Need advice on water pump replacement

My '96 SL has an intermittant coolant leak which I traced to the water pump area. It only seems to leave a small puddle when it has been sitting in my driveway for a couple of days - it doesn't seem to leak while running or leave a spot during the day at work.

Since the pump has over 100K on it, I bought an aftermarket replacement to change out this weekend. It came with an 0-ring type gasket. Would you use any sealant on this, and if so, what type?

TIA!!!

Larry

Reply to
Larry
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When I changed out my water pump ('95 SW), I used just a thin layer of Permatex on both the water pump and engine block flanges. It's been over two years now, without a drop leaking...

Reply to
William Hughes

With respect, Permatex is a brand and not a product. They market a wide range of products some of which are suitable for this application.

IMHO proper installation of O rings require some type of lubrication in order to allow the rubber to squirm or move into place as the part is tightened, and also to prevent the rubber from being cut or abraded. You also do not want the ring to seal or bond itself to the housing as you may need to remove it at some future time. The best product will vary according to specific application but in general almost anything will work, many people use grease as it will also help to hold the ring in place as the part is positioned but RTV silicone also works well, plain oil or in this case coolant will also work. Most of the Permatex gasket glues will work but some of the hardening types will be difficult to remove if you need to remove the part in the future. Do not overuse anything as the excess will only contaminate the contained fluid, (in this case the coolant). As a general rule lubricating with the contained fluid is seldom wrong.

I would also add that water pump seal failure is often caused by the drop out of the abrasive silicate used in standard aluminum compatible antifreeze coolant to reduce galvanic corrosion between the iron and aluminum parts of the cooling system. Now would be a good time to drain and flush the cooling system then wash with a solution of Calgon dishwasher detergent before repeated thorough flushing and installing new non-silicate type long life coolant. It is important to remove ALL of the standard coolant before installing most types of long life coolants as most are incompatible.

Those who continue to use standard aluminum compatible coolant and especially those who use old coolant will probably need to change their water pumps sooner than those who do not.

Happy trails, YMMV

Reply to
Private

Around here (San Antonio, Texas) "Permatex" is the term used generically to refer to any silicone-based sealant. In this case, the black, high-temperature, oil-resistant variant. Comes in a blue squeeze tube. You are correct; I should have been more precise - not everybody speaks Texan...

Reply to
William Hughes

IIRC, In the pre RTV days 'Permatex' #2 was a black general purpose tacky non-hardening gasket glue. I think it was called #2 because it got all over everything and was hard to get off your hands or tools, I don't remember a #1 :-)

Reply to
Private

Permatex #1 is still sold. It is a brown hardening gasket sealer (as opposed to the black non-hardening silicone based sealant for the #2). Permatex also makes a Blue RTV and a black high temperature RTV sealant. I generally use a little blue RTV in the channel and on the mating surfaces with water pump O-rings.

Bob

Reply to
Bob Shuman

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