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Coolant Leak

17K views 12 replies 6 participants last post by  2003Z71 
#1 ·
I got a 2000 Sierra with the 5.3L, the motor runs great but a little buit ago, I noticed a small leak on the ground. At first i wasn't sure what type of fluid it was, because it almost looked like P/S fluid, but my resivoir was full. Not to long after that, my coolant light came on, so I filled it.

Well I've been keeping an eye on the ground and I have seen any leaks lately but now, my coolant light has been coming on every other month, so I fill it again and drive it.

Problem is, I can't find the leak because it's small. Could it be that the water pump gaskets are shot because at one time it had the pink anti-freeze in it and I had it replaced.

If it is the pump gaskets, the motor has 120K on it, should I just go ahead and replace the water pump with a new one or just the gaskets?

Any thoughts?

Thanks

Bruce
 
#2 ·
Weakest point in that system with that many miles are the hoses (if original). If you thought it ws PS fluid I take it the leak looks like it's back towards the motor and not underneath the radiator. May be the bottom hose if you can't find any staining higher up.
 
#3 ·
Isn't it true though that the pink "GM" anti-freeze caused issues with the gaskets?

Thing is, I can't find a trace of the leak, not wetness on the underside, nothing dripping when it sits...
It leaked for a little and now I'm using fluid but the leak has gone away.
If I remember correctly, I found fluid on the crossmember by the front of the motor which made me start to think it was the water pump gaskets.

I'll check over my hoses.

Thanks

Bruce
 
#4 ·
Bruce, I would bet it's your water pump gaskets. I just changed the gaskets on my brother's 2001 Sierra, and his truck only has 45,000 on it, there was coolant on his front crossmember as well. I would probably change the pump too with that many miles on it since you have it off anyway. I checked my brother's pump and made sure there wasn't any staining coming from the weep hole, and reinstalled it since only has 45K. Hope this helps.
 
#7 ·
I actually changed the oil just the other day and yes there was a film or deposit under the oil cap.

I had the system flushed out the other year due to some heating issues and the coolant, was replaced with a universal type coolant and not the "pink" stuff.

I understand to replace the water pump, it's not a big job but I heard you have to have a special tool to take off the clutch fan.

I don't have this tool, so what else can you use?

Thanks

Bruce
 
#8 ·
Bruce, you can usually rent special tools from Auto Zone, Napa, Advance Auto, etc. I recommend Napa. Most times it's just a holding deposit you get back upon return.
 
#10 ·
Bruce69Camaro said:
I actually changed the oil just the other day and yes there was a film or deposit under the oil cap.

I had the system flushed out the other year due to some heating issues and the coolant, was replaced with a universal type coolant and not the "pink" stuff.

I understand to replace the water pump, it's not a big job but I heard you have to have a special tool to take off the clutch fan.

I don't have this tool, so what else can you use?

Thanks

Bruce
The tool I used was a 1 3/8 inch combo wrench. It's tight but it works. You also need a pin type spanner wrench to hold the pulley. Hold the spanner tight and smack the combo wrench with a dead blow mallet. The fan will break loose.
 
#11 ·
If this were my truck I'd bring it in and have the cooling system pressure checked. The mech will use a special tool to pressurize the radiator simulating the pressure developed when the engine is hot. I believe they also use florescent dye so that small external leaks can be detected under black light. I had a water pump in my '98 start weeping and, since I had an extended warranty, brought it in to my local GMC dealer. When they pressurized the system they found both the obvious pump leak but also discovered the intake manifold gasket was leaking (coolant circulates through the intake manifold for better fuel atomization).

This is really the best way to trouble shoot your problem; it'll confirm the obvious and maybe uncover the not so obvious.

And DexCool ...I've heard so many guys complain about this stuff and all I can say is they must not be taking care of their truck ...at least when it comes to the cooling system. My '98 has had nothing but DexCol in it and, for the past ten years that I've owned it, I have had zero problems with this coolant. As long as you keep the expansion tank filled to the proper level you should have no problems. Where you run into bad juju is when you *neglect* the coolant level, the expansion tank runs dry and starts sucking air into your cooling system ...yes, then you will have problems. Or, someone has inadvertently added the green or yellow stuff to your cooling system ...and then you've got a mess.
 
#12 ·
2003Z71 said:
Bruce69Camaro said:
I actually changed the oil just the other day and yes there was a film or deposit under the oil cap.

I had the system flushed out the other year due to some heating issues and the coolant, was replaced with a universal type coolant and not the "pink" stuff.

I understand to replace the water pump, it's not a big job but I heard you have to have a special tool to take off the clutch fan.

I don't have this tool, so what else can you use?

Thanks

Bruce
The tool I used was a 1 3/8 inch combo wrench. It's tight but it works. You also need a pin type spanner wrench to hold the pulley. Hold the spanner tight and smack the combo wrench with a dead blow mallet. The fan will break loose.
Instead of a spanner wrench, could you use a C-clamp vise grip?

Bruce
 
#13 ·
Not sure you would want to use a C-clamp Vise Grip, don't want to crush the pulley, but a strap wrench to hold the pulley tight would work too.
 
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