6.1 204 engine - wrong oil cap fitted at factory - major oil leak knackered alternator!

nickb77 · Nov 17, 2022

My 2021 T6.1 204 had a fairly major breakdown at the weekend up in the Lake District. Got a warning that the 12v battery wasn't charging. When I managed to stop to look under the bonnet - oil sprayed all over the left side of the engine. Had to be recovered home by the AA (recovery service was handled really well I have to say).

Just heard from the dealer that the oil leak was due to 'the wrong size oil cap being fitted at the factory'. Presumably all the shaking about travelling on the lanes up there caused oil to escape and get into the alternator. New alternator and oil cap due to be fitted tomorrow.

I'd guess that mine isn't an isolated case so if you have a 204 built around May last year, be warned! They seemed to go through a period of not having all the right components so wondering if they fitted the wrong oil caps to a batch of engines as they didn't have the correct ones and hoped it wouild be OK.

Brendan eldridge · Nov 17, 2022

Will ask the question when mine arrives in December

subthree · Nov 17, 2022

Sorry to hear that. Our 6.1 had a loose jubilee clip on an oil pipe and dumped all the oil after 600 miles. German quality.

nickb77 · Nov 17, 2022

subthree said:
Sorry to hear that. Our 6.1 had a loose jubilee clip on an oil pipe and dumped all the oil after 600 miles. German quality.

I thought I had the same problem at first but everything looked intact. Seems a build-up of pressure forced the dipstick to pop out and oil to spray everywhere.

Perfectos · Nov 17, 2022

Sorry to hear your woes,

things you may want to discuss with the dealer

Do you have front assist, ACC etc ?

when the dealer replaces the Alternator, they remove the front bumper assembly,
they should then check & recalibrate the front assist as a matter of safety (not all dealer have the facilities) To ensure it works correctly and does not throw up faults.

Similarly the aux belt should to be replaced as it can become damaged when the alternator fails, presumably the aux belt was / is covered in vented engine oil ?
If the Aux belt becomes damaged, the timing belt is at risk If it fails, causing catastrophic engine damage.

the under engine tray has a felt liner attached to the inside face, the liner may well need to be replaced as well if it is soiled with engine oil ?

I presume the dealer will ensure VW give you a good dollop of good will for their failings and your ruined trip ?

nickb77 · Nov 17, 2022

Perfectos said:
Sorry to hear your woes,

things you may want to discuss with the dealer

Do you have front assist, ACC etc ?

when the dealer replaces the Alternator, they remove the front bumper assembly,
they should then check & recalibrate the front assist as a matter of safety (not all dealer have the facilities) To ensure it works correctly and does not throw up faults.

Similarly the aux belt should to be replaced as it can become damaged when the alternator fails, presumably the aux belt was / is covered in vented engine oil ?
If the Aux belt becomes damaged, the timing belt is at risk If it fails, causing catastrophic engine damage.

the under engine tray has a felt liner attached to the inside face, the liner may well need to be replaced as well if it is soiled with engine oil ?

I presume the dealer will ensure VW give you a good dollop of good will for their failings and your ruined trip ?

Thanks - good points to check with the dealer although I don’t hold out much hope of any recompense from VW!

Sent from my iPhone using Tapatalk

subthree · Nov 17, 2022

nickb77 said:
Thanks - good points to check with the dealer although I don’t hold out much hope of any recompense from VW!

Sent from my iPhone using Tapatalk

VW gave me zero goodwill. Although I had extracted a LARGE discount in the first place. As long as it is fixed I would just move on.

antontdi · Nov 21, 2022

nickb77 said:
I thought I had the same problem at first but everything looked intact. Seems a build-up of pressure forced the dipstick to pop out and oil to spray everywhere.

Hi Nick

The oil cap will not cause this to happen - its a sealed unit and doesn't regulate anything. If there is pressure building up inside the crankcase which causes the dipstick to blow out then this is a crankcase ventilation issue and needs to be properly addressed otherwise you will have further bigger issues. Crankcase pressure is regulated by the PCV valve which also separates oil from blowby gasses and then sends the vapour back into the intake to be burnt off. If this valve isn't working properly or some other aspect of the system then crankcase pressure will get too high and cause things to pop such as the dipstick but potentially other things like oil seals, turbo bearing seals etc that are far more expensive to fix.

