I have an intermittantly noisy lifter (I think). I've been using Mobil 1 for the last70,000 miles (total of 150k) on my car, but in searching here have learned that lifter noise sometimes gets better with synthetics, sometimes gets worse.

Another thing I've learned from Duke and Larry Bible is that historically, oils intended for diesel engines have more detergents and thus can be used to clean lifters.

However, on some threads I've seen reference to diesel oils like Delo 400 being "the next best thing" to synthetics for cleaning the innards of a gas engine.

Just wondering -- between Mobil 1 and Delo 400, which actually does a better job of cleaning an engine?

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Steve
'93 400E

thats a loaded question that i doubt can or could ever be answered.
so i won't. but you did not state what mobil 1 you are using. mb only
likes two of them. 15/50 and 0/40. on your car i would use the 15/50
and go from there.

george

Good point, George. I did wonder if this is an unanswerable question.

RE: Mobil 1 viscosity, I had been using 15W-50 but switched over the the 0W-40. Maybe time to go back to the other weight.

Here's a new question for you: my local independent thinks that using the 15W-50 makes it more likely for the oil tube caps to come off (since oil pressure runs a bit higher with the higher viscosity oil). He just checked 'em and they're still on, so I figure if they've stayed on for 150 k miles they will probably stay on. Any concerns about the 15W-50 being too high a viscosity?

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Steve
'93 400E

WHy not just use a can of engine cleaner before you drain the oil ? Ive used it with much success.

I've considered that, too -- sounds like it might be just the ticket.

Any particular brand you recommend?

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Steve
'93 400E

I was running "regular" Mobil 1 (10w40?) in a Jetta TDI a few years back, and switched to Mobil Delvac 1 (synthetic, not 1300) because I had heard it had great detergents. I ran the D1 5k before changing it, and my soot level was in the neighborhood of 8% - unacceptably high. That tells me the Delvac 1 cleaned the hell out of my diesel engine, and that the standard M1 wasn't cut ou for diesel use. I'd say 5w40 Delvac 1 is a safe grade to run for maybe 1000-3000 miles, just for cleaning, then switch to the M1 0w40.

Interesting! Very helpful comparison.Thanks!

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Steve
'93 400E

Note this is for a diesel, so the comparison may not be applicable. I was running Chevron Delo 400 with 2,500 mi changes for 4 years. Last June the lifters began to tick. I switched to Mobil Delvac 1. After two weeks, lifter noise gone.

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Chris

'04 ML500 - 53k, Inspiration Edition, Desert Silver
'11 Audi A4 Avant - Brilliant Black
'87 300SDL sold
'99 C280 Sport sold
'85 190E 2.3 sold

You should be using an oil rated for diesel engines ALL THE TIME in a Jetta diesel. What in the heck were you doing using a spark ignition engine oil?

Duke

Mobil 1 is a CF-rated oil, and this was 5 years ago.