Got a new (not reman.) water pump for a '96 Intrepid, 3.3L
engine, was surprised to see that the replacement part, a
Master CP7140, had the water pump weep hole at the top.
The OEM part (with an asymmetric mounting flange) has the
weep hole at the bottom. First time I've seen this. Is this now
common? Might the reason be to avoid paying a royalty on
the original patented design?
I've heard that hole referred to as either a weep hole or a hole
necessary to allow pressure relief when pressing seals/bearings into the
A hole in the top would be useless as a weep hole, but would work for
the latter reason.
Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com
Despite being on top, I think it could still function as a
stopgap safeguard against the introduction of coolant
(caused by a leaking seal) into and resulting in a
catastrophic failure of a pump shaft bearing, should
that even be the purpose of that hole.
I did however wrap a piece of tape over the hole,
not as any type of seal, but for the sole purpose of
preventing the accidental entry of foreign chemical,
clogging or abrasive material dropping into the hole.
I remain curious as to whether others have observed
such a possibly non-standard placement of that hole.
it's a mistake. if you look at the same part supplied by most
manufacturers, they have the hole at the bottom in the normal way. that
this one has it at the top is a design error by that particular
manufacturer. you'll see this is you search online and look at the pics.
as to top vs. bottom location, top is a very bad idea. in fact, if you
wanted to /deliberately/ mess up someone's car, you should make this
mod. why? because it allows coolant to pool against the bearing seal
[there are usually two sets of seals on a shaft - one for the pump, one
for the bearing. the weep hole should be connected between so the
inevitable seepage from coolant can run out before it accumulates], let
that coolant seep in, and ruin the bearings. top location is a /very/
bad idea. but i supposes it's a great idea if you want to sell someone
a new pump again in a few months.
bottom line - it's not worth trying to save a few bucks with an
aftermarket component - buy the 100k mile warranteed oem that has the
weep hole where it should be. don't wait - do it now before you get
stranded by that piece of garbage.
I largely agree with your analysis but its having failed on a
Sunday, leaving no option to acquire the OEM part, the two
nearby parts stores having a sum total of one replacement
item between them combined with an immediate need for the
vehicle, meant that there was little choice but to accept what
An interesting side note though, the gasketless aforementioned
is very quickly and easily removed and reinstalled (a total of
5 mounting and 3 pulley bolts plus one o-ring) and carries a
lifetime, free replacement warranty.
I've never seen that before. Are you sure you don't have your engine
mounted upside down? :-)
Anyway, it sounds like a good idea to me - you might be able to see if
the bearing is leaking. I always have to stick my hand under the bearing
housing and feel for coolant. Not having to do this would suit me fine.
Hopefully, nobody's paying any royalties on a weep hole. :-)
First of all you are talking about a 14 yr. old car with a part that has
been around for decades. There isn't anything in the law preventing an
after-market supplier from copying the original part except competence.
An after-market part may vary from the original because it was copied
I was only hazarding a guess as to the reason it might deviate
from the original design. Perhaps you're correct, although I
can hardly fathom the staggering incompetence required to
manufacture and continue to produce a device that poorly
copied lo these many years. I wonder if a defective product
class action suit might be in order ;-)
Hole on top may even be a manufacturing mistake. Weep holes
go way back to the days of rope packing type seals. They
required a certain amount of leakage/weepage to ensure the
seal was not too tight and overheated to completely fail as
the wax melted away. In later designes, it was left there
as a good way to detect leakage while allowing the coolant
to drip harmlessly out preventing more rapid damage and
total failure of shaft bearings. I suspect the coolant will
collect around the bearings with the hole on top.
I concur that at incipient seal failure, coolant will commence
to pool and subsequently spill from the hole. Being an old
car though, I'm hoping that it might survive the remaining
service life of the vehicle. In any case I'll keep an eye on it.
Unlike in days of old there's fortunately no chance that a
failed shaft bearing can put an attached fan into the radiator ;-)
Thank you all for your considerate responses.
One of the places where I used to work was a cotton oil plant.The pumps
in the solvent extraction area where I worked, the pumps had square
graphited rope packing.It was a constant chore not having the packing
glands not tightned too tight and not too loose.That was Hexane fluid
(it is kin to lighter fluid) being circulated around inside of the
pipes.Very Flamable stuff it was too! The tools we used in there were
bronze non sparking tools.Breathing too much of that Hexane fluid would
make you ''high'', but it was the wrong kind of a ''high''
The health effects of hexane can be a lot worse than was thought just
a few years ago. MSDs today often dont show the full nature of the
Neuropathy and liver damage, perhaps cancer, may result from
hexane's breakdown products in the body.
It might collect a little bit, but would that really be an issue?
Those bearings are, IIRC, bronze bushings and they tolerate coolant
pretty well. The contact with coolant may provide part of the
lubricity. (As you would remember, people used to put water
pump lubricant in their radiators, which was nothing more than
"soluble oil". Ate up the hoses, but maybe lubed the pump shaft
I don't know of any modern automotive water pumps that use
bushings for bearings. Bushings do not wear well in high
speed applications like modern cars and trucks or small to
medium marine and industrial engines. Every automotive app
I can think of uses frictionless (ball or roller ) bearings
in the water pump. In the old days - and I am sure is
currently the case - pumps using bushings required zerk
fittings and frequent lubrication during operation. I have
seen those in older units. I have also seen pumps that use
oil cooling and lubrication for the WP bearings. The weep
hole in most of these applications is between the water seal
and the neaeest bearing to minimize the chance of coolant
getting to the bearings. Water pump lube was never for the
bearings. It was to provide some protection and longer life
for the coolant/pump seals. Most commercial
antifreeze/coolant has enough lube quality for this
nowadays. You will still find packing type seals in
applications that use raw water like marine units to supply
water-to-water heat exchanger cooling systems.
I cant challenge you because I havent taken a water pump apart
and rebuilt it in a long time. And that last one definitely had a
Water or coolant does have some lubricating ability. Block polyols
were evaluated as coolant system lubricants, and did work, but it
was for the bearing surfaces, not the seals.
The old "soluble oil" lubricants were also for the pump shaft, and
probably worked some, but they did eat up the hoses, etc.
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