Frustrating Coolant Leak!

[pastorsean]

I have a 2005 silverado 1/2 ton crew cab z71 with a 5.3 v8. It has 147000 and has been perfect up intil the last 6 months or so. It has started to lose coolant. You can smell it but cannot see any leaks. I have had the system pressured up and no leak. The oil is fine no foam. I have looked all over the motor and cannot see even a wet spot. The smell comes from under the hood and not out of the tail pipe. Any thoughts would be greatly appreciated!?!?

[nickvrebel]

do a search on this site for "castech"

[txab]

It takes very little coolant to make a smell appear. How much are you loosing over what period?

 

You can have a leak that is evaporating almost as fast as it is leaking. Water pump and WP gaskets are one of the big leak points. Looking into the Castech head issue is one thing to keep in mind, but there are other areas to look into as well

[Wires]

I have a 2005 silverado 1/2 ton crew cab z71 with a 5.3 v8. It has 147000 and has been perfect up intil the last 6 months or so. It has started to lose coolant. You can smell it but cannot see any leaks. I have had the system pressured up and no leak. The oil is fine no foam. I have looked all over the motor and cannot see even a wet spot. The smell comes from under the hood and not out of the tail pipe. Any thoughts would be greatly appreciated!?!?

 

 

My 5.3l had an issue where the lower rad clamp cracked in 2. When I stopped hot, it would puke out some coolant after it sat for a while. Rest of the time it was fine. I grabbed each clamp with a pair of pliers, and the lower one broken in 2 and fell under the truck. It was just fused to the hose from the heat, but wasn't holding anything. And the hose was bonded well enough to the rad pipe that it wouldn't pop off.

[Guest pjblurton]

You can smell it but cannot see any leaks. I have had the system pressured up and no leak. The oil is fine no foam. I have looked all over the motor and cannot see even a wet spot. The smell comes from under the hood and not out of the tail pipe. Any thoughts would be greatly appreciated!?!?

 

Had the same symptoms about seven months ago in my 03 w/200K miles... I found some light staining at the weep hole of the water pump. It eventually started to leak enough that you could see it but it took about 6 months and would only leak when the engine was cold.

Replaced the water pump last month, no more leaks.

Hope yours is as simple!

[rodram]

... if this was a 96-99 5.7L Vortec ... and once you rule out hose clamp, coolant pump, and radiator leaks then the coolant smell leads you directly to a leaking Intake Manifold Gasket ... don't know if this is a same critical issue with the 5.3

 

.. the gasket can leak coolant onto the top of the engine where it will sit in there and evaporate with no leak detected on the garage floor or pavement under your truck... but you can smell it

[dlstewart01]

... if this was a 96-99 5.7L Vortec ... and once you rule out hose clamp, coolant pump, and radiator leaks then the coolant smell leads you directly to a leaking Intake Manifold Gasket ... don't know if this is a same critical issue with the 5.3

 

.. the gasket can leak coolant onto the top of the engine where it will sit in there and evaporate with no leak detected on the garage floor or pavement under your truck... but you can smell it

 

4.8, 5.3, 6 liter engines have a dry intake...no coolant flows through them.

[gapost]

Well, it could be the castech heads, but not sure you would smell the coolant. But, if you have the dexcool (orange) coolant, you may not see it in the oil because it makes a black sludge. The sure way to tell if you have the castech heads that develop cracks is to pull the rocker arm covers. If you see chocolate pudding anywhere in rocker arm area, you have bad heads. It's not that hard to pull the rocker covers if you do a lot of your own work. Another way would be to check the oil pan when you change your oil. After you drain your oil, stick a long screwdriver in and see if you can scrap out any black crude from the bottom of the pan. That would indicate dexcool coolant getting into the oil.

 

But, it could be as simple as a loose clamp or a crack in some of the plastic parts of the cooling system. I guess it could also be a bad heater core, but I would think you would smell or have coolant in the passenger compartment.

[98 Z71 SLT]

your coolant pump gasket is seeping, and burning off before it hits the ground. Look closely at the passenger side coolant pump gasket area. You will see a white-crust in the area. Replace your coolant pump and gaskets, making sure the engine block is spotless before you install a new pump.

[jwhjr]

My guess is also with the water pump gasket. I had the same symptoms as you, could smell it for months, and I was not losing any coolant. When it finally showed itself externally I was able to trace it to the passenger side WP gasket. I had 111K on the original pump, so I put a new one in. Easy to do, and no more smell.

[pastorsean]

i will replace a quart or two of coolant every couple of weeks. after looking today, the last time was several weeks ago, i can see coolant running down the front of the oil pan and then drips on part of the frame and does not reach the ground. with the amount of miles on it should i just replace the water pump, gasket, hoses and clamps?

[Wingnut]

That's where I'd start.

 

What sucks about replacing parts of the cooling system though, and prepare yourself for this, is that once you replace a failing water pump with a new one...It works too well. So well in fact, you'll now spring leaks in your radiator and hoses, and your thermostat will quit working.

 

 

Or maybe that's just me

[Guest pjblurton]

What sucks about replacing parts of the cooling system though, and prepare yourself for this, is that once you replace a failing water pump with a new one...It works too well. So well in fact, you'll now spring leaks in your radiator and hoses, and your thermostat will quit working.

 

 

 

The thermostat and the thermostat housing are attached to the water pump. You'd be nuts not to replace it at the same time. With your mileage, I would do the hoses too then you have none of the above to worry about.

Just be prepared when you go to buy the inlet hose for the water heater... That booger is nearly $100!!!

[txab]

What sucks about replacing parts of the cooling system though, and prepare yourself for this, is that once you replace a failing water pump with a new one...It works too well. So well in fact, you'll now spring leaks in your radiator and hoses, and your thermostat will quit working.

 

 

 

The thermostat and the thermostat housing are attached to the water pump. You'd be nuts not to replace it at the same time. With your mileage, I would do the hoses too then you have none of the above to worry about.

Just be prepared when you go to buy the inlet hose for the water heater... That booger is nearly $100!!!

 

If you're talking about the thermostat to heater hose, it's under $30, for a gates hose (part #22554). Where are you buying to spend $100? You're getting ripped off

[Guest pjblurton]

 

If you're talking about the thermostat to heater hose, it's under $30, for a gates hose (part #22554). Where are you buying to spend $100? You're getting ripped off

 

 

 

The OUTLET hose is $24.99..... The INLET hose has a molded branch assembly built into it and is $95.99.

http://www.autozone.com/autozone/parts/Hos...PartNumber=true

AutoZone Part #E88412