2006 Forester- overheating- headgaskets?

[Stevo F]

I recently acquired a 2006 Forester X with 204K on the clock and receipts showing full headgasket and timing job was done at 160K miles by a local mechanic. I did notice a little oil seepage from the passenger's side headgasket but not really concerned as it's common on the EJ253 engine, but the car runs really well. A couple of weeks after I purchased it, I was checking under the hood, preparing to take it on a 90 mile round trip drive, and noticed coolant was now a little low (never a good sign- had to add about about 6 ounces, but no coolant leaks I could find). I set off on my trip and after about 9 miles after sitting at a light, the temp gauge rose slightly over halfway, then back down again. I pulled off at the next light and, lo and behold, saw a nice stream of bubbles in the coolant overflow tank. I took it back home figuring pretty classic symptoms of an internal headgasket leak. 

Several days later, I took it on the 9 mile drive to my mechanic and about 4 miles in, the needle went almost to the red before I pulled off and shut down for a few minutes. It settled down the rest of the trip there.

My mechanic has had a lot of jobs but did have time to do a hydrocarbon test of the coolant which surprisingly came out negative. he next wants to check into the water pump, radiator, pressure test the cooling system, etc... I also sent over a gallon of Subaru Long Life coolant and an OEM thermostat.

My main question still is what would be causing air bubbles/ pockets to get into the cooling system. It ran about 100 miles before it started losing coolant/ overheating and coolant was full up to the top when I bought it. May some stop leak in the radiator masked the problem? It will be interesting to see what else my mechanic turns up.

[idosubaru]

1.added 6 ounces to the overflow or the radiator?

2. Did any spray out and how low was the radiator (not the overflow tank) after the overheating event? 

3. Was it bubbling or boiling and do you know the difference?

4.  what brand headgaskets and were the heads resurfaced?

5.  Does it have a new Subaru thermostat and radiator cap? This is unlikely but you indicate “no issues” and then experience overheating 9 miles after working on the cooling system. The only thing you did was (maybe - see question #1) remove the radiator cap.  So maybe the radiator cap is suspect. Though I’ve found Subaru radiator caps fairly robust even when they’ve deteriorated and they’re symptoms usually obvious  but when all we have is text to go on….

Heres the two diagnosis's you’re looking at:

A:  It was low due to a slow external leak, tstat, or rad cap failure.  Pressure test is the next step.  It overheated due to being low and you saw boiling, not “bubbling” in the EJ25 exhaust gas sense.

B. head gaskets.  A liquid test was used for hydrocarbons and those are notoriously inaccurate. 

If he used a $$$$$$$$ exhaust gas analyzer then he should test it again

The bubbles are very damning evidence but pressure testing for leaks is excellent move on the mechanics part due to the ambiguity of “bubbles and boiling” and unknowns about how quickly it’s loosing coolant or not and wether that is a causation or correlation to Overheating. 6 ounces low isn’t enough to overheat but again answer question #1.  
 

 

[Stevo F]

On 5/21/2022 at 2:37 AM, idosubaru said:

1.added 6 ounces to the overflow or the radiator? I added it directly to the radiator

2. Did any spray out and how low was the radiator (not the overflow tank) after the overheating event? Actually didn't check it after the final overheat as I left it at my mechanic's before it cooled down

3. Was it bubbling or boiling and do you know the difference? I think this was bubbling, not boiling. Here is a YouTube link (note that the nasty coolant is what came in the car):

 

4.  what brand headgaskets and were the heads resurfaced? No idea as it was 2 owners ago. The receipt indicated heads checked for warpage. IMO they used cheapo head gaskets

5.  Does it have a new Subaru thermostat and radiator cap? This is unlikely but you indicate “no issues” and then experience overheating 9 miles after working on the cooling system. The only thing you did was (maybe - see question #1) remove the radiator cap.  So maybe the radiator cap is suspect. Though I’ve found Subaru radiator caps fairly robust even when they’ve deteriorated and they’re symptoms usually obvious  but when all we have is text to go on…. No idea on the thermostat but guessing replaced with non- OEM. I tried an OEM radiator cap from my other Forester but still had bubbling and temperature fluctuation

Heres the two diagnosis's you’re looking at:

A:  It was low due to a slow external leak, tstat, or rad cap failure.  Pressure test is the next step.  It overheated due to being low and you saw boiling, not “bubbling” in the EJ25 exhaust gas sense.

B. head gaskets.  A liquid test was used for hydrocarbons and those are notoriously inaccurate. 

If he used a $$$$$$$$ exhaust gas analyzer then he should test it again

The bubbles are very damning evidence but pressure testing for leaks is excellent move on the mechanics part due to the ambiguity of “bubbles and boiling” and unknowns about how quickly it’s loosing coolant or not and whether that is a causation or correlation to Overheating. 6 ounces low isn’t enough to overheat but again answer question #1.  
 

Update- my mechanic texted my that he pressure tested the cylinders with a hot engine and found bubbling more from the passenger's side cylinders but some on the other side as well, So definitely a headgasket leak. I'm opting to use OEM EJ255 headgaskets because they are better than the originals (MLS).

