Hi again. I still am perplexed by a smell, which I believe is a coolant anti-freeze smell inside when heater is on. Now, I am wondering if it may be a oil smell, because that seems to be the only fluid I can find under the engine. This is a small amount which seems to run back and accumulate on the crankcase housing near the oil plug. It seems to be oily, but light in nature. It seems to come from around the black (plastic?) cover just behind the crankshaft pulley. A small amount of fluid seems to run down along the black cover seam behind the shaft, and drip off and get blown back, I suppose, toward the oil pan area. Diligent inspection for a manifold gasket leak by removing air box and other components finds nothing significant. All looks clean and dry. Water pump & lower radiator hose was recently replaced, and inspection then revealed nothing as well. I can find nothing to indicate the heater core is leaking inside or out. My oil remains level and there is no indication of contamination. I may be loosing some coolant though as my reservoir was quite low, but the radiator was able to take almost nothing to top it off. It is hard to know what's up, because it is below freezing here in Minnesota, so one has to account for some contraction of fluid. Also, I am not driving much. Mostly short trips of perhaps 25-40 miles at a time. Often less.

So, still up for some ideas. Whatcha think guys? Merry Christmas. Hope you all have a Happy Holidays.

 

Wow Tuna, sounds like you hit all the usual suspects. Could still be heater core or water pump, my guess would be water pump. Which is way better then heater core.
If it were me I would pick up a coolant fluorescent leak dye kit. They come with the dye you put in the coolant and a small black light.
Not a lot of $. Go to amazon or ebay for the best price.

 

That stuff sounds like the way to go, as compared to a full disassemble just to find the source of the leak. I'm going to look for it now. Thanks!

 

"I still am perplexed by a smell, which I believe is a coolant anti-freeze smell inside when heater is on."

I had the same problem last year and it did not go away until I replaced the heater core. If you can smell it inside, the heater core is leaking internally into the ducting. Mine got to the point where moist air was coming through the defrost, a few weeks later passenger floorboard was damp. The only passage for antifreeze into the cabin is through the heater core...

Replacing it took me about 8 hrs IIRC. Schedule some time in a nice warm garage and have at it. I wasn't that bad, just time consuming and tedious. Good luck!

 

Thanks Magman.

I have researched the heater core issue and watched some videos on that. I probably have been trying to avoid that possible reality. Unless I see even the slightest indication that it is the heater core, I have been hesitant to tackle that job, knowing it is a real PITA. I am going to try to locate a UV light and some coolant dye and give that a try. If it reveals nothing, I may try the heater core over that holidays. I remain curious as to where the small trickle of oily fluid is coming from running down along the black cover behind the main pulley shaft near the power steering unit. It is not P. steering fluid. It seems too light to be engine oil, but doesn't really have the look or smell of coolant. I recently replace the rear oil cooler line, which was leaking at the crimps. That went a long way to cleaning things up down below, but something is still getting out. These Blazers sure keep one busy!

Thanks again for the reply.