Hi everyone,

I’m looking for some advice on tracking down an oil leak on my Ford Duratorq TDCi engine. I've noticed a fair amount of fresh, wet oil pooling and spreading around the top and side of the engine bay, and I’ve attached a few photos to show exactly what's going on.

Here is what I'm seeing:

Around the Oil Filler Cap: There is a significant amount of wet oil pooling in the recesses around the Castrol oil filler cap and the valve/rocker cover area.

The Large Boost/Intercooler Hose: The thick rubber hose right next to the filler cap is completely coated in wet oil, especially around the lower bend and the metal clamps.

Side of the Engine/Wiring: Looking down the left side of the engine (near the belts and wiring harnesses), the oil has run down and is coating the corrugated wire looms and brackets below.

A few extra details:

The car is a Duratorq TDCi (as seen in the full engine bay shot).

I haven't noticed any major performance drops but I have noticed black smoke under hard acceleration. I’ve sprayed the engine with engine degreaser but it’s failed it’s mot (which has now expired) so do not want to drive it. The garage suggested it needs a new sump however the leak is coming from the top of the engine and leaking down the sides of the sump.

Before I start throwing parts at it or stripping things down, I wanted to ask the experts here: What are the most common culprits for a leak in this specific area on this engine? Could it be as simple as a failed oil cap seal, a weeping rocker cover gasket, or is it more likely oil vapor blowing out of a split in that large rubber boost hose/PCV system?

Any advice on the best way to clean it up and pinpoint the exact source would be massively appreciated!

Thanks in advance!

Hi,

These always were a leaky engine. The sump probably is leaking as most of them do. But as you say, there are definitely some leaks higher up as well.

Have you checked the oil level? Even with a dodgy seal I wouldn't expect that much to be blowing out past the cap.

A split boost hose is the second most likely culprit, if the oil level is not excessively high. (A few mm over max is acceptable).

The best way to clean it up is as you've already started to do. Spray foaming engine degreaser all over the affected areas. Leave it to soak in for a few minutes. Agitate with a cheap paintbrush or similar. Then rinse off with water.

Check your top turbo boost pipe (as per 1st & 3rd pics) small black pipe connecting to inlet manifold beside the oil filler cap, Mine did exactly the same, My pipe had a small tear at the bottom and was leaking oil out over the top of the engine, not a great sign oil in the boost pipes but all higher mileage turbo cars especially diesels have oil in the air intake system - This was the cause of my oil leak plus it was underpowered & hissing air out, New pipe is £20 off the net & very simple to fit