Have a look on YT for info on this, one example:

Perfectos · Nov 21, 2022

subthree said:
VW gave me zero goodwill. Although I had extracted a LARGE discount in the first place. As long as it is fixed I would just move on.

first one would have been fine IMO

nickb77 · Nov 21, 2022

antontdi said:
The oil cap will not cause this to happen - its a sealed unit and doesn't regulate anything. If there is pressure building up inside the crankcase which causes the dipstick to blow out then this is a crankcase ventilation issue and needs to be properly addressed otherwise you will have further bigger issues.

Thanks - I was also expecting the diagnosis to be PCV related (in a previous life I worked on the design of engine management systems for diesel trucks and cars...). I'm collecting the van this afternoon so will try to get more details from the dealer. Will also try to find out it this is a common problem as they seem to have arrived at a diagnosis of 'wrong oil cap' pretty quickly.

kurienp · Nov 21, 2022

antontdi said:
Hi Nick

The oil cap will not cause this to happen - its a sealed unit and doesn't regulate anything. If there is pressure building up inside the crankcase which causes the dipstick to blow out then this is a crankcase ventilation issue and needs to be properly addressed otherwise you will have further bigger issues. Crankcase pressure is regulated by the PCV valve which also separates oil from blowby gasses and then sends the vapour back into the intake to be burnt off. If this valve isn't working properly or some other aspect of the system then crankcase pressure will get too high and cause things to pop such as the dipstick but potentially other things like oil seals, turbo bearing seals etc that are far more expensive to fix.

Have a look on YT for info on this, one example:

Agree on this. Not having an oil cap on does not leak oil. I topped up my oil and forgot to put the cap back on. For almost a month I think, I drove around without the cap on. When the van went in for a service at Breeze Poole, the nice mechanic sent me a video very cheekily advising me that the location of the oil cap is not behind the headlights, but on the oil filler spout. :headbang

nickb77 · Nov 21, 2022

kurienp said:
Agree on this. Not having an oil cap on does not leak oil. I topped up my oil and forgot to put the cap back on. For almost a month I think, I drove around without the cap on. When the van went in for a service at Breeze Poole, the nice mechanic sent me a video very cheekily advising me that the location of the oil cap is not behind the headlights, but on the oil filler spout.

The oil escaped from the dipstick rather than the filler cap. When I opened the bonnet, the dipstick wasn't seated properly and the spray pattern looked like oil had hit the underside of the bonnet with some force. I'm sceptacal about the filler cap explanation but doubt I'll get much sense out of the dealer when I collect the van later today.

Corradobrit · Nov 21, 2022

nickb77 said:
The oil escaped from the dipstick rather than the filler cap. When I opened the bonnet, the dipstick wasn't seated properly and the spray pattern looked like oil had hit the underside of the bonnet with some force. I'm sceptacal about the filler cap explanation but doubt I'll get much sense out of the dealer when I collect the van later today.

Certainly sounds like over pressure in the crank case. The dip sticks are not particularly securely fitted so under normal operating conditions will not force oil out through the access port. My money is also on pcv which historically has been an Achilles heel on these VW engines.

andyinluton · Nov 21, 2022

My money would be on the dipstick not being pushed fully home when the oil was last checked.

If there's spray on the underside of the bonnet, thats probably a result of it flying off the alternator drive belt.

If there's enough crank case pressure for anything to be blown out - ie dipstick, oil cap etc you've got a major fault on an engine this new.

It it was the Oil Cap it would have been wrong from the day you took delivery, it wouldn't suddenly go wrong & you would have had an oily smell every time you drove the van. I would have thought that there would be a build up of oil round the cap that would that would get bigger every time it was driven & drips down covering the barcode / labelling immediately below the cap.

Have you ever checked your oil level?

nickb77 · Nov 21, 2022

andyinluton said:
My money would be on the dipstick not being pushed fully home when the oil was last checked.

