Firstly a Very Happy New Year to you all - I hope that you had a great Christmas and chance for a decent break.

Unfortunately 2022 had a final slap in the face for me. Driving back from Norfolk after a much needed break with my wife who's had a tough year with family and health stuff, my XK decided to dump it's coolant (without my knowing) just as I was about to join one of the big ring road roundabouts near Norwich on our way home. As I pulled away to get off the roundabout the car spluttered and stalled - restarted it and it was misfiring, then the overheating warning came on and so I switched off immediately and but hazards on, wisps of steam coming from front of the car. We were in an unsafe place so the the police towed us to a service road on the other side of the roundabout and we sat there and waited for the AA (came after 2 hours).

I looked in the expansion tank and it was virtually empty. Also looked in the sump and no sign of water just oil. AA Bod filled the system with coolant and asked me to start the car - it ran but misfiring and sounded pretty sick. Car now at garage where I bought it and they think it lost its coolant at bottom of the rad (bottom hose?) but aren't sure why its misfiring so compression tests on Tuesday then go from there. Car is 1 day out of the 6 month warranty I had when I bought it.

Devastated to be honest, absolutely gutted. My feeling is the heads are cooked but I did shut down the moment the overheating warning came on. I just hope to god the block isn't warped - hopefully not.

Just wondered if anyone on here has had a similar failure - my car is 2006 with full history.

 

Well that just sucks.
Sorry, no words of wisdom, just condolences, hoping for the best for you.

 

Thanks mate - I've never had this on a car I've owned in 40 years of driving. Feel sick to be honest.

 

I had the same thing happen with my 4.2 XKR in 2017 after I had owned the car for 5 years. I had a load of vapour just come straight out of the car as I was driving along, nursed it back home with low revs and an eye on the temp (I have a plug-in OBD2 port. Took it to my local indie who found it was a split hose. No engine damage - although was off the road for a couple of weeks while the hose had to be sourced by Jaguar from the US... At the time I though what's going on! looks terminal, in the end was £300 - so hope it's the same for you.

 

Hoping that 2023 is a happy new year for you and that your repairs are minimal!

 

Same thing happened to my car. A hose under the intake manifold gave out and the waterpump was starting weep. Car shut off and when restarted It was misfiring and running really bad. Once the WP and hoses were replaced my Indy reset everything and car has been running fine with no issues or coolant loss. The system can tell that you have no coolant so it hopefully protected the engine, by cutting off power to your coils which in turn makes it run like crap. Start with addressing the coolant leak and replace the WP with a metal impeller type. I think you’re going to be ok

 

Ouch!

Fortunately it sounds like you caught it fast enough to prevent serious damage.

The misfire is naturally a concern but my approach would be to find the source of the leak and run SDD diagnostics before doing a compression test or any other dismantling.

Graham

 

Thanks chap - the misfire makes sense now ! Fingers crossed that it's no more than that.

 

Please update this thread once you get back on the road.

 

Hi there - yes no problem will do. A bit of an update.

The leak has been traced to the rad failing. There's no sign of oil in the coolant tank and no sign of water in the sump (just oil) but a compression test has shown that compression in No 8 is very low so they are going to stick a borescope down and have a look tomorrow plus a leak down test I expect. I'm wondering if its a valve issue with that cylinder (car has done 90k).?

 

dropped a seat guaranteed

 

Does sound like it doesn't it ....

 

So, is this seat separation from the sudden heat soak from rapid coolant loss? Is it a typical result of coolant loss on the 4.2? Or is it a separate event?

 

total loss of coolant to the heads yes. i did it once deliberately on a parts car took a long time.

 

Morning all

I heard back from the garage. They suspect that the rad lost coolant and that head gasket failure accounts for no compression in No 8. I'm waiting on the comp test readings and also what the borescope found, no mention made of valve seat. I am concerned by the rest of the response though which states that they don't repair the engines and that a recon unit is an option but none can be found and have not been available for some time. They have have offered to give a price for a brand new engine if I want it.

That may be the case and they have always been pretty decent but am I missing something here ? Obviously there is a risk that it may have affected the other head (and bottom end) but on the assumption of my taking a risk on those surely its just a question of fitting a new rad and a new head ? Slightly stunned that I'm now left with the option of seemingly throwing the car away or fitting a brand new engine!!

I have rebuilt car engines in the past (but only small 4 pot stuff when I was younger) but the V8 is way, way, way past my capability ..... I would be grateful if anyone on here knows of any Jag engine specialists (UK) who could either work on mine or supply an exchange engine. I'd rather keep my own unit in the car but the no 1 priority is getting it back on the road.

Any thoughts welcome - feeling pretty sick to be honest.

 

Sheesh. If they don’t repair engines, I don’t think I’d trust their diagnosis. You’ve already asked for leads on a real repair shop, and I think that’s your best bet.

 

Agreed. In truth I'm a little staggered by the response and the task now is to get it to someone who can sort it.

 

Yes, you need a proper repair shop that knows engine repair. Anyone can quote you a new engine and install it. Personally I would spend the least amount and throw in a new rad just to see what happens. Youre gonna need it anyway.

 

A few things --

1. The coolant should be tested for exhaust gases. Exhaust gases are injected through the failed gasket into the coolant, and can be detected. Common test. Cheap chemical kit.
2. If it is confirmed that there is a HG failure, replacing it is no more difficult that any other V8. The 4.2 is not a magical Ferrari engine; it's just a straightforward V8. I'm a shade-tree mechanic, and I'd have no trouble taking it on. Any good mechanic should be able to, particularly in the UK.
3. Take it to another shop, and have the "diagnosis" re confirmed. Pick a place that can replace the head gasket if needed.
4. If you're in the UK, I can't believe that 4.2 XK engines aren't available at multiple breakers, if it comes to that. That they claimed one couldn't be found makes me doubt them. I found two for L1K each more or less, in five minutes.
5. No need for a new engine, except perhaps to make the garage owner's next 10 boat payments.

Keep us updated.

Cheers

 

Thanks P99 - have PM'd you