I did a search but no result what is everyone's oil pressure running mine starts out above 50.But as the temp rises it drops. Changed out the sending unit not a fun thing to do mine was stuck on. But same result the idiot light don't come on when driving but does at start up. Just curious as to what other people are seeing.

 

I think that generally run a bit low compared to other engines; mine drops to about 20 psi on tick over although the oil has just been changed for Millers Motorsport CFS 10w60 (triple ester formulation whatever the hell that is) so I will be interested to see what the difference is when I get it back.

 

Perfectly normal for the pressure to drop when the oil gets warmed up.

Cheers
DD

 

Once warm mine pretty much sits at zero at idle.

 

It depends what type of XJS one has - 5.3, 6.0, 3.6 or 4.0. You haven't mentioned what car you have. And also depends if you've fitted a Jaguar sender unit or aftermarket.

Paul

 

sorry bout that mine is the 5.3 and she also sits about zero on the gauge. the unit I replaced was am aftermarket but the oringal was jag and it read same thing but was destroyed in the removal.

 

All of my 5.3's do the same thing. I have never heard of a 5.3 going bad due to low oil pressure so I no longer worry about the gauge reading.

Mark

 

OK now worried. My 5.3 on startup slowly climbs to about 20 then while driving sits at 30 and at warm idle will slip back to 20. Oil light only ever came on once when cornering hard under brakes.

 

Are you running the correct spec oil? I would suggest either a 20W50 or 10W40 weight oil. My 90 V12 runs about 55-60 oil pressure at cruising speed. At warm idle at a stop sign it is about 15-20... BUT my car only has 32K miles. Maybe your gauge is failing.

 

mine is running lucas and 20-50 so I am guessing that it is going to be normal till I see the light I am not going to worry bout it.

 

The general rule of thumb is 10 psi for every 1,000 rpm (call it the yard stick rule and yard sticks can vary). Low pressure at idle is usually fine, as long as there is enough oil in it.. HA!

As long as you are seeing 35-50 while cruising down the highway, you ought to be fine, and a lower reading doesn't mean trouble (always) either - if your gauge jumps up rapidly when you goose the throttle, this is good stuff. 20/50 is good in these old engines, the down side being that it can pump up the oil temp a bit.

An interesting note, on our V12 XKE, rev for rev, the XJS always reads lower pressure. I'm sure there is a known reason that I haven't bother to source, but should.

Cheers,

Jeff

 

The guy that sorts my car has put Millers 10/60 in; He hasn't mentioned the oil pressure reading but he reckons that it has certainly quietened the cam chains down.

 

Correct me if I'm wrong but I believe the numbers on the gauge 0-8 are for pressure units in Bar. So multiply the reading by 15 to get psi. I see where Jaguar had a couple service bullitins out that tell you not to pay any attention to the gauge reading. As long as the light is off keep going. I got my 92, 5.3 convertible running and on the road for the first time this weekend. It's very difficult to ignore that gauge. Mine was in the red at idle and about 1.5 - 2 bar at cruise fully warm. I may put a sticky note over it so I can keep from being distracted.