How to tell where I'm burning oil?

[240sxDann]

So my car is burning oil somewhere, but idk where. Short background, its an s13 with a red top sr20det. Unfortunately I know nothing about the motor. I don't know mileage or anything like that. It's a basic set up, stock motor, 550cc injectors, hks gt25 turbo, and supporting mods. The turbo boosts just fine, and fast. The motor pulls strong as helllll. But, when my oil was checked the other day I was half a quart low, and I keep randomly puffing out blue smoke. Idk exactly what causes it to blow smoke (like if I'm idling or boosting) but it SEEMS as though it happens when I rev down to a slower speed or to a stop. I can see smoke in the rear view, then once I start moving it puffs a cloud then stops. I'm thinking the turbo is going out...but what do I know? lol So any input?

[Nors]

Usually burning oil on deceleration is indicative of valve seals or valve guides. I also have no experience with SR's though so I could be wrong. I would check simple things first like the pcv system and turbo shaft play.

[240sxDann]

Well that sucks!

[TalonTsi97]

Originally Posted by 240sxDann

Well that sucks!

Don't get to upset yet, search around on a nissan specific site and see their opinion as well. Maybe have a friend take a video of you driving to see when the smoke appears for sure.

Check pcv and turbo for now.

[TNTramair]

if its smokin at idle id say turbo seals. which would also happen under accel or deaccel situations. valve seals would generally just smoke at start up. and as stated, you should also check to make sure its draining properly b/c if its not, it could just be blowing by the seals under pressure...so also check pcv.

[240sxDann]

Ok so I have figured out exactly when it happens. It doesn't happen on start up, it only happens when I deccel or stop, then start going again. Like if I'm in 3rd gear and let of the gas and decel for a few seconds then get on it again, it blows out smoke. Also, if I come to a stop (whether I decel in gear, or just throw it in neutral) once I start moving again it smokes. It's pretty bad too.

[russiankid]

It sounds like valve seals, but it could also be the turbo. Have you done a compression and leak down test? I know of a motor that has a rebuilt head but burns out as you described because of oil rings.

[Nors]

Sounds like turbo seals. My buddies subie smokes after sitting at a light for a bit once he starts moving and its his turbo seals.

[Honduh]

i also agree on the valve seals. why didn'y you replace all the rubber before dropping the motor in?

[4DR_DB7]

its an old motor, could be piston rings/blow by too I guess?

[TNTramair]

if it doesnt smoke during start up than its not his valve seals. thats your first sign that they are going bad.

[240sxDann]

I would prefer that it's the turbo lol. Much easier to deal with. I will gladly find a t28 to use cuz that's basically the same thing. Is there any way to tell for sure? I don't want to go replacing one things or another, and it not be the right thing.

[240sxDann]

Thank you whoever moved this to the right section!

[Honduh]

Originally Posted by TNTramair

if it doesnt smoke during start up than its not his valve seals. thats your first sign that they are going bad.

huh? when you have bad valve seals oil gets pulled in during the intake stroke.

[russiankid]

Originally Posted by Honduh

huh? when you have bad valve seals oil gets pulled in during the intake stroke.

I think he means that if the valve seals were at fault he would get smoke on start up after sitting over night. However, my Honda smokes on start up during the winter because the valve seals don't want to seal when cold, but in the summer it doesn't smoke.

[Honduh]

well I don't think much oil would really "seep" in over night. Its not like the valve seal is constantly in a pool of oil.

And I think most cars generate 'smoke' or steam in the winter.

[evomike]

its probably the turbo

[DsmRob]

Why not start w/ a dry and wet compression test and go from there. Assuming whats causing the oil loss isn't gonna fix it.

[russiankid]

Originally Posted by Honduh

well I don't think much oil would really "seep" in over night. Its not like the valve seal is constantly in a pool of oil.

And I think most cars generate 'smoke' or steam in the winter.

A huge blue cloud of smoke is not normal.

[TNTramair]

Originally Posted by russiankid

I think he means that if the valve seals were at fault he would get smoke on start up after sitting over night. However, my Honda smokes on start up during the winter because the valve seals don't want to seal when cold, but in the summer it doesn't smoke.

exactly.

dry/wet compression check would be a good start. if thats good across the board, than you can move on. keep in mind though...you could have more than 1 thing going on in there.