Temperature Gauge goes up when driving uphill 08 LGT

Hi guys! I am new to the forum so please excuse me if I am not posting right. I live in Europe and had imported an 08 LGT AT from the states last year. Its a great car and I love driving it especially here, but Since the beginning of the summer I am having an annoying problem with it and i hope you guys can help me.

There arent many GTs here and I am sure it could be a typical issue with it which is easy to fix but they dont know much about it at the dealership here.*

Before I explain the problem I just wanted to say what I have done with the car: cobb downpipe with cat back, stage 2 maps on the AP and some other not so important upgrades. I dont think any of these would actually cause the problem but who knows.

On a hot day when driving uphill in the mountains for example I noticed that the gauge for the engine temperature goes up almost to the last white mark right before the red zone. It never overheats but stays there until I slow down or start driving downhill. I should mention that this happens when I drive a bit heavy. So, I had watched on the access port the coolant temperature when that happens and it goes up to 215-217 F and the gauge goes up. The other thing I noticed is that it only does this when driving uphill. On a flat road I can drive as fast or as hard as I want and the gauge would never move.*

These are the repairs I have done since then in a desperate attempt to fix problem and none of them worked: first changed the thermostat and flushed the system, changed the radiator and the waterpump, both radiator caps, and the head gaskets on both heads. I thought the last one would fix the problem but no luck. I am not loosing any coolant, i cant see any leaks jn the system, and I also tried bypassing the whole cycle for the heater, in other words drove the car without coolant going on the heater for couple of days and it seemed to be ok until today when same thing happened.

I dont know if this is normal for these cars on hot days driving up the hill full power or not but it doesnt seem right to me. I was also wondering if the downpipe and the increase in power could require better cooling, bigger radiator, etc.*

I would really appreciate it if you any of you with these symptoms can share how they had their GT fixed or at least give me any other ideas to try. Thanks in advance!

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Now that we've got that covered.

 

The temp needle shouldn't be moving higher than halfway, regardless of power level. If the thermostat is the appropriate part, the coolant flowing through it should be enough to cool the engine.

 

My next question is, how did you fill the system? what I do is fill the radiator first, put the cap on, then fill the turbo res, leave cap off, run engine, fill as necessary. jacking the pass side of the car up while doing so can fill it a bit more.

 

Do your electric fans work properly? do they come on at all, like if you turned the a/c on?

 

Even under the heaviest of loads and romp sesh, like on a dyno, the gauge shouldn't move, yes even on a modified car. There are aftermarket radiators available from mishimoto and koyorad but you'd need an external oil cooler with thermostat for the ATF fliud.

What he said.

 

Make sure you don't have a air bubble in the cooling system.

 

When I put the new short block in. I left the cap off the turbo tank and the right front corner jacked up for a few hours while I went and got more coolant.

 

I used some left over Peak and Prestone from when I replaced the timing belt years ago and topped it off with some new Peak Global pre-mix. The gage never goes above 1/2.

 

You can see the air bubble in the coolant if you lok in the tank.

 

I checked the tank over the weekend after the car sat overnight and it was just below the neck.

Wait are you guys sure Subaru designed their cars to go uphill???

That is really weird that you still have this problem after changing the thermostat, the water pump, the radiator, and the head gaskets! And this is an 08 .

I can only think of air bubbles at this point.

 

Off topic, in which country do you live? Did you install the cobb downpipe yourself?

I'm having the same issue with my 05 GT. I took it to the dealership ( having just bought the car from them a few days before) and they replaced the same things as you, and are currently replacing the heads.

 

Your post is making me worry that either the mechanics messed up burping the system twice and all the word did not need to happen, or that even after replacing the heads the problem will continue.

 

please keep us updated with how your problem gets fixed

Most people dont understand how to properly fill an burb a turbo subaru system with two fill caps.

Thank you all for the replies! I did burb the system exactly like max capacity suggested. I will try one more time today and let you know but I highly doubt it it would change anything? Could it really be the heads? Do you have any more suggestions?

had similar problems and did pretty much everything you did and turns out my heads were warped.... well i knew they were warped after i replaced the head gaskets and the temp still rose

had similar problems and did pretty much everything you did and turns out my heads were warped.... well i knew they were warped after i replaced the head gaskets and the temp still rose

 

 

 

ouch.

keep us posted on your burping and future temps. welcome to the site.

My car tends to overheat like almost at H if I have been flooring it often and turning at a high speed and possibly flooring it while turning. I seem to have some oil in the coolant, but no coolant in the oil nor does the overflow tank overflow or rise above the normal point during the overheating.

 

I will flush my coolant soon but curious if the 5eat tranny cooler in the rad is leaking oil back into the coolant or if the heads are indeed leaking allowing oil to mix.

 

OR if someone put oil in the coolant purposely to cause a much worse overheating issue to make money (never flushed coolant since I bought the car).

Overheating that high can warp the heads.

 

Any time you remove the heads they should be checked for flattness.

 

If you had a overheating problem, they must be checked for flattness.

