2004 Chevrolet Silverado loosing coolant

RANDY SHARP

MEMBER
2004 CHEVROLET SILVERADO
4.8L
V8
2WD
AUTOMATIC
110,000 MILES

I have been losing coolant, every couple of days I am having to add coolant. It is not leaking any coolant at all, I have pressure tested it, I have also did the test for the combustion gases in the coolant you know the one with the column and you add the liquid to the line and squeeze that also passed, it has a new water pump thermostat, and I also know this year falls into the years were a company was making the heads that they could crack around the head bolts under the valve cover. So does anyone have a theory for this problem, what would be the next step and also it has a new cap also.

3 Replies

CARADIODOC

MECHANIC
33,723 POSTS

Consider adding a small bottle of dark purple dye to the coolant, then search a day later with a black light. The dye will show up as a bright yellow stain that you can follow back to the source. Check inside the tail pipe and around the intake manifold. Auto parts stores will have the dye, and those that rent or borrow tools should have the black light.

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Monday, April 20th, 2015 AT 11:10 PM

RANDY SHARP

MEMBER
160 POSTS

So just add the dye without pressure testing it? How much dye should I add?

And thanks by the way.

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Tuesday, April 21st, 2015 AT 9:15 AM

CARADIODOC

MECHANIC
33,723 POSTS

You're losing coolant now without performing a pressure test, (although the loss may be only occurring when pressure builds up in the system). The loss will continue just as before, only now there will be dye in the coolant. The goal is to maintain the same conditions as when the problem occurs.

The bottles of dye aren't very big to start with, but I usually used only half of one bottle. That's enough for it to show up easily with the black light.

The people at the parts store will ask what you're using this for so they give you the right product. The dyes are different depending on the fluid it's going into.

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Tuesday, April 21st, 2015 AT 5:18 PM