First off, hi, i just joined this forum, I own a 2000 ZR2 Blazer, and before I get jacked for "use the search function," i have but cant find the right info to help my situation.

OK, i have been dealing with not having heat for almost 2.5 Michigan winters now, and i am cold and frustrated.

I have flushed my heater core probably 8 times, each time the heat returns HOT, but after shutting the motor off 2 or 3 times... no heat! I have flushed the entire cooling system twice. The first time i noticed that my rad cap rubber seal was 1/2 gone, so i replaced it, but noticed that the dexcool was getting chuncky around the rad fill spout, so i cleaned all i could. The second full system flush i decided to switch to the green stuff.

After the most recent core flush i began smelling coolant from under my hood, nothing inside the cab, only outside. I dont see any leaks or steam or any sign of a leak, only smell.

I dont think my core is bad because i do get heat until i shut down and restart a few times. ANY IDEAS??

 

I had a simialar problem on my 97.... ended up taking a flashlight and found my lower intake manifold gasket gave out and i had a puddle sitting along the intake up on the corners.. common problem with dexcool eating away at the gasket... take a look.

 

which intake are you talking about? the radiator?

 

Have you back flushed your heater core? As in the opposite direction the coolant normally flows?

If so, it really sounds like you have so much crap floating around in there that you are in need of a MAJOR engine/radiator/heater core flush.

As far as the smell, one place that leaks have developed are on the backside of the intake/engine from the intake gasket. Extremely hard to find as the coolant dries up on the hot engine and you never see any drips and hard to get an eye on the area of the actual leak.

 

there is a trick to find out whether or not you have a leaky intake manifold, a mechanic told me to spray carb cleaner along the outer rim of the intake manifold (where the gasket sits). It might be hard to reach but once you do the suction should suck it through if there is a leak, thereby causing an acceleration in the motor. At the least, it is a cheap way to find out how severe the problem might be. It goes without saying that there could still be a leak but not bad enough to suck the carb cleaner through the exterior of the intake manifold.

 

I need to flush my coolant system. I never heard of back flushing the heater core can you tell me how this is done or point me in the right direction?

 

This is how I backed flushed my heater core.

1. Remove hoses from heater core (inside engine compartemet)
2. Install 2 or 3 feet of hose on each heater core inlet and outlet pipes, secure with hose clamps. (I purchased about 5 feet of hose and cut it to length for this job)
3. Run the hose attached to the inlet side over the fender, you can see what is coming out of the hose.
4. Use a garden hose and hose nozzle/gun, insert into the outlet hose and start flushing away and observe the water coming out of the inlet hose. (If you want to trap any debris coming out you could attach a sock/filter to the end of the hose that will allow water to flow but capture any debris.
5. When complete if you have compressed air you can blow out the tap water. If not use a funnel and fill with coolant from the outlet hose untill all tap water is removed from the core. (Coolant will flow out of the inlet hose)
5. Remove hoses and re-attach the inlet and outlet hoses. Run the engine and top off with 50/50 mix of coolant.

 

Thanks for the answer. Much appreciated.

 

It sounds as though your lower intake manifold gasket is disintegrating and the pieces of it are lodging in your heater core. A common problem on these trucks.

You will need to replace the intake manifold gaskets both upper and lower since you will have to remove the upper to change the lower. Then you will need to do a through flush of the whole system including the heater core afterwards.