meowy84

I read somewhere on this forum that the M-B V8s are thirsty for oil as well as fuel and that it's not uncommon to have to add a litre (quart) of oil every 1,000 miles or so, even when the cars were new?

Is this true? My '84 500SEL pretty well holds to this if it is. I just did an 800 mile trip to Canada over Christmas and when I arrived at my family's place I had to add just a little over a litre of oil. My car has 185,000 miles on it and runs perfectly. I can see no blue smoke nor smell that distinct oil smell from the exhaust that would indicate work valve seals and blow-by and there are no leaks under the engine. So where is all this oil going? If it is indeed being burned and even when these cars were fairly new they were known for burning oil does anyone know why they were designed this way? My well-used domestic 350 V8 burns maybe a quart every 2500 miles and most of that I've determined to be lost because of oil coming from the valve cover breather, through the tube and being sucked into the air filter and burned.

So what do you guys think?

Mark Pedersen

I would bet you need valve guide seals. My 560 burns no oil between changes. Had the timing chain and valve guide seals done at 100K miles.

meowy84

What's the current mileage on your 560? Also, any idea on the cost of the seals (just the parts, not labor).

And finally so is there any truth to the M-B oil burning thing? I can't find the thread now but I swear that I read it on here that the V8s have an above average oil consumption even when new and low mileage.

w123_w126

This may occur in the V8s of this era if too light of an oil is used, like 5w 30 or even 10w 40. Switching to 15w 40 or better yet (if your climate allows) 20w 50 may result in a decrease of oil use, provided the valve guides and rings are in good shape and the engine is not leaking badly.

Mark Pedersen

My 560SEC has 120k. I use Mobil 1 15w50. Checked it tonight with 8500 since last change - it has used less than half a quart. Valve guide seals are cheap.

meowy84

Aha! As it happens I use 10W40 right now. In fact I think it was recommended on this board that I use this viscosity. I'll try switching to 15W40 at the next oil change (which is coming up in a few hundred miles) and see if that improves the situation any.

As for something like 20W50 what is the 'climate' that you mention? I share my time between Indiana and Minnesota where it's fairly chilly *brrrr* in the winter. Is 20W50 suitable for cuch a climate or will it overstress my oil pump during those winter morning start-ups?

As for the valve seals, I guess I have to remove the camshafts and take the timing chain off the sprokets to get to the top of the valves? This concerns me because since I haven't been able to find a repair manual for my car I don't know any of the torque settings for the top end.

rickyfanmdr

I had a 1985 380 SE for 17 years and 105,000 miles until I bought my present car. It was never an oil burner, and I would think that you have something that needs to be fixed.

Mark Pedersen

If you change the valve guide seals, check the chain tensioner and guides while you're in there. Chain, tensioner etc are cheap compared with damage if chain breaks.

w123_w126

No, 20w 50 is for Florida, Texas, SoCal, etc – for your application synthetic may be in order provided there is not excessive leaking. There’s a school of thought that synthetic causes small leaks to get worse, others maintain that newer synthetic formulas avoid that problem.

farooq

what viscosity of oil is best for driving in hot deserted climate??

meowy84

So would 15W40 be ok to use in the Chicago area climate and also some in Minnesota climate?

I don't think I'll go for synthetic because of first, the price and second, I've read that it's not advisable to switch from natural to synthetic oils when the car is older and has known only crude oil....not sure what the reasoning given behind it was.

w123_w126

20w 50 is fine for dino oil.

meowy84

Thanks.