I have a 2003 Polo 9n with the 1.2 3 cylinder engine, a few months ago I had the exhaust valves replaced as they were worn. I am aware this is a common problem.

However, since I have had this work done, my car has been burning oil quite rapidly (1 litre per 250 miles).

The garage told me that it could be the piston rings that are worn because having restored compression the piston rings have come under stress etc.

However, they also said that it could be the valve stems which they had not put in 100% correctly that could be causing the car to be burning oil this rapidly.

Can anyone advise on whats a good move from here, having spent £600 to fix the valves I'm not partial to spending another £600 on the piston rings.

Would it be useful to get a compression test done to see if its the piston rings?

Has anyone else had this problem with their car?

Any help would be appreciated, thanks. :)

Get a compression test done, if there is a low reading (normal compression 7 - 15 Bar) then pour a bit of oil into the plug hole/s and re-do the compression test, if the figure is higher the second time, you are looking at worn bores/rings, if there is no change it's a valve problem

Was the engine burning oil before you had the valves done?

If not, then you should be talking to the garage that did the work.

When they say that the valve stems may not have been put in correctly, they almost certainly mean the valve stem SEALS.

They should have checked the valve GUIDES for wear before fitting the new valves - I am assuming here that they did also check the inlet valves when they replaced the exhaust valves - for £600.00, they certainly should have done.

Regards.

I've just rebuilt one of these myself at work and the valve stem guides were really worn.. So if they haven't replaced those id start by finding out what exactly they have done and what they have checked!

Was the engine burning oil before you had the valves done?

If not, then you should be talking to the garage that did the work.

When they say that the valve stems may not have been put in correctly, they almost certainly mean the valve stem SEALS.

They should have checked the valve GUIDES for wear before fitting the new valves - I am assuming here that they did also check the inlet valves when they replaced the exhaust valves - for £600.00, they certainly should have done.

Regards.

The engine was not burning oil whatsoever, its suddenly started burning it after its had the exhaust valves replaced. They said the inlet valves were okay and that it was only the exhaust ones that needed replacing. They have told me that the piston rings could be damaged because returning the compression back to normal has put them under stress. Which I find a bit hard to believe, but I'm not a mechanic so its hard to know what to do really.

What would you do?

Regards

They are 'spinning you a line' here. The MORE compression pressure that there is in the cylinder, the more it will tend to push the oil back DOWN past the pistons.

Another old trick, which is often overlooked these days, is to leave the carbon around the edge of the pistons and that at the top of the cylinder bore, the theory being that this acts as something of an 'oil seal'. However, many people tend to 'kill it with kindness' and remove said carbon deposit - some claim that it doesn't make any difference anyway.

The point about valve guides/stems and seals, is that it is the inlet ones that do need to be good - there is a positive pressure at the exhaust valve, so if the stem or guides are worn, exhaust gas will tend to be blown into the crankcase, causing pressure and maybe blowing oil out of whatever type of crankcase breather is fitted - but at least you would know about it, as either the engine would be covered in oil, or the air cleaner element/throttle body would be.

With the inlet valves, there is a partial vacuum, so any wear in the stems/guides/seals would allow oil to be drawn into the combustion chamber - The tell-tale for this condition would be BLUE smoke in the exhaust gas and in the case of it getting in there via said stems/guides/seals (as opposed to getting past the piston rings) it would be more noticeable when pulling away or revving the engine after a period of idling (maybe waiting at traffic lights.)

When oil gets into the combustion chambers via cylinder bores/pistons/rings, the blue smoke that it produces is more noticeable when pulling hard (up hill, in a high gear,say)

When oil gets in by this route, a cylinder leakage test will confirm that either cylinders/ pistons and/or rings are worn.

After spending that amount of money, if the garage won't put the problem right for you, I would have a word with the Trading Standards Department at your local Council.

Regards.

They are 'spinning you a line' here. The MORE compression pressure that there is in the cylinder, the more it will tend to push the oil back DOWN past the pistons.

Another old trick, which is often overlooked these days, is to leave the carbon around the edge of the pistons and that at the top of the cylinder bore, the theory being that this acts as something of an 'oil seal'. However, many people tend to 'kill it with kindness' and remove said carbon deposit - some claim that it doesn't make any difference anyway.

The point about valve guides/stems and seals, is that it is the inlet ones that do need to be good - there is a positive pressure at the exhaust valve, so if the stem or guides are worn, exhaust gas will tend to be blown into the crankcase, causing pressure and maybe blowing oil out of whatever type of crankcase breather is fitted - but at least you would know about it, as either the engine would be covered in oil, or the air cleaner element/throttle body would be.

With the inlet valves, there is a partial vacuum, so any wear in the stems/guides/seals would allow oil to be drawn into the combustion chamber - The tell-tale for this condition would be BLUE smoke in the exhaust gas and in the case of it getting in there via said stems/guides/seals (as opposed to getting past the piston rings) it would be more noticeable when pulling away or revving the engine after a period of idling (maybe waiting at traffic lights.)

When oil gets into the combustion chambers via cylinder bores/pistons/rings, the blue smoke that it produces is more noticeable when pulling hard (up hill, in a high gear,say)

When oil gets in by this route, a cylinder leakage test will confirm that either cylinders/ pistons and/or rings are worn.

After spending that amount of money, if the garage won't put the problem right for you, I would have a word with the Trading Standards Department at your local Council.

Regards.

This has all been very useful information and will help me address the problem with more knowledge.

Many thanks