Difficulty Locating Coolant Leak

[The Critic]

Originally Posted By: doitmyself
Water pump/weep hole? Maybe just intermittent?

I replaced the water pump recently and it is not leaking.

Originally Posted By: Vikas
Is this the same car where some chain shop had told you very bad news without doing any diagnosis?


That was someone else, not me.

Originally Posted By: tonycarguy
+1 for the fluorescent dye and overnight pressure tester.

The dye is how I found a very slow leak at my water pump. This is a DIY job. No need to take it to a chain shop like Firestone


So I got the car back today. They did a block test and it came back OK and they pressure tested it for hours with no pressure drop. The tech did find air in the system and bled it for me, so I'm not sure if that will have any effect on the leak.

 

[firefighter]

What is a block test?? One good way to check for a head gasket leak is warm up car to operating temp, have pressure tester on so it can maintain some pressure, or pump it up as pressure drops from it cooling off. Remove spark plugs and the next morning look in cylinders with a borascope for coolant. I have found a ton of them that way.
Then with the plugs out put air in cylinders and watch for bubbles in radiator, I will do this hot and cold.
The big question is does the car miss for a little after sitting over night?? this is a tell tale sign, as it takes a second to burn off that coolant.

 

[The Critic]

Originally Posted By: firefighter
What is a block test?? One good way to check for a head gasket leak is warm up car to operating temp, have pressure tester on so it can maintain some pressure, or pump it up as pressure drops from it cooling off.


http://blockchek.com/instructions.htm

 

[brianl703]

Originally Posted By: PandaBear

My bad, I should have word it differently: you can't trust the shop really did an overnight pressure test when they charge you the $ for it. Doing it yourself is fine.


I would suggest that anyone do their own pressure test, especially as it doesn't take a whole lot of effort and Autozone gives you the entire deposit back when you return the pressure tester, making it essentially free to rent.

 

[mechtech2]

One home test for a bad gasket/head is to simply put a plastic bag at the radiator cap, and start the car. Of course it has to be tied/sealed. Some expansion is normal.

There are also cool coolant testers that 'smell' the fluid and gas there, and minute leaks can be ascertained. It 'smells' HC and CO from the combustion process.

 

[PandaBear]

Originally Posted By: brianl703
I would suggest that anyone do their own pressure test, especially as it doesn't take a whole lot of effort and Autozone gives you the entire deposit back when you return the pressure tester, making it essentially free to rent.


I also tried renting / borrowing the Autozone pressure tester, but it doesn't fit the radiator cap / neck on my car. It is much bigger. Is it normal? how many types of cap size are there?