Are both fans kicking in? Turn on your AC and see if both come on.

I hate to say it but it sounds like a blown head gasket problem....your exhaust is blowing into the radiator and pressurizing it.....I bet if you look into your coolant reservoir while idling, you'll see an occasional bubble burp into it from the overflow hose....and I bet that burp will smell like exhaust....reason I know this is cause I had the same problem with a 2002 H-6....

 

Hopefully I am wrong, but I'm afraid it won't be an easy fix.

Thank you for the replies and all the suggestions. I am sorry for the late reply but the car was with at the shop for more than a week. They did all sorts of tests to it and at the end installed a separate cooler for the transmission oil. That way there is no heat going to the radiator and it seems to work for now. I am hoping this will solve the proble but was wondering if anybody had experienced this and found a separate cooler to be the answer.

 

I will post again when I test the car for a little longer but it seems to e ok for now.

Thank you for the replies and all the suggestions. I am sorry for the late reply but the car was with at the shop for more than a week. They did all sorts of tests to it and at the end installed a separate cooler for the transmission oil. That way there is no heat going to the radiator and it seems to work for now. I am hoping this will solve the proble but was wondering if anybody had experienced this and found a separate cooler to be the answer.

 

I will post again when I test the car for a little longer but it seems to e ok for now.

So if I read your first post right, you can bring the car up to temp, not drive it heavily, and not have this problem happen while going uphill? That's what bothers me; if you can beat on it everywhere except for climbing hills and not have it overheat, I wouldn't be thinking headgaskets, I'd put my money on an air pocket. Keep us posted.

Yes, exactly.... It only overheats when going uphill. The rest of the time I can drive in the red for a long time and nothing would happen(not that I would do that).

 

I did change the HG a month ago and didnt help the problem so I would think it is something else. Now with the transmission cooler it seems to be doing a lot better but I will be testing it in the mountains over the weekend and will let you know how it does.

 

My questions was if any of you had a cooler installed for the transmision oil and if it is likely to help cool the temperature of the coolant. thank you

I have a 2009 LGT Limited w/94k miles. (Completely stock).

I commute 70 miles/day with NO tendency to get hot with aggressive driving, however, the temp gauge will approach, and get to the beginning of the 'red zone' during steep canyon road climbing.

There are no mechanical issues such as head gasket leakage, and all factory recommended maintenance is completed on time.

Maybe there was little response to this because there are not many mountains for this type of driving outside of Utah and Colorado(?)

Three questions:

1. Has anyone had any experience with so called performance coolants like 'Engine Ice'?

2. Regarding the idea of using an auxiliary oil cooler; does that provide adequate cooling for the auto trans? Are these used to avoid cooling trans fluid with the radiator, or used in addition to radiator trans fluid cooling?

3. A bigger higher performance radiator seems to be the real answer...has anyone had experience with these? Is a bigger, more efficient radiator available without fitment issues? Can I 'have my cake and eat it too'?

You should read this:

 

http://legacygt.com/forums/showthread.php/properly-plumb-your-5eat-transmission-cooler-221643.html?p=4872367

I had a similar problem on my 2009 with driving the passes here in Colorado at the speed limit and not romping on it. No one was able to figure this out, including the dealer.

 

I do not know if you are aware of MY2008 and some MY2009 apparently had an engine block foundry problem which led to #4 rod bearing failure due to oil starvation. I point this out because, apparently, elevated running temps can be an early sign of the #4 oil starvation if there is not coolant issue. Do you know if your car was part of this or if repairs were made prior to your purchasing of the car? http://legacygt.com/forums/showthread.php/all-08-09-lgt-obxt-fxt-and-sti-owners-85483.html?t=85483

 

My 2009 spun #4 rod bearing @ 18 K miles after noticing the aforementioned temperature variation. It was determined that my engine was one of the MY2009 which got a bad block/rod bearings.

t^Lewis7

My engine was rebuilt by the dealer @22317, then @23108 they replaced the short block. I had read about the foundry problem, but the Service Adviser insisted they didn't know the cause.

MrTris...thanks for the trans cooling info.

t^Lewis7

My engine was rebuilt by the dealer @22317, then @23108 they replaced the short block. I had read about the foundry problem, but the Service Adviser insisted they didn't know the cause.

MrTris...thanks for the trans cooling info.

 

Very good! One less major thing you can likely check off the list. Hope it turns out to be something simple like a faulty sending unit or temp gauge.

 

By the way, I do have the smallest Long Tru-Cool transmission cooler (4451) hooked up in series after radiator cooler with the air flow blocked off until I get a chance to instal the Derale thermostat and have noticed that the engine tends to run cooler. Hope adding your tranny cooler helps.

I wonder if the fins are coming unbonded from the core.

 

My old Civic had that issue. It would gain temp going up hills.

 

Try pushing on the fins of the radiator. See if they move?

 

The car ran fine, now it gets hot going up hills. Putting a trans cooler is a bandaid, fix the problem.