Hello.

I posted earlier about some unsettling engine noise which manifests itself only at startup (for 0.5s, until I get oil pressure and only on a cold engine). The area Jag dealer won't touch it, saying it's too expensive to tear into even to diagnose the problem. So I sought the advise of a Jag specialist in the area.

The specialist pointed to the cheap, plastic timing chair tensioners and quoted an estimated price over the phone of $2800US to remedy the issue. He has not seen the car. He went onto explain how cheap Jaguar was to make that component of plastic instead of metal.

OK. I'll bite. I've read about that issue as well as the VVT solenoid issue (also, someone helpfully suggested both these situations as possible explanations in my original posts -- right on).

Before I take the car there for the recommended exam and likely surgery, I want to verify that my 2007 XK 4.2L V8 actually HAS the plastic timing chain tensioner. Didn't Jag smarten up by 2007, suck it up, and use the aluminum version by then? Just want to check as this seems really, well, short sighted and cheap if the problem has been identified early in the model's life (as X100) and not remedied by 2007.

Anyone care to weigh in on this? Thanks in advance.

 

My understanding is Jaguar solved this problem by MY 2001-2 when they introduced the third generation all metal tensioners.
The MY 2003 and up 4.2 engine is not known for timing chain tensioner problems as all were metal, but on an individual basis anything can happen.
If the VVT is suspect one way to identify it is to try a heavier grade oil, or some sort of aftermarket additive the will do the same thing, i.e. A viscosity improver. This might damp down the noise created by excessively worn gears.
Good luck.
Regards,

 

No way does it have the plastic-bodied ones that were prone to failure. (Ceased being used in 2001.)

I suppose anything can fail, even the new type, but looks like someone was waaaayyyyy out of date.

 

 

Definately VVT solenoids on some high mileage 4.2 v8's they seem to suffer from oil starvation on startup which only lasts very briefly. Still pricey to get them changed, but much less than a chain tensioner overhaul which is not required as they are mk3 all metal timing chain tensioners NOT plastic!

 

Find another Jaguar 'specialist' to look at your vehicle.

 

NBCat is absolutely correct, I was remiss in not spotting this right away. Proof one should always carefully RTFT.
Regards,