2004 Suburban Coolant Leak

BugsandJeeps

Member
Joined
Oct 12, 2006
Location
Concord
I have a coolant leak that I can't find. Suburban 1500 with the 5.3. My driveway is on a slope and I tend to park facing uphill. Lately I have been noticing a small stain on the driveway and looking at it, it is coolant. I crawled under the truck and it appears to be running down and dripping from the base pan. I have looked all around the block and the hoses and see no leak. This has been more noticeable since it has gotten cold. I am topping up the resevoir to keep it full but need to find the leak. Any ideas?
Mike
 
crank it up and let it run until warm, the leak should be worse enough by then to maybe find it.
 
water pump is most likely, but there is a coolant cross over tube ( about 1/4" in diameter) under throttle body from one side of block to the other that has had a history of having bad seals and leaking. ( spans the valley under front of intake)

2 possibilities
 
My 01 6.0 did the same thing, I kept looking ,but couldnot find the source of leak. Finally took it to a radiator shop . It was the water pump gasket. $400.00 later, new gasket pump and belt. It doesn't leak anymore.
 
moldman05 said:
My 01 6.0 did the same thing, I kept looking ,but couldnot find the source of leak. Finally took it to a radiator shop . It was the water pump gasket. $400.00 later, new gasket pump and belt. It doesn't leak anymore.
Click to expand...

Is why I said water pump, may as well do it since you have to pull it anyway, won't be long before it pukes

If I remember, that was a warranty item, but not a recall as it isn't a safety issue.
 
Blkvoodoo said:
water pump is most likely, but there is a coolant cross over tube ( about 1/4" in diameter) under throttle body from one side of block to the other that has had a history of having bad seals and leaking. ( spans the valley under front of intake)

2 possibilities
Click to expand...

X2 I also see alot of intake gaskets on the backside, where to little silicone is used at the distributor. Check your quickdisconnect. That is seldomly overlooked and would be the easiest fix.
 
jackedHB said:
X2 I also see alot of intake gaskets on the backside, where to little silicone is used at the distributor. Check your quickdisconnect. That is seldomly overlooked and would be the easiest fix.
Click to expand...

except that this a 5.3 LSx probably "Z" engine, with no distributor and the intake is composite, and no coolant runs though it.

You are thinking an "R" series engine with the 2 piece aluminum/composite intake with the heater bypass running thru the intake and SCPI fuel injection

"R" engines were notorious for intake coolant leaks,

"Z" engines are known of vacuum leaks from warped intakes and poor gasket materials, and water pump/gasket failures. Oh, and piston slap.
 
Had a closer look and the coolant is dripping from the bottom of the base pan. I looked around the water pump and it is not leaking that can be seen. Is the coolant crossover tube visible with the intake manifold cover (big plastic thingy) on or do I need to remove it?

Mike
 
crossover

the coolant cossover runs right through the bottom of the throttle body. there are two black rubber hoses with clamps. the easiest way to view it is to remove the intake air duct from the back of the air filter box to the throttle body. having said that i agree with blkvoodoo that it is probably the water pump gaskets leaking. this is so common on the gen III style engine and can be difficult to see from the top or side. typically when these gaskets leak coolant can be seen streaming down the oil pan and dripping off the skid plate.
 
Had another look yesterday. At full operating temp with the truck running I crawled underneath and pulled the big plastic cover off to get a better look. Nothing was leaking at all. But from under the engine I could see on the passenger side a wet area on the couple of plastic wiring harness looms that run along the base pan. This wet area is around 3/4 of the way towards the front of the engine on the pass side. Used a flashlight and damn near broke my neck trying to trace the wet area. Nothing. So does this sound like a leaking water pump gasket? If so what are my options? Pull the pump and replace the gasket? What's the priority on getting this done and worse case scenario if I let it go til after xmas?

Mike
 
BugsandJeeps said:
Had another look yesterday. At full operating temp with the truck running I crawled underneath and pulled the big plastic cover off to get a better look. Nothing was leaking at all. But from under the engine I could see on the passenger side a wet area on the couple of plastic wiring harness looms that run along the base pan. This wet area is around 3/4 of the way towards the front of the engine on the pass side. Used a flashlight and damn near broke my neck trying to trace the wet area. Nothing. So does this sound like a leaking water pump gasket? If so what are my options? Pull the pump and replace the gasket? What's the priority on getting this done and worse case scenario if I let it go til after xmas?
Mike
Click to expand...

sounds like alot of water pump gaskets i've seen leak on these engines. :shaking:the dexcool runs and drips off that lower wiring harness. options depends on milage. if you've got over 80k and have never repaced the pump i would recommend replacing it instead of just replacing the gaskets. if you need to wait, make sure you check your coolant level on a daily basis and keep it filled to the proper level.
 
Thanks Jeepman. I have 108000 and to my knowledge the pump has not been changed. I'll keep an eye on it and get to it ASAP. Any concerns of catastrophic failure or just the leak getting worse?
 
BugsandJeeps said:
Thanks Jeepman. I have 108000 and to my knowledge the pump has not been changed. I'll keep an eye on it and get to it ASAP. Any concerns of catastrophic failure or just the leak getting worse?
Click to expand...

ok for now as long as the pump isnt making any abnormal noise and engine is operating @ normal temps.
 
Back
Top