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Coolant Leak

Re: Coolant Leak

Postby jocko463 » May 17 2011, 2:13am

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.

I'm not so much a smart guy as a guy smart enough to know how to find out....
'98 Sierra SL 305 Reg Cab Short Bed

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Re: Coolant Leak

Postby Bruce69Camaro [OP] » May 17 2011, 1:00pm

2003Z71 wrote:
Bruce69Camaro wrote: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?



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?

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Re: Coolant Leak

Postby 2003Z71 » May 18 2011, 1:54am

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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