I’m in the process of eradicating the engine oil leaks on my car. I replaced the timing cover gaskets (with rtv in the 8 joints), the harmonic damper seals, the oil dipstick o-ring, the valve
cover gaskets, spark plug o-rings, valve cover bolt grommets, crankcase breather vent o-rings, and the fuel line o-rings from the line that sits on top of the valve cover. I also cleaned up everything as I went along and made sure everything was torqued to spec.

I also had the rear main seal, oil gasket plug seal, and transmission front seals replaced a couple months ago. I did my oil cooler lines a couple of years ago (less than 8k miles)

Yesterday I began the end of this saga with an oil and filter change. I drained the oil, replaced the filter (I made sure that the old filter’s gasket was not stuck to the housing), and placed a copper washer with the oil drain plug. I then cleaned the bottom of the oil pan and on up of it as well. I let it sit overnight and today I decided to give it a check before filling it up with oil.

I somehow found it was still leaking oil from the rear of the oil pan (odd considering the pan is empty), so I ordered a new oil pan gasket and will wait for it to arrive before filling up with oil. I also saw 2 drops from around the oil filter area.

Sleuthing around the forum, I found mention of the oil filter housing gasket for the 4.2 engines mimicking an oil pan leak, but none of it was specific to the X100. In fact, most of the information of regarding the S-Type, XF, X150, and X350 4.2 engines. The part number from those threads (NCE1842AA) does not seem to fit the 4.2 X100 nor do I find any such gasket in the parts catalogues and diagrams for our cars.

Is the oil filter housing adaptor gasket relevant to the X100 4.2 V8?

I also read that a sensor around that area can also mimic an oil pan leak. Is it the oil pressure or is it the oil temperature sensor?

 

Never heard of an oil filter housing gasket on these cars. Looking at my SNG Barratt parts catalog (received in February 2014), page 6, "Engine Sump & Oil Pump", I see a listing for an "Oil filter adapter" (NCA1702AB). The drawing shows it located between the oil filter and the base of the housing that the oil filter screws onto. I have changed the oil & oil filter every 6,000 miles on my wife's 2006 XK8 since we acquired the car in February 2012 and I must admit that I have never noticed this so-called adapter. Take a look at the threaded stalk upon which you screw your oil filter on and see if there is indeed an adapter there....

 

Those engines are more akin to the AJ28 (4.0 S-Type introduced in 1999) upper sump that does mount to the block differently.

 

I just spoke with Frank at SNG Barratt. All XK8s and XKRs indeed have that oil filter adapter, because that is what you are actually screwing your oil filter onto. The other side of that adapter screws into the block....

Because your oil filter's gasket completely surrounds the entire oil filter adapter, even if the adapter leaks, your oil filter's gasket will keep any oil from escaping as long as the oil filter's gasket is not faulty....

By the way, the oil filter adapter is no longer available so always be careful when removing an old oil filter or installing a new one....

 

Thanks guys! From the information you shared and what I have investigated it seems that those other Jags have a different oil filter adaptor. Their oil filter adaptor, instead of being bolted directly to the engine, is attached to a bracket that is held by three bolts and which compresses a double-o-ring gasket.

In our cars, unlike those other Jags, the oil filter adaptor stud is bolted directly to the block (or upper sump?). The adaptor is the part which our filters screw onto.

Why Jaguar felt the need to change this, I don’t know. But our design uses 3 less bolts and 1 gasket less, which in my eyes is a superior design.

 

The oil filter mount (right hand, front of the engine) is BUILT-IN/CAST-IN to the upper sump on the X100 and X308. Only the filter 'O'ring seal is needed.
Other normally aspirated V8 engines have the oil filter/oil cooler mount BOLTED to the upper sump on the front of the engine.(between the oil filter and upper sump)

Maybe that is the difference?

 

Yes, that is definitely the difference. You explained it much better than I did.

It's important to note that that means that the oil filter adaptor/mount is not going to be a concern for leaks unless the filter is loose.

What about the sensors? Which of the oil sensors is known to be a source of leaks? Is that oil pressure or oil temperature? Does it use an o-ring or a crush washer?

 

I installed the oil pan gasket and finished the oil change today. Took it out for a test drive a couple hours ago. I checked under the car a few minutes ago and there are no oil leaks.


Will check again tomorrow, but hopefully I have finally eradicated the leaks. Fingers crossed! 🤞

 

Well done...

Where did you source your oil pan gasket, who made it, and what was the part number?

 

I bought it locally for $39+ tax. It was the Eurospare gasket. The part number is: NCA1730AD. It’s the only gasket non-Jaguar branded gasket I bought because it is so easy to change.

The Eurospare was a perfect fit, seems to be good quality, and looked identical to the old gasket.

 

Good to know. Is it all rubber, a mix of cork and rubber, or something else?

 

All rubber, just like our valve cover and timing cover gaskets. They’re really more like o-rings. It sits in a groove on the oil sump.

 

Reporting back there hasn’t been a single drop of motor oil that has leaked since I completed this R&R of the gaskets.