I havnt yet managed to locate the source of the leak, any suggestions.


On my 1999 x308 AJ27 4.0, I have a small but persistent oil leak from above the Air compressor, (see diagram below) but where from exactly?
Is there a common failiure point around this area apart from the timing cover bolts in that area itself?


Its not the crankshaft thankfully, (seal replaced and have checked carefully its not the problem)


best regards
Peter

 

Start by checking the timing cover (Y shaped) bolts on the left outer side. Bolt heads are 8mm or 5/16" head.


There is a rubber seal that fits in a groove along the perimeter of the cover. I hope that the bolts are loose. The seal might be age hardened, but it can be changed with some effort. Read some of the posts about timing chain tensioner/guide replacement. You will have to buy the tool to pull the harmonic balancer in order to remove the cover in order to replace the seal.


The item that you are asking about in the drawing is the serpentine belt tensioner.

 

The 'What's this' is the bottom of the Drive Belt Tensioner.

Given the oil is dropping onto and around the drive belt, it could be thrown well away from the source.

As Mike suggests, I'd also look at the Cam Cover rubber seal first. After that check the seal arrowed in blue;



Graham

 

The item you have labeled as the idler pulley is not an idler pulley. It is the power steering pump pulley. Are you sure it's not the power steering pump or hoses leaking?

 

Just a point of interest - the blue arrow (Graham's post) is pointing to the VVT on an AJ26 engine, at least my AJ27 has the VVTs on top of the cam cover, or am I off base here ? Can you tell if it's oil leaking or power steering fluid ?

 

Sniff test. Power steering fluid is ATF and has an unpleasant odor.

 

Hello
The oil leak is engine oil , not power steering fluid. The oil is a nice yellowish colour, so im sure its engine oil. ATF is red to my knowledge.


No oil smears or anything from the cam covers, I think its emanating from the drive belt tensioner area somewhere. Nothing around the crank shaft oil seal, I recently replaced it anyway, its all bone dry around it.


Could the oil leak be from the bolt that secures the drive belt tensioner to the body of the engine? Or is that bolt external to the oil gallery of the engine and hence not a possibility? I cannot see this said bolt but it must be somewhere, im not sure if the bolt goes into the oil gallery or not.
I have loosened and re-torqued (13nm) one timing cover bolt in this drive belt tensioner region, so will know after a drive if its the cause.


Are there any oil cooler pipes in this area or to consider between the aircompressor pump and the body of the engine?
best regards
Peter

 

The part that you are pointing to with the "what this" is part# NCA7739E Drive belt tensioner:

Part no. NCA7739AE | Drive belt tensioner parts from Jaguar Classic Parts UK

Jim Lombardi

 

Ok
I think I located the leak, so far after a good run , no leaks . What I did was loosen and retorque the timing cover bolt near the belt tensioner. Torque is 13NM for these timing cover bolts incase other wish to know.
Another good run or 2 with the car should prove the point imo.
regards
Peter