After getting the oil changed in my 94 XJ6 with Mobile 1 Synthetic High Mileage 10W30 and a new oil filter, I started sometimes getting the low oil pressure light when I am at a stop and the engine is idling around 600-700rpm. The oil pressure gauge will drop to just above the zero mark but when driving, it's around the 4 mark. The owners manual says that it must be above 2.75 at 3000rpm which mine is usually around the 4 mark. I live out in the desert about an hour and a half from Las Vegas. I am thinking that 10W30 may be too thin for this environment and that I should go with 10W40 or even 10W50. It does not have any leaks anywhere and it does not burn any oil. The car runs like new so I am hoping that I just need to run a thicker oil in this hot environment. What do you all think? Any thoughts or suggestion are much appreciated!!

One more note: The woodgrain on the center console is cracked and I would love to replace it. Any ideas where I could get this replacement trim at a reasonable price?

 

The warranty coverage specification in Mexico is full synthetic 20W-50 for the AJ27.

So, you are in a hot climate, an older engine design, and high miles.
At least 10W40, maybe 15W50. Have to also consider cold nights even if the days are hot.

 

My oil gauge is acting like you as well. It is just above 0 when idling and goes run past 4 when in motion . I don't think blend of tea oppss I mean blend of oil has nothing to do with the oil gauge .
As for the cracked wood . I have an ebay source , check their link
myrtleltd items - Get great deals on XJS, XJ6 12 Series 2 items on eBay.co.uk Shops!

 

Oil viscosity was what I was recommended by a local Jag shop. I see what they mean by when the oil get hotter, it thins out which would result in lower oil pressure. That why they recommended a thicker oil. Thanks for the link on that trim cadillac!

 

Anytime, I use Castrol 10W60 Edge recommended by jag service as well . If it was up to me I would go for 10W40 .
We were using 20W50 in my old bugger ('88 XJ40 )

 

My 88 XJ6 had same problem,changed preasure switch but no better,I use 15-40,I am
now in processe of doing a ring job and have noticed bearings have some ware so that may be a couse of low oil psi at low rpm,maybe there is a trick to boost the pump up a couple of lb's

 

Here is an additional tip.

Consider 15W-40 DIESEL formulations if they are suitable for your older vehicle. They cost a couple of dollars more than the equivalent conventional gasoline formulation.

They still have the higher levels of detergency and anti-wear additives of earlier oils.

Don't forget that life inside a diesel motor is much more stressful on rings and bearings than a gasoline motor.

-- "better living through chemistry"

 

Depending on the engine, it is as simple as shimming or replacing the pressure relief spring.

It will not change anything at idle, but you will see higher oil pressures at highway cruise.

Try the diesel oil as above. You want the zinc anti-wear additives that were dropped out.

Diesel engine bearings take a real pounding because they are basically, well ... dieseling, all of the time.

 

When I first got my XJ40 a few months ago, I noticed erratic behaviour from the oil pressure gauge - in normal driving it goes up, in traffic it was going near, and sometimes into the red. After doing some research, I discovered that these gauges were temperamental, and Jaguar eventually replaced them with a gauge that simply pointed to the OK zone and didn't move from there if the pressure was OK - it would simply go all the way down if there was no oil pressure at all.
I am not suggesting that you ignore your concerns, but this could be your problem.
Like my friend said above, you can get a ski slope on Ebay (UK) for as little as 10 pounds, though some want as much as 35 for them. Up to a few months ago, Jaguar Classic Parts (Part of Jaguar) had them brand new for somewhere around 50 pounds.

 

I would think if it was a major problem I would have seen way more ware on bearing shells so are now leaning towards calabration of gauge,with 195000km's on engine,crank and pistons are in great shape,to bad I didn't change that fuel filter!

 

In an 'older' Jaguar (like my 3.2 '92 XJ6) I use Castrol 25-50.
Now has 260000km and runs like a watch.
Just my 2c mate.

 

I have exectly the same problem on my XJ40 4.0 Hearse, normal pressure on running, once its up to temparature though its dropping in to the red on idle

 

My 88 did that when I first bought it. After reading up, I swapped the out out to 20w50, and I went from being in the red to the gauge maxing out.


this is at idle now.

 

I realize this is an old thread but wanted to give my 2 cents... My 92 Vanden Plas is having the same annoying issue. On hot days when sitting at a light, the oil pressure gauge is near zero, and the idiot light blinks intermittently. The car has 146K original miles and runs perfect. I've always used Castrol 10W-40 as recommended in the owner's manual. I will follow the advice on this thread and use a thicker oil this summer.

Cheers.

 

Sounds like you need a new pressure sender like the rest of us did, yours is worn out.
You can get an aftermarket one (Uro brand) from Rock Auto for about $20, though you might have to fit a 75 ohm resistor between the sender and the dash gauge to calibrate it properly.... Maybe not, it might read ok, usually they read high out of the box, do most of us fit the resistor ... haven't tried the Uro unit myself though, maybe it's calibrated ok.

Larry

 

Thanks for the quick reply.


I see it on rockauto.com for $17.99, but I also did a quick web search and came up with the two shown below from partsgeek.com.

I'm familiar with the one on the right since I've replaced sensors on other vehicles before. Is the one on the left possibly for the V12?



Thanks.

 

No the one on the left is what is called an "idiot light", with the correct resistor it will always show good pressure at the same reading regardless of actual pressure. The one on the right will record the correct pressure if fitted with the correct resistor.

Several brands use a 75 ohm resistor.


Larry

 

Hi Palmero,

Using 20W-50 oil may help. As Larry says, your oil pressure sender is probably past its prime. It often helps to remove the sender and clean the threads on the sender and in the port on the engine block, but it's such a hassle to do it makes sense to install a new sender while you're at it. Don't forget to clean the electrical connector too, since it often develops a coat of gunk.

Cheers,

Don