We have a 2008 Karoq 1.6TDI and there’s oil pooling in the injector wells on top of the valve cover. The oil seems to be starting to pool near to the injector nearest to the oil filler.

I have had the injector seals and washers changed for new ones but it still persists. I have also swapped the injector loom as there was a little diesel mixed in it. That’s now cured but the oil is still appearing. It’s not a fast leak, about 1ml a mile.

Has anyone else had this?

I’m led to believe that the rocker/valve covers can crack and cause this. It is my next port of call. I can’t see anywhere else where the oil would get from the engine to the top cover.

Edited 9 March, 20251 yr by Oli

I am going with the rocker/valve covers or the gasket.

Going to follow this guide:

Just a quick update.

I ‘ve had the fuel lines (injector loom) to the injectors replaced but that didn’t change anything.

The seals and washers for the injectors have been replaced (twice now) and the plastic rocker cover or cam cover has now been changed. This included a seal set, gasket, new oil filler cap and all washers/orings.

Looking at the engine from the front the two left injectors remain bone dry. The well nearest to the oil filler is pooling a little bit of oil again. Most of the oil is on the left of the pairing that recess (number 3?) injector but 4 (nearest the filler) is wet too.

After a 50miles round trip there a few ml of oil.

Does anyone have any advice of where to look now?

Small aside anyone have any idea why the previous garage has rubbed off details at the top of the injectors?

Here’s some photos of the current oil state:

Edited 22 April, 20251 yr by Oli

Mine (yeti)had the same. Replaced the injectorseals of #3 & 4, did not cure the leak.

I just cleaned it once in a while. No worries.

Btw, show me a 2008 Karoq😇

Did they use this problem engine in the karoq? They should have known better.

Ah yes.. fat fingers! 2018 Karoq

Problem is the oil pools then drips down the engine quite a bit. We were losing a litre or so every 1000 miles

That is serious leakin’! Mine did only a bit.

If you have a leak this serious I wonder if the valve cover isn’t cracked?!

I’ve replaced that. The old valve cover had a small crack around injector #1.

The injector fuel loom, seals, gasket, valve cover, hold down bolts, oil cap, orings and washers have all been changed.

Hence why I am stumped. I can only assume that injector 3 itself is causing a leak for some reason.

Injector #1 is nowhere near 3&4.

Understand that you’re stumped… I would be too. Sorry that I can’t help you any further.

Sorry probably not clear as was typing on my phone. The old valve cover had at least one crack around the injector seal on the far left. I just presume it’s 1 or the first.

We were getting most of the oil pooling around the third and fourth injector but there was so much it was hard to tell if it had just poured over having filled up the injector well area.

With all the parts changed the left pair of injectors (1/2?) are now dry as a bone. Sadly there’s still oil appearing around the right hand pair of injectors, mostly around the left of the right hand pair (3?).

Edited 22 April, 20251 yr by Oli

Think have it figured out now. The pooling fluid is diesel. One of the injector fittings isn’t quite holding. Probably need to swap the o rings on the leak off or the high pressure line.

So for anyone who has similar problems ours in now fixed. We had an oil leak from the cover and a diesel leak from the low pressure return line in at least one place. Final replacements were the high pressure feeds to 3 and 4, new orings on the return line and a new return line.

The problem with fault diagnosis and taking things in and out is that most of the parts are considered single use and to be replaced after they are removed.

If anyone has leaks from the oil seals around the injectors my advice is don’t bother getting new seals for the cover, get a new third party cover as the seals come with it. A lot of the time the cover cracks anyway when you pop the new seals in due to age and heat damage.

The tiny green o rings for the low pressure line need to be swapped every time you pop the lines.

Obviously (and sadly) the hold down bolts and arguably the sealing washers and orings for the injectors need replacing every time you pull of fiddle around.

Just my own personal findings!