So I have put about 25k miles on my XJR since ownership, now at 165k. Did the complete main and secondary timing system early into ownership. I had a tiny leak in the cooling system which I finally figured out to be the coolant bottle was cracked.. So I threw on a junkyard bottle with the cap it came with. A week later I look down at the gauge and the low coolant light is on and am creeping all the toward the red but not yet into it. I pull off the cap and it's split in 2. Now I get 40 miles after topping off the reservoir before low coolant message pops up. It's pushing pressure past the cap into the fender well bottle. To think all this could have been avoided over a 20 dollar new coolant cap..

So here I sit with a car worth 500 dollars in its current state. Haha. Alldata calls for 25 hours of labor for both gaskets. On top of that the heads could need machine work. I would be doing all the labor myslelf..

For anyone that has done the job I would appreciate any tips or suggestions. Are the x308 heads interchangeable as for as na and supercharged? I'd like to maybe send some core heads out to get a jump start on the job if I go ahead with it.

 

The head gasket repair has been covered several times here- have a look in the archives.

My "only" disaster was rounding a head bolt in disassembly which made the job a nightmare. I suggest not working on it when you are tired, in a hurry and not being careful! I would say the Alldata hours are optimistic!

The heads are the same, but I am pretty sure the cams are not and certainly the drive is different in that the NA has VVT.

Good luck

 

Thanks, I tried to start it up earlier and it stopped mid crank. Tried again and it started up, ran rough for a couple seconds than smoothed out. I think the coolant is going directly in one or more of the cylinders.. Now I don't even want to start it again until it's fixed..not sure if you can damage an engine at cranking speeds.. I scanned it hoping it would log a misfire on a certain cylinder but nope

 

Yes! You can bend a connecting rod even at crank speed, but it is unlikely. It is almost for sure you have a bad head gasket.

 

Pull out the plugs, and manually crank it with a 24mm socket and see if anything comes out.

 

I will do that after work. I pulled the thermostat and did a coolant flush yesterday thinking about running some blue devil head sealer to buy me some time. But if it's this bad I need to just bite the bullet..

Thanks, I will keep this updated

 

I'd stay away from any headgasket repair in a bottle repaid gimmicks. They will cause more problems down the line. Do it right.

 

I dropped a valve seat and ended up replacing a head, doing both head gaskets, as well as replacing tensioners and all of the other typical things to do when it's torn down that far.

As far as interchanging heads between your s/c XJR motor and the n/a XJ8 motor, you can definitely do that. In fact, that's exactly what I did on mine. You HAVE TO PLUG the oil port on the front of the n/a head; it's used to control the VVT on the non supercharged models. If you don't plug that, you will have oil pressure issues. I ended up just tapping the hole and plugging it.

If you end up using a head from an N/A motor, I believe the cams are also different. I swapped over my XJR cams to the n/a head. IMO, the cheapest way to do all of this is to just find a junkyard head, get it checked out at a machine shop, swap over your cams and possibly tappets, plug the VVT oil port, and throw it on. Mines been going strong for about 20k miles with an upgraded lower pulley and, some cross country road trips, and some occasional very hard driving.

I think i paid about $150 for a salvaged head then $75 to get it checked out at a machine shop. Of course, you should replace all of your gaskets and replace those coolant hoses that run under the s/c while it's torn down.

There are some other hurdles when breaking down the motor to the head gaskets, but we can get into that if you decide to do the work yourself. As others have said, there are a few write-ups on the project.

Also, DO NOT use any gasket repair additives, they can cause serious damage.



A.J.

 

Thank you for the in depth info. I found that running with no thermostat had the engine running on the 1/4 mark on the gauge and there was no build up of pressure. It was also in the 50's out which may have helped in the engine staying that cold.. I put the stat back in and pressure comes back.. so ya going to buy the timing tools this time around and just do it.

 

As an Update & Addendum....
Land Rover owners forum talks of flushing system with white vinegar (1/2 gallion) as a cleaning agent for cooling system.
Flush system with heater on high several times with plain water...
Followed by adding 1/2 gallion of white vinegar and "topping off" cooling system with water and running the engine for 20-30 minutes, before draining all remaining crud from the cooling system...followed by final 100% water flush ... then refill with coolant concentrate (OAT or Dexcool) and bal;ance until full of distilled water.

Why concentrate? On chance that some air-locked water in the system might dilute a 50/50 premix coolant.
Why vinegar? An exceptional cleaning agent of calcium buildup in aluminum parts, plus easily available and inexpensive.

Question to all experienced Jaguar techs... What are your thoughts of negative effects, if any?