When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
SBS, not advice to offer and llease be reassured there won't be any wars going on on this thread. Simply as there's no contentious issues, your a member thst needs advice.
Just some question's though:
1) Does your car have full service history?
2) Anything funky done by you (e.g. larger injectors)?
3) No warnings or misfires whatsoever?
I think thst the average age of mkst XK owners averages out at 50something+ as such we may be an opinionated lot. And while we may have had the skill (Ive ported and polished a few and evsn reprofiled my own CAM's) now I'd not even attempt such things.
I wish you a the best in finding a low cost diy fix, but it certainly does sound as if your competent and diligent to see it through
full service history.
Owned the car for 5 years, never a moments problem.
Completely standard
No misfiring, just over heating light on for a mile or so. Sudden stop.
I'm 55 , 35 years engine building experience.
I'm no jaguar expert, just like fixing my cars and motorcycles.
Dont mind opinionated, that's what happens on forums. I am just to long 8n the tooth to accommodate it.
Just posting this for the interested because there seems to be very little out there.
I'm no jaguar expert, just like fixing my cars and motorcycles. Dont mind opinionated, that's what happens on forums. I am just to long 8n the tooth to accommodate it. Just posting this for the interested because there seems to be very little out there.
(Don't feel like the Lone Ranger, brother. There's a few of us around, and you're definitely in good company...)
- Glad to hear that you've sourced some oversize seat inserts; that was my first thought also
- Ditto that all that cylinder coolant didn't get in there while the engine was together
- Having clayed a few engines, marvelous that the pistons came through OK (just try THAT with your 5.0L JLR lump)
Hmm sorry hope you get her back better than it was before. Any idea on why overheated ?
I know Xkr cars won't show low coolant level in the tank since sensors aren't there which might be what have caused possibly?
Hey, I dont usually post in depth things on the internet. I find forums can be a very toxic place, some people would start an argument with them selves. I don't want this being one of them please.
However I though there might be some genuinely interested partys that might like to see some pictures along with progress reports over the next few weeks.
Two weeks ago my 2008 4.2 XK was over heating. That was down to the water pump which was easy enough.
So after two days of driving the car suddenly gave an over heating warning light on the dash. I was maybe a mile or so from my home, so I drove slowly and the light went of. The engine was running great, no noises ....nothing. Then once on my drive the engine just stopped....nothing. It would not re start so I thought I would let it cool down over night before I investigated. The next morning the car struggled to start and when it did it sounded like half the cylinders were running. Strange because the engine sounded great up to the point of when it stopped.
Next day, I did a compression test and on both cylinder heads the last two cylinders were not registering. Mmm, two blown head gaskets maybe.
Started stripping it down and eventually rook the left head of, dam. Valve seat pushed out and has chewed the material around were it sits. Some thing tells me inside that the right head will be the same. It is.....in fact it's worse
Guys and girls, I will keep you updated and pictures posted for your entertainment.
I'll turn my engine off if I see that overheat notification. You probably saved a lot of us major headaches with this post.
Yes, very common on Jags and Jeep 4.7 motors. When they get hot they continue to run lovely as the valve moving keeps the seat in place. Then you turn them off and then the seats fall out of the valves that are not closed. So if one ever gets hot you have to try and cool it down without turning it off, not easy !!!! Often people don't notice they have gotten hot, park them in the garage and then they are surprised when they sound like a bag of nails when started the next day.
Yes, very common on Jags and Jeep 4.7 motors. When they get hot they continue to run lovely as the valve moving keeps the seat in place. Then you turn them off and then the seats fall out of the valves that are not closed. So if one ever gets hot you have to try and cool it down without turning it off, not easy !!!! Often people don't notice they have gotten hot, park them in the garage and then they are surprised when they sound like a bag of nails when started the next day.
I guess I will have to install actual temp gage to be sure I don't burn mine up.
Something similar happened to my 2010 5.0L . Turns out there was a second faulty fan switch BEHIND the engine. We found this after replacing, thermostat, water pump and front fan switch. Good luck.
Originally Posted by SBS
Hey, I dont usually post in depth things on the internet. I find forums can be a very toxic place, some people would start an argument with them selves. I don't want this being one of them please.
However I though there might be some genuinely interested partys that might like to see some pictures along with progress reports over the next few weeks.
Two weeks ago my 2008 4.2 XK was over heating. That was down to the water pump which was easy enough.
