Hi can anyone help Forester 2006 overheating

[spif]

I had a new radiator fitted about 4 weeks ago (not Subaru) and after about 3 weeks I broke down as all the coolant leaked from a hose to the engine. My mechanic fixed this but then after 20 to 30 kms whens slowing or idling the temerature went up to the top. He then changed the thermostat valve but I still have the same problem. When it overheats the coolant in the expansion tank is bubbling. when it cools the coolant retracts and is not visible in tank therefore I am adding water. If anyone could give any suggestions I would appreciate it. Im in Saudi and there are not many mechanics I trust to doa good job.

 

Thanks in advance

 

Spif

[Dj7291993]

I'd make sure the fans are plugged in. Would have been disconnected for the radiator, and they're easy enough to check.

[porcupine73]

Hi sorry to hear about that. It's possible there's just air trapped in the system. But the bubbling coolant in the overflow tank is generally very bad. It may mean the head gaskets are shot, which may have happened when the coolant leaked out and it overheated. What is now happening is exhaust gases are blowing into the coolant, which results in the bubbling in the overflow tank.

Edited December 29, 2015 by porcupine73

[spif]

Fans seem to be working. I agree about head gasket but the oil looks ok and it only overheats after about 20 Kms. Is that a common symptom of head basket? Mechanic rekons head gasket ok. Thank you for your help.

[porcupine73]

Well everything else aside if it's blowing bubbles in the overflow that's bad. The oil may be unaffected, i.e. the oil passages in the head gasket can be fine while a coolant passage could have failed. Because the gases are coming from somewhere. If it's just air trapped it should stop eventually provided the overflow is kept plenty full so that when it cools it can draw in more coolant. Otherwise it could be the exhaust gases blowing into the coolant. And the fact that it leaked out most of the coolant due to the bad hose is not a good indicator for the head gasket integrity.

[golucky66]

Hi sorry to hear about that. It's possible there's just air trapped in the system. But the bubbling coolant in the overflow tank is generally very bad. It may mean the head gaskets are shot, which may have happened when the coolant leaked out and it overheated. What is now happening is exhaust gases are blowing into the coolant, which results in the bubbling in the overflow tank.

While I do agree with your statement about the bubbles being bad, but if the car was overheated and spif checked it while the car was still red lined hot, then the bubbling could simply be the coolant actually boiling from the heat. Which makes sense as they said once the car cooled the coolant retracted back into the radiator to the point where there was none in the overflow.

 

While the overheating may cause a bad head gasket I wouldn't connect the dots that rapidly. But from steps already taken including the fans, t-stat, hoses etc. Imo there's only a few things left.

A ) The cooling system still has air in it. 

B ) The radiator is actually bad (defective) and it may be clogged causing restricted flow

C ) Head gaskets.

 

Just to make sure, do you have heat in the car when the engine is at normal operating temperature? If not, there's air in the system.

 

Unrelated as your radiator is new, but I once had a 00' OBW that was overheating...Tried everything, turned out to be that over 50% of the fins in the radiator were missing and it wasn't be able to dissipate heat fast enough at idle or below 30 mph. Never leaked a drop though, quite funny.

Edited December 29, 2015 by golucky66

[spif]

Thanks once again for suggestions. However I started the engine last night and for a few seconds it sounded rough and the body shook. I've not heard the engine like this before and think this is again sounding like head gasket. Back to the mechanic tonight for him to investigate. Cheers.

[idosubaru]

ideally this happens:

1. engine is properly burped

2. coolant is carefully monitored to check for coolant loss in the radiator (not due to boiling over), bubbles in overflow (not due to boiling).

 

don't give much weight to archaic headgasket tests like oil/coolant mixing or do compression tests - those are not the failure modes of this engine. I don't ever bother looking there, no need to. if they fail that way it's because they've been worked on before or are so bad the diagnosis should be obvious.

 

rough and shaking is a cylinder misfire, not really that alarming, most of us have seen that 1,394 times. can be caused by headgaskets or nearly any other component.

it does seem ominously like a HG but don't let shaking be a confirmation of diagnosis.

 

bubbles in the overflow while the gauge is not in the red/overheating significantly are nearly positive HG signs.

 

there are hydrocarbon testers for testing the coolant for exhaust gases.  there's a chemical test which is decent and electrical testers much more conclusive.

 

when you get around to repairing it:

1.  use EJ25 turbo headgaskets

2.  resurface the heads

3. do not skip those two steps for any reason

[spif]

Thanks for advice.

[bakedpotatoechips99]

I just replaced head gaskets on a  EJ251 SOHC engine in a '03 Forester. I used Cometic MLS .051 gaskets.

 Really high quality. I also gently block sanded the heads and block with 220,280,320,400, and finally 600 grit sandpaper

 to remove the old gasket material as Justin Stobb at awd auto in Seattle suggests. I did not resurface the heads, only because I was at a loss for time,

  as winter was coming fast

 and I was doing the repairs out in the street. Otherwise I would have had them resurfaced. And, to be honest, I knew that Cometic gaskets are of such high quality,

 that any slight warp of the head would be significantly negated by the Cometic MLS. JE pistons also makes an excellent multi layer steel head gasket. The Subaru turbo head gaskets are also multi layer steel I think. But the standard Subaru OEM are crappy single layer, which do not have the reliability or longevity of multi layer steel gaskets. Also, do not overlook the crossover coolant pipe on top of the engine under the intake manifold, get new o rings and black silicone to re seal it before re installing the intake manifold. One more thing, you can lock the flywheel, by removing the plastic inspection cover to expose the flywheel teeth, with a large flathead screwdriver or small pry bar or similar tool in between one flywheel tooth and the engine block to prevent movement while loosening the front crank pulley/harmonic balancer, after removal of the intake manifold,

  instead of using a special pulley locking tool which is either too expensive or too hard to get or make.