Subaru Forester Owners Forum banner
1 - 5 of 5 Posts

·
Registered
2005 Subaru XT w engine swap w 2006 STI
Joined
·
2 Posts
Discussion Starter · #1 ·
hello, i really need some help, i’m really unsure of what to do.

i recently bought a 2005 Forester XT..... w a swapped engine.... a 2006 STi engine.
all was good but when given back to me after letting family borrow it, i heard knocking in the engine. i checked the oil and it had none. i put engine oil in it and the knocking stopped but my check engine light started blinking. i changed the spark plugs, and when that didn’t make the light go away, i did a compression test. while all other cylinders were running at 140, cylinder 2 was at 75.
i drove it a couple times around to see any differences and while it runs a bit slower it also stalls when reversing going a bit uphill.

pls, this is my first subaru and idk what to do
 

·
Registered
2012 Forester X Auto
Joined
·
2,769 Posts
@morelivingpls Did you check the oil before you let them use the car?
You might have had an issue already, and obviously the car using all/most of its oil is a problem in itself.
That might be why it was sold in the first place.

Get a code reader or get your code checked at most auto parts stores for free. It may be revealing.
Replacing spark plugs only fixes a problem if the problem is the plugs, and obviously that wasn't your problem.

Assuming the compression test was done correctly, you have a major problem.
When doing a compression test and you get one (or more) bad reading(s), an old mechanic's trick is to put a teaspoon of oil in the spark plug hole and retest.

If the psi reading goes up considerably after adding the oil, you have a cylinder/piston/piston ring problem. (because the oil makes temporary seal)
If there is no change in the compression test reading, it's likely to be a valve problem.

Either way it could be an expensive fix requiring rebuild or replacement, and there isn't much you can do to get an engine running well on 3.5 cylinders.

BTW - If the engine was actually run out of oil, the big red oil warning light should come on.
If a family member drove the car that way, they would lose their driving privileges to any vehicle that I own.
 

·
Registered
2005 Subaru XT w engine swap w 2006 STI
Joined
·
2 Posts
Discussion Starter · #3 ·
@DragonSubie7 cool, tysm! also, i forgot to mention the but where i did buy a code reader and it didn’t say anything which was why i did the compression test last since it was the only thing i could think of that would not show up on the code reader.

my family never mentioned a red light popping up (and they are also pretty good with maintaining cars) and yes i did check the oil before they used it, so the whole situation really was weird.

but again, tysm!
 

·
Registered
2008 XT Sport 5-speed
Joined
·
456 Posts
When doing a compression test and you get one (or more) bad reading(s), an old mechanic's trick is to put a teaspoon of oil in the spark plug hole and retest.

If the psi reading goes up considerably after adding the oil, you have a cylinder/piston/piston ring problem. (because the oil makes temporary seal)
If there is no change in the compression test reading, it's likely to be a valve problem.
This trick won't work on a boxer engine, since the oil will all pool on the low side of the piston. To the OP, this is an interesting one...How long did family have the car? For that much oil to disappear in one drive...Something catastrophic went wrong in the engine. If they had it for a month, then that might be a different story. How many miles are on the engine, and how long ago was it swapped. The engine might have spun a bearing, or your timing chain might have stretched/broken which allowed your piston to hit a valve. Have a reputable shop (or you, depending on how mechanically apt you are) do a leakdown test. That will tell you if it is a piston/rings problem or a valve problem. Either way if your compression is that low, your probably looking at pulling the engine and rebuilding it.
 
1 - 5 of 5 Posts
Top