Engine oil for diesel engines? - PeachParts Mercedes-Benz Forum

ericnguyen · #1 03-25-2003, 11:25 PM

Dear friends,

Is it true that only engine oil (API CF4/CH4) designed specifically for diesel engines can be used in diesel engines. Can I use regular engine oil (for gasoline with API SL) TEMPORARILY in
a diesel engine without any harm (240D)?

Thank you very much for your info.

Best regards.

Eric

#2 03-26-2003, 12:15 AM

It shouldn't harm anything, just make sure it is the right weight. The diesel rated oil just suspends soot and other junk better and has some other additives that are good for the engine. I used Castrol 10W40 for a while, and it did no harm.

The Warden · #3 03-26-2003, 04:27 AM

Eric, if you do it for a very brief period of time, it's okay. However, I don't think I'd let my diesel go more than 500 miles at the absolute maximum without a CH-4 rated oil. And that's a max number; I would try to get it out and put a CH-4 rated oil in as wuickly as I possibly could.

123c's right about the soot; however, one thing to take into consideration is that oil in a diesel turns almost pitch black about 5 minutes' worth of running the engine after an oil change.

Soot build-up doesn't end there...personally, I'd prefer to make sure I've got an oil that can properly handle the soot.

And Delo is roughly the same price per quart as the gasser oils, and you can get it in gallon jugs to boot.

Just my $.02...good luck!

md21722 · #4 03-26-2003, 11:01 AM

Many people have high milage diesels and don't know anything about diesel oil. They change their oil every 2500-3000 miles using gasser 20w-50 or 10w-40. You should be fine. Just follow the severe service schedule and change the oil by 2500-3000. If the car smokes I'd change it sooner than that.

Palangi · #5 03-26-2003, 11:01 AM

Just about any automotive oil made today meets the diesel requirements at the time the car was built, even if a Cx rating is not shown on the bottle. It's just that oil technology has improved tremendously over the years, so nowdays, most people use oil made specifically for diesels. You can use most any oil made nowdays, but you would want to change the oil more frequently if using ordinary gas station oil. You might want to use a lighter weight oil such as 10w40 until you get your starting problems resolved. Your starting problem will probably be either bad glow plugs, incorrect glow procedure, or bad starter.

Thomaspin · #6 03-26-2003, 11:15 AM

....is in the eating.

rwthomas1 · #7 03-26-2003, 12:02 PM

Thomaspin,
I have a VW that is way cleaner than that picture you have. No blackness in the galleys or on the cam. 300K with synthetics.... To each his own. RT

Thomaspin · #8 03-26-2003, 12:10 PM

...but that's not the point I am trying to make in my slide.
I'm talking about wear.

As for the galleys (I assume you are referring to the unmachined part of the camshaft) that's how the forging process leaves it. Not related to cleanliness.

rwthomas1 · #9 03-26-2003, 01:14 PM

Thomaspin,
I quite understand your point. I don't see any wear on the cam lobes either. I do however see what appears to be a "blackening/browning" or carbon buildup below the tip of each lobe on the base circle of the cam as well as in the unmachined/raw metal areas of the cam and head. This may or may not be so given issues that can occur in photographs. It still isn't the cleanest I have seen, judging by the pics, and lack of wear aside. If you are happy to run whatever you feel is necessary by all means do so. My experience has been that synthetics do a superior job of keeping the inside of an engine spotlessly clean in addition to superior performance at the extreme ends of the temperature spectrum. You have a nice website that is extremely informative and you are entitled to your opinion. There are other opinions though. RT