Smokey Exhaust

[mii11x]

Hey guys,

I've noticed white smoke coming from my exhaust the last couple of times I've driven down Bulli pass when I stop to turn left on Lawrence Hargrave drive. It doesn't do it any other time except coming down that hill which is a pretty steep grade - 1 in 6 I think its posted as.

My car is a r32gtst with an rb25, 3071r turbo, injectors, power fc etc. The engine and mods have only seen about 40000km in three years since the conversion. It does not appear to be using more oil than usual, coolant levels are good also. I have checked most vacuum/boost lines and I don't their is any air leak.

Any idea what could be causing the smoke??

Thanks

Mick

[Hadouken]

How cold is it in that area?

White smoke = coolant burning which usually means head gasket leak.

But if you don't loose coolant then it must be super cold out

[R32GOJIRA]

I had a problem with my gtr where it would blow smoke out of the exhaust on engine brake going down hill. It was a leaky rear turbo seal, leaking oil into the hot exhaust. You dont notice the oil level a it only needs a couple of drops in a hot exhaust to smoke like crazy.

[mii11x]

I dont think it was particularly cold outside, maybe low 20s, would that be considered low??

Also I know the turbo was brand new when I did the conversion and upgrade, well when the workshop did the upgrade and conversion, I also got them to replace all coolant hoses on the engine, rear main seal on the engine, new water pump, timing belt cam seals etc, basically everything was replaced with new while the engine was out and easy to get to, however the engine itself wasnt opened up. It was a low km 2nd hand series 2 rb25 so I was told. It was a known workshop, but has since closed down, but the owner now works at a powertune. Im sure the seals for the turbo to exhaust would have been new also if thats what you mean??

I will prob take it to powertune - where the owner now works as he knows the car, just trying to get an idea of what the problem could be, hence how much I am looking at to getting it fixed as money is kinda short at the moment.

Thanks for your help guys so far

[jiffo]

Valve stem seals springs to mind.

[mii11x]

Im not too mechanically minded jiffo, my mates brother said this could be it also (he is a diesel mechanic but currently overseas). Can I ask why you say this??

[jiffo]

On over-run with throttle closed, the engine will pull max vacuum.

Worn valve stem seals will allow oil to be sucked down the valve stem into the combustion chamber.

Worn guides make the whole show even worse.

These engines are getting old and often the valve stem seals, if they're still there, have gone brittle.

You probably find under normal driving, you wouldn't see any smoke but a long downhill is a good test.

[mii11x]

Ah ok thanks for the explanation.......yeah if you know the road its a long steep downhill run. I rarely touch the accelerator pedal so what your saying makes sense to me. Expensive fix?, while the seals are getting replaced, what else should I be doing/replacing to keep the engine maintained?? would the car need a retune after??

Edited June 25, 2014 by mii11x

[jiffo]

Don't forget this is just an internet diagnosis, would pay to have a hands on inspection for verification.

Valve stem seals can be done in situ, but it's a fair old job.

Cams, lash adjusters and so on out which automatically means cam belt etc all off. (so it's the ideal time to do that service)

Don't mix up the lash adjusters, they go back exactly where they came from.

Then systematically work on each pair of TDC cylinders.

With the crank locked, spark plug out, adaptor fitted and pressurise the cylinder.

Using your Snap-On tool, remove the valve collets, spring and you'll be looking at the old valve stem seal.

Remove old seal and fit new one. (check inlet V's exhaust valve seal, they may differ)

Spring etc back on, collets in your Snap-On tool and whack……. that one's done.

Only 23-more to do.

You'll do 8-each time then rotate the crank to your next TDC, lock it and go again.

Very important, TDC and crank locked.

I think I could live with a bit of smoke on over-run, don't you?

[Ben C34]

Won't need a retune.

It is possible to replace the seals woth b the head on. Which will seriously reduce the costs.

As for how much no idea. I would do it myself.

Obviously thing to do is ring a mechanic.

Edit..

Beaten

With way more info!

Edited June 25, 2014 by Ben C34

[mii11x]

Yeah, I couldnt attempt this myself. My mechanical abilities are limited to general servicing lol - the biggest thing ive done myself is replacing a water pump when I had the rb20 in it and swapped over the shocks/springs to coilovers twice. It just looks embarrasing really, like I dont look after my car. Looks like I will be waiting for my mates brother to return for a couple of months.