[Vwdiesel] dumb question re diesel-rated oil

[Doyt W. Echelberger]

Without knowing which modern gasoline engine you plan to experiment with 
and which diesel-rated oil you have in mind, I can only speculate in 
general terms about how diesels and gasser work.

In general, diesels run longer and hotter than gasoline engines, and 
generate soot. And, diesel  fuel frequently is contaminated with water. 
Diesel oils are formulated with additives to manage these expected 
conditions and water separators are designed to keep the water from getting 
in to the injector pump.

Gasoline engines tend to be used for shorter trips where the engine either 
never gets up to operating temperature, or doesn't stay there very long. 
And soot isn't a major problem.

Let's keep the discussion general, and within those boundereies.

If you asked a Mobil oil engineer your question, the reply would probably 
be about a specific Mobil oil product such as Delvac (for diesels) running 
in a gasoline engine, and the answer would be that it probably wouldn't 
harm the gasoline engine.  But there would be a question about exactly 
which gasoline engine you were going to experiment with and what oils the 
manufacturer of that engine specified.

Personally, I run Shell Rotella T 10-W40 in my older diesels and gasoline 
engines, and I haven't had any problems doing that. It is convenient to 
keep a supply on hand of just one kind of oil. But for my newer engines, 
like the one in my Mercedes, I use exactly what the manufacturer specifies 
and I follow all the other maintenance protocols.

If the manufacturer of your modern gasoline engine specifies a diesel-rated 
oil for your engine, you can expect it to stay a lot cleaner than the 
little old scrapper engine mentioned in your question, especially if you 
follow all the other protocols for engine maintenance. You won't be dealing 
with the soot.

In closing you might want to consider that the gasoline engine you are 
asking about has a whole lot of unique engineering in it that would work 
better and longer if the lubricant you use resembles what the designers had 
in mind.

Doyt


"I am often asked how radio works. Well, you see, the telegraph is like a 
very long cat.
You are yanking his tail in New York and he is meowing in Los Angeles. Do 
you understand this?
Now, radio is exactly like this, except that there is no cat."
Attributed to Albert Einstein, by Dave Ross N7EPI

 >>>>>>>>>>>>>>>>>>>>>>>
At 03:40 AM 2/16/2010,David Ross wrote:
>Not too long ago I pulled the valve cover off a 1.6 NA engine that I
>removed from an ebay scrapper car (an '82 Rabbit).  The oil had the
>usual diesel look to it -  it looked filthy-dirty.
>
>But I was amazed at how clean the engine internals were -  I could wipe
>the oil off the head casting or the camshaft or the valve cover and
>expose clean metal.  No staining from combustion products, no sludge, no
>varnish, no nothing, just spotless aluminum or steel.
>
>So why is that?  Am I just out of touch with modern oils and do they all
>have so much detergent in them that all modern engines are as clean as
>this one?  Or is it something about diesel oil in particular that kept
>this engine so clean?
>
>Enough pointless rambling.  The questions are these:
>
>  -  Is it safe to use modern diesel-rated oil in a gasoline engine?
>
>  -  If so, can I expect a modern gasoline engine to
>     remain as clean as I found this little diesel to be?
>
>thanks
>Dave Ross    N7EPI
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