New engine?!? Help!!! VW POLO 1.2 S

New engine?!? Help!!! VW POLO 1.2 S

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jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
Hi all,

Am after some advice following a VW dealership informing me I need a new base engine at a cost of £4310.

Around 11 months ago the timing belt on my car went and I had it repaired at the dealership as it was still under the extended warranty I got with the car. I had had problems with the car starting for weeks prior to this, but was told that they had caught the problem before any damage to the engine was done.

Fast forward to last Tuesday, got in the car and it wouldn't start. Roadside assistance came and thought it was a problem with the fuel pump, and so I had it towed to my local mechanic. He had a look and found there was zero compression and thought it was a problem with the timing belt again.

Called VW and they agreed to take it in as they had done the original repair, and so I had it recovered to their premises.

They initially felt it was to do with the timing belt and so I agreed they could investigate further. When I reminded them it should not be of a cost to myself as the initial repair was obviously not fit for purpose they have now said it is the piston ring sealing that has faulted and they cant strip the engine down fully as it is not possible with this type of engine.

I have done some research online and it seems this fault can be caused by a timing belt problem, and I was surprised last year when they said there had been no damage to the engine. On the work sheet from last year they have replaced 3 seal rings, is this something that needs doing with a timing belt change? Like, could they be unrelated to the piston seal ring?

So, I just need some advice, is what they are saying plausible? Could the new problem be unrelated to the timing belt problems last year? Does the price they have quoted for a new engine seem reasonable? Seems excessive to me.

The car is maintained as it should be with regular servicing etc. and is around 6 years old.

Any thoughts greatly appreciated. Totally in the dark here. Thanks in advance.


HJG

461 posts

106 months

Thursday 18th April 2019
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When a timing belt breaks, the camshaft is no longer in sync with the crankshaft and as such, it is usually likely that the pistons will make contact with the valves, which are in the wrong position becauase of the broken link between crankshaft and camshaft. When this scenario is possible, the engine is referred to as an 'interference engine'. Some engines are 'non interference' whereby there is enough clearance to prevent this happening. However most modern engines are interference type due to requirements of high compression ratios.

The damage done during such a collision between valve(s) and piston(s) depends on engine speed at the time of failure and how quickly it was shut down. Often however, valves will be bent and the piston crown sufficiently damaged to warrant replacement.

The top piston ring can become trapped by any deformation of the top-land of the piston caused by the aforementioned collision. A trapped piston ring renders it pretty much useless. It'll then be up to the second ring to now do more compression/sealing work, which it is not optimised to do in absence of a fully functioning top ring.

However the fact your engine has been ok for almost a year since the belt failure suggests no such damage occured. However it may be that minor damage was done to the piston and as a result has led to 'hot spots' and caused some detonation/knock which has then damaged the rings.

Or there has been an oil film breakdown between the rings and the cylinder wall caused by no oil in the engine or too much fuel in the oil or too much fuel injected.

In any case sudden compression loss due to 'piston rings' is unusual. It's usually progressive. Has the car been burning oil?

Get them to use a bore scope to see if there is piston damage or cylinder wall damage.
Also get them to prove to you the belt is still in one piece and the engine still timed correctly. This is an easy task.

Don't understand their comments about the engine being a type that cannot be stripped down...afterall how was it built.

Apologies for long reply....bored waiting for a train!

jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
Hi thanks for this,

Spoke to technician a little while ago and it appears the engine can be stripped down, but they do not have the tools to do it.

The car has not been burning oil not, the oil level dropped about a month before timing belt went, topped it up and has been fine since.

Such a nightmare man, such an expensive fix!

Thank again and no need to apologise for a long post, all information is great at this stage!

jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
Jobs technician said they had done;
no electronic fault found
timing checked and is fine
compression test - very low compression in two cylinders
wet compression test - found compression increased
therefore feels problem with pistons.

I asked what would cause such problems with pistons he said supermarket fuel, this causes carbon build up! Is this right? I know there are different grades of fuel but it cant be that bad can it?

jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
sorry, I don't know what you mean by, which engine?

