Sludge In Engines?

Just read an article in Automotive News that there is a growing problem
with sludge developing in engines. Particularly Chrysler. Anyone know
anything about this and what is causing it?

D

Actually, this 'sludging' or 'gelling' is most often associated with
Toyota and it seems to be caused by excessive operating temps and the
way the oil flows through the engine (rate at which it's returned to
the sump where it is cooled before recirculating).

Typical 'cures' are switching to synthetic oil like Mobil 1, Amsoil,
Red Line and/or cutting back drain intervals.

Try a Google search for more info.

--- Bror Jace

wrote:

> Just read an article in Automotive News that there is a
> growing problem with sludge developing in engines.

Can anybody explain to me why sludging could be more a problem now than
10-20 years ago, when engines and oil change recommendations weren't
that different and motor oils were considerably inferior to today's
SL-rated oils?

My father changed the oil of his 1970s car every 5,000+ miles and when
he adjusted the valves every 15,000, and I never saw sludge on the
valve train, only varnish. And with the Toyota he bought in the late
1980s and maintained about the same way, he commented that the valve
train looked perfectly clean.

Sludge is nothing new to engines. It's cure is usually found by taking
care of the engine by: Changing the oil more frequently than
recommended and by running the engine until the oil is thoroughly
heated, usually for a couple of hours.

"larry moe 'n curly" > wrote in message oups.com>...
> wrote:

> "...Can anybody explain to me why sludging could be more a problem now than
> 10-20 years ago, when engines and oil change recommendations weren't
> that different and motor oils were considerably inferior to today's
> SL-rated oils?"

A couple possibilities:
1. Since oil in general was cheaper ten & twenty years ago, people
changed it more often than now.
2. The engine compartment was less cramped than it is now, with all
the extra stuff. This has made the space hotter and petroleum based
oil does not do well when it gets hot.
3. The latest API and SAE ratings include SM. Synthetics do not
contain hydrocarbons which is one of the causes of sludge.
4. People are changing their oil a minimum of 5,000 miles, even closer
to 8,000 mile frequency and driving conditions are a lot different
than they were 10-20 years ago without using superior synthetics and
superior oil & air filters. They're expecting the same performance
wothout making adjustment to the components that contribute to sludge.

wrote in :

> Just read an article in Automotive News that there is a growing problem
> with sludge developing in engines. Particularly Chrysler. Anyone know
> anything about this and what is causing it?
>



Actually, sludge is much LESS of a problem than it used to be.
http://www.tegger.com/hondafaq/misc/pistonring1965.jpg

Sludge is old oil, oil that has become saturated with soot, water and
acids. It's oil that has been left in the engine too long. ANY engine will
develop it if neglected long enough, and some engines seem less tolerant of
neglect than others.
http://www.tegger.com/hondafaq/sludge/index.html


--
TeGGeR®

"Rudy Hiebert" > wrote in message
om...
> "larry moe 'n curly" > wrote in message
oups.com>...
> > wrote:
>
> > "...Can anybody explain to me why sludging could be more a problem
now than
> > 10-20 years ago, when engines and oil change recommendations
weren't
> > that different and motor oils were considerably inferior to
today's
> > SL-rated oils?"
>
> A couple possibilities:
> 1. Since oil in general was cheaper ten & twenty years ago, people
> changed it more often than now.
> 2. The engine compartment was less cramped than it is now, with all
> the extra stuff. This has made the space hotter and petroleum based
> oil does not do well when it gets hot.
> 3. The latest API and SAE ratings include SM. Synthetics do not
> contain hydrocarbons which is one of the causes of sludge.
> 4. People are changing their oil a minimum of 5,000 miles, even
closer
> to 8,000 mile frequency and driving conditions are a lot different
> than they were 10-20 years ago without using superior synthetics and
> superior oil & air filters. They're expecting the same performance
> wothout making adjustment to the components that contribute to
sludge.

Synthetic oils don't contain hydrocarbons? Sorry to have to say that
you're wrong on this one. Synthetic oil base stocks are made from
organic compounds or synthetic hydrocarbons using a process that
re-arranges the structure so all the molecules are uniform in size,
shape and weight, a phenomenon that does not occur in nature. In
contrast to petroleum oils which are pumped from the earth and
refined, synthetics are custom-designed to produce, in effect, the
ideal lubricant.

http://www.offroaders.com/tech/synthetic.htm

Just one of many responses that I got from Googling synthetic motor
oil hydrocarbons.

Ken

On 4/24/2005 4:20 PM, larry moe 'n curly wrote:
> wrote:
>
>
>>Just read an article in Automotive News that there is a
>>growing problem with sludge developing in engines.
>
>
> Can anybody explain to me why sludging could be more a problem now than
> 10-20 years ago, when engines and oil change recommendations weren't
> that different and motor oils were considerably inferior to today's
> SL-rated oils?
>
> My father changed the oil of his 1970s car every 5,000+ miles and when
> he adjusted the valves every 15,000, and I never saw sludge on the
> valve train, only varnish. And with the Toyota he bought in the late
> 1980s and maintained about the same way, he commented that the valve
> train looked perfectly clean.
>

After an initial 1K mi change, the next change for my 2004 SAAB 9-3 is
at the recommended 15K mi point. Actually a computer monitors the
engine oil and such to determine the exact time of service. But I
assume SAAB uses a very high quality oil filter along with synth oil.

Dan

wrote:

> Just read an article in Automotive News that there is a growing problem
> with sludge developing in engines. Particularly Chrysler.

Chrysler? I think Toyota is the current king of sludge. There've been
some reports of problems with the Chrysler 2.7, but several Toyota
engines are exhibiting problems.

> Anyone know
> anything about this and what is causing it?

Several possible causes have been proposed, but I don't know that anyone
has a definitive answer. Some of the potential causes include changes
made to the PCV system in an effort to reduce emissions which had the
side-effect of increasing sludge accumulation, higher spot temperatures
inside the engine that increase oxidation of conventional oils, etc.
Whatever the cause, the Chrysler 2.7 apparently responds well to
synthetic oil and rarely has a problem with it.

I would tend to agree with the PCV theory, personally. I think Toyota in
particular has been pushing hard on emissions systems (a good thing, in
general) but with some un-intended results. For the past several years,
I've been noticing that Toyotas *STINK* under load. Something they've
done with the catalyst system causes it to create a lot of sulfur
dioxide or hydrogen sulfide when climbing hills. I haven't smelled that
so often since the very early catalyst systems when engines still had
carburetors back in the 1970s. Toyota has claimed it's sulfur in the
fuel, but no other car brand makes the stink as predictably as toyota.
Its gotten to the point that when I catch a whiff of sulfur stench, I
start scanning for a late-model Toyota ahead, and almost always find one.

TeGGeR® wrote:

> wrote in :
>
>
>>Just read an article in Automotive News that there is a growing problem
>>with sludge developing in engines. Particularly Chrysler. Anyone know
>>anything about this and what is causing it?
>>
>
>
>
>
> Actually, sludge is much LESS of a problem than it used to be.
> http://www.tegger.com/hondafaq/misc/pistonring1965.jpg

I agree and disagree. Sludge was certainly common in the 50s and 60s,
but pretty much disappeared in the 80s-90s. Now its back to being a
common problem in SOME engines.

>
> Sludge is old oil, oil that has become saturated with soot, water and
> acids.

Modern oils are capable of handling a lot of soot and acid (the retain
TBN extremely well and neutraize acid) but they still tend to oxidize
when overheated. I think oxidation of oil is a bigger contribution to
sludging than just contamination.