Engine tapping when cold 4.0L

[xjscharlie]

Hello Folks,
I have an engine tapping noise on cold start up. Its a definite tapping rather than a rattle & it speeds up with revs. It goes off after 10mins when the engine heats up and afterwards disappears until the next cold start.
I have been assured that the timing chain tensioners have been changed to the latest steel ones.
I recently have undergone a 220 mile run with no problems.
Any advice would be much appreciated. Thanx. Rgds. Charlie.

[Andy P]

Hi Charlie,
Knowing the year and whether it is N/A or Supercharged would help for a positive diagnosis .
Thanks,
Take Care,
Andy .

[xjscharlie]

Thanx Andy its a 2000 4.0L N/A. Charlie.

[Andy P]

Hi Charlie,
Same as mine ,lovely engine .
If your sure the tensioners have been done,no need to worry to much,but it would be good to know if the lower ones(primary tensioners)have been done as well.
The tapping could be a number of things.
First thing I would check would be the auxiliary drive belt tensioner bearing and idler pulley bearing just in case,you never know .
The tapping has also been related to using a cheap oil filter with no ball valve as it allows the oil to drain back down into the sump and then takes longer to fill up the hydraulics on start up.
Since yours is an AJ27 like mine it uses a VVT system which could be taking it's time in getting up to pressure but it's hard to determine.
They are quite expensive to replace so it's best to check other possibilities causing the noise.
Personally I would give the engine a good flush,maybe twice and also remove the sump and clean the oil pick up screen(which seems to get overlooked)if partially blocked it can/could block oil flow,reducing pressure.
Noises are always hard to resolve but if it is the VVT then it is not serious.
Hope that gives you some where to start.
Keep us updated if you can.
Good luck.
Take Care.
Andy

[xjscharlie]

Thanx Andy will do some checking out. It seems to be temperature related as it occurs after start up and goes on for about 10mins until the temp comes up then it dies away and the engine is quiet after that. Think i'll make a video recording in case it changes. Cheers.. Charlie.

[xjscharlie]

Thanx Andy,
Do you know anyone has has done the job of changing out the VVT solenoids or assemblys. Just trying to get an idea of whats involved and cost. Cheers. Charlie.

[Andy P]

Hi Charlie,
Never had to change one myself but I'm pretty sure there's only one bolt that holds it in place.
Quite easy to change I would think.

Hope that helps
Good luck.
Andy

[xjscharlie]

Thanx Andy for all the info. You mentioned flushing the engine~what did you use to do that? Dont want to use the wrong stuff. Rgds Charlie.

[Andy P]

Hi Charlie,
I use BG 109(EPR) when I change the oil.
I also drop the lower oil pan to clear out anything that might be in there and to check the oil pick up pipe for any debris,but that's just me being me,too much time on my hands you see .
Take Care.
Andy .

[xjscharlie]

Thanx Andy, dont think that's being pedantic if you have the time. Good to do on an older engine. Rgds.

[xjscharlie]

Just a follow up Andy when you use the BG109 how long do you run the engine for before changing the oil? Rgds.

[Andy P]

Hi Charlie,
Get engine up to normal operating temp then add BG 109 and idle for 15-20 mins.
Then drain straight away.
I always make sure I use a Genuine Jaguar oil filter so I know it has the non-return ball valve which some of the cheap ones haven't got and a top quality oil 5w30 fully synthetic.
I must say I only use BG 109 because that's the product recommended by my brother-in-law who owns his own MOT Center and he offers that service if the customer has asked for the engine to be flushed on their car,but any good quality engine flush will do the job.
Good Luck.
Take Care.
Andy .

[xjscharlie]

Thanx Andy will follow that. Think i'll take the oil pan off also may as well when its over the pit.
Cheers..
Charlie.

[xjscharlie]

Hello Again,
I carried out a flush and oil/filter change and it looks as clean as a whistle in there. It has improved the tapping in that it has reduced the volume and the time it goes on for. Does anyone know why it goes on for about 10mins until the engine warms up then disappears? One would have thought that if it was due to contamination that the symptom (tapping) would be there all the time?. Also anyone ever tested the VVT solenoids in situ? Assume you can check for continuity? Rgds. Charlie.

[Andy P]

Hi Charlie,
Here are a couple of pages taken from the X308 Workshop Manual about testing the VVT Solenoids:

It's a shame PDF documents are not permitted to be added to the post:( .
If you would like the whole X308 Manual PM me your email address and I will gladly send it to you along with the correct Electrical Manual for your year.
Hope that helps.
Take Care.
Andy