2009 supercharged XF w 44K has a start-up rattle that sounds just like vanos or vvti start up rattle in BMW or Audi.

Goes away in about 5 seconds. Happens once in the a.m. then is good the rest of the day.

Is this common? I didn't find anything in search.

I assume it is a vvt actuator, but there is no CEL or DTC.

I guess it could also be a chain tenisioner but seem unlikely

 

Also, does the vvt system on the xf work like the one on the 4.0 xj8's?

 

Good day!

Got the same rattle on SV8 '08 35K.
Just 2-3 sec-s after starting.
BTW if it's cold outside and the starter needs a little more turns to start engine no sound appears.

I'm 100% sure we've got the same problem, so have you figured out what is this?

Thanks!

 

Try adding a 1/2 quart of Lucas Oil Stabalizer see if it goes away. My Infinit did this if I didn't run some Lucas.

 

The dealer had been doing the oil changes with the recommended conventional 5w 30 Castrol. While I am not really worried about the engine with the Castrol in it I thought maybe a "better" oil might help. I switched to the Motul full synthetic. So far the noise has greatly decreased, only the tiniest rumble for less than one second. I'll post again if it returns.

 

Noise is back...goes away so quickly I cannot get a read on the VVT valves vs chain tensioners.

 

Please wesmc2,

Could you say if you finally solved the problem? I'm having the same issue.

Thanks

 

I haven't. The Motul helps, but doesn't solve it. The car is now at 75K and it hasn't gotten any worse. But it is dang loud at start-up. I wish this thing purred like the little X-type does now.

 

My 2003 Infiniti did that also, it was the timing chain tensioner. Your trying a different brand or weight of oil was a shot in the right direction, did that with my G35 in addition to switching from Fram oil filters, and the noise was GREATLY reduced. Nissan redesigned it in the 2005 VQ engine, once I put in the new style tensioner problem was permanently solved.

 

Yep, a common cause of this type of rattle at start up is a stuffed timing chain or cam belt pre-tensioner. On some cars the easy way to tell if this is the source of the rattle is to start the car up, then turn it off, leave it off for about 10 seconds, then start it up again. If no rattle on re-start then it's probably the pre-tensioner. But I don't know if this works for Jag V8s.