# Valve seals



## Cobra_chicken (8 mo ago)

Hey I have a really smoky car lol. It starts and runs good I have a miss though. 
Previous owner removed cat and abused it pretty good. I get a bit of oil consumption i just did a oil change and its already turning pretty black. Little carbon floatys on the dipstick.
I plan on bringing it back to life its a 2008 nissan sentra S with a 6 speed manual. My biggest question or thought is it could be the valve seals giving me grief. I dunno if its the rings because it has good compression when I down shift the engine slows the car down pretty good and its pretty snappy when I floor it even with 3 cyclinders hahaha.
Has another sentra owner had this problem can you fix this yourself at home or should I take it in to a shop? 
I know you can do valve seals yourself but I'm unsure with this french renault engine. I'm almost thinking about doing a engine swap but if I can fix it for cheap I will.


----------



## VStar650CL (Nov 12, 2020)

If the compression is good, I think I'd make sure the PCV system is working before assuming it's something major. A bad PCV Valve, plugged up hoses or plugged baffles in the valve cover can all make it use oil. If the previous owner abused it, sludge is pretty good bet.


----------



## smj999smj (Jan 1, 2006)

A cylinder leak down test can be performed which can help determine if there are bad rings, head gasket or poor valve sealing. With the materials they make valve seals out of these days, you usually don't see a lot of Nissan vehicles that have leaking valve seals. That doesn't mean it can't happen, but just that it's not very common.


----------

