Valve Stem Seals AND Piston Rings, at the same time?

[FlashG1975]

My car is currently at the workshop for the valve stem seals to be replaced. They have told me that they can't guarantee that it will fix the heavy exhaust smoking and suggested i do the piston rings at the same time. However disassembly of the block is going to double the repair cost.

Does anyone have any advice how I should proceed. Take the risk and only do the valve stems or should I go ahead and get the piston rings done as well while the engine is out?

Is there any way to verify if the piston rings are bad?

At the moment the garage are going ahead with the valve stem seals and say they will remove the lower oil pan to visually inspect the pistons. Can they really determine if the piston rings are bad by doing this?


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[White94RX]

I've never replaced piston rings, nor have I seen anyone do it in 12 years in the business. Not unless it was just a high mileage rebuild. Replace the valve stem seals and have a nice day.

[FlashG1975]

Thanks! I think I'll just do Valve Stem Seals in that case. It only has 86k miles on the clock which I don't think would be considered high for a 2010 vehicle.


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[peter2772000]

Has something changed since my day? Used to be that smoke on start-up was seals, smoke on acceleration was rings?

[FlashG1975]

From what I have read you don't always get smoke on startup when the seals are bad with a bimmer, it's tends to be smoke on idle. Also, if I rev her up a bit I can clear out the smoke for a couple minutes before it comes back


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[White94RX]

Define "your day". LOL. Are you referring to old school pushrod engines?

Since the introduction of the N62 V8 engine, valve stem seals have been a huge wear item, causing smoking from the tail pipes and excessive oil consumption. To my knowledge, BMW engines rarely seem to suffer from piston ring issues.

[peter2772000]

Define "your day". LOL. Are you referring to old school pushrod engines?

Big block Chevys. SBC's. Good ole 'merican v8's. If it smoked on start-up, it was due to oil seeping past the valve guide seals. If it smoked on acceleration, it was due to blow-by. But we had no turbos back then. HP depended on cubic inches. Ah, the good ole days LOL