300 SDL oil dipstick dimensions, overfilled sump & sudden blow-by condition

[Sveinn]

Hello -
I have reason to believe that the oil dipstick in my 1986 300 SDL is not original and not the correct length. I think that the previous owner may have substituted a dipstick that is from a gasoline Mercedes, which caused the sump to be overfilled by about a gallon to 1.5 gallons.

Could someone with a 300 SDL do me a big favor and provide the following information: 1. What color is the plastic handle of the oil dipstick and/or 2. How long is the dipstick measured from the flat surface that makes contact on the top of the dipstick tube to the high oil level indicator.

A related question is this: the car initially had minimal blow-by and suddenly came down with a case of severe blow-by. A mist of oil spews out the fill hole when the cap is removed (with the engine running) along with a healthy flow of air. When I first purchased the car, there was no blow-by that I could detect. The blow-by developed over the course of about a 2 week period in which drove the car to work ~ 10 miles each way, with no lengthy weekend trips.

Could overfilling the sump have caused this rapid onset of a blow-by condition and if so, what components are most likely to have been damaged by the excess oil, resulting in the blow-by?

Thanks in advance for any help with this questions.
- Sveinn

[kerry]

You could drain the oil and fill the engine with the specified amount and see where it measures on the dipstick. Have you checked for a blockage in the PCV hose which might be causing your crankcase pressure?

[NJ300sdl]

Black, 19 11/16 ". The required amount of oil, 8 quarts, puts the level around the middle of the high and low indicators.

[rscurtis]

If you have a vacuum leak somewhere, that will contribute to BB also as the vacuum pump exhausts into the crankcase.

[layback40]

Your sig may give a hint to the problem

"WVO & biodiesel when I can get it "

WVO use will cause stuck rings & blow by.

[Sveinn]

Thanks for the tip, but this particular vehicle has never had any SVO or bio-diesel in it, since I just recently purchased it and haven't been able to get WVO or biodiesel in over a year.

I don't agree that using WVO will cause problems if you have a conversion that handles gets the viscosity near that of dino-diesel and don't use oil that has other issues like too much acidity, etc. If you use clean, good WVO and get the viscosity near that of dino-diesel, I believe that you will never have problems using WVO.

I haven't modified this particular vehicle yet (& may never do that), but on vehicles that I have I made my own system because there is only one system commercially available that does it right - Elsbett - but it costs more than I pay for my vehicles. 2 tank systems are O.K., but I want to be able to operate the vehicle normally - one fuel tank, turn the key and go - no worrying about keeping the little diesel tank filled or remembering to switch to regular diesel when nearing your destination, etc. I do use a 2 tank system on my F-350, but it came stock with 2 tanks, so it made sense (besides it is not viable to heat the common rail cavity before cold start, short of using a block heater).

The problem with most 1 tank COTS systems is that they start the vehicle on cold VO. I engineered an injection line heating system that heats the lines while the glow plugs are heating. In about 7 seconds, the injection lines are at ~ 80 deg C, so the oil injected after the cold oil in the injector is depleted after starting has ~ same viscosity as dino-diesel.

I have been operating my 300SD with this system for a bit over 5 years now, with no problems, no coking issues, no blow-by increase, etc. I did blow a head gasket on it once though because I got carried away turning the turbo boost up to ~ 29 PSI after I rebuilt the turbo. I put a valve in the waste gate feedback hose so I can dial in the boost easily. I have it set to peak out at 15 PSI, if I really push the vehicle.

I hope I didn't bore you with this. It probably is way too much information. I'm sure that you can tell that I'm a diesel nut.

[Sveinn]

Thanks. This will save me a lot of time and angst. I could have drained and refilled & measured the height, but there would always be the uncertainty of how much oil remained in the cooler, lines, injection pump, etc., so I wasn't feeling too confident in that approach.