If there's spray on the underside of the bonnet, thats probably a result of it flying off the alternator drive belt.

If there's enough crank case pressure for anything to be blown out - ie dipstick, oil cap etc you've got a major fault on an engine this new.

It it was the Oil Cap it would have been wrong from the day you took delivery, it wouldn't suddenly go wrong & you would have had an oily smell every time you drove the van. I would have thought that there would be a build up of oil round the cap that would that would get bigger every time it was driven & drips down covering the barcode / labelling immediately below the cap.

Have you ever checked your oil level?

Just back from collecting the van from the dealer. I asked if they'd ever seen this mysterious 'oil cap' issue before and they said not. However, they told me that they contacted VW technical support who told them there had been several other instances of this issue. I'd done about 1500 miles since the last oil service. I hadn't checked the oil myself since the oil service so no idea whether or not the dipstick was secure. I'm wondering whether it was the kind of driving I was doing the Lake District which triggered things - I was up and down quite steep inclines on the the backroads - very different to what it's done before, i.e. up and down motorways and flatish A and B roads. Can only speculate and hope this is the end of it.

flying banana · Nov 21, 2022

A quick check I would do is put a rubber glove over the oil cap filler. Run the engine. If the glove inflates slowly you have an issue as said with crank case pressure. Don't listen to any of these vw techs. It's like they don't know about the internet

GrumpyGranddad · Nov 21, 2022

Did they not elaborate on the root cause if there has been several other instances? Are they saying it was the dipstick not pushed fully home? If so, it doesn’t ring true to me? Potentially VW could fall back on this and refuse warranty claims stating ‘user error’!!

nickb77 · Nov 21, 2022

GrumpyGranddad said:
Did they not elaborate on the root cause if there has been several other instances? Are they saying it was the dipstick not pushed fully home? If so, it doesn’t ring true to me? Potentially VW could fall back on this and refuse warranty claims stating ‘user error’!!

No, no mention of user error or anything like that. They've stated it's a known issue and said straight away it was covered by the warranty given that it was a manufacturing defect - wrong oil filler cap fitted at the factory.

Corradobrit · Nov 21, 2022

nickb77 said:
No, no mention of user error or anything like that. They've stated it's a known issue and said straight away it was covered by the warranty given that it was a manufacturing defect - wrong oil filler cap fitted at the factory.

I just don"t buy it

flying banana · Nov 21, 2022

nickb77 said:
No, no mention of user error or anything like that. They've stated it's a known issue and said straight away it was covered by the warranty given that it was a manufacturing defect - wrong oil filler cap fitted at the factory.

It's a bit odd though. As already said you can run a cali engine without a filler cap on. If the filler was straight above the cam shaft only then would you see oil being spat out.

Corradobrit · Nov 21, 2022

I would be checking my oil level regularly. I think bananas idea to use the glove to check for pressure is a good place to start too.

flying banana · Nov 21, 2022

Corradobrit said:
I would be checking my oil level regularly. I think bananas idea to use the glove to check for pressure is a good place to start too.

I got the idea off Mike brewer on wheeler dealers

nickb77 · Nov 21, 2022

Corradobrit said:
I would be checking my oil level regularly. I think bananas idea to use the glove to check for pressure is a good place to start too.

Going to check the oil level tomorrow as there was no mention on the paperwork for the job of oil being topped up. You’d hope the technician would think “lots of oil has come out - better put some back in”

sidepod · Nov 21, 2022

I was under the bonnet of my Golf at the weekend and I noticed the yellow dipstick tube was cracked and loose at the bottom where it enters the sump.
The design is similar on most VWs in that this tube pokes through the engine cover. Easily damaged if the engine cover is man handled back in to position?
Could be the cause.

Corradobrit · Nov 21, 2022

I really don't think this has anything to do with the dip stick which extends down into the sump. My Porsche just had a friction lock and my Audi A4's plastic dipstick tube disintegrated but there was zero mess in both cars. The oil is a symptom not a cause.

6.1 204 engine - wrong oil cap fitted at factory - major oil leak knackered alternator!

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