hella supertones to try and get even more air in.

really not sure what could be wrong still. Only runs hot on the track, not on the street. The A/C condensor is pretty ****ed up on the bottom half, but because i have air being forced through from the top and bottom, i dont see how it could be the problem still. Also because I really opened up the top half to air (which looks fine) it doesnt make sense.

what soultions should I be looking at here? any help is appreciated

[treekiller]

could be head gasket, (not that I wish that on anyone) but having worked on several overheating subarus I know how fickle the gaskets can be. it might just take a couple G's to get the air bubble to fall into a place where it prevents flow. Nice thing is the heads are short and don't often warp.. although the single overhead cam engines tend to be better.

check for telltale signs air bubbles in the coolant, or disappearing coolant, white smoke, they don't often milk up the oil or vice versa. it's usually between the water jacket and cylinder. but without pressurizing the cooling system it's going to be hard to diagnose.

I've seen 2.5, 2.0, and 2.2 motors all shit the gaskets.. and more often then not the overheating is intermittent. I thought the STI semi closed deck was supposed to be better, but who knows.

[Jordan Y.]

Are you certain your system is bled completely and free of air? Some systems have high points that like to trap air and make bleeding a pain. An air separator tank setup can be nice to make sure and they're pretty cheap on ebay.

Hate to go there on such a new setup, but what about the headgasket? If it's only doing it at the track maybe you have a head gasket sealing problem under boost/wot. Maybe try one of those hydrocarbon test strips.

*edit /\/\ beat me to the punch, haha.

[Charles]

Are you certain your system is bled completely and free of air? Some systems have high points that like to trap air and make bleeding a pain.



Edit, I was going to agree with air in the system but if it doesn't overheat on the street I find that hard to believe too.

IIRC correct fill procedure for the suby is filling from the highest opening to the coolant system over on the turbo side....... heater on/fan on high is prob a good idea too

[Mars_302]

are you front mount or top mount still?

[jblaine]

Something is broken or you have air in your system (but as Charles said, in that case you would see it on the street too).

I run a FMIC, undrilled thermostat, and have no cooling/diverter panels added on. I ran at Sebring for 4 20-minute sessions in 90F heat.

My experience with EJ2x headgaskets does not match that of treekiller's at all. Head gasket problems, from all I can tell in the last 9 years of reading forums daily, are very rare on our engines. Most engine builders and tuners alike will recommend the stock headgasket even to 500HP. Who knows though...

[Chuck 98 RT/10]

What rpm are you shifting and what is redline?

[treekiller]

Jblane: I'm not sure if it's related at all to Location (e.g. weather or temp).. but the OLD EJ25 DOHC 1997-1998 was a horror show. you could set your watch by the headgaskets going at 60,000-70,000 miles. (From my communication with some rally guys apparently even JDM cars of that vintage were the same) The SOHC EJ25 solved most, if not all of those issues, but I have seen 2 so far early (02-03) 2.0 wrx DOHC motors let go too, one just in June at a rallycross.. some early 2.2 turbo kitted cars I did were hard on gaskets too.

and I personally cooked a loaned early 2.5RS during a rally. funny thing is 4 years later that same exact 2.5RS came into my shop for another engine, which we thankfully had in stock, and rebuilt with the then "new" gaskets

you are right I thought the multi-peice coated gaskets were the holy grail in solving that problem, but apparently subaru felt it required to beef up the the 2.5 turbo cars. I thought this was in direct response to more Headgasket issues, but I have been VERY removed from any subaru work for nearly 6 years, so please take it with a grain of salt. I've never turned a wrench on a USDM STi engine so I cannot comment with 100% confidence, Now give me an EA82t and we can talk :-)

[Charles]

You thinking cavitation at high rpm Chuck ? or is that still even an issue with modern water pumps/cooling systems?

[Chuck 98 RT/10]

You thinking cavitation at high rpm Chuck ? or is that still even an issue with modern water pumps/cooling systems?

Nope, the heat. A few hundred rpms can make a big difference in maintaining reasonable temps. There really is no need to run every lap like it's a qualifying lap, the pros don't, why should an amatuer?

I don't know anything about the Mishimoto Radiator but if it doesn't have a larger capacity than stock it really isn't much of an upgrade.

He says the thermostat has been drilled out but he doesn't give details. If it's just a 1/4-hole so the air can escape then it shouldn't be a problem, but if the whole thermo is gone then that is his problem. The water is moving too fast through the engine and not spending enough time in the radiator to cool down.

If none of the above applies then I would look at the underbelly. It could be holding up airflow in the engine bay.

[RoadRacer]

I was also thinking cavitation.
Nissan changed the design for the SR water pump because of high rpm cavitation, so it may be an issue with some Subaru's.

Are you sure the Mishimoto has better flow? It may look bigger and better but internally it may be restricting coolant flow.

[LDadrenaline]

i considered cavitation, but one weekend i decided to shift at 5k rpm (usually do around 6k) and it still had the problem. pretty damn sure there is no air in the system, ive opened the cap and refilled quite a few times and also done the squeezing the pipes thing.

thermostat has 6 small holes drilled in it to let fluid by in case it is stuck, but not so much that it flows too quickly.

update from today is that i saw the temps go up a little while sitting in traffic... i was sitting outside a restaurant with the car on and i smelled a little burnt coolant. also when i got back popped the hood and saw the fluid level in the tank (the main one, not the reservoir by the turbo) has risen quite a bit since this weekend with no added fluids.

