My dad has a '91 Chevy with a 350 in it (around 150,000 miles on it), the
intake manifold gasket was recently replaced by a mechanic but shortly after
that the oil pressure dropped to about half that it used to be so we sent in
an oil sample to a lab. Finally got the results, although so far just
verbal not the actual print out:
The mechanic said there was significant amount of anti-freeze and traces of
steel and aluminum. He said the aluminum comes from the bearings.
Aluminum from bearings??? I am not expert but I cannot fathom that any
bearings would be made out of aluminum!? I'm wondering if he used poor
technique when he was removing the old gasket and got aluminum in there from
the scouring pad and now is just trying to cover his tracks? He is a well
known mechanic at a small town so its not like he is a scam artist but this
still sounds very fishy to me. What do you think?
Al is right.Bearings are made from Aluminum.No way there`s metal in
there from new intake gaskets.It`s from something else.Anti-freeze yes.
If it`s alot of metal,maybe the motor is just pooping out.
Metal shavings are normal.I`ve seen that on every vehicle I`ve had,on
every oil change.
Depends on what traces mean. Small amounts of metal are from normal wear.
Aluminum may come from piston wear. Some bearings do have a sacrificial soft
metal but I'm not sure about factory bearings. You are correct that aluminum
may be in there from his cleaning methods. I'd be worried about the
antifreeze. But then it all comes down to amounts. Get the printout, the lab
that does my oil samples (Detroit Diesel) allows viewing online as soon as
the sample is complete.
First thing. I would flat out ask the mechanic if he used a 3M roloc disk
for removing the intake gasket material. There is actually a TSB out from
chevrolet about NOT using these. THe problem is the disk it self has some
aluminum particals in ti and also they throw things everywhere. I know
becuse I had to replace my OWN motor after using one of these. My advice to
everyone on this grorp.... STAY AWAY from the roloc disks they are a major
problem waiting to happen.
I use 3M Medium Grit Roloc disks, 3M Rust removial disks (black made
for drills) and 3M light sanding disks (again for drills) on engine
parts. They key is with heads on a block, and the block, to plug any
holes with shop towels, cover the lifter valley. Then blow everything
off with compressed air from a blow gun. Steps often overlooked.
Any sanding/cutting/rust removing grit/material in a engine can cause
damage. Including dust from emery cloth (also a type of sand paper).
Around 11 years ago I did a stint working at a company that made sand
paper products. We did D/A paper, Long Board Paper, Cartridge rolls,
flapper wheels, even scotch-brite pads. All sand paper products start
out in the same way. Large rolls from the manufactor that get cut in to
strips. The stirps come out of a machine cut to lienght. Then someone
uses a sheer or a stamper to cut them down. In the case of cartridge
rolls a foot sheer. Then they are either glued on the back side, or come
with a "glue-bond" already applied. then they get set around a arbor,
the press winds them, heats, compresses them tight. From there they go
in to a box. Even if the brand is different the paper used may be 3M.
BTW: the company I worked for was bought out by Standard Abrasives a few
It was real common to encounter the type of problem that you
are describing if someone was not careful cleaning the old
intake gasket material off. Those old gaskets would weld
themselves to the head surfaces...especially around the exhaust
crossover ports. A lot of guys would use the roloc discs and
grind away at the gasket....which would be okay....if you take
the proper care and cover the intake valley and the intake
ports up. But if you don't, you get both roloc material and
the ground up gasket material in the engine. This will destroy
the engine usually within a week. I've seen it happen in
our shop. In theory, we are not allowed to use the roloc
discs when doing internal engine gasket cleaning. I think
the key is knowledge...knowing when and where you can
use them....and keeping internal parts and passages covered
while cleaning gaskets off. This even applies if you are
not using any kind of disc...you still have to be careful that
gasket parts don't get into the engine.
This might sound strange,but if your worried about metal shavings
getting in after taking the intake off,spray shaving cream in there,and
then use a shop vac to suck it out. I was taught that years ago,and it
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