After running M1 5w-30 for the first 5 years of the cars life, and living with the piston slap through most of that time, I wanted to try a thicker oil to see if it would surpress the noise any. Went in to buy 10w-40, only to find that the only 40 weight oil in stock was 0w-40, so went ahead and got that. Apparantly its the OEM oil for Mercedes.

Anywho, i now have a really fast tap/knock in the engine, sounding different than the orginal piston slap, from just off idle to about 2K rpm where itll smooth out. The engine also seems to be running really rough when revved just off idle, before it smooths out around 2K and seems to be fine thereafter. The problem is most of my driving leaves me about that range when im cruising, so im living with a constant vibration. I figured maybe the oil just needed to be fully heated and the noise/vibes might go away, but it seems to persist even at full temps. Was the 0w simply too thin? Just a coincidence or my imagination? Any ideas? Its been in the car for about ~2000 miles and the motor has consumed about a quart of it. Should I switch back to 5w-30 and note if theres a change?

I also did the GM Top engine treatment just before switching to the new oil, so thats a variable as well. The engine didnt sputter a bit despite sucking up 2 bottles of the treatment, and no smoke after letting it soak for about 15 hours. Keep in mind this is the California variant of the treatment, since the chemicals in the normal GMTEC treatment arent allowed in Cali. Out here we get a small small bottle of the solution with a different blend to coincide with california law. I used two bottles of the treatment to get a similar volume compared to the treatment offered in the other states (Possible error of judgement on my part). Somewhere in the back of my mind im worried that the treatment did something funny internally.

 

AFAIK, anything is better than 5W30.

 

Go with a heavier 10w weight if you notice more taps/ticks. That would at least rule out the oil variable if you're trying to see if the TEC caused you problems.

 

I have been using Mobil 1 0W-40, as reccommended by Patman, since I bought my car and did the ported LS6 pump. The pump raised my pressure significantly and then the switch from dino oil to synthetic(at 97k miles, no less) raised it some more. I'm almost at 108k miles now and it's doing perfect. I've changed it twice since March 05 and it doesn't use a tick of oil.

 

mobil 1 5w40 here.

 

Now thinking about it, what are the odds the TEC fouled a plug or 8? I guess it couldnt hurt to pull a few and have a look-see.

 

never hurts to check, but I dont know if it would have or not.

 

ok...so patman is the "man" when it comes to oil and everything? how do i get into touch with him?

 

I'm right here.

 

i have used 5w-30 since i originally bought the car.....and i have noticed some oil consumption, do you think that if i switch to M1 0w-40 it will remedy some of that consumption? As far as i am reading, this may help it? Care to add some insight?


BTW, i tried to search on this, but I think that that feature is not working

 

So far my car is consuming the 0w-40 at the same pace as the 5w-30, about 2 quarts per 5000 miles. So it didnt help me any in that regard. Maybe others have had better luck, however.

 

ok just so i know...is the 0w-40 u are using fully syntethic????????

i use nothing but royal purple in my car and i have no noises or problems with oil consumption at all

 

patman...what kinda setup do you suggest for me on my t/a? i know i'd like to run a full synthetic and my car's only got 28K on the clock...plus i'd also like to get rid of as much as possible of the piston slap that's common with the ls1's...thanks patman

 

If you can't find German Castrol 0w30, then try one of the 5w40 synthetics (Amsoil, Redline, Castrol, M1 Truck & SUV)

 

FWIW, I was using M1 5/40, and it was OK. I had no consumption over 3k miles, unlike the M1 5/30, which was "evaporating" at the amount of 1 qt per interval. After a couple of days with the German Castrol, I've noticed it's less noisy, especially in the A.M. At $5 per qt at the "Zone", I'm quite happy. I hope it doesn't go away...

 

now this 0w30 you guys are talking about...how thick of an oil is this? i was just curious since i've never dealt with it before...

 

oh i forgot patman...i know you recommended the 0w30 German Castrol...what type of filter do you think i should finish out the job with? thanks for all the help...

 

from the oil tests, patman says its more a 40w oil.
ive run it, and the clatter is less than with 10w30 M1.
i have had the best luck keeping the valvetrain quiet with the M1 5w40 T&SUV

 

@ about 140K miles I've found no significant difference
in oils for cold start up clatter (valve train only).
However, mine quiets up when warm.
I'm using M1 0W40.
Engine runs great, so good it scares me it's gonna quit.

 

same here w/the M1 5W40. Thats the quitest ive had it too with this oil. Patman, any results on the Castrol 5W40? Im looking for a replacement until the M1 comes back.