[Chuck 98 RT/10]

Are you running a 50/50 mix of coolant?

[omgwtfbbq!]

Coolant resovoirs filling up are generally a symptom of a blown HG.

[treekiller]

someone mentioned one of the hydrocarbon test strips, sounds like a good Idea to me. If it is the gaskets, make sure you get them done by someone familiar with Subaru... If the Bolt torquing sequence is not followed exactly it can cause future issues. and it's about the most confusing one I've ever done..

oh here it is (for the old cars, don't know if it's changed)
i know it's no good without the pictures but just for refrence

Cylinder Head Installation
1. Apply a coat of engine oil to washers and bolt threads.
2. Tighten all bolts in sequence as shown in Figure 2 below to 22 ft. lbs (29 Nm or 3.0 kg-m).
3. Then, tighten all bolts in sequence to 51 ft. lbs (69 Nm or 7.0 kg-m).
4. Back off all bolts by 180° in sequence first; and then back them off by 180° again.
5. Tighten bolts 1 & 2 to 25 ft. lbs (34 Nm or 3.5 kg-m).
6. Tighten bolts (3), (4), (5) and (6) to 11 ft. lbs (15 Nm or 1.5 kg-m).
7. Tighten all bolts an additional 80-90°in sequence.
8. CAUTION: Do not tighten bolts more than 90° at this time.
9. Further tighten all bolts by 80-90°in sequence again.
10. CAUTION: Ensure that the total re-tightening angle [in steps 7 and 9] do not exceed a total of 180° rotation

You get that ?

[omgwtfbbq!]

What. The. Fuck.

[LDadrenaline]

if i ever need work done to the car that i cant do myself, i take it to mike over at S&R performance. he is very knowledgeable about subarus, and they have consistently done top notch work on my car


i dont think the headgasket is the problem, i see no signs of leakage anywhere on the engine. most likely will end up replacing the thermostat, getting a crawford water pump, external oil cooler, and replacing a section of the bottom radiator hose with solid pipe (dont know if i posted it before, but a subaru race team found their water pump cavitating under high load and collapsing the hose. fixed it by replacing a 3" section in the bottom hose with solid metal piping).

[treekiller]

That's cool, but since subaru head gaskets don't leak externally, before I spent a penny on any parts I'd do some testing, it's cheap insurance. it'll be a bummer if you pay a ton of money and not fix the problem. I'm glad to hear you have a good scooby tech, they are hard to find! I had to hire a part time dealer mechanic back in the day and he tought me a TON about these unique beasts. like the shop rate clutch change :-) when we were rallying, not a lot was known about the EJ engine in America when stressed.. since, until 1998 no one REALLY raced them here.

[jblaine]

i dont think the headgasket is the problem, i see no signs of leakage anywhere on the engine. most likely will end up replacing the thermostat, getting a crawford water pump, external oil cooler, and replacing a section of the bottom radiator hose with solid pipe (dont know if i posted it before, but a subaru race team found their water pump cavitating under high load and collapsing the hose. fixed it by replacing a 3" section in the bottom hose with solid metal piping).
I think you're way ahead of yourself here, with the possible exception of replacing the thermostat.

You have a problem with the existing cooling system, not simply a wall you are hitting on track with a functioning OEM system. You can't even do 3 laps you said. Something's wrong, not just "not up to the track demand".

What the other Jeff said above.

[LDadrenaline]

well im putting my money on the cavitating water pump and collapsing bottom radiator hose seeing as a suby race team had that problem. instead of just replacing the hose though, i would like to replace the water pump as well just in case that has also gone bad. and because my thermostat is drilled I would like to replace that as well. Also, an external oil cooler can't hurt. For the way I beat on the car on the track, it is definitely a safety precaution.

[treekiller]

Tell us how it works out... I know I'm curious to see.

<the other> Jeff

[Chuck 98 RT/10]

well im putting my money on the cavitating water pump and collapsing bottom radiator hose seeing as a suby race team had that problem. instead of just replacing the hose though, i would like to replace the water pump as well just in case that has also gone bad. and because my thermostat is drilled I would like to replace that as well. Also, an external oil cooler can't hurt. For the way I beat on the car on the track, it is definitely a safety precaution.

Sounds like a good opportunity to back up what the race team claims. Replace each piece one at a time and test in between. Change the pump before you go to the track and if it still overheats you can easily replace the bottom hose and get back on the track same day to test.

[LDadrenaline]

ended up deciding not to replace the water pump, wouldve driven the cost up too much.

doing the thermostat, replacing the pipe, and straightening some condensor fins though. Taylor Durdan over at S&R has a sweet tool to check if there is any exhaust present in the coolant and he said he would test it for me when I take it in next.

I would like to be able to replace each part separately to test, however I don't ahve the money to go out to the track 3 or 4 times *just* to see if one part works. I would rather replace all the possible problems (also takes care of some preventative maintenance) and run it.

[treekiller]

sweet, how'd it work?

[gritt]

I didn`t know Taylor was at S&R with Mike. Cool....