I had been kind of leery of switching my beloved 85 SD over from Delvac Super 15w40 to Mobil 1 Truck & SUV 5w40 (I hear it's really Delvac 1). I took the plunge yesterday morning. I have to say I am IMPRESSED.

Maybe it's just mental, but the car runs MUCH smoother and has noticeably more EFFORTLESS acceleration. Don't get me wrong, this was an awesome running car to begin with, it's just much more quiet and SMOOTH now.

I put in the same amount as usual (8 qts) but it seems to read a bit higher on the dipstick, like about a quarter inch or so above full (Problem?). The car also runs about a needle's width cooler, maybe more, in all operating conditions. The oil pressure reading is higher at idle. I've run it hard both yesterday and today, long cruises at between 70 and 80 mpg, plug city traffic. I have been getting about 25 to 26 mpg combined and once 28.5 highway. Can't wait to see what syn does for mpg. I plan to run it to about 3/4 empty and see.

And finally, nothing is leaking. There weren't any to start with though. I did sometimes get some seepage on valve cover oil cap area after long trip. It's clean as a whistle right now!

I'd like to post some hi-res photos of my SD, but it won't let me put anything bigger than 60k file size.

How many miles on the engine? I've always been tempted to go synthetic....but have so far avoided it with 231k on my engine and no probs....

Everything else is synthetic though, tranny and differential were switched over to synthetic this year. I just don't know about the engine, I don't want to cause any probs/leaks, and the synthetic oil is more $$$

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

for your hi res pics use a photobucket.com account and post the links to them

Running with the oil above the full mark can be very dangerous. You can have failed seals, or in the worst case, a runaway engine.

If it were mine, I'd siphon some out right away.

erg, that couldave been a runaway if u added too much more... SO do you have a co2 fire extuingisher or a ton of rags handy? If not the third options a rather expensive (which is running away, and finding cover... then let the problem solve itself natrally)


Yeah, I'd be on my back draining it... and I think you aggravated the diesel gods, and your more than likely going to drop the plug into your pan...

~Nate

i use to put synthetic into cars that burned oil real bad and they would
stop smoking... so i dont think synthetic will burn.....

I dont think the engine can run away on a fully synthetic oil... i might be
wrong....but usually when you put a synthetic into an old engine that burns
oil what you get is oil driping out the tail pipe rather than smoke...

get one of those oil pumps and take out that extra oil to put it back into normal operating levels. those pumps are great for oil changes, too, although i know some people don't like them.

anyway, supranormal oil levels can be very bad to a nice car.

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PagodaLOVER
1967 230SL, manual
1959 180D, manual

I don't want to be the bearer of bad news, but you are completely wrong.

Synthetic oil WILL burn and your car CAN run away on it just as fast as it will on dino juice.

If you switch from a light dino oil to a heavy synthetic, it might stop burning as much, but it will still burn the oil. If it gets past the turbo seal for any reason, you're going to have a runaway, just like on dino.

moondawg

So how can a supranormal oil level cause oil to get past the turbo seal? Where is this seal located? What other damage can overfilling cause? I changed my oil recently before a trip to NYC. Put in 8.5 qts per the owner's manual, didn't acct for the oil cooler, ended up with ~3/8" above full. Didn't show until I was on the road. Haven't had time to suck some out, how much damage have I done? Car ran great the whole time. Haven't driven it since, but will siphon some out with my Mityvac before I drive it again.
How much does 3/8" on the dipstick equate to?

__________________
'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

Turbochargers usually use a thin film of oil to act as a bearing for the turbo shaft (which can spin at 100,000 rpm or higher!) If the seals keeping this oil in place fail, they can start spewing oil into your intake manifold. If this happens, you get a "runaway" which means that the engine WILL RUN until:
1. You remove the air supply
2. You have a manual tranny and you dump the clutch with the brakes on.
3. The engine bearings say "ENOUGH" and you seize the engine

Overfilling an engine with oil can cause several things to happen:

1. The crank can dip down into the oil, which whips the oil into a foam and causes lots of parasitic loss.

2. Higher crankcase pressure, causing oil to be forced out of every available orifice (dipstick tube, ccv valve, piston rings)

3. A rise in crankcase pressure also raises oil pressure. If this gets too high, it can force itself out of the turbo seal.. or an old oil cooler... or a weak head gasket... etc, etc.

You probably haven't done anything bad to your engine. Just siphon enough off to get back to the full mark.


moondawg

Just when you think you have heard everything.....

I hear it ruins your clutch belt too

~Nate

I used to run synthetic oil in my 300SD (Amsoil). After the switch from dino to Amsoil, I didn't notice any differences in engine noise or performance. I will say though, that since I put two quarts of ATF in my fuel tank, I've noticed that the engine is much quieter at 60+ mph.

__________________
1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver

You've never heard of dipping the crank? Sorry. It happens. And when it does, it's not nice.

While it won't come foaming out your dipstick hole, it will introduce alot of air into the system. Your oil temperature goes through the roof (because the oil cooler can't do it's job well)

I just saw it last year on an ISM that was overfilled by 2 gallons (normal capacity 9 gallons) Everytime we got on a long grade, we got an oil temperature STOP light (shut down or else) and oil temps were going haywire.

The problem was an incorrectly made dipstick that showed "Full" on 11 gallons instead of 9.

It took us forever to figure out what was wrong. Drained oil, problem went away.

As for parasitic loss, just dipping the crank a little bit can affect fuel economy noticably. Next time you're in a pool, stand in waist-deep water and try to do a "windmill" with your arms. Takes alot of energy doesn't it? Now imagine doing it 3,000 times a minute for a few hours.

So, just because it doesn't match your experience doesn't mean it doesn't happen.

Google: "dipping the crank" and see if you get any hits.... like this one.

moondawg

After a couple of days of reading these post, I got under the car today and drained a tad over a quart. Now it reads just below the full mark (although there's no real mark on the dipstick (I have the brown handle version). I wonder why on the other side (the passenger side of the dipstick) it always reads higher? I assume it's angled and the driver's side is true reading.

Hey since it's only been a couple of days, can I re-use this oil next change. My car doesn't seem to use any in between?