Hey Guys, Me and My dad just bought a 2007 4.2 L SC XKR with 63,000 Miles. I bought the car about 3 hrs from home and drove it back. I'll admit I had never been inside nor driven a supercharged V8 before. The excitement caused me to push the car fairly hard on my drive home but the car made it home fine with no issues whatsoever. I passed the car to my dad since it was his and he drove it with completely no issue for about 5 days.(AC blower out was his only complaint) My dad kept repeating to me that the car is 17 years old and not to beat on it but of course i didn't listen...
A few days later, I drop my dad off at the airport in the car and when I'm on the way home, I'm messing around with the paddle shifters in S, downshift a bit to low into 2nd while still going 30 and the car starts misfiring in 3,5,7 and throws me into RP. I pull over on the side of the highway clear the codes, wait a minute then start the car up again. Drives fine for 30 minutes then I downshift to low again and it plumes white smoke and when I try to accelerate it puts me into RP again. I check the DTC's and its only misfiring cylinder 1. I clear codes and try to accelerate past 2.5k rpms and it throws me into RP.
I limp it home and got on forums. Decided the car needed spark plugs and did them. Car started up fine and drove fine for about an hour then started misfiring in cylinder 1 and saying bank 1 is lean. Limp it home again and now the car wont stop smoking white smoke whenever the car starts or is running. I checked the oil when I got home and it was 3 quarts low.........Put 3 in. The car will now not accelerate beyond 2-3 k rpms without misfiring and running rough. Decided that I couldn't fix it myself and took it to my local Jag shop. They called me today to tell me that there is something wrong with Cylinder 1 and 2 and they recommend a new engine. They didn't elaborate because they didn't go any further because our car is very low on there priority list as a shop and they are more profitable working on different cars. My concern is, Did I ruin my dads engine? :/ I know there are a few things it could be Piston rings, scratched cylinder walls, low oil ETC. I'm really not sure and the guilt is honestly destroying me. Any thoughts or advice on what may have exactly happened is appreciated. I do not feel very smart after this one.

 

Did the engine run without knocking or making other unusual noises? If so, the shop that said that you need a new engine without identifying what parts were damaged either wanted to rip you off or scare you away.

A lot of things can cause RP mode without doing catastrophic engine damage. White exhaust smoke usually means water being mixed into the combustion chamber, a tell-tale sign of a blown head gasket. That's a whole lot cheaper to fix than a new engine.

​​​​​​I'd find another mechanic to diagnose your engine.

Good luck, and keep us informed.


Stuart

 

The engine was running very rough when I took it to the mechanic and I took it while in RP. The mechanic later recommended a new engine but he didn't want the job because he can make more money with other cars. Which is why in I think he's being truthful. There was a certain ticking in the engine bay but I believe that to be the supercharger bearing gone bad and no knocking that I could ascertain. He also said its eating oil inside the engine and its low (no leaks) even after I topped it off before I left it with him and still smoking white out the exhaust.
Another question. Could I buy a non SC 4.2L and stick my supercharger on it as a replacement engine? (only if needed)

Thanks for your time,
Ian

 

Nope.
Need to find someone willing to work on the car to get a straight answer as to what’s wrong.
Hopefully, as mentioned above, just a head gasket.

 

perhaps the mechanic is the truthful sort…. but where is the analysis for the hypothesis? where is the evidence?
Pushing an engine can be the catalyst for a blown head gasket.
And as already stated, white smoke is fluid (coolant), not oil.

If you were 3 qts down on oil, are you certain it was burned as opposed to leaked? Or were you always 3 qts down?
As suggested twice already, you need a proper analysis. Especially before entertaining a game of musical engines.

 

Unless something happened that isn't horrible, being as it was three quarts low you may very well have blown that engine up to the point of either a full rebuild or a replacement.
SO, pretty much sell it for parts and buy a new one. You killed it to the point that repair will cost more than the value of the car.
IF something major has happened.
OR, maybe you got lucky and something minor messed up. As was stated above, white smoke is water, not oil. Was the oil brownish when you checked it? Brown milkshake oil is a sure sign of a head gasket blowing. Not the ONLY sign though. If you did beat on it with water in the oil, the bearings could very well be compromised.
As everyone else has stated, you need a COMPETENT guy to look at it fully, which means paying a premium for a really good diagnosis.

 

Hey guys, Thank you for your time. I'm going to pick up the car today and talk to my mechanic face to face. All I know is that there is something wrong with cylinder 1 and 2. He hasn't really provided much info yet besides that and a recommendation for a new engine. (which he doesn't want to do) I think I may have screwed something up but I don't think it needs a new engine..... Let's see what he says. And yes the car is eating the oil not leaking. Under the car is bone dry. Sadly.

Thanks for all the replies!
Ian

 

+1 on finding a competent shop to diagnose the issue(s).

Have someone perform a compression test and post the results here.

Do not keep erasing the DTCs. Post them here.

 

Doesn't 3 quarts low mean the engine already had problems? Agree w/ everyone about finding someone COMPETENT who can give you an accurate diagnosis and good solutions.

 

Was the oil full when you bought it? An engine doesn’t go bad with age but plastics and rubber do. It’s likely something was amiss prior to you driving it which’s why PPI’s or at least taking it to a specialist for a baseline evaluation’s critical on any preowned vehicle purchase. I realise this advice doesn’t help you now but I reckon diving it hard wasn’t the cause, it was going to happen at some point.