1993 XJ6, 128000mi, Drives nice, no stalling, recent Oil &
Filter change, The Oil Pressure while driving is at 4, When
at idle the pressure gauge drops to just above 0, The Oil
light Might go on momentarily, but only once in a while, This car has been sitting for a couple years, started regularly ???
Thanks
Jim

 

If your oil level is okay, then next oil change you might try something a little thicker, say a 10W40. Just guessing on what "thicker" is because no mention of current oil grade was made.

 

Or even 20W50, which is what I run in my 92.

 

My usual first choice too. Castrol conventional.

Although lately the 15W40 diesel formulations are looking really attractive. Shell Rotella in particular.

 

Would you guys know if this series of engines has flat tappet cam and lifters?

 

The good thing about rotella is that it contains zink which cuts down on wear of the cam and buckets.For non diesel oil try brad penn its the old kendall gti.

 

Mine does same thing too, I do use 10 W60 Castrol Edge , I asked numerous times and they said dropping oil pressure when the car idling was normal

 

You could try changing brands or upping the base weight from the 10 of the 10W60 to 15 or 20. Within a API rating grade, various brands can meet the grade but still be considered thick or thin for that grade. 20W50 Castrol conventional, 15W40 Castrol Diesel conventional or 15W40 Shell Rotella T5 conventional.

 

Thanks for the info, I am using 5W30 castrol high mileage, Winter is on the way around here, I live in the Buffalo, NY area, But I will try a thicker grade at next change.
Jim

 

There may not be anything wrong at all, actually. The original gauge transducers were notoriously erratic, and showed low pressure when there wasn't low pressure. Ultimately Jaguar came out with a kit to replace the transmitter with the one the X300 used, and added a link lead that contained a resistor. That was part number JLM20791. I don't think the kit is available anymore, so the best bet would be to get the LNA5642CA transmitter and see if the LMD3325BA link lead is still available. If it's not available, post back and I'll try to find out what the resistance was so it can be duplicated.

I personally wouldn't be a fan of using a heavy weight oil, the AJ6 just never really had any oil pressure/delivery problems.

Cheers,

 

Hi & thanks for the info, It looks like part #JLM20791 is available on eBay, I will update after I change it out.

 

the 5w-40 diesel synthetics will serve you well in those conditions. I'd prefer to use Valvoline....but a gal. of Shell Rotella T6 is about $5 cheaper - makes a difference when the Excursion consumes near 15 qts for a change and the X300 8-9. "Winter" in TX not the same as what you face...but last winter I was still "searching" and had Valvoline 20w-50 racing oil in there....considerable noise on startup - better fuel mileage with the 5w-40 as well.

I've also had the transducer issue - but in my case - pressure went to 0 and the light came on. I found the kits fairly readily available from Rock/Amazon/Ebay on the order of $50. Not sure if it is the same resistor value for the earlier model or not though. According to the TSB...one should reprogram the X300 IP after installation, but my needle goes to very near the middle of the guage, so for me, it is ok. Just be aware, you are replacing the transducer with an 8 psi pressure switch.

 

That's true, but remember we are on the XJ40 forum, that bulletin never applied to the XJ40. But if this is done to an X300, the IP needs to have the programming change.

For the XJ40, the part just superseded to the kit in the parts catalog, the X300 got the Tech Bulletin.

Just want everyone to be clear.

Cheers,

 

The resistor in the link lead P/N LMD3325BA is 150 Ohms, 5% tolerance, one watt. Color bands for that resistance are Brown/Green/Brown and Gold tolerance band.

Cheers,

 

Could this fix be applied to the 1988 Jaguar if the oil presure is also dropping intermittenly...I've been driving my car this way for over a year and not had any problems but it does make me a bit worried when the pressure drops.

 

The 1988-89 cars used a different transducer than the 1990 and later cars as the instruments are different. You would need part number C46272, which is still available. I honestly don't know if you could get away with using the switch and resistor on your car, never tried it.

I know there are a couple of industrious chaps here on the forum that have switched out a 1988-89 instrument pack for a 1990; and I don't recall them saying they changed the transducers. So you might be able use the switch and resistor. If it were mine, I'd just use the original part.

Cheers,

 

The other thing you might want to try early on is to hook up another gauge to see what the oil pressure is. There is a chance that you got a bad oil filter. Years ago, I changed the oil filter in my Mercedes (using a name brand), drove about 250 miles, and the next time I cranked it the oil pressure was close to zero. I even took the valve cover off and confirmed this. Changed oil filter again without changing oil and everything was fine when I started it.

 

I use Castrol Edge Sport. 25-50 mineral oil in my '92 3.2 @ 260000 kilometres.

Some details.
• Gives low oil consumption.
• Excellent oil pressure at high temperatures.
• Excellent protection against wear. Protects radical cam profiles,
tappets and other highly stressed components.
• Resists viscosity breakdown at high temperatures giving higher
viscosity at extreme temperatures than traditional "straight 50"
oils.
• Synthetic components increase load-carrying characteristics for
crankshaft bearing protection in older technology street machines
and “big bore” competition engines.
• Formulated to give better cold start performance than traditional
"straight 50" oils.
• Race proven performance, including wins at Bathurst, Auscar
championships and Drag racing.
• Assists in maintaining optimum oil pressure in older cars.
• Complies with the Australian Motor Industry agreed phosphorous
limits for prolonged catalyst and oxygen sensor life.
• SAE 25W-50 APISG/CD. Incorporates full API SM detergent and
sludge control additive system.

Typical Characteristics

SAE RATING: 25W-50
KV @ 100C : 21
KV @ 40C : 212
cP @ -10C : 9,500MAX

HIGH TEMP
HIGH SHEAR VISCOSITY : 5.4

POUR POINT (C): -24
TBN: 8.0
API SERVICE RATING: SG/CD

 

Alldata has some info for the engine oil posted for the 1990 XJ-40.

ENGINE OIL
* CASTROL GTX

^Above -10°C (14°F)15W/40, 15W/50, 20W/40, 20W/50 [1] ^Between -20°C (-4°F) and 10°C (50°F)10W/30,40,50 [1] ^Below -10°C (14°F)5W/20, 5W/30, 5W/40 [1]
* preferred Brands

SPECIFICATIONS
[1] BLS.22.OL.02, BLS.22.OL.07, CCMC G3 (if not available use min. SF)

I have been using GTX 20/50 for a while now but in the dead winter I have changed to 10/40 as it can get to the - here early morning.