I'm checking out a 2007 Nissan Sentra 1.8 inline 4, 170k miles, for a friend. I have never witnessed this vehicle while running so here's what I "know."

It takes like 20 minutes of cranking before it will start. It runs for just a second then dies during that 20 minutes. Once it's running well it has good power. He took it to a dealer who said compression was like 35 psi, head gasket is not blown, fuel pressure checks out and it's getting spark. A year or so ago it consumed maybe 1qt of oil on a 1k trip.

I pulled just one plug so far (you have to remove the intake to get to the coil-on-plugs on this thing!) and yes it does look dirty and coated like with burned on (but not wet) oil.

So it's probably rings, right? Does that happen on four all at once?

If it is rings, I'm deliberating on whether or not I want to continue helping out. I don't really want to remove the heads. However, would that be easier than trying to pull from the bottom? Can pulling pistons from underneath be done in-car? Removing the engine is a... non-starter. If from below I'd have to remove the crank and how much of a hassle is that on these? Just the harmonic and belts?

Also, do I need to hone out cylinder walls for this? Thanks

  • 35psi sounds very low. Any error codes?
    – PeteCon
    Oct 16, 2017 at 21:19
  • That's just my recollection of the exact PSI. I have the sheet the dealer gave him, it just says "very low compression" Good question on the CEL. I haven't checked that yet. Oct 16, 2017 at 21:27
  • 1
    Has anyone done a leakdown test? Excessive blowby when it does run? Cam timing OK? If you want to remove the crank you need to pull the trans so you can unbolt the flywheel from the crank. at that point you might as well just pull the engine.
    – Ben
    Oct 16, 2017 at 21:47
  • As far as I know, no leakdown test, and they didn't say anything about cam timing. How do you check for excessive blowby? Thank you for the note on the crank; that method is definitely out of the question now. Oct 17, 2017 at 14:51


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