Coolant Loss

[seadoons]

Guys,

 

In late November I took my truck in under GMPP for a coolant loss problem. They isolated the problem to the water pump and replaced it. Well, here we are about a 1 1/2 months later and the plastic resovior seems lower again (and before they changed the pump, I would add coolant to it and this is about how long it would go before I noticed it).

 

Problem - my warranty expires on Feb. 4th - do you have any other ideas where it could be losing coolant? They "said" they did a pressure test after replacing the pump - what does that acomplish?

 

Thanks!

[02 Silverado Z71]

Since you have an extended warranty, here's what I would do.

1. Take your vehicle to GM and document this issue with them.

2. Get a black marker. Fill up the coolant resovoir to FULL HOT, with the engine hot of course, and in FRONT OF THE SERVICE ADVISOR, mark the coolant level in the resovoir with the marker. This way you have documentation of it.

3. Also, when they replaced the pump, it is possible that you had some air bubbles in the mix. After time, those bubbles naturally become purged out of the cooling system, thus allowing the coolant to take the spot where air was. This would result in the level going down.

Look at your oil; it should be clean and not see any coolant mixed in it. If your oil looks "creamy"; you would be looking at a poss head-gasket problem, cracked head, etc...

Pressure testing allows the tech to hook an adapter to the coolant resovoir, then with the aid of a hand-held pump, you can apply pressure to the entire cooling system, while checking for any leaks.

The hand-held pump not holding pressure would indicate a leak in the system, allowing antifreeze to leak.

4. With your antifreeze tank marked with the marker, keep an eye on the level. If you keep consistently loosing coolant, you have a leak somewhere. Here's where the documentation comes in handy.

Hope this helps.

[97chevy350]

Yeah, I would suggest maybe a gasket too such as a head gasket or an intake gasket, which I know was common on the older vortecs but have not heard much of it with the new ones.

[03blackburb]

Take a flashlight and do a through inspection of the radiator and block. Carefully check around the water pump and thermostat housing. If you have a leak there will be coolant residue where the leak is. Sometimes a leak will only "leak" at a certain temp. Maybe cold, maybe hot or anywhere in between.

In my old 96 caviler, had a thermostat gasket leak BUT only when the block was cold and the outside temp was below 60 degrees. Found the residue and took it in and explained the scenario. Left the car with them like 2 days, but they did indeed get the system to loose coolant at the spot I noted to them. The appreciated my locating the leak and coting the conditions that it occured. It never did leak when it was up to temperature.

[pm26]

In addition to what others have suggested, take a close look at the plastic overflow reservoir. I had a coolant reservoir bottle leak on my Mazda 626 and it was so slow that I could not even see it. I was losing coolant slowly though. The bottle was leaking along the bottom plastic seam, which was defective.