I was just told by the mechanic that I need a new main seal on a used car I just purchased: 2006 Subaru Forester 2.5XT turbo 139k miles. He said that he can see the oil when he looked under the car. How can I verify that's an issue - I haven't noticed any oil myself, should I be looking for oil drips under the car or a burning oil smell?

Seems like an expensive job so I don't want him to pull out the transmission and get into it if it's not totally necessary.

1 Answer 1


Take a second opinion, as always.

To see if it needs replacement; reverse the car 20ft. If there is a pool of oil where the car has been sitting, you should find out where it is coming from and fix it. If not, don't worry.

The rear main seal does give way occasionally, but as you say - it's an expensive job if that's the only thing you're doing. $12 for the seal, and $1000 to remove the engine so you can get at it. If you have the engine out anyway for any other reason (e.g for the head gaskets), then that's the perfect time to replacement (amongst other parts).

When did the car last have it's timing belt changed? That needs to be done regularly every 105,000 miles, and if you don't have documentation of that, then that's where I'd be putting my money at the moment.

  • the timing belt was replaced at it's 105k service - 2 years ago and it's at 139k miles now. I put out some cardboard under the car overnight and in the morning saw 2 drips of oil - each about 1.5" diameter. Sep 27, 2016 at 15:52
  • Whereabouts was the oil dripping from? At 139,000 miles, I'd look at the valve covers (the drips would be either side of the engine, around the middle of the block). A pretty simple fix, even with the engine in the car..
    – PeteCon
    Sep 27, 2016 at 18:27
  • it was around the middle front spaced a few inches apart Sep 27, 2016 at 20:01
  • If you don't have the cash, just monitor the oil level and top it up as needed. It's not gonna blow up because it drips a couple drops of oil every night.
    – cory
    Sep 27, 2016 at 20:14
  • The 2nd opinion mechanic I got tells me that it's not worth fixing because it's only got a partial success rate anyways - is the main seal fix really that unpredictable? Sep 27, 2016 at 20:43

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