 

 

[idosubaru]

No surprise - “Recently acquired” often means prior owner sold at the sign of ominous repairs.

Correct MLS Subaru gaskets. Resurface the heads. Clean and lube bolt and threads.

“Checking” to see if they’re warped is a waste of time.  You don’t need the full valve job many machine shops say you need for a warranty. I tell them I don’t need the machine shop head warranty on a Subaru.

Id install a complete Subaru or AISIN timing kit while it’s apart.  They’re likely original or aftermarket pulleys both of which are failure prone and lead to bent valves which means redoing the headgaskets again to repair.

The timing belts have to come off to replace the HGs anyway so it’s essentially no labor.

Water pump, reseal oil pump, tighten the oil pump backing plate screws, cam seals and reseal rear separator would cover most other major items easily accessible with the engine out and engine apart.  Although timing belt oil pump and water pump are not hard to do in the vehicle either if you want to DIY that later  

The oil pressure switches Leak all the time too and are only like $15 or something cheap. I sometimes replace those preventively if I expect a lot of miles/years/long trips out of the car. 
 

Edited May 23, 2022 by idosubaru

[nvu]

1 hour ago, idosubaru said:

Correct MLS Subaru gaskets. Resurface the heads. Clean and lube bolt and threads.

Second this.  If the previous two were composite gaskets and you're going to MLS, definitely have the heads resurfaced.

[Stevo F]

Thank you. I'll pass that on to my mechanic to resurface the heads. Likely will anyway as I imagine there is warpage assuming the previous owner overheated it.

In the process of the ordering the parts and I found the for the '06 Forester engine, that the Aisin TKF-006 kit is only listed for manual transmission and not auto (like mine). I dug into the OEM part numbers and found the OEM water pump for manual trans is 21111AA280 and for auto is 21111AA290 (this only applies to 2006). Apparently the 21111AA290 was a one year only part and the Aisin kit likely comes with the 21111AA280 part, (which is why they say it won't fit my car). To be on the safe side, I'll order the Aisin TKF-006 kit plus order an OEM water pump # 21111AA290 (OEM is the only thing I would trust other than Aisin) to make sure my mechanic is installing the right parts.

My mechanic also noted that he saw signs that someone put stop leak or some other sealer in the cooling system (not a big surprise!). I'm just hoping that things aren't too gunked up inside the engine and cooling system. I've talked to people that said piece of that sealant gunk can break loose and clog up water jackets or other parts of the cooling system causing more overheating- definitely would not want anything like that to happen! 

 

[idosubaru]

8 hours ago, Stevo F said:

Thank you. I'll pass that on to my mechanic to resurface the heads. Likely will anyway as I imagine there is warpage assuming the previous owner overheated it.

In the process of the ordering the parts and I found the for the '06 Forester engine, that the Aisin TKF-006 kit is only listed for manual transmission and not auto (like mine). I dug into the OEM part numbers and found the OEM water pump for manual trans is 21111AA280 and for auto is 21111AA290 (this only applies to 2006). Apparently the 21111AA290 was a one year only part and the Aisin kit likely comes with the 21111AA280 part, (which is why they say it won't fit my car). To be on the safe side, I'll order the Aisin TKF-006 kit plus order an OEM water pump # 21111AA290 (OEM is the only thing I would trust other than Aisin) to make sure my mechanic is installing the right parts.

My mechanic also noted that he saw signs that someone put stop leak or some other sealer in the cooling system (not a big surprise!). I'm just hoping that things aren't too gunked up inside the engine and cooling system. I've talked to people that said piece of that sealant gunk can break loose and clog up water jackets or other parts of the cooling system causing more overheating- definitely would not want anything like that to happen! 

 

Use AISINs online catalog to look up the kit number you need. edit - I just did and they only listed one for turbo-charged?!  Odd. 

Ive never tried but maybe you can contact them and ask? I’ve heard of people getting responses from them about timing belts before  

That’s wild 2006 has a one year water pump. Still an EJ so it must be the same with a minor difference .

 

Edited May 23, 2022 by idosubaru

[1 Lucky Texan]

Subaru TSB or some such once spec'd the Subaru Coolant Conditioner (relabeled Holt's RadWeld leak-stop) for a generation of cars. That could be the stuff the mech spotted.

[Stevo F]

4 hours ago, idosubaru said:

Use AISINs online catalog to look up the kit number you need. edit - I just did and they only listed one for turbo-charged?!  Odd. 

Ive never tried but maybe you can contact them and ask? I’ve heard of people getting responses from them about timing belts before  

That’s wild 2006 has a one year water pump. Still an EJ so it must be the same with a minor difference .

 

Yes that different water pump has me stumped especially since EJ engines are usually interchangeable between manual and automatic transmission cars (EGR vs. non- EGR is the only other difference I've heard of). I checked Aisin's website itself and they only listed one kit for turbo and the other (manual only). I believe the water pump used with the manual was the one used on al N/A EJ25's from 2007 on, so that's likely why all for the Aisin TKF-006 kits have it (I know that's the kit installed in my 2008 Forester with automatic). Not sure what the difference is, but I don't want to discover it only after everything is back together, so I'll save the water pump that comes with the kit as a spare for my '08.