Engines that are prone to sludge

From somewhere in the later 1970s, possibly when catalytic converters
started putting more heat into the exhaust system, the manufacturers
started using piping with more stainless steel content rather than just
"steel" as they had been. In more recent times, the pipes look like
they have more stainless content in them than they did 10 years ago . .
from the exhaust manifold back. No more greasy hands from handling
them, either, when new.

C-BODY

Back when I was in college in the earlier 1970s, I found the SAE
Journals in the university library. I started pouring over these books
and found lots of interesting and neat "papers" in there. Even the
original paper the Chrysler engineers did when they introduced the B/RB
engine in 1958, which told all about the engine.

In the papers I found which were presented in the earlier 1960s, one was
by some GM engineers who were studying the effects of crankcase
ventilation on sludge issues. For the tests, they had a fleet of plant
security cars (1961 Chevy Biscayne or BelAir sedans with the 235 cid 6
cylinder engines). They adapted the road draft tube to be a closed
ventilation system, recycling the crankcase gasses back to the base of
the carb. They used one pcv valve flow rate as the baseline and also
did one with double that flow rate. These cars usually idled around
with no highway miles as such, therefore they were known to build sludge
in the valve covers. It was also somewhat common for the road draft
tubes to get gunked-up on normal cars that saw a good deal of city
miles, too.

Adding the dedicated ventilation to the crankcase did decrease sludge
buildup. Doubling the flow rate decreased it still more, so they could
then determine the more optimum flow rate with these two tests. Later
vehicles were coverted to the pcv systems until they became production
items in about 1967.

With the addition on the pcv systems, the carb calibrations usually
needed a little finessing as the pcv valve is a variable controled
vacuum "leak" of sorts.

I recall reading of several class action suits against Toyota for engine
sludge issues in the 1990s. As it was "Toyota", this was page 15 news,
but if it had been Chrysler, it would have been page 2 news, I suspect.
It's interesting that they are still having these issues with Lexus,
even! Seems like they initially tried to claim it was an owner
maintenance issue, but finally had to admit it was THEIR issue and make
ammends.

Mercedes had some issues about 5 years ago with failed engines. It had
to do with the type of oil being used and when it was changed. ALL of
the "longlife" or "extended drain intervals" with VW/Audi and BMW are
spec'd for synthetic oil rather than dino. Most of what they sell at
the dealerships is Castrol, with some being a Euro-spec Castrol that you
don't generally find at the auto supplies.

When GM introduced the current generation TrailBlazer vehicles, they
also introduced their algorithm-based oil life system. The oil change
light comes on related to vehicle use rather than just a mileage
interval. With short trips and little highway miles, it comes on pretty
soon (probably at about 2500 miles or so), but with more highway miles
in warmer weather, it can stretch things out to up to 15K miles. All of
the research they did on that system was done with normal motor oil.

I have an '80 Chrysler with the 360 2bbl V-8. If I drove it with
shorter trips during the cooler months of the year, the pcv hose would
get gunked up and it would idle flaky. I have even pulled out the
dipstick and found milky residue at the handle end, but normal color in
the oil. It's a known fact that the Chrylser A-blocks are "cool
running" engines compared to the B/RB engines. In the summer time, the
milky stuff didn't happen. When I put a new pcv hose on it (pcv valve
to the back of the carb), I'd try to get enough of it such that the hose
would not droop in the back and remain more level so the gunk would not
settle out in the low section.

On the Quad 4 GM engine family, they don't use a pcv valve, but a vapor
separator instead. The orifice that controls the pcv rate is elsewhere
near the throttle body of the FI system. In that separator is a length
of flat and thick copper with an electric wire going to it. Obviously
to help control moisture buildup in the separator box.

Obviously, Amsoil is trying to sell their product to owners of the
targeted vehicles. Seeming to be performing a public service at the
same time?

In reading the maintenance schedule in the owner's manual, more times
than not, "normal" use is really "severe use" (as determined by trip
length and such). Some also consider the 3000 mile oil changes as "too
much maintenance", but they tend to not admit to the fact that people
used to have somebody look under the hood and check the oil with EVERY
tank of gas. That earlier attention probably saved many from engine
repairs later on . . . unlike more modern times when people typically
don't look under the hood at all.

In the 1990s, Walker Exhaust touted their "rust-out free" muffler. I
got one for my '67 Chrysler as it came with a lifetime warranty. What
they did was to put an absorbent coating on the floor of the muffler,
inside it, to absorb moisture and hold it until it could get cooked out
with a more fully warmed up engine. Of course, those older Chrysler
mufflers had drain holes, too, at the back lower seam.

One reason for the oil sludge problem probably decreasing is the better
oil specs of modern oils in resisting sludging in the first place. As
things have progressed, most of the normal oils are probably more
semi-synthetic than many might like to admit.

Just some thoughts and observations,

C-BODY

> Exhause systems really do outlast the old ones substantially. Many of us
> tend to
> forget how they used to rust out.

This is exactly why Midas and Mienecke had to resort to brakes and
shocks to stay in business.
HTH,
Ben

wrote:
> Bill, I used to be a Rep for Chrysler and back in 2003 we had a meeting with
> Walker exhaust. Talking with the engineer, he stated that because the
> exhaust system is aluminized or treated with stainless, people think there
> exhaust last the lifetime of vehicle. He then said the actually engineer
> them to onliy a liife of 80,000 miles. He said the mufflers are shot on the
> inside. They study the used exhaust by buying them at scrap yards. Good- old
> Tenneco...

Yeah - hah! The "screw the consumer" philosophy works great until your
competition or the original manufacturer starts using a "make it last
the life of the car" philosophy, in which case the "screw the consumer"
company deserves a huge downturn in business. He who has the last laugh...

By the way. Chrysler determined the PVC system was causing a sludge
> condition, and redesigned it in the later 2.7. I think it was in 02 or 03.

They added a heat exchanger to the pcv hose (steals heat from the heater
loop) to keep the blowby from condensing out into the hose and
clogging it up - that was in '00 or '01 - I added that heat exchanger to
my '99 Concorde. They may have done some internal things too for better
breathing. It's hard to tell from the LH car forums if the '01-'04 2.7
is less prone to the problem, but I haven't heard anything on the later
platform that uses the 2.7 as its base engine, and I think they've been
out long enough to where they'd be getting failures if that were the
case (60-80k miles is the usual failure window) - probably means they
fixed the problem.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

Built_Well wrote:
> This is a list from Amsoil of engines prone to sludge.

You misspelled "Scamsoil."

>
> For Dodge/Jeep:
>
> 3.9 L V6
> 5.2 L V8
> 5.9 L V8


Horse ****. These engines (the A/LA v8 family of which the 3.9 v6 is a
derivative) have been around in one form or another since 1955, and they
DON'T sludge the oil.

wrote:

> Bill, I used to be a Rep for Chrysler and back in 2003 we had a
> meeting with Walker exhaust. Talking with the engineer, he
> stated that because the exhaust system is aluminized or treated with
> stainless, people think there exhaust last the lifetime of vehicle.

As far as I can tell, the exhaust on my '00 300m is 100% stainless (and
not aluminized or "treated" with stainless).

After 8.75 years, there is no pit-through on any of the pipes, but there
are some perforations on the rear muffler shell. There is no way I'd
see that much life out of them if the entire system wasn't stainless
steel.

Walker makes **** aluminized aftermarket crap.