2003 Blazer, 4.3 V6, of course, still looks, runs, drives great, has only 84k miles. Owned since 05 and planning to keep this limo forever.

Have lately noticed that coolant disappears. There are no visible leaks under the hood or on the ground. Also, no visible evidence at the tailpipe- no white smoke, no drips, nothing. Runs like a champ. Even without the smoke, my best guess is that the coolant is getting into the combustion chamber(s) from an intake manifold leak, since a blown head gasket would show up via a ragged idle. Service light not lit, no codes set.

Seems to me there are exhaust sniffers that can detect coolant in the exhaust using a probe in the tailpipe. Anyone have experience with this?

 

Check your oil, if foamy or over full. Head gasket. Don't drive it unless you want a new motor

 

My guess would be the lower intake gaskets? Mine does the same thing over the course of a few weeks. I doesn't show visibly up anywhere as a leak, so I imagine it is getting mixed into the combustion chamber & coming out the exhaust. I've just been adding it regularly until I can get around to doing the spider injector assembly & the lower gaskets at the same time.

 

Thanks for responding. I neglected to mention, oil is clean, no antifreeze in the crankcase.

 

That's the only thing I can come up with as well. I hear the 4.3 is famous for this.

 

Yeah, pretty much. Glad I didn't know that when I bought mine or I probably would have bought something else. I like it a lot though & I miss driving it. I like it better than my 09 Yukon. Mostly because it's paid for & it's a heck of a lot easier to work on. Going to tackle the lower intake job, injector assembly & rebuild the tranny in the next month... Hopefully.

 

So, back to my original question- anyone have any experience with an exhaust sniffer that can detect antifreeze in the tailpipe?

 

I have used the ones that you do with the antifreeze and it test for exhaust gasses in the antifreeze. Worked good told me what I expected