Water pump leaking after rebuild
 

I have just installed my rotary resurection rebuild in my 86. The last thing I needed to do was add coolant before trying to start it back up. After adding about 3/4 of a gallon of anit-freeze to the cooling system I heard the dreaded leak. Coolant was pouring out of the bottom of the water pump. I reused the old pump when I put the motor back together, but of course used a new gasket and plenty of black rtv. Is it possible to use to much rtv? The bolts/nuts were tightened to torque following the sequence in the haynes manual(rtv oozed out the sides). What would cause such a bad leak under 0 pressure/heat?

Funny..Landers rebuilds usually only have oil leaks.. :)

C'mon now, Kevin's been great to work with, saved this rx7 from the junkyard!
Any help on the leak?

well if it's just coming out from where the pump meets the block then just remove the pump and check the pump and block mating surfaces to make sure they're perfectly flat.. if they're fine the i gues you might have done something wrong.. is it possible to install the gasket the wrong pay?? maybe there was a bump somewhere.. just recheck everything..

maybe try using less RTV and giving it some time to settle?

Frank

I looked at the mating surfaces when I removed the pump, seemed okay. There was one small area where the rtv bead didn't make a complete circle, but I can't imagine it being a large enough opening for the amount of leakage I got. The rtv had about 2 weeks to settle as I had to wait for oil cooler lines. Too much time too settle? Should I only put the rtv on 1 side of the gasket, I put it on both last time.

dunno if you should put it only on one side.. i think i'd put it on both but put just enough to put an even thin smooth film on the gasket, i dunno if you did this last time but just hand tighten the bolts by sequence first then tighten then a little harder with a wratchet again by sequence and then torque them to spec with your torque wrench

lol i dunno how to be more carfull then that

Frank

How old is the water pump? Could be that just its sitting out in the air could have dried & cracked the internal seals, and the coolant you're seeing is coming from the weep holes?

Its normally not the weep holes unless the engine is running.

Hate to be a party crasher but did you replace the water pump manifold gasket...? Its a must...

When you have 2 dissimilar metals come in contact the anode (aluminum) corrodes and the cathode (iron) survives. Cleaning and sealing the area improves corrosion behavior but that's not always possible. Using a gasket or completely covering the area with silicone sealant helps greatly. Anyone who has removed their water pump has seen this. The pitted area is the corrosion. That area must be cleaned and siliconed and not just gasket as it will leak again if badly pitted.
Also, never use tap water as it's elements increases corrosion. You must use antifreeze and distilled water to fight corrosion. Redline Water Wetter helps.
Distilled water is cheap.
Besides, you don't drain and flush the system as often as an oil change.

did you make sure that the spacer washers are on the two studs on the pass side?
(the two really thin washers that go between the motor and the pump housing)
if they are not there it will leak.

matt

The 2 spacers are there. The water pump housing to front cover gasket was also replaced. I get to replace it again since it ripped when the housing and front cover seperated while I was throwing my tantrum removing the water pump. I used about a 1/4 inch bead of rtv on both sides of both gaskets(followed instructions on rtv package). I've since been told to just smear a thing layer of rtv over the metal mating surfaces. What is the correct way to apply this stuff? Maybe to much made it leak?

Use sealant and make a complete bead and let it cure a couple minutes. No matter how much sealant you use, if you over toque it it will ooze out. Torque it in sequence to about 20 lbs. and it won't leak. If you can find Hylomar, use that with the gasket. The good thing with Hylomar is that it will always stay soft and easy to clean. It fills gaps and useful in areas where oil and coolant are used. It's especially useful in the housing O-ring grooves. Hylomar doesn't need to be cured, RTV does.

sounds like weep hole to me. add coolan again and see if its coming from that lilitty bitty hole in the bottom of the pump, right below the pulley. if it is, then your pump needed replaced anyways b/c the seals are dried out, its not a gasket issue.

i got my pump on without a gasket just fine :-D .... but the housing gasket is another story..

Got the pump gasket today, waiting for the housing gasket. So is there a way to check the weep hole for leaks w/o putting it all back together and filling w/ coolant? I'm pretty sure it was leaking from the pass. side where the pump meets the housing, but I was looking at it w/ belts, fan, ect. still on. I was to pissed off to be logical and check closer once I removed belts, fan, ect.

are white coolant dry marks coming out of the pulley shaft? if so, yes new pump needed. also with some gloves, grab the shaft and jiggle it. it should have NO play whatsoever. if the pumps old, might as well blow the 80$ for a new one..

Correct way to apply RTV on our engines-

1) clean both mating surfaces with a scoth brite pad (round ones available at auto parts stores) on a pneumatic or electric "die grinder". This removes any oxidation/ corrosion (which the RTV will not adhere to) and makes millions of tiny scratches on the surface for ultimate adhesion

2) wipe a thin layer on both sides of gasket material, making sure that any small passages in the gasket are not going to be blocked when the item is torqued down and the RTV "squeezes"

3) do not let cure for more than a couple of minutes. If you do, the RTV won't be pliable enough to fill in any small defects

4) perform an initial torque to the item, using a cross-torque pattern, until item is seated, and RTV starts to squeeze out

5) let sit for 5 to 10 minutes

6) perform final torque, again using a cross torque pattern

Easy enough, eh? :)

I dont even have a gasket there. Just red RTV. What Ive used for the past 2 years and never had a leak.

Sure, takes a bit more RTV, but it works. Still need to follow the application and torquing times listed above. My oil pan, ACV, oil level sensor, front cover, and thermostat housing are on with just RTV, from the rebuild 7,000 miles ago...Probably more than that, can't remember now...No leaks yet :)