Gary C

12,312 posts

178 months

Thursday 18th April 2019
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jessie81 said:
sorry, I don't know what you mean by, which engine?
Sorry, just noticed your car is 6 years old. VW have had several 1.2 engine designs and the AZQ engine was popular for jumping its timing and I have overhauled one of these.

But that engine was in a 2003 car, so its not going to apply to you, sorry

Gary C

12,312 posts

178 months

Thursday 18th April 2019
quotequote all
but with regard to strip down

Certainly the AZQ engine block and lower case were machine torqued up to form a very solid bottom end, unfortunately that means the crankshaft is in that sandwich and de-tensioning the bolts can in theory cause the block to twist. Maybe the case on the later engines.

jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
Thanks. Appreciate the replies. But unfortunately you said a lot of words I don't understand. Complete novice here. Sorry.

stevieturbo

17,229 posts

246 months

Thursday 18th April 2019
quotequote all
jessie81 said:
Thanks. Appreciate the replies. But unfortunately you said a lot of words I don't understand. Complete novice here. Sorry.
Then you need an independent assessor local to you who can intervene.

Of course the dealer will try and word anything so as to absolve them from all blame.

Cheapest option is get it away from the dealer and source a good used engine, or have someone competent and trustworthy diagnose things and go from there.
Sadly all of those are hard to find.

Coilspring

577 posts

62 months

Thursday 18th April 2019
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Firstly, I think it is likely that your engine has a timing chain, not a timing belt, but similar consequences can happen. Im assuming it is a 3 cylinder engine, which is borne out by the fact 3 sealing rings were fitted. But I have no idea what these rings actually are.

The timing chain tensioners on these engines (if yours is a chain engine), are oil fed under pressure and it is essential the right oil, and oil level is kept correct. Loss of oil, and or pressure coupled with wear in the chain can easily let the chain jump a tooth or more and then not start. Changing the chain and tensioner is not an everyday job, but it is not horrendous and can usually be changed for around 350/400 possibly more in expensive labour locations.

I have known a few of these where new chain, tensioner and guides need fitting, and have never encountered 1 that suffered internal engine damage. That is not to say it is not possible.

The alarm bells for me though is that the breakdown people suspected fuel pump issues, and an independant, and vw suggests compression issues. The symptoms for these are totally different. A slipped chain will give poor compression figures.

I would suggest asking another independant for another opinion, I would strongly suspect a timing issue, and it is a 5 minute job on the 12v engines and 30 minute job on 6v engines to check.

When the problem happened was there excessive rattling preceding it, or bangs, knocks, smoke etc? Was there a lot of rattling (best described as sounding like a bag of spanners), for some time prior ?

Rebuilding the engine if it is major internal damage is unlikely to be worth it, but I think a good second hand engine should be available for a lot less than quoted by vw. Its a 6/7 year old car, with the best will in the world it doesnt warrant a full price vw engine.

Difficult to give a proper opinion without looking, but I would want another opinion on the timing marks before accepting the information given to you so far. Bank holiday weeked doesnt help though.

Edited by Coilspring on Thursday 18th April 19:00

jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
Hi,

Yes, it does have a timing chain not a belt and it is a 3 cylinder engine.

There was absolutely no warning before it broke down. No rattling, bangs, smoke, loss of power etc. All was fine. The only minor hint was the day before when I went to start it it only started on the second turn on the key, but I just thought I hadn't turned it far enough. Then the next day got in and it just wouldn't start.

Recovery thought it was a problem with fuel pump as he used a spray (no idea what its called) directly into a part of the engine (i think) which ticked the engine over for maybe a second or so and then it stopped. So he felt the engine wasn't getting any fuel.

Independent felt that it was zero compression caused by a timing chain issue, but he doesn't have the tools to rectify and so car went to VW as this was the work they had done previously and had said they would pay for repair as it was their work that was faulty. They then said it was piston seal that has gone, hence no compression.


Coilspring

577 posts

62 months

Thursday 18th April 2019
quotequote all
jessie81 said:
Hi,

Yes, it does have a timing chain not a belt and it is a 3 cylinder engine.

There was absolutely no warning before it broke down. No rattling, bangs, smoke, loss of power etc. All was fine. The only minor hint was the day before when I went to start it it only started on the second turn on the key, but I just thought I hadn't turned it far enough. Then the next day got in and it just wouldn't start.

