I agree with Pistonbroke, I think the issue points at the oil pump relief valve which may have some debris holding it open or a damaged spring that lets it open too easily. Pull their pump out and tear it down to see what's going on. Also look at the VVT units to see if they are leaking oil, they may have been pulled and reinstalled wrong.

 

You will have to find a diagram of the pump and look for a ball bearing with a spring behind it .Sometimes its external ...

 

Regardless of what oil pressure problem may be going on in any car, I like to see a mechanical gauge reading.
I do not know how difficult the special Jaguar adapter is to buy now.
I am finding an international thread adapter on Amazon ( ) which looks like it would work with my gauge (1/8 NPT fitting).
Also, it looks like Thread Tool Supply offers a wide range of international thread adapters.
( https://www.threadtoolsupply.com/thread-adapters.html )

 

The

https://www.thejagwrangler.com

sells a very well made “stand alone” adaptor that is designed to be permanently installed into the existing oil pressure warning sender port in the engine block adjacent to the oil filter.

it’s a perfect match for the odd sized factory hole and the jag wrangler adaptor has a provision for installing an aftermarket oil pressure gauge, either permanently ( my choice ) or temporarily. The jag wrangler adaptor also has the provision to keep the original low oil pressure warning sender.


If one desires to only temporarily install a mechanical oil pressure gauge, the threads in the adaptor are the universally used 1/8” NPT. So it’s simple to used an easily sourced plug until the port is needed again.

Z

 

I should mention that saying "remove the oil pump" is not an easy procedure. The oil pump is not in the sump, it is on the crankshaft under the front cover and is driven by a key on the crankshaft. I would look into whether you can pull the relief valve without removing the pump.

 

OK today I put a mechanical test gauge on the car. when it started it went right to 50psi. as it ran and heated up it steadily dropped to 5psi. When I would rev it up oil pressure would go to 40psi but I noticed a tapping,clicking sound coming from top front of the engine. If the oil pump was bad wouldn't it be bad all the time not just when it is warmed up? any ideas what it could be and how to check to find out what it could be?
Thanks in advance,
Jay111

 

Does tapping diminish as the motor warms up ? If so it could be piston slap, which I believe is commonplace on our cars, I certainly have it on my ‘02 XKR.


I’m sorry l, but I have no suggestions other than what’s already been posted.

After a blow out failure on a 3 year old (Jaguar branded) oil cooler hose I finally got around to installing an oil pressure gauge, along with a new hose set.

For comparison, my cold oil pressure is 75 psi at idle. Once the car is fully warm the oil pressure is about 25 psi at idle, 35 at 1,000 rpm, and 60+ at any rpm over 2,000.

Am saving up for a full sweep electric AutoMeter gauge with an adjustable warning point. I prefer the full sweep gauges as they are easier to read at a glance, and
likely more accurate.

Z

PS: the oil being used is Mobil 1 0w-40 or Mobil 1 5w-40. Both show the same oil pressure. Those viscosities are the owner manual’s recommendations for my climate.

 

I would think the 50 psi is the opening pressure for the releif valve or the max the pump can do with the leak you have.
I would investigate the tap..my piston slap does not go away when hot always it has a mind of its own.
I suspect some leak in the area near the click ...VVT ? maybe .

On an older simple 4 cyl ford I would have said main bearings but I think its more subtle than that.

 

Where does the oil leak in the VVT ,how do you check for a leak there?
Thanks for the help,
Jay111

 

I am no expert on VVT but as it rotates and the oil feed is fixed it must have an oil seal.
Considering the other guy has 75 psi I am not totally convinced about the oil releif valve and 50 psi.
Am sure micheal can tell us the correct setting ..Hope there is not a bit of plastigauge stuck in it .

Investigate the click first with a stethoscope

 

For what it’s worth, my manual says the oil pump pressure relief valve opens at 65 psi.. The way those things work, it may not be fully open at that setting. So I would expect the maximum cold oil pressure to vary slightly from car to car, but be close to 65 psi.

Z

 

Maybe this has been mentioned?

On each of the two VVT solinoid carriers are 2 slip style seals that can wear. Then there is a seal (I think it's just a hard mating face to mating face seal, on each VVT solinoid carrier... The 4 slip style seals are readily available BUT I don't know how much pressure them things would carry.

See seals below.


These ride at the area circled above.

 

I generally replace those seals if I have everything apart. (at least check them before assembly)

 

I would guess that if those seals had failed,,, you would be getting codes for a failure in the area of timing advance... I know that there are codes like p1396 (I think it is) but I don't know if a code like that (or what code would be) would be triggered for a failure in these seals... Maybe someone else knows...?

 

Pressure relief valve sticking open when the motor is hot ?

At this point it seems like some degree of disassembly is going to be required to successfully troubleshoot the issue.

Z