Thanks again.
- Sveinn

[Sveinn]

Thanks for the tip. Yes, the sudden onset could be a tip that this could be the true source of the blow-by. I couldn't really correlate the blow-by to the overfilled crankcase, because it seemed that I did the oil change long before the blow-by issue appeared. I've got my fingers crossed that this is the problem. It likely would be a whole lot easier to rectify.

[t walgamuth]

Dont worrry about residual oil in the cooler etc. They have accounted for that in the designated amout to fill.

[barry123400]

If you drained it for a previous oil change yourself and added eight quarts or less. Plus have added no more since the change. Overfilling is probably not your issue.

Of course needless to say if you added more oil to fill it to the mark you have too much in there. You want the oil level at the halfway point anyways even though this means monitoring it more. On cars as ancient as these the oil level shouild be checked at every fill up. It was convention anyways a long time ago.

I really cannot see the vacuum pump exhaust as strong enough in volume to produce what you are reporting. Once the vacumm reaches it's nominal pressure probably little if any exaust is produced except to makup what vacuum is bled off.

If everything checks out to indicate the oil level is correct I agree the pvc system is your hopefully next and cheapest possibility.

You did put a 15-40 oil in there? If the pvc system checks out and the weather is warm I might try a straight forty oil to reduce the amount of blowby at the next oil change.

Just remember that some of these engines for whatever reason do not like the fill level up to the full mark. Symptoms are not usually as severe as you mention though.Usually just additional oil burning until the level decreases.

[babymog]

If you were overfull to the point where the crank were hitting the oil, you'd notice the blue smoke and probably have a runaway.

Black dipstick, add 2gallons at a change, should show almost full.

The 603.970 has longer crank throws and puts an extra quart in the main sump and it's fine(ish).

[WDBCB20]

Originally Posted by Sveinn

Thanks for the tip, but this particular vehicle has never had any SVO or bio-diesel in it, since I just recently purchased it and haven't been able to get WVO or biodiesel in over a year.

I don't agree that using WVO will cause problems if you have a conversion that handles gets the viscosity near that of dino-diesel and don't use oil that has other issues like too much acidity, etc. If you use clean, good WVO and get the viscosity near that of dino-diesel, I believe that you will never have problems using WVO.

I haven't modified this particular vehicle yet (& may never do that), but on vehicles that I have I made my own system because there is only one system commercially available that does it right - Elsbett - but it costs more than I pay for my vehicles. 2 tank systems are O.K., but I want to be able to operate the vehicle normally - one fuel tank, turn the key and go - no worrying about keeping the little diesel tank filled or remembering to switch to regular diesel when nearing your destination, etc. I do use a 2 tank system on my F-350, but it came stock with 2 tanks, so it made sense (besides it is not viable to heat the common rail cavity before cold start, short of using a block heater).

The problem with most 1 tank COTS systems is that they start the vehicle on cold VO. I engineered an injection line heating system that heats the lines while the glow plugs are heating. In about 7 seconds, the injection lines are at ~ 80 deg C, so the oil injected after the cold oil in the injector is depleted after starting has ~ same viscosity as dino-diesel.

I have been operating my 300SD with this system for a bit over 5 years now, with no problems, no coking issues, no blow-by increase, etc. I did blow a head gasket on it once though because I got carried away turning the turbo boost up to ~ 29 PSI after I rebuilt the turbo. I put a valve in the waste gate feedback hose so I can dial in the boost easily. I have it set to peak out at 15 PSI, if I really push the vehicle.

I hope I didn't bore you with this. It probably is way too much information. I'm sure that you can tell that I'm a diesel nut.

Thank you. It's a tiresome job that seemingly never ends but someone has to do it: presenting hard-earned real-world evidence and experience to squelch the armchair bloviators with too much time on their hands who haven't driven a mile on WVO yet get their kicks trolling fora such as this spewing recycled old wives tales that they got from other armchair bloviators with too much time on their hands who haven't driven a mile on WVO yet get their kicks trolling fora such as this spewing recycled old wives tales that they got from....

rant over, temporarily.

[babymog]

Aww, and you're just getting started with your copy/paste finger!