this is on my 95 blazer 4.3 it started yesterday with a burning smell at low speeds. its been about a dozen times ive smelled in in the last day. it smells almost like something electrical burning, yet there is no smoke and no obvious burning items. nothing is contacting the headers, all my wiring is secured away from them. its in the passenger side area, and is getting sucked into the cabin. i did notice though when i stopped to check it out, i could hear a bubbling sound inside the engine, and i noticed when opening the air vent on my heater hose, there was no pressure. i have long suspected a head or intake gasket, but i dont have the other signs of steam, sweet exhaust smell, or coolant loss. all i have is the coolant turns into a nasty rust mix in about 10k miles, no matter how often its changed and flushed

 

On my old Jeep Comanchee, when I had a bubbling sound in the engine, it turned out that my radiator was stopped up. I flushed it several times but it did no good. I changed the radiator and have had no more issues. Truck did not overheat or anything, just a bubbling sound once I shut it off. I did have a smell of some sorts coming from the burp tank when it did this. Also, might want to check the wiring on the heater motor. I have had them corrode and heat up and melt the plastic molded piece because of bad contact.

 

alrighty, i went and checked all the wiring. everything is good. peeled back the wire looming, checked the blower motor and resistor and found no issues. i smelled it once this morning. for ****s n giggles, i did a gasket leak detector, and it showed up nothing, but i may not have done it correct. i also used a heat gun on the headers. at idle at operating temp, the passenger side was about 400-440 degrees, yet the driver side was about 330-360. im thinking maybe the lower intake gasket could be starting to go, but still doesnt explain the smell

 

could be the cat burning off excess oil. are you using oil?

 

not using oil, just leaking some. used to leak a bit at the valve seals on start up, not anymore now that i use mobil. no cat either. i did notice a tiny bit of a coolant smell in the exhaust on startup this evening. im going to bite the bullet and just replace the heads. that side has always made a ticking noise like it was an exhaust leak, yet no matter how many gaskets or manifolds i put on it would fix it

 

well, found the burning smell. trans vent tube had contacted the y-pipe. also found out all my exhaust valve seats were gone, and there was a crack through the seat and head on intake for cylinder 3 or 4, which was the cylinder that had issues with ash build up. 1, 5 and 6 had coolant getting in them