Best high mileage oil for 2004 Forester XT with EJ257

[va_life]

There is an unknown oil leak on my 2004 Forester XT where it is dripping onto my passenger side exhaust manifold rather slowly. I replaced the valve cover gasket and half moons just 50k ago along with the turbo oil return line.

I am short on time and would like to know if HM oil might work to stop the leak until I can find the time to get to it.

What is the latest and greatest HM oil in 2025?

Thanks!

 

[cptbarkey]

No oil or black magic will stop your leak. Fix it right. Its probably the turbo line again, but like my first statement, nothing will substitute proper diagnosis.

I used to have the same year XT, nice car and its a keeper. Strange that it has an aluminum hood.

 

[va_life]

If it's a valve cover leak then I don't see why this car would be any different than any other car being relieved by high mileage oil.

Diagnosis is cool and all, but still need to get by for now. If it's the return line again well that is a different story. I had no idea that the hood was aluminum actually.

 

[himemsys]

There is an unknown oil leak on my 2004 Forester XT where it is dripping onto my passenger side exhaust manifold rather slowly. I replaced the valve cover gasket and half moons just 50k ago along with the turbo oil return line.

I am short on time and would like to know if HM oil might work to stop the leak until I can find the time to get to it.

What is the latest and greatest HM oil in 2025?

Thanks!

I compared several VOAs of high mileage oils awhile back. They are on their own tab in my VOA Database. Based on oxidation (which some believe the additional seal conditioners contribute to oxidation levels), Mobil 1 and Valvoline are the two with highest virgin oxidation.

 

[Rand]

those cars are known leakers they leak everywhere from everything unless you keep up on it.
probably should clean it up then check it fresh to see whats leaking.

I'd go with the thickest high mileage oil you could find..
maxlife 10w40 etc. Prefer synthetic in that engine.
might slow it down.

 

[Corollaman]

The only high mileage oil that has ever stopped or reduced an oil leak for me was valvoline maxlife. I went up one viscosity from what the vehicle called for and it worked for me.

 

[JavierH19]

Pennzoil high mileage oils tend to do pretty well. Home depot sells them.

 

[ltslimjim]

Regulator Valvoline MaxLife in the all red bottles have helped me in the past. Not a fix, but possible to slow a weeping leak.

Others have reported success with other high mileage offerings by other brands.

With regard to Valvoline, anecdotally I’ve noticed better results using their red bottles synthetic blend rather than their full synthetic in the gray bottles.

 

[OilStainedNapkin]

Valvoline maxlife the goat high mileage oil

 

[Lawnman23]

I can personally vouch for Castrol GTX High Mileage syn-blend (green jug) resolving a weepy rear main on my 98. I used 10w-40.

Heard plenty of good things about Valvoline MaxLife HM as well, also a blend.

 

[bluesubie]

Agree with the 10W-40 recommendations. Don’t know if that will help your leak issue though.

 

[MetalSlug]

Valvoline synthetic blend HM or Mobil 1 HM