[MountainTrek]

Hello,
160K miles 04 2.5xt 4EAT
Overheating when purchased driving up 15mi hill. Found 1/2 of fan unit non-op, replaced. Seemed to fix the problem. A/C broke. lame.

Overheating, losing coolant up to 1/2 gal. per trip up or down 15 mi. hill. No drips, no smoke. Heater works fine; A/C doesn't work; faint smell of coolant but could be from sloppy refill.

Replaced thermostat and new coolant.

Using the no-spill funnel on radiator cap, bubbles when revved and randomly..continually every 10-60 seconds 1-2 bubbles. i let it run for 3 hours, raising engine revs to 3-4K every few minutes.. coolant in funnel burbles and raises level and a couple of bubbles.

I have done this 6-8 times.

Used new fluid and autozone rental block test kit, 3x, fluid stays blue indicating no head gasket leak

chasing this for a while, any suggests?

 

[Kevin]

Certainly seems like a head gasket issue! Especially as there's no external evidence of a leak i.e. that coolant has to be escaping "somewhere"

I guess you've checked the oil for a milky appearance?

 

[MountainTrek]

Oil looks fine tho consumes ~1qt/1500 miles on avg

 

[dave5358]

Head gasket. The coolant is being consumed inside the engine (which is not a good thing). Excess engine combustion heat is being put into the cooling system (another not good thing). Bubbles in the coolant is enough evidence for a conviction. The cooling system is (or should be) a sealed system. Once air is purged from the system by means of the overflow bottle, there should be no more bubbles.

FWIW, the cooling fan issue you mentioned should be fixed, but that was not the problem. As long as your vehicle is moving more than 20-25 mph, the cooling fans are just along for the ride. They turn on with the air conditioning - really needed for that purpose - but they don't contribute much to actually cooling the engine. Natural air flow through the radiator should be adequate.

 

[ForesterCub]

I concur with Dave - virtually certain to be a head gasket issue.

The good news is, once repaired with MLS gaskets, it's usually a permanent fix. With over heating issues such as you've had, particular attention should be given for signs of both head and block warpage.

Two tests you can / should do - pressure test cooling system and pressure test cylinders. These will give definitive head gasket failure (or not) results.

These 2 articles are very informative. I highly recommend reading them if you hacven't seen before.

https://allwheeldriveauto.com/subaru-head-gasket-problems-explained/

https://allwheeldriveauto.com/subaru-head-gaskets-problems-explained-part-ii/

 

[MountainTrek]

Well I guess I'm going exploring the Forester engine internals...

Any recommendations as to where to purchase kits with the necessary parts for head gaskets, timing belt and water pump? I know 10 places for BMW parts but not Subaru.

 

[Inactive_55959]

If you want the repair to last: I would send heads out to a machine shop to verify flatness and perform any necessary resurfacing professionally. While the heads are off - probably a good time to verify that all is well with the valvetrain. Probably a good idea to have the shortblock tested for trueness as well since you mentioned that the motor got hot. Depending upon how hot it got and for hoe long ... you might also want to look into the shortblock’s general health.

 

[Kevin]

@MountainTrek

Contact Jackie (SubaruPartsGirl) from supporting vendor Annapolis Subaru: https://www.subaruforester.org/vbulletin/f125/

Jackie looks after our members and really knows her stuff!

 

[Greytimberwolf068]

Did you check for any small cracks on the radiator, that is what killed my 346k miles 02 forester. You might not see it when the rad is cool but under pressure it can push the coolant out and air in.

 

[vtdog]

We used this product on my son's '02 Forester: https://www.kseal.com/ which had leaky head gasket which was common in his model year
It ran for over 40k miles without issue after treatment until he sold it with about 150000 miles and bought a new one

I know that many people are against coolant system sealants, but its a $ 15 investment vs $1500 for head gasket if you have it done (including water pump). Its hard to be more broken, than broken