My wife and I bought our 1988 XJS Coupe last April. First thing we did was change fluids then the coolant hoses. We drove it off and on for almost a year with only minor issues but it has recently developed a knocking in the engine. It has had a flutter in idle since we got it but a jaguar mechanic I took it to didn't suggest I do anything about it immediately. The knocking seems to be coming from the drivers side (left) bank and blows blue smoke out the right side exhaust. I want to do as many repairs myself if I can and am very excited to get deeper into auto mechanics. I have the XJS service manual, Haynes book, and the 700pg Jag Experience guide, a good mechanic that charges a healthy amount and now this forum. I have some experience with auto/mechanical repairs but nothing involving fuel systems. I have many questions but here's a few to start...

1) Is it possible to repair a valve problem without removing the entire engine?
2) After depressurizing the fuel system will the fuel pump prevent more fuel than is already in the lines from pouring out when I start disconnecting fuel lines?
3) Is a special tool needed to disconnect the hoses between the fuel rail and the injectors?

Of course any and all advice is immensely appreciated! - Thank you

Submitted by jtallman23@gmail.com on Thu, 03/11/2010 - 12:17

I had a feeling you would get a laugh at the rocker arm bit... I'm obviously out of my depth for the full repair. I did read in the Kirby Palm book that the removal of the intake manifold is challenging at best and that the heads can be next to impossible if they are 'glued' to the block like you are saying. So I'm going to do what I know I can do for now which is an oil change and a compression check. Then I suppose it's off to the professional for a thorough diagnosis.

Thank you both for your good advice.

Submitted by jtallman23@gmail.com on Thu, 03/11/2010 - 11:59

I had a feeling you would get a laugh at the rocker arm bit... I'm obviously out of my depth for the full repair. I did read in the Kirby Palm book that the removal of the intake manifold is challenging at best and that the heads can be next to impossible if they are 'glued' to the block like you are saying. So I'm going to do what I know I can do for now which is an oil change and a compression check. Then I suppose it's off to the professional for a thorough diagnosis.

Thank you both for your good advice.

Submitted by dwcurtiss@virt… on Wed, 03/10/2010 - 17:55

Hello Jesse,

Before you dive into the project you may want to research removing the heads. While I have never personally removed the heads on my 1990 XJ-S (thankfully and knocking on wood) I understand they can be very difficult to break free from the block. A well-know local Jaguar technician here in the Seattle area made (or acquired) a special rail looking device he uses to pull the heads since they can seem to be super-glued to the block.

Good Luck,
Dwight

Submitted by SE98-32482CJ on Wed, 03/10/2010 - 17:07

Jesse--good luck and use this at your own peril with your father in law--No Jaguar since 1951 (and only the MKV) had a rocker arm(s). LOL I hope you find a broken spring or stuck valve but more than likely you have dropped a valve seat or (and I hope not) you have a rod bearing problem. Best of luck. PS there are test you can do to further determine where you are such as a compression and leak down test.

Submitted by jtallman23@gmail.com on Wed, 03/10/2010 - 13:36

Thank you for such a quick response! I can't recall it overheating since we've had it but the symptoms do point that direction. My father in-law suggested, in a ray of hope, that it might be a broken rocker arm, but he's never had to deal with this kind of problem either. So thank you again, I'll let you know what I find!

Submitted by SE98-32482CJ on Wed, 03/10/2010 - 13:21

Jesse in a few words yes you may remove the heads without removing the engine--no special tools are necessary to disconnect the fuel and no it will not pour out (assuming the car is on level ground). I would tell you it sounds like the car has been overheated and doubt that you have simply dropped a valve seat--but removing the heads will be a first step and might be the answer. Good luck!