Hey Guys,

Another issue I have been noticing is that I get a quick chatter from the motor on initial startup.

I remember this always being an issue when I owned a Porsche 928S years ago. My driveway is on an incline so initially I thought this was the problem and I am sure it isn't any good for the motor parking on an incline so I parked it on the street overnight and I still get a quick chatter.

Since I have cam cover gaskets on my to-do list, I was wondering if there was anything that could be addressed to offset this noise. Only lasts for a second and then the motor runs completely quiet.

Will be changing the oil to Royal Purple XPR racing synthetic here soon as I do my first oil change on the car. Extremely high quality oil that should improve things for the motor. Not sure what's floating around in there right now as I just purchased the car a couple of weeks ago.

Cheers
Bernie

 

You're making a bunch of (incorrect) assumptions. You're presuming the noise is from the valves and/or is lubrication related. There's sufficient residual oil on engine components for start up even after years of storage, never mind overnight.

Unless the driveway is so steep that the oil pump is sucking air, the angle doesn't matter. The car would need to be at 45 degree angle or more for that to happen.

How do know that the clatter is not from the fuel system or some other accessory?

There's no evidence indicating there's anything deficient with standard plain-jane oils, or that there's anything to gain with so-called boutique oils such as Royal Purple.

Using them may make you feel better, the car couldn't care less.

 

Thanks for the info.

It sounds very reminiscent of the noise my 928 used to make on startup. Could be something else, just wondering if anyone else has experienced the same sort of startup noise.

The 20 cases of RP XPR oil sitting in my garage drives my desire to throw it in this car - not all at once of course

 

Mine does. They all do, AFAIK.

 

Not the same car, but my 95 trans has what I feel is a light valve rattle on cold start and acceleration for a brief moment but is gone with in a min or so.

 

There's been some past discussion on this subject; some have attributed it to non-OEM-spec oil filters not having a non-return valve, thus allowing the oil to drain back. Or is that just the 4.0? Here's one: https://www.jaguarforums.com/forum/x...clatter-97872/

If you can capture the noise, I'm sure one of the gurus on here will be able to identify it.

Would purple oil stop the 'green shower'?

I'll get my coat...


HTH,
Mike

 

Hey Razor, Perhaps you did not see my las t few posts, one of the was regarding a similar noise my '03 xk8 had on start up. I can assure you it is not the valve train, and I doubt it's oil related. Check the EGR pipe, it is located under a shield and connects the r/h exhaust manifold to the egr valve that attaches to the rear of the throttle body. The pipe has a section of corrugated stainless steel and is very thin. You may have to remove the pipe to fully inspect it. Mine was split about 50%, since I replaced mine the moise is GONE! My car can sit for 3 weeks and when she starts now there are absolutely NO mechanical noises at all... with 150,000 miles on the clock.

 

So anything more than a matter of a few seconds shouldn't happen from lack of oil on top of the motor unless you have an issue of some type related to why you don't get oil on top quickly.

The valve train is where the oil is trying to get to quickly when starting, so normal is if you were standing outside the car with bonnet or hood open and had someone else started the motor for you, might hear the valves to cam clatter just a couple of seconds before oil reaches them and starts to quite things.

Too thick an oil in cold temps is something that will make you hear some clatter on startup and then seems to go away as it warms up. This is why many of the modern engines run a 5W something oil so they pickup quickly. Old or broke down cheap oil will allow it to clatter a little more than normal and may still do it once warmed up.

Engines that have not had regular good oil used can build up on crap causing lower oil flows. In these cases some careful cleaning through high detergent oils can help clean them up some. In really bad abuse you sometimes have to pull the oil pan and be sure you are still have good clean pickup filter on the oil pump. Hopefully not something happening to a car of this class, more likely with grandmas station wagon that is 30 years old.

Do you have a mechanics stethoscope? For the $15 bucks it can help you determine where the sound is actually coming from if not easy to tell.

Single tapping from a single source (valve) may mean something isn't allowing oil up or something is worn.

Hope all the rambling give you something to ponder.

 

Chances are good the noise is the VVT (variable valve timing) unit(s). My 2005 started making that sound on a cold start-up year or so ago. Just a half second and it's gone. More a "cosmetic" issue for me at the moment. Unless the car has sat for a few hours, which allows the oil to drain from the VVT, there is no noise. If it gets worse, I'll deal with it then. Some guys have had success with thicker oil or additives. I'm used to it so I've stopped worrying about it. Relatively common issue.

 

Funny you should mention that because I had that issue right when I bought the car. I knew it had an exhaust leak and initially I thought it might have been a cracked manifold. It was simply the EGR tube which I have since replaced. But its not that

 

I will get one of my sons to start it up for me today and grab a quick video of it. It is over in about a second so trying to catch it with a stethoscope would be very difficult.

 

Definitely not valves then.

 

Mine does the same thing and it gets worse if the oil level is around a quart low. But even perfect, mine does it, but it is much quieter.
My mechanic told me the VVT sensors go bad and cause the valves to chatter.

 

I don't think it is actual value noise so much as it is the VVT units themselves being charged with oil. Apparently, they have check valves in them to prevent them from draining and the valves eventually weaken. So the units are empty on startup, but fill almost instantly. Honestly, I have not researched them much since I decided to ignore the brief chatter for the time being.

 

Certainly seems the most likely.
It was check valves in the heads of my 928S that had to be replaced as well.

Is this something on the XK8 that can be accessed when I get to changing out the cam cover gaskets or does it require dis-assembly of components?

 

They VVT units live on the ends of the intake camshafts, so they are accessible when the valve covers are off. What is involved in removing them and whether they can be repaired or must be replaced, I don't know. As I mentioned, I am basically ignoring my noise for the time being. Seems harmless – so long as it is momentary. No doubt a member with more knowledge than me can explain it.

 

You misunderstood me, I was talking about the VVT sensor, not the VVT unit itself. They go bad and do not change the timing and cause the chatter.

 

Hi Randy,
I think your guy meant the VVT solenoids, not sensors. The VVT wouldn't cause valve chatter, just the noise of the VVT unit before it gets pressurized by engine oil. If the noise lasts for more than a second, then it is from another cause. You can see the shuttle valve just behind the solenoid in the attached illustration.





VVT Units&Solenoids





VVT Unit

 

Great information.

Digging into this a bit more now and shot a quick video so you can hear the very noise itself.

Certainly seems as though the VVT check valve could be the culprit.

 

+1 ....My 03 XK8 does the exact same thing. If it turns out to be an easy straightforward fix I would consider it.