Diesel mixing with oil

[Leigh78]

Hi all,

I have a VW transporter T6.1 on a 2020 plate which has done 83k. In recent weeks I’ve encountered an issue with high oil level and diesel mixing with the oil. Initially I thought it was the problem relating to the DPF regen. But after a couple of visits to my local garage one to do a forced regen and reset the values, all the obvious things such as oil filter, oil change etc (out of pocket £600) and it still hasn’t resolved the issue. If anything it has got worse. Just wondering if anyone has had any similar experiences and can provide any advice on what the issue could be and possible fixes. Thanks

 

[Sasquatch]

It's worth searching the forum as there is a lot on this topic.

There are three main thrusts;

1. Garages tend to put too much oil in and that eventually upsets the oil level sensor. This may become apparent on a longer journey as the heat causes thermal expansion in the oil. In this case carefully reset the oil level the exactly half way between the MAX-MIN marks on the dipstick and the problem goes away. This is probably the most common scenario.

2. The oil level sensor can be a lying bar steward and will tell you there is too much oil in there when there isn't. Mine does this. There is a software update that allegedly fixes it but it's not universally successful. I just live with it, and make a point of manually checking my oil weekly or before a long journey.

3. The least common scenario is genuine oil dilution. It does happen, but genuinely rising oil levels instead of 1 or 2 above is fairly unusual. Faulty injectors, the peculiarities of regens and certain types of motoring, and even faulty fuel rails can be the cause. If this is the case a proper diesel specialist is likely a better bet than a garage for diagnosing the exact problem.

If you haven't already done so ensure your oil level is no higher than halfway between the marks on the dipstick and monitor the situation to determine which category above yours falls into. While that's all going on have a search and a read.

Best of luck. Let us know what transpires so we can add the knowledge to the collective mind.

 

[Leigh78]

Hi Sasquatch thanks for the advice. In regards to points 1 & 2 I have had these checked, oil dumped out and replaced with new to a level lower than the high mark. After which the same issue reoccurred and the warning light came on again. I manually checked the oil level and it was high. I’ll keep researching and seek advice from a diesel specialist thanks

 

[catfood12]

Sounds like number 3 fella. Not that uncommon. Also known as making oil. Over fuelling for whatever reason. Used to always be faulty injectors in the olden days prior to common rail. On the T6 could be a faulty injector, or confused ECU regen cycle for whatever reason.

Google diesel engine making oil. I'm sure there's a few similar topics on here.

Next steps are probably check the regen cycles on VCDS and then get the injectors tested...

Good luck!

 

[Leigh78]

Thanks for the advice catfood12 much appreciated