Recovery thought it was a problem with fuel pump as he used a spray (no idea what its called) directly into a part of the engine (i think) which ticked the engine over for maybe a second or so and then it stopped. So he felt the engine wasn't getting any fuel.

Independent felt that it was zero compression caused by a timing chain issue, but he doesn't have the tools to rectify and so car went to VW as this was the work they had done previously and had said they would pay for repair as it was their work that was faulty. They then said it was piston seal that has gone, hence no compression.
Im not there to prove or disprove. But your description of the fault suggests timing chain issue to me. Sudden non start issue suggests chain has jumped due to poor hydraulic oil pressure at start up. Do you know if it is a 6v or 12v engine ?

Edited to add.

You would be very unlucky to have suffered major internal damage from that scenario. Unless, and it would be difficult to prove, that the easy start type stuff the recovery people used incurred such damage. Not a good thing to use if not 100% sure the timing was right.

Edited by Coilspring on Thursday 18th April 19:19


Edited by Coilspring on Thursday 18th April 19:21

jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
Hi,

Yes, it does have a timing chain not a belt and it is a 3 cylinder engine.

There was absolutely no warning before it broke down. No rattling, bangs, smoke, loss of power etc. All was fine. The only minor hint was the day before when I went to start it it only started on the second turn on the key, but I just thought I hadn't turned it far enough. Then the next day got in and it just wouldn't start.

Recovery thought it was a problem with fuel pump as he used a spray (no idea what its called) directly into a part of the engine (i think) which ticked the engine over for maybe a second or so and then it stopped. So he felt the engine wasn't getting any fuel.

Independent felt that it was zero compression caused by a timing chain issue, but he doesn't have the tools to rectify and so car went to VW as this was the work they had done previously and had said they would pay for repair as it was their work that was faulty. They then said it was piston seal that has gone, hence no compression.


jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
Im afraid I dont know that. How would I find out?

jessie81

Original Poster:

22 posts

59 months

Thursday 18th April 2019
quotequote all
can I ask what difference does it make if a 6 or 12v engine?

everyone at VW seems to think ive been unlucky. but kinda feeling like i cant trust anyone right now. present company excluded obviously. :-)

Coilspring

577 posts

62 months

Thursday 18th April 2019
quotequote all
jessie81 said:
Im afraid I dont know that. How would I find out?
Regarding 6v or 12 engine? Should be on car paperwork, but doesnt really matter. Just that 12v is much easier to check the timing. On these, most often it just affects 1 camshaft not both, so just need to undo 2 screws to look, no special tools needed.

Coilspring

577 posts

62 months

Thursday 18th April 2019
quotequote all
jessie81 said:
can I ask what difference does it make if a 6 or 12v engine?

everyone at VW seems to think ive been unlucky. but kinda feeling like i cant trust anyone right now. present company excluded obviously. :-)
Its really difficult to say (remotely) if you have been VERY unlucky, or fobbed off.

You do need another opinion 1st before you do anything. Any (half) decent independant should be able to check timing on these quite easily, certainly no more than an hours labour even on 6v engine.

stevieturbo

17,229 posts

246 months

Thursday 18th April 2019
quotequote all
jessie81 said:
Independent felt that it was zero compression caused by a timing chain issue, but he doesn't have the tools to rectify and so car went to VW as this was the work they had done previously and had said they would pay for repair as it was their work that was faulty. They then said it was piston seal that has gone, hence no compression.
There is conflicting information here.

You've stated one person says zero compression, which would indicate a valvetrain issue, but another one you've mentioned says low compression. The two are not the same, so details are important.

jessie81

Original Poster:

22 posts

59 months

Monday 22nd April 2019
quotequote all
Noted. However, I am just repeating what I was told. Going to call independant and VW tomorrow to clarify a few things based on what you have all said.

Appreciate the help!

Thanks.

jessie81

Original Poster:

22 posts

59 months

Monday 22nd April 2019
quotequote all
Does anyone know if supermarket fuel would cause piston ring seal to fault? This is what VW are blaming and I just dont know if this is possible, everyone I know uses this and Ive used it in numerous cars much old than this one and had no problems.