I'm looking at a 1996 xjs 4.0 and the pictures show 680 rpm on the tach and barely above 0 on the oil gauge, when I asked about it he send me 2 pictures , the tach is at 800 and the oil gauge in the middle. So might this be the gauge, sending unit or something more serious Are there any common problems with this in the 4.0 U.S. model with 65,000 miles???? I'm just trying to decide how much to offer the dealer with what repairs it might need. Thank you. Ed.

 

Hi Ed

In that case don't offer him anything for it, until you have actually seen the Car in the flesh and seen how long it takes to build up Oil Pressure and what that Oil Pressure is

And then report back with your findings, or you could be making a VERY Expensive mistake

 

Orangeblossom gave the safest advice. I'll take the opposite approach.

Problems with gauges and sending unit are common on these cars. Internal engine and oiling problems are rare. Personally, I wouldn't think too much of it. There are other risks with buying a car sight-unseen that are more worrisome, IMO.

If your comfortable with the purchase in all other respects I wouldn't let this issue kill the deal.

Proof of proper servicing might help assuage your anxiety.

Or, hire an inspection service to give the car a once-over.

Just my two cents. We all have different comfort levels !

Cheers
DD

 

Ed,

A couple of thoughts:

The gauge reading on a 4.0 XJS is subject to a number of vagaries. First of all the sender units can be slightly unreliable. And secondly the gauge is subject to under-reading due to the problems that are caused by poor current integrity in the instrument cluster. When hot, gauges can drop very low on idle but invariably immediately rise as soon as revs go above 1000rpm.

In the 90s, as a result of US owners moaning that their gauges fluctuated (which they should do, depending on engine revs!) Jaguar introduced a revised sender unit that forced the gauge to sit at 4 bar unless the pressure was almost zero. I've always kept my original sender as I want to see the real pressure as it fluctuates with engine rpm.

The "official" pressure on a 4.0 XJS is 2.75 bar at 2000 rpm, so even a mid-position gauge (4 bar) is indicating a very healthy pressure.

Personally, I wouldn't worry about the engine as it's probably fine (AJ16 engines are extremely strong) but I would use it as a bargaining tool to get the price down!

Good luck

Paul

 

Common fault that Jaguar addressed in a few TSBs for the AJ16 and V12 engine.

bob

 

If you look up a pressure sending unit on eBay you will see a pressure switch with a wire and resister to add resistance to read mid scale on the gauge. Which turns the gage into an idiot light. The service bulletin removed the pressure transmitter and added a pressure switch just like the one for the oil light on the warning panel. If when the engine starts and the low oil warning light goes out you have pressure. When cold starting the gage should read 4 bars shortly after the light goes out.