[primejo07]

Hi all...


Buying a new Sierra tomorrow. Engine only has 143,000kms, however I have been told it is blowing a bit of white smoke. The fella still drives it every day and other than that, it appears to be running well.

I'm thinking stem seals or rings... what should I check? Is this a deal breaker?

Thanks

[greavesyzook]

You can get replacement engines fairly easy but I wouldn't worry to much about the smoke just drive it. How much you paying?

[primejo07]

Very clean hard top Sierra, 91. $2250. I’m going to look at it this morning, so if it’s just blowing a small amount I won’t worry too much. If it’s a shit load then I’ll steer clear I guess. Thanks!

[Gwagensteve]

TBH it doesn’t really matter what the volume of smoke is, it’s all about where it’s coming from. It’s most likely valve stem seals. If it’s rings then in my opinion it’s not worth rebuilding the motor- it will end up owing you more than a G16b swap. If it’s stem seals it can be done readily without lifting the head, which these motors don’t seem that happy with.

If you’re interested enough a compression test should show excessive ring wear. If compression is within spec then the cause should be stem seals only.

[primejo07]

Thanks very much for that, your wealth of knowledge comes in handy again. I have heard that if you let the car idle for a bit, and stab the accelerator, and only a bit of smoke comes out then that is the stem seals? Or is this not a reliable way to check it?

[Gwagensteve]

Sort of. It will normally show after long periods of overrun where there’s high manifold vacuum if it’s stem seals.

[primejo07]

Proud new owner of a 1991 tin top Sierra. Thanks all

[primejo07]

I checked the oil today, the oil is a good 2-3cm above the top hole on the dipstick... could this much extra oil be the cause of the smoke?

[shep]

Yes. Drain it and refil with 15/40 oil and see what happens

[primejo07]

Roger, thanks Shep. I’ll do the oil and filter tomorrow and hopefully no more smoke! The smoke is only there for about 2 minutes after starting cold, and goes once warm

[Gwagensteve]

Valve stem seals.

[henno]

Gwagensteve wrote:

Valve stem seals.

Short money, definitely.

[primejo07]

Oil change seems to has fixed the smoke issue, and looking through old receipts has revealed that the engine was fully rebuilt only 4 years ago. It looks like I have got myself a bit of a bargain! Thanks all for the help.