Oil Pump problems
 

I recently replaced the head gasket in my 1991 Jaguar XJ6. After reconnecting everything and starting it up, I found that I have no oil pressure. I have changed the oil pressure switch, but still have no oil pressure. Additionally, I changed the oil and filter prior to start up.

Anybody have any ideas? I really don't want to tear the motor down.

Terry

Terry,

You appear new to this area, and a '91 Jaguar fits into what is known as an XJ40 series.

I reckon a Moderator will shift this to the correct area as soon as they catch up.

I can see no reason why the head gasket work would give zero oil pressure.

Try a couple of things:
1) Remove the wire of the oil pressure switch and ground it, and with the ignition ON the dash gauge should read full scale. This will eliminate the wiring, and dash unit.
2) Fit a master mechanical oil gauge, and note if it also reads zero, engine running of course, which would indicate something sinister inside the engine, and that would be a first.

Also note that when the oil filter is changed, it will take some serious seconds (which feels like hours) to fill, and hence obtain pressure.

Thanks Grant. I will try this and get back with you. Incidently, while testing the TPS (according to the Haynes manual), I managed to cook and explode my ignition coil. I have issues with other gauges on the dash as well. I will let you know what I find.

Oil Pump problem solved
 

After speaking with a number of techs on this matter, I found one that had an out of the box idea. He suggested to prime the pump from the top through the filter tubes. I used heavy duty oil and introduced it via a basting tube. It was slow going but got the pump primed and now I have oil pressure throughout the motor.

Good result.

That is the first time I have heard of a pump needing priming by simply changing a head gasket and oil filter. I suppose if it sat for a longish time with the system open (filter off, and oil drained) it is possible for it to drain back.

Hi Grant,
Thanks for your input. Yes, the car sat in the garage for almost a year before I got around to changing the head gasket. The oil and filter were only changed as a result of the gasket change to minimize any possiblity that contaminates would be circulated in the system post gasket change. I am now dealing with the gauge package issue not working most likley related to the coil incident that I had. If you have any thoughts on that I would like to entertain anything.