Time to give up?
 

After a couple of month of not sitting my engine developed a couple of problems:
1. Oil pressure light comes on at idle. It only starts doing it after warm-up (~10 minutes of driving) and it stops coming on after ~40 minutes of driving. I can understand why pressure is higher with cold oil, but why pressure gets higher after 30-40 miles of highway driving is beyond me.

Anybody cares to provide an explanation?

The oil pressure switch is an aftermarket one (Warner), I don't know exact pressure it comes on. The factory one is supposed to be 2psi, but that seem to be an awfully low pressure. Besides the aftermarket switch worked fine for 6+ months.

I've measured the oil pressure - it is about 8-10psi at idle (hard to tell with my gauge) and hits it's upper limit of 85psi at ~2400 RPM. The idle pressure is a bit low, the spec is 14psi. The engine has 170k on it, oil has 1k on it.

There are no abnormal noises from the engine - it sounds just fine.

2. Coolant started overflowing from the expansion bottle. Temp gauge is steady, never overheated. I think I could see occasional stream of air bubbles coming through the expansion bottle, but it's not steady enough to say for sure it is a leak from cylinders.

The engine had a long history of coolant loss to oil, even had head gaskets replaced 50k miles ago (with no noticeable effect), but pushing coolant out of expansion bottle is something new it developed after a couple of month of sitting in garage.

I did do a cylinder air leakage test, mostly out of curiosity to see if the engine is worth any repair effort. None of the cylinders visibly leaked air to coolant. The leakage rate results are:
Cyl 1 - 18%
Cyl 2 - 15%
Cyl 3 - 16%
Cyl 4 - 12%
Cyl 5 - 12%
Cyl 6 - 15%
That's cold engine with 170k on it. I'd be interested to compare it with a low-mileage engine.

So my choices seem to be
1. Get new oil, new oil pump, new O.E. pressure switch, new head gaskets. Lots of work with uncertain outcome.

2. Get new used engine with new seals, oil pump, pressure switch etc. Even more work, fair bit of money with also uncertain outcome.

3. Make a tax deductable contribution to charity... No work, certain outcome.

1) I think the oil pressure comes back up after the oil completely warms up after about 40 minutes. The clearance in the oil pump are very small. The oil pump I think is marginal. I thnik there must be wear. When the oil is cool and the engine metal hot it has more clearance. After the oil warms up the clearances are okay.

2) That I think is still a head gasket leak.

If you want to try and keep it running then change the oil pump and put some of that coolant sealer in. This is the stuff that's dealer sold for the 2.5L engines with head gasket leaks.

How did you do the air leakage test?

What kind of oil are you running? Go back to an OEM switch.

Who changed the head gaskets?

Have the coolant tested to see if there are hydrocarbons present.

Mineral oil 10w40, 1.3k on it. Going back to OEM switch will only hide the problem and may destroy the engine since the pressure is definitely too low - I should have 14psi, I have less then 10.

Any particular recommendations - Alumaseal or something else?
I obviously don't want to ruin radiator by trying to resurrect the engine...

Holy crap.
I was gonna say "never give up, never surrender," but man, you might need an overhaul.

Head gaskets changed at 50K? What did they do to that machine?

There are tools similar to compression testers, but they rely on compressed air and they measure the rate the compressed air leaks at a stationary engine. The benefit of air leakage tester is that you get to hear where the leak is - valves - inlet manifold, exhaust, pistons - oil sump or gaskets - see it in coolant.

I'd recommend finding a lower milage used motor and drop it it, you can do it in a day, and would probably cost less than replacing the head gaskets, oil pump and seals on your current motor.

if you are interested there is a low mileage 94 engine listed on ebay with a FWD tranny attached. claims to have 28k on it. Price is at 1800.00 with no bids yet.

http://cgi.ebay.com/ebaymotors/ws/eB...sPageName=WDVW

good luck

Yes I tried to do this to my used engine and had some success. How do you hold the piston at top dead center so the valves stay closed?

Well I really do not know what is in the stuff. I am talking about the sealant available from a Subaru dealer that is used in the 2.5 engines. This was developed to help the lekaing head gasket problem on the 2.5L engine. I used some of this recently in a 2.2L for a Legacy. It can't hurt the engine or coolant system as all the materials are the same in the engines, 2.2, 2.5, 3.3.

I used a cheapo tool from harborfreight. It operates at 30-35psi.
At this pressure the engine does not rotate by itself if the piston is reasonably close to TDC - I really did not have to hold it down or to search for exact TDC position.