Hey peeps I have been trying to deal with this issue for a while now! I was getting a smell from the heater vents while the truck was started. (super strong smell that makes me get an instant headache & would make me sick to my stomach if I was driving for more than 5 mins)
When I picked up the truck I cleaned the floor mats & didn't have any idea to look on the passager side for a leak or stain.


I have been reading alot about heatercore issues?

This is where I am now...

Checked coolant level in rad & couldn't see any by looking down in top. But noticed that there was some redish orange sludge (Dex-Cool) not much but mostly around the rad cap.
Unplugged my drain plug & drained what I guessed to be 1 litre plus! maybe!
Bought a flush kit / cut my heater inlet hose / hooked the hose up to it/started my truck & let it run while flushing it didn't take long before I was seeing the coolant draining into my catch bucket-Wasn't sludgey & it looked pretty clean. in no time it seemed to become clear. While making sure everything was doing its thing ok I noticed that I could smell the strong smell which I got from inside...now outside from the rad. I carefully smelled the rad front grill & the smell was just like the inside! I also quickly noticed that I could see a light spray coming from one of the AC hoses......(don't know much about AC) I looked at the AC Motor (Looks like an alternator kinda, with a belt attached). It was doing a weid thing... like cutting in and out and I think the front of the ac motor had this plastic thing that stop when it cut in & out. Also I noticed like steam or something that seemed like it was coming from the AC silver like bottle. Wasn't alot, (it would steam a little & then stop & a few mins later the same thing. With that going on I started to panic!! as it would cut in & out I would see a quick spray from one of the AC hoses next to it. Sounded like it was coming from the AC motor sparying to on eof the hoses or vice versa....but not sure? Shut of the truck, let it cool, drained it & then proceeded to do a flush with prestone super flush additive & top it up with water. This time I disconnected the ac plugged into the motor. Ran the truck for 10 15 mins for it to curculate/let it cool & drained it, proceeded to give it one more flush with straight water & then go to adding coolant, but I stopped & figured it could be a bad idea to add coolant to this headache & wait to see whats wrong! I would love to have someones guidance to help me fix this prob! AC is bad it seems (can deal with that) Heater core? Need a new Rad?

Thanks for your patience ( I get carried away with typing to much)

Cheers,
Chris

99 Chevy S10 ZR2 Blazer

 

Sounds like everything in the engine cooling system went fairly well. You should replace the thermostat while you have the system drained. You should also flush it for quite awhile after you ran the cooling system chemical flush to it in order to make sure you get all of the chemicals out. Then add 1.5 gallons of concentrated antifreeze to the system and top off with water. I like to flush the block, etc with distilled water so I do not put any minerals or other contaminants into the system, but if you have city water, it should not be all that bad.

The puzzling thing is your description of the A/C leaks... Are you sure that you did not cut one of the lines while you were cutting the heater hose? Your description of the A/C "motor" (aka compressor) and its clutch sound perfectly fine. It should not be cycling all that quickly unless the charge is low. If you have a leak that you can see, the charge would definitely be low. You should get this looked at ASAP if you want to keep the repair bill from climbing exponentially.

 

Tks...I will take your advice & replace the thermostat! I will also have my AC looked at! Any idea on what the horrible smell in my cab is??

 

The smell in the cab was probably from the heater core leaking and when the air blows across it into the cab, well it carries small amounts of it with it.

 

The smell inside the cab could be mildew on the A/C core in the HVAC housing. I had this problem with my old 2000 Bravada.

I started by cleaning out the drain in the bottom of the HVAC housing. To do this, I found it easiest to remove the inner fender on the passenger side. The drain is where the outer two halves of the housing meet the firewall and is directly above the frame.

Once that was clear, I moved to dealing with the mildew on the core. I used a full can of Lysol through the recirc door. Here is a thread I wrote up when I did it: A/C Evap Core Odor - Here's the fix!