'01 4.0 waterpump time!

[sempar]

I was getting the Aurora ready for Summer use ( it's stored in the Winter) Changed the oil and filter using MaxLife Semi synthetic, NAPA Gold filter. Everything went fine, started it up chekced for leaks, none found. After cleaning the car, started it up to move it when I noticed a bifg puddle on the driveway. Hoses all look good; I can only think that the waterpump seal is gone after I checked everthing to be sure it's dry. Not a big deal, should I buy GM / AC Delco or have others had good luck with other brands? While I'm at it, I might as well buy the special tool to remove it.

Thanks,

John

[plato442]

I bought a pump from AutoZone and rented he tool. What year?

[sempar]

Its a 2001. GM Parts House lists just the gasket for the pump to drive pulley as well as the O-rings for the pump to front cover. Couldn't I just replace those? From what I can fell it's the pump to drive pulley gasket at the rear that's gone.

[plato442]

When I replaced mine, there wasn't necessarily a problem with it leaking at all. I just went through and replaced it since the coolant crossover was off the engine and even though it wasn't leaking you could tell it wasn't Turing as freely as a new one and still had over 12 years of use on it. I'd replace the pump of you're going through the trouble, but that's my own opinion. Also, I did have a leak at a coolant fitting at the back of the block right above the tranny that was a real b***h to replace.

[sempar]

plato442,

Thanks for the insight. I've ordered a new pump with the proper o-rings after I found out that GM wanted over half that cost just for the o-rings themselves. The only place I can tell where it's leaking was behind the waterpump pulley, could barely reach in there with my fingers. Either the rear seal or the waterpump shaft seal has eet go suddenly. I had no noise or loss of coolant until then.

John

[plato442]

John, about 1 day after posting my suggestions, I noticed a small puddle under my Aurora. So I did the taste test and sure enough it was coolant. I pulled it forward and crawled underneath and couldn't find the source. Started it back up and NO leaks. Drove it around and parked it and no leaks again. Jump 18 hours to this morning and I started it to warm it up and a small puddle formed when I got back. I will check for the source again, but $#%!

[sempar]

plato442,

Sorry to hear about that!. I hope I didn't jinx you! I double checked everything again. The only place I can see is the waterpump.... or else the crossover cracked ( but I doubt that ), car hadn't been warmed up.

Hope yours turns out to be a leaky hose / connection.

John

[Randy T.]

You are close, but the crossovers do not crack that I have ever heard. You need to check your coolant crossover gaskets, the ones between the coolant crossover and the heads, all of these are bad if they have not been changed yet, on 3.5s and 4.0s, 1st and 2nd gen.

[sempar]

Hi Randy,

I've thought about those crossover to cylinder head gaskets too, I don't want to have to replace the pump unnecessarily. Mind you, I think doing those would be a bigger job!
I'll check them once again before I start to remove the pump. There was coolant behind the pump drive pulley, so I'm fairly certain that's the culprit.

John

[jnick2013]

anyone ever have issues with the rpm's of the water pump at idle speeds on the 4.0? at idle it over heats but as soon as you raise the rpm's it drops back down.

[Paulaurora]

It might be pump or you might have air in a system.

[jnick2013]

brand new pump from autozone. how do you get ait out of the system since there is no bleeder valve?

[sempar]

When you go to install the pump make sure the locking ear with the notch is at the 7 o'çlock position. I also used the tool to properly install the pump.
The FSM says to start the engine and have the HVAC control at any setting except MAX with the Temp setting at highest setting. Idle engine until lower rad hose to water pump is hot. Let engine cool overnight then check and top up overflow tank if necessary. Personally I found I still had to top up the tank for a week or two to purge all the air.

John