So after two days of driving the car suddenly gave an over heating warning light on the dash. I was maybe a mile or so from my home, so I drove slowly and the light went of. The engine was running great, no noises ....nothing. Then once on my drive the engine just stopped....nothing. It would not re start so I thought I would let it cool down over night before I investigated. The next morning the car struggled to start and when it did it sounded like half the cylinders were running. Strange because the engine sounded great up to the point of when it stopped.
Next day, I did a compression test and on both cylinder heads the last two cylinders were not registering. Mmm, two blown head gaskets maybe.
Started stripping it down and eventually rook the left head of, dam. Valve seat pushed out and has chewed the material around were it sits. Some thing tells me inside that the right head will be the same. It is.....in fact it's worse
Guys and girls, I will keep you updated and pictures posted for your entertainment.
Coincidentally, my newly acquired 05 XJ8, with 87k has this exact same issue. I bought it thinking the misfires were a minor issue, easily resolved. Jaguar Joe in Mt. Juliet TN is working on it now. We’ll see.
No the 4.2L is NOT known for dropping valve seats. In fact that is the ONLY example I have ever seen. The main problem is once the low coolant light comes on you must stop. Regardless how close you are to home. We have post after post where they just keep driving for only a little bit. You can't do that with an all Al. engine. High chance of major engine damage if you do!
Took my 2005 S Type R to 132K before selling it. The 4.2L is one of the best engines Jaguar ever made. Especially compared to the troublesome 4.0L!
.
.
.
Coincidentally, my newly acquired 05 XJ8, with 87k has this exact same issue. I bought it thinking the misfires were a minor issue, easily resolved. Jaguar Joe in Mt. Juliet TN is working on it now. We’ll see.
Who is Jaguar Joe in Mt Juliet? I am in Mt Juliet area and need a good reliable guy who can work on jags
Great pics! Here in California we have green coolant for all engines. The head damage is nothing that an engine machine shop hasn't seen before, and while he's at it he will probably skim the mating surfaces to make sure there's no warpage!
Wow. I’ve read many posts that the 4.2 Al engine has no tolerance for even 30 sec of overheating. I regularly ck coolant level and specific gravity but these pics have me spooked. Also that factory temperature gauge is unreliable and a numeric temp gauge is needed. So, how big a deal is installing one? What kind? Where available? Who’s done it?
Thanks
Great info, I've never had the heads off my car but have replaced tensioners and timing chains on a 1998 XK8 4.0 engine because this forum explained it step by step and made it possible. If I have tackle removing the cylinder heads I won't be going into it blind thanks to this thread. Also never knew that the valve seats could drop that easy..
Hey, I dont usually post in depth things on the internet. I find forums can be a very toxic place, some people would start an argument with them selves. I don't want this being one of them please.
However I though there might be some genuinely interested partys that might like to see some pictures along with progress reports over the next few weeks.
Two weeks ago my 2008 4.2 XK was over heating. That was down to the water pump which was easy enough.
So after two days of driving the car suddenly gave an over heating warning light on the dash. I was maybe a mile or so from my home, so I drove slowly and the light went of. The engine was running great, no noises ....nothing. Then once on my drive the engine just stopped....nothing. It would not re start so I thought I would let it cool down over night before I investigated. The next morning the car struggled to start and when it did it sounded like half the cylinders were running. Strange because the engine sounded great up to the point of when it stopped.
Next day, I did a compression test and on both cylinder heads the last two cylinders were not registering. Mmm, two blown head gaskets maybe.
Started stripping it down and eventually rook the left head of, dam. Valve seat pushed out and has chewed the material around were it sits. Some thing tells me inside that the right head will be the same. It is.....in fact it's worse
Guys and girls, I will keep you updated and pictures posted for your entertainment.
So sorry for your experience. Have a 2006 XJR which probably shares the same block. Overheated it and ended up swapping out the engine. Before doing that I replaced all coolant hoses and had the radiator serviced. Hoepfully I get another 100K out of it as I love the car, but it is Jaquar-relaible! LOL.
I have similar problem, not overheating, but loss of compression and I am having the dickens of a time removing the head bolts. I have only been able to remove 3. What sockets did you use?
thanks
09-15-2020, 03:15 PM
2008 XKR Convertible, (mods: AlphaJagTuning ECU Tune , 1.5lb pulley, (200cel cats( are now melted), xpipe, Bosch 001 pump, 180 Thermostat.
