Water Pump Leak -- a Cry for Help :(

[CTron]

I'm relatively new to working on cars, but I thought I could fix my leaky water pump. I was wrong. I had a pretty bad leak from the water pump that caused me to have to pour water into the radiator every 100 miles or so.

1. Finnaly I removed my old water pump and cleaned and sanded both surfaces.

2. I applied a silcon gasket sealant between the gasket and the new (slightly used) water pump and promptly installed it.

3. I put the fan and belt back on.

4. Then I poured water back into the radiator to test it for leaks. I noticed a very slight leak.

5. I took the car for a short test drive and when I got back the car didn't appear to leak much at all.

6. Next day, after 20 minutes on the freeway I lost almost all my water- much WORSE than before!

Other info:

I had a new radiator recently installed, no problems with it at all.

I'm missing the Air Pump Fan Belt entirely- how bad is that?

I'd really appreciate any advice anyone can give me about the Water Pump and the need for a Air Pump Fan Belt.

Thanks,

Chris

[2ManyZs]

Where is the water leaking out of the pump? Is it coming from around the shaft behind the pulley? If it is you need a new pump. If it is coming from around the gasket you could try to re-mount it with another gasket.

Can't tell you much without knowing where the water is leaking from. The missing belt shouldn't have any effect on the water pump.

[Phacade]

If you did not replace the pump do so now. Worst case scenario: You have a new pump. When I rebuilt my L28, I used the red sealant and used it sparingly. I have has 100% no leaks and a cool engine. You might want to consider having the front cover bead clasted for an extra clean cover, it pretty much guarantees no leaks. Don't buy the pump from Pep Boys, a friend of mine did and it was no good. I spent the extra buck and got it from MSA.

[Daniel]

Did you try to reuse the old gasket with that used pump?That won't work.Also when you remove the water pump,it drains the block of coolant.You can refill the radiator but,when your car reaches normal temp the thermostat will open and take all the coolant from the rad. If you don't add more you will overheat.That will cause your car to spit out the coolant appearing as a big leak.I would not advise " sanding" those parts.Use a gasket scraper.You don't want to remove any metal when cleaning the area as sandpaper would.It can also cut tiny grooves into the surface causing a poor seal.Timberwolf is correct.Get a new factory pump and it will last for years.The fan belt should be tightened to where you can push hard on the alternator cooling fins and it will move.Overtight will cause alt. and waterpump bearings to wear prematurely. Have Fun !! Daniel

[CTron]

The leak is indeed coming from around the gasket. The only moisture I felt was from the lower area on the gasket- and that is where the water was visibly dripping from.

Do you reccomend using a gasket sealant? The one I used said it needed 24 hours to cure, perhaps I filled it with water too soon (within 1 hour).

So do I even need the missing belt at all?

[CTron]

I was using a brand new gasket.

What you described sounds like exactly what happened to me:

Originally posted by Daniel

You can refill the radiator but,when your car reaches normal temp the thermostat will open and take all the coolant from the rad. If you don't add more you will overheat.That will cause your car to spit out the coolant appearing as a big leak.

Where would this 'big leak' appear to come from?

How tight should I bolt on the water pump?

Do you guys run without the air pump belt?

Thanks so much to everyone for responding. You guys are life savers! I'm without a car until I get this fixed...

[Daniel]

I think the pump is bad and leaking out the weep hole on the bottom of the pump.I've never seen the gasket go bad,of course it could happen.Careful running just water,antifreeze has a lube in it for the pump.Tighten the bolts in an X pattern a little at the time.If you tighten one down all the way then the next you could warp the pump.Tighen evenly and gradually.The coolant would spit out of the overflow under the rad. cap.The fan would spray it all over. Daniel

[240znz]

Always, always ALWAYS use antifreeze in your coolant.

It contains an anti-corrosion additive that helps slow down the aluminium eating bug. With it help run your engine cooler in summer and you won't pop those frost plugs in winter....better yet your head water galleries will not corrode further. Look on the bottle for quantities for winter/summer use.

Zed not Zee

[CTron]

Well I have taken the time to carefully install the water pump, gasket, and used a gasket sealant. After waiting more than a day, then adding the coolant I find that it is leaking out of the lower weep hole.

Does anyone know why this is happening? How can I fix this?

Thanks,

Chris

Originally posted by Daniel

I think the pump is bad and leaking out the weep hole on the bottom of the pump.I've never seen the gasket go bad,of course it could happen.Careful running just water,antifreeze has a lube in it for the pump.Tighten the bolts in an X pattern a little at the time.If you tighten one down all the way then the next you could warp the pump.Tighen evenly and gradually.The coolant would spit out of the overflow under the rad. cap.The fan would spray it all over. Daniel

[Daniel]

Don't feel bad that gets everyone.I did just like you when I was a puppy.It's part of learning.The pump has an bad internal bearing/seal.That is allowing coolant to leak past.A new pump is required.On the bright side you are a lot faster at the task now!!Since the cooling system will be drained you may think about new radiator hoses and thermostat.Summer's coming.Put your old hoses under your spare tire for emergency.Remember new coolant with a 50/50 water mix.You can leave the cap on but loose so you can remove it to add when the thermo opens.----In the future, please think of this experience when you consider a "slightly used part".Used part cost +labor+new part+labor again=cost more than just buying new part to begin with.I know you supplied the labor but your time has value.Another part of learning.We've all done it. Have fun!! Daniel---At least it wasn't a used heater core!!!!!!ugly!!

[CTron]

Thanks for everyone's help. It would seem that the problem is fixed by the new 'new' water pump. I ran the car for an hour and drove it but never got the thermostat to open up. I didn't want to take it on the freeway in case it opened up and I had to pull over.

-Chris

[2ManyZs]

I'm not sure what you mean by the thermostat not opening up. I can guarantee that the thermostat opened up if you ran the car for an hour. If the thermostat hadn't opened up you would have fried the engine.

The themostat is closed when the engine is cold, then when you start the engine it begins to heat the coolant in the block. When the coolant reaches a certain temperature (governed by the temperature the thermostat is supposed to open) the thermostat will slowly open to allow coolant to circulate through the radiator. The thermostat will then begin to slowly close up to slow the flow through the radiator so that the coolant doesn't cool off too much. A thermostat is constantly fluctuating the size of the opening in order that the coolant remains close to the temperature that the thermostat is set for. In stop and go traffic this keeps the car from overheating and also over cooling. The engine needs the heat to allow for complete combustion in the cylinders while not over heating and ruining the engine. The thermostat will stay at the same opening while cruising down the interstate at a steady speed, but any variation in terrain or throttle opening will cause it to start varying the restriction again. If the thermostat were to open fully then close fully, the temperature of the coolant would not remain near a constant temperature. It would hit a peak, then drop very sharply to a low, then gradually rise to a peak again. This is not how an engine is designed to operate. It needs the temperature to remain at or near a constant temperature to run at peak efficiency.

Older engines like the L-series prefer a cooler temperature(160-180 degrees) while todays newer engines are designed to run at higher (180-200 degrees,some may be higher) to promote better combustion to meet todays emission standards.

I just thought I would add a little here since it seems there may be a lot of people who think a thermostat opens and closes completely. I had a "mechanic" at the local Dodge dealer argue the point with me when my last pickup started having a problem with a large fluctuation in engine temperature that I said wasn't right. His "explanation" was that the radiator was so large to cool the Cummins engine that this was normal. I promptly explained that I had been driving tractor trailers for almost 20 years and this was not normal. Needless to say I got a new thermostat and the problem was solved.