marineboy0

ALthough it husts my mechanical sensitivity - does anyone have evidence that recurrant tappet excessive noise which clears after maybe 2minutes of warm up will be be the kiss of death?

The vehicle is a ML320 with 75k miles and only ever had Mobil1 at 3-4k oil changes since birth - BUT seen a lot of short journeys (~4miles) over 7 years.

The noise is definately valve train related and sound like a sinlge sticking valve. Once the vale clicks in everything runs smoothly and there is no issue on warm starts.

Can anyone recommend whether it would be good prevention to pull the head and have it fixed. How do you know which of the two heads and which valve to tackle?

CalifSLK

If it goes away after warning up, I won't fix it. Just take it easy on the engine until it warms up. Generally it should not be a big problem around 2-3000 RPM.

I don't know whether your engine has VVT or not. If it does, it is a big deal to remove the CAM. The pulleys are throw aways.

vettdvr

I would just drive on and leave it alone.

However the Blackstone oil test done (www.blackstone-labs.com/) on a new LS1 Corvette engine indicated that Mobile 1 is good for up to 14,000 miles. One interesting point was that for the first 3000 miles on
new oil change the wear would be higher than after 3000 miles. So perhaps your frequent oil changes are removing the oil before it has a chance to become stable. I run my E500 14,000 miles then change the Mobile 1. My corvette also runs 10,000 before change. I think you can do yourself a favor, save $$ if you run the Mobile 1 longer and this alone might have an effect on your valve train.

Jim

marineboy0

Thanks for both your comments.

As a professional chemical engineer - I find it har to understand why Mobil1 should become less damaging to an engine after 3000m. The additives within the oil are all meant to be supportive of wear prevention and reduce the oxidative effects of combustion products that end up contaminating the oil.....

I will however go with teh advise of trying to treat it as an annoyance and monitor the situation.

Bif powell

Are you sure it's not a purge valve? I have a sound like this as well. Can you record the sound and post a file?

toaster

If it is a valetrain noise, and it only happens for a short time after you start your car you should have no worries. It's a sign of an engine that is just getting slightly tired.

I my experiences, that valvetrain noice that only occurs for the first minute or so after startup is usually hydrollic lifters. As the lifters age they leak down when the engine is off and it takes a few moments after startup to get them pumped up again.

If the noise is lifters, you can try two things....

1. A thicker oil. Thicker oil can stay in the lifters better and wont leak down as bad.

2. A thinner oil. I thinner oil can get circulated through the engine and into the lifters faster after startup.

Again, my info only applies to you if your noise is lifters.

vettdvr

[QUOTE=marineboy0;1780001]Thanks for both your comments.

As a professional chemical engineer - I find it har to understand why Mobil1 should become less damaging to an engine after 3000m. The additives within the oil are all meant to be supportive of wear prevention and reduce the oxidative effects of combustion products that end up contaminating the oil.....
QUOTE]

Engineer here also and I agree with you,, but if you check the blackstone data,, it provides the data. And as an Engineer I have to use the data and since I drive about 10,000 miles on M1 it doesn't change any of my service intervals. Jim

paulv

Since your a chem eng, you should join up with the Bob Is The Oil Guy forums (http://www.bobistheoilguy.com) and talk to all the tribologists there -- I've learned a whole bunch of stuff from them.

BTW, did you guys check out the article on Blackstone's site where a couple of guys did a study comparing Mobil 1 to Amsoil? They ran the oils for about 18K and did analyses every 1K miles -- great reading.

Regards,
paul...

marineboy0

As a skeptic - I don't believe everything that is published. There is an expression the " baffles brains" LOL . I remain open minded about the article, but don't understand the result.

Anyone remember Cold Fusion?