I recently did headgaskets on a customers car ( 2001 obw 2.5 sohc 98,000m) and it seems to be going thru oil pretty quickly. I did the engine a month ago and when it came in for a cv joint I checked the oil and it was barely on the end of the stick. I inspected the crosshatching/ cylinder walls while the engine was apart and they looked good and other than the oil that was seeping out the bottom of the gasket I dont think it had a previous oil consumption issue.

I had a full valve job done with new valve stem seals and I am worried that the seals were installed incorrectly a or are defective.

Any thoughts?

my subaru with "minimal" (seeping sep plate etc) oil leaks with 180k used a quart every 1500 miles. Pulled the heads on that motor after it blew a HG and still had beautiful crosshatching. I drive 400-500miles a week so a quart goes quick.

Assuming there are no exterior leaks, the initial level may have been slightly low. Check spark plugs for signs of oil. This could also be a stuck PCV valve or clogged breather hose.

My 2001 Forester with 112k miles seems to have transformed itself into a 2-stroke engine.

I check and fully expect to need to top up my oil level monthly. I am guessing it burns a quart every 2k miles or so. Smokin like a banshee with a cheap cigar habit.

 

Assuming there are no exterior leaks, the initial level may have been slightly low. Check spark plugs for signs of oil. This could also be a stuck PCV valve or clogged breather hose.

 

definitely triple-check all hose routing after any major work and try a new PCV valve.

When i do head gaskets i remove the pistons and clean out the oil ring lube holes. The bottom holes are always pluged up and makes for poor lube on bottom of piston. Witch may cause it to burn oil or hurt piston i knurll them when they are out to tightens them up in bore.

by knurl do you mean remove them and clean out the gunk?

Ive never removed pistons from these engines. Do you need to split the case?

Ill check the PCV valve and related hose routing.

PCV valve can cause a lot of oil consumption.

By knurl i mean put a cross hatch on outside of piston to make it tighter in bore i have a machine to do it makes a world of differance no more piston slap ever again.

Check to make sure the PCV hoses are all clear and put a new Subaru PCV valve on. Especially check the 1" dia hose that comes up from the oil separator on the back of the block, it can get really clogged with carbon crusties.

 

When the hoses get restricted by deposits, the air flowing through them has to travel faster. That keeps the oil droplets in suspension instead of letting them condense and drain back to the crankcase, so they get sucked into the intake manifold.