'99 Astro AWD - Water Pump Leak?

ctroll · 05-22-2008, 06:17 AM

Hello, I have a '99 w/ ~110K AWD w/air.

I have a pretty good leak of what smells like antifreeze and feels like antifreeze. I can see the bottom of my water pump is wet and the fluid seems to be finding the low spot (the back of the pump) before dripping down. The pump is wet underneath from the front where the pulley is to the back. I cannot see it actually coming out of the weep hole, but the area around the weep hole is all wet. It looks like the leak is in the front where the pulley is and is running towards the back of the pump. Everything looks dry up top.

Here is the somewhat confusing part... the fluid leaking is pink in color and all I can ever remember putting in it is greenish-yellow colored antifreeze. The coolant in the radiator is green also. Other people have serviced the vehicle on occasion.

So here is my three part question... Is there such a thing as pink antifreeze, could this be something other than a straight-forward coolant leak, if it is a water pump - any tricks of the trade for us less experienced guys?

Any input would greatly be appreciated - Thanks!

Leeann94astro · 05-22-2008, 09:05 AM

Well, GMs Dexcool is orange. But I don't think orange + green = pink.

Someone might have done the dumb thing of putting RV antifreeze (the pink stuff) into your radiator. And that's only meant to winterize the water system, not for the radiator.

Does sound like your water pump is gone, which is a good time to do a flush and refill anyway.

brcidd · 05-22-2008, 10:08 AM

Hardest part is holding the water pump pulley tight while unscrewing the fan connector- I usually use a chain vice grip- others have had luck in hold the belt tensioner tight, and let the serpentine belt grip the water pump pulley- a long wrench and an impact to the end of it will usually loosen it- it is a standard right hand thread- so don't worry about direction--I have seen them loosen right up- and I have spent a half an hour trying to loosen one-- so roll the dice.........the rest is straight forward...........

They make a holding tool for it-- but I never had needed one yet......

ctroll · 05-23-2008, 01:03 PM

I haven't done anything yet, and won't be able until Saturday night. However, I just remembered that when the tranny was rebuilt, they spilled fluid when refilling. I think the pink color I'm seeing in the leak might be from the coolant picking up some residual tranny fluid before dripping to the ground???

I have a water pump question. How should I apply the blue rtv gasket sealer? I was told two different stories - one was to put it between the gasket and the pump only. The other was to put it on both sides of the gasket and coat the bolts.

What is the correct thing to do?

Thanks!

old_master · 05-23-2008, 02:30 PM

1999 calls for Dexcool coolant ONLY. Mixing green ethylene glycol and Dexcool will turn the coolant to sludge and clog the entire cooling system, including the heater core and radiator. The green ethylene glycol coolant is far more abrasive than Dexcool and will destroy the water pump seals rapidly.

Disconnect the upper radiator hose from the water outlet and the lower hose from the water pump, then flush the radiator with clear water, (garden hose works well), in both directions until it comes out clear. Then remove both heater hoses from the heater core and flush the core in both directions. Flush the engine block via the heater hoses in both directions also. Reconnect the hoses and refill with 2 gallons of new Dexcool.

The only reason to apply anything to the water pump gasket is to hold it in place while you start the bolts. If you decide to use RTV, make sure it is oxygen sensor safe. If not it will destroy the oxygen sensors.

Blue Bowtie · 05-23-2008, 10:07 PM

Havoline DexCool is orange tinted. Shell DexCool and some other brands are more of a reddish-orange, and may appear pink to your eyes.

ctroll · 05-27-2008, 06:13 AM

Great. sounds like my problem was self-inflicted. Thanks for the post about the wrong coolant. Sure enough my Haynes manual calls it out for '96 and later and I just plain missed it. Hopefully someone else can learn from my mistake.

I did not have a chance to work on the van this weekend as planned as a plumbing leak in the house took priority (if not one thing, it's another).

I did review your instructions for flushing and have a question...

What is the best way to connect a garden hose to the heater hose or ports? Seems like I need some type of special fitting or something?

Thanks

brcidd · 05-27-2008, 11:44 AM

I use a cut-off washing machine fill hose- it slips inside the heater hose and you can use the existing heater hose clamp....

old_master · 05-27-2008, 02:37 PM

As brcidd suggested, an old washing machine hose works very well. Using a "pistol grip" spray nozzle on a garden hose will allow air bubbles into the components when flushing, and that helps agitate and loosen the crud. Your choice, either way will do the job.

ctroll · 05-27-2008, 04:06 PM

Old Master, thanks for the info.

Just clarifiation... when I flush the heater core I shoot water into each hose aiming towards the fire wall and when I flush the engine I can use the same coolant path but shoot the opposite way?

Also, do you think because I mixed coolants I should replace the thermostat incase it got gunked up?

Thanks

ctroll · 05-27-2008, 09:02 PM

Any of you guys recommend a flush kit? I saw one at Advance Auto here for $4. Do these help make the flushing process easier?

Thanks

ctroll · 06-02-2008, 06:58 AM

Just an update...

I finished this job this weekend. Thank you everyone for your input. The tip concerning using washing machine fill hose for flushing was pretty slick - worked great!

Thanks again!

old_master · 06-02-2008, 09:23 PM

Quote:

Originally Posted by ctroll

.....Just clarifiation... when I flush the heater core I shoot water into each hose aiming towards the fire wall and when I flush the engine I can use the same coolant path but shoot the opposite way?...

Been out of town... sorry for the slow reply. Yes, flush both directions in every hose. You want clear water to come out of every hose and every connection, (both heater core tubes, both heater hoses, both radiator hoses etc).

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