Two times now, the water pump gasket on my 92-Mercury Sable (3.8L V-6) started leaking!

When I originally installed the new pump, I meticulously cleaned all of the mating surfaces so there were no traces of old gasket material left behind.

I used a thin coat of Blue RTV on both sides of the new gasket but a few weeks later, the gasket developed a small leak. So I removed the pump, got a new gasket, cleaned the surfaces again and re-installed it using Blue RTV. Again, it sprung a leak.

Should I be using a different gasket sealer other than Blue RTV? The Haynes service manual says to use “Contact Adhesive” but I’m not sure what they’re talking about. Is that rubber Contact Cement?

Any help would be greatly appreciated. On the plus side, I’ve gotten really good at removing and re-installing a water pump on ’92 Sable, 3.8L; I think I’d got it down to about an hour and a half job!
Thanks,
Phil

 

I have had good luck with a Permatex product that comes in a can with a brush built into the top like most pvc pipe cement or solder flux. You won’t be able to tell that it is red, but it is a liquid (shake it) and it’t probably the only thing they sell in a rigid screw top can.

Clean both mating surfaces until they shin. I use those 3M plastic scrubbing pads soaked in lacquer thinner. Apply the sealant to all four surfaces, both sides of the paper gasket, the pump and the block. Before you do that, soak all the nuts/bolts in lacquer thinner too. If you can, run a tap in to all the holes and a die up and down the bolts. Chances are remote that any bolts thread into oil or water passage but look before you clean them. If they are oily and dirtier than the dipstick, they do not enter oil passages. If bolt have clean oil or coolant on them put the read stuff on those threads too.

Do whatever it takes to get a torque wrench in there and tighten per spec. If that fails, go with Bar’s Leak.

 

When they say contact adhesive, it means anything, super glue, rtv ect. If you used to much rtv, when you tightened down the pump, there is a chance the gasket "slipped" out of place. HEre's what I recommend you use.

I recommend the use of 3M Weatherstrip adhesive on the water pump side of the gasket and Permatex #2 gasket sealer on the engine side of the gasket.

This should solve your issue. Make sure the mating surfaces are not damaged to badly.

 

A co-worker told me the reoccurring leak on the water pump gasket could be caused by a worn idler pulley or tensioner pulley or both. Not the bearings or bushings in the pulleys; but the pulleys themselves!

He claims, as the pulleys age they wear at the outer edges and they can cause the serpentine belt to run uneven. When that happens, it causes stress on the water pump gasket from the vibration and uneven transfer of power to its pulley.

Ever hear of that one? Its news to me but it does make sense. I guess it won’t hurt anything to inspect those pulleys when I got the water pump off to reseal the gasket……..
Phil

 

I wouldn't subscribe to that theory; a LOT of idler and tensioner pulleys wear to the point of failure without taking the water pump out.

My product of choice to hold the gasket in place is the 3m Weatherstrip adhesive that HotinOKC mentioned.

 

i wouldnt hold to a theory as such either, each incident is different and it would take haveing to see it to know for sure what is going on

but contact adhesive on a brush in the cna is the way to go on things like this

a whole different animal than RTV

RTV isnt nearly as adhesive as anything else

i would get a can of the brush on adhesive, the stuff lasts forever and ever in storage and its some mean stuff and great for stubborn items like waterpumps and thermostat housings and such

RTV is good for other items such as valve covers and intakes and so on


good luck

 

if the gasket is paper/fiber, then the brush-on gasket sealer is the way to go..apply a thin layer to all surfaces and let dry 20 minutes before reassembly..be careful, as it will stick permantly on touch.

with neopreme seals, clean surfaces carefully, and dont use a sealer. it is not needed and usually causes the seal to slip

 

rule of thumb is:

seals no

gaskets yes

seals seal themselves

but not all are named seals, as some gaskets such as fel pro head gaskets are self sealing


if are cork good luckr paper then you can use anything you want really

 

I would check the timing chain cover and water pump with a straight edge and feeler gauge. Could have a uneven spot? But I would not use Blue RTV. Copper Coat is another good choice for gaskets.

 

First off, let me thank everyone who offered help with my water pump leak!

What I did was put the car up on jack stands; remove the radiator antifreeze catch bottle, serpentine belt and a couple of brackets so I could have a clear view of the water pump mating surfaces.

Then I pumped up the cooling system to about 16psi and immediately found two small hose leaks; one heater hose and one of the returns to the water pump. Repaired those leaks and pumped it up again......This time I could see a slight leak on the top, left side of water pump. So I started snugging up the water pump bolts in a crisscross pattern until the leak stopped.

I noticed that a couple of the bolts were way too loose; don't know how they got so loose, because I used a torque wrench at the original install. Maybe I should have used some blue LocTite?

Put it all back together, topped it off and so far so good. No Leaks!
Phil

 

Glad the problem was solved!

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