My 4.2 is noisy on start up (1000 mies after an oil change) and I get the feeling that I sould be doing some preventattive mantenance work on it since it is now at 116,000 miles.

However I know nothing about these engines and am not sure where to start.

Is this kit any good? Jaguar XK8 - XKR | Jaguar | British Parts UK

I am keen to hear what other have done on their 100k+ milers for engine maintenance.

 

Noisy in what way?

One common thing is that the valve train clatters on start up and quiets down after a second of two. One common reason for this is either a cheap oil filter or one with a bad check valve that allows the oil to drain completely back to the pan.

I only mention it since you say there was a recent oil change.

 

Yes its a jag filter I have on.

Sounds bit like a diesel for the first 15 seconds or so, and then have a sewing maching noise only under load that is is not related to rpm or engine speed for a minute or so.

 

The first one sounds like it could be a bad check valve in the filter. Did it make that noise before the most recent oil change or did it come on very suddenly?

For the other one, hard to say exactly without more description. I'm not sure what you mean by a sewing machine noise.

 

The diesel noise it not new, it has been there since we got the car, aleviated by oil changes but comes back, the sewing maching noise is maybe a fast tick tick tick, at about 10Hz but as I say not related to rpm or speed. I tried to record it but it does not show up on recordings but is easy to hear when you are there.

 

It's a 2002... does it have 3rd gen tensioners?

 

How can I check, there is no detail on any engine work in the service history.

It is a MY2003 4.2 engine.

 

All of the 4.2L have the 3rd generation tensioners, Europe just got it somewhat earlier than the US did.

 

XK8s have Variable Valve Timing units.

The VVT Actuators can become "sticky" and cause a clicking noise.

First gen (97-98) VVTs are 2 position units.

Second gen (99 up) are variable position units.

 

Is there a cure?

This does not sound too good https://www.jaguarforums.com/forum/x...sioners-71904/

I could be mistaken but my gut feeling says the "under load" sewing machine noise is also ambient temp related, the cooler the weather the less pronounced it is, so would be oil viscosity related.

The loud start up clatter is there regardless of the temp.

 

Hi there,
F.W.I.W... I've noticed this also with my '03 xk8 w/ 4.2, it's done it since I've owned it. I've looked into it to a degree, from what I can tell, it comes from the throttle body area only during the fast idle stage of warm-up. It goes away fully after the idle settles down. I think it's the throttle plate rocking open and closed ?... I cant prove this as the engine wont run with-out the air hose connected. In any case, mine has done this for the past 40,000 miles and has not gotten worse nor caused any problems to date. I'm sure with all the great minds on this forum, one of the Jag techs may know more about this? I think there are other threads on this too. Next time you start it, listen in the TB area.

 

My car only does it under load for the first minute or so, so it is very difficult to pinpoint as I need to be driving it to hear it.

 

Well, I must say the "only under a load part" confuses me. I can't figure why oil circulation or the valve train would be load sensitive. Are you sure the noise is coming from the ENGINE?... I'm thinking maybe the torque converter?... I've heard of some issues with them.

 

More than likely, the noise is the VVT units. They are adjusted by the ECM based on enigne running parameters such as rpm, water temp, engine torque and so on. Just be sure you have clean oil of the correct viscosity and it should be fine unless you get a code. The VVT units are acutated by oil pressure controlled by a solenoid valve that is under the connector you see on the front of the valve cover. If you are real nervous, ull the valve covers and look at the cam chain tensioners, that is about the only other thing it could be. They are both mechanical and hydraulic and oil pressure affects them too. An oil pressure check could be in order if you really want to be thorough.

 

I like the way you think Oldmots, and I agree about the correct oil and oil pressure... one question; could he try starting the car with the vvt solenoids disconnected and see if the noise changes?... I know this would log a code for the vvt's but, they could be erased easy enough after the test. What do you think?... worth a try to pin-point the source of the noise?

 

I have to drive the car to hear the sound, is it ok to drive the car with the vvt solenoid disconnected, or both disconnected?

I had a hunch there was an ambient temp related factor, it is close to zero degrees here so I just went out for a quick run to check for this, but no the noise was there as clear as ever, but disappears within a minute.

The sound comes from the right of the car, to be honest it sounds like it comes from the right rear of the engine rather than the front of the engine but its pretty difficult to tell from inside the cabin.

 

I had a search for others asking if it was ok to drive with the vvt disconnected, there were lots of questions but no answers.

So being a bit of a risk taker I tried it. I only disconnected one side, I presume this is the connector.



Surprisingly, no engine light after starting the engine, I then drove for a couple of minutes, it made no difference at all to the mystery sound, still no engine light so headed back home and reconnected it.

Is there any other electromechanical device on the right hand side of the engine bay?