96 Jimmy - smell coolant

Hi, Ive just recently purchased a 1996 GMC Jimmy SLT and not quite familiar with these vehicles. Ive noticed that I can smell coolant when I put on the heat and is only there for a couple seconds then I cant smell it anymore after a few moments while the fan is on. Now, once I turn it off and start the heater once again - I can smell it.
Could it be the heater core?? I dont see any leaks on the interior... Any suggestions what this smell might be?
Ive noticed as well that the coolant is the 'green stuff on it' not DEXCOOL. Is it imperative that I switch it to dexcool or just simply flush it once a year and replace with regular coolant?

Thanks in advance.

Hi, Ive just recently purchased a 1996 GMC Jimmy SLT and not quite familiar with these vehicles. Ive noticed that I can smell coolant when I put on the heat and is only there for a couple seconds then I cant smell it anymore after a few moments while the fan is on. Now, once I turn it off and start the heater once again - I can smell it.
Could it be the heater core?? I dont see any leaks on the interior... Any suggestions what this smell might be?
Ive noticed as well that the coolant is the 'green stuff on it' not DEXCOOL. Is it imperative that I switch it to dexcool or just simply flush it once a year and replace with regular coolant?

Thanks in advance.

It could be a pinhole leak, just enough to vaporize into the heating ducts. On cold days do you notice the heater\defroster fogging up the windshield when turned on? I would run a bottle of Bar's Max Coolant Stop Leak. The stuff is AWESOME, I use it in all my vehicles, not only with it NOT hurt anything but it will lube the water pump and continue to float in the coolant and patch holes\leaks as they occur. I even used a bottle of it in my buddy's beater pathfinder and, believe it or not, it actually sealed a cracked cylinder wall! He was losing 1qt of coolant a day into the oil pan from the cylinder wall and since the truck was only worth about 300$ he didn't want to fix it, we ran a bottle of bar's through it and the leak stopped, the truck lasted 2 more years before it was t-boned by a lady running a red light.

Also I'll add to CanukGMC's good susgestion is to check the hose connections under the hood ... while checking, its best to make sure they are all tightened really snug ..... I had an Areo star that use to do same thing ... one of the hoses that went into the heater housing was really loose but never showed signs of being wet or anything.... after tighening really good .. smell went away ................

I dont notice any fog but I suspect that it is the heater core that may be leaking. the smell only lasts for 2-3 seconds when the heat is on; then nothing thereafter. I tried putting that aluminum filings thingy some stop leak brand... but it did not stop the smell...

I dont notice any fog but I suspect that it is the heater core that may be leaking. the smell only lasts for 2-3 seconds when the heat is on; then nothing thereafter. I tried putting that aluminum filings thingy some stop leak brand... but it did not stop the smell...

I wouldn't bother with the alum based ones, get the Bar's, it has these "magical" pellets in there that dissolve in the coolant and seal everything up tight. If there is even the slightest leak it will seal it up.

I wouldn't bother with the alum based ones, get the Bar's, it has these "magical" pellets in there that dissolve in the coolant and seal everything up tight. If there is even the slightest leak it will seal it up.

Using any type of stopleak can cause more problems then they cure... He should just do it right and replace the heater core.

Using any type of stopleak can cause more problems then they cure... He should just do it right and replace the heater core.

I think thats what Ill be doing on my days off coming. However, reading through past posts - anyone here know exactly if I have to remove the whole dash to get to the heater core???

Using any type of stopleak can cause more problems then they cure... He should just do it right and replace the heater core.
here here!! agreed, mechanic in a bottle :nono:is only for dire emergency's, and should be drained out and a correct fix done asap, unless this is a beater and you will drive it til it stops and buy another one. if you do it right, it will do you right.:smokin:
i don't know when gm went to dexcool as a mandatory coolant, maybe blazee or old master or blazlt remember. sorry. if i remember right, dexcool can be used in older aluminum radiators, but green coolant can't be used in place of dexcool if it is required.

Using any type of stopleak can cause more problems then they cure... He should just do it right and replace the heater core.

I know most fixes in a can are not good things, this stop leak however is not one of those. I've run it in many vehicles, low and high mileage, in all of my own, everything from imports to domestics, SEVERE problems and minor ones (like the one listed here), and not once have I had a single major issue (or minor for that matter). I was just listing a cheap easy way to seal up a very minor spot leak which is so small it's only vaporizing some coolant into the vents. If my engine had a very small tick in it would it be wise to just overhaul the entire engine or maybe try looking at small fixes first?

Should you choose to do the heater core go right ahead, I had a leaky one in my jeep and decided to redo it, the new one ended up leaking just as bad because I ended up disturbing all the hoses in there causing them to leak, I ended up doing all new hoses, housing, and the core in the end. Hope it all works out for the better in the end, I have yet to do a blazer\jimmy core so I don't know how much of a headache it is.