The heater core on my daughters GMC Jimmy seems to be plugged. Its not a full plug as some water comes out but the hose is cool. I have called around and its over $700 to replace it and its not a job I can do with my shoulders. I was told by a shop they could flush it for $70. I went to auto zone and found Prestone Super Cleaner.
What are your thoughts of investing the money for a flush or should I try the cleaner and flush it myself. I was told by one garage they flush with a garden hose and I am thinking hell I can do that.
I did flush it the best I could with a garden hose. I replaced the cap it was filled with a rusty gum. The reservoir is a reddish rust color. Inside the radiator the spring looking thing that I think is part of the transmission cooler was covered with this same rusty looking crap. My question is will the cleaner do as good a job as the $70 flush from a shop?
The flush is worth a try in this case. Although it sounds like you have a coolant leak somewhere. Maybe the intake? The coolant gets rusty, slimmy, like your saying when there is a air leak. So the flush might help for a while but intil the leak is found and fixed you might run into this again in 6 months.
The rusty looking crap might very well be stop leak.
Better parts stores will have Permatex radiator flush available, comes in a quart bottle. It's acid so use appropriate caution.
1/3 to 1/2 bottle depending on how dirty the system is. Follow the directions on the bottle. You need to reverse the flow thru the heater core to loosen the muck. Your FLAPS should be able to sell you 5/8" to 3/4" hose adaptors, you need two and one piece of 5/8" heater hose and one piece 3/4" heater hose, 4"-6" long. Install the short pieces of hose with the size adaptors so that the inlet and outlet heater hoses can be reversed, flush the cooling system until clear water runs, add the Permatex radiator flush and drive the truck for
15-20 minutes fully warmed up. Flush the system again, let the water run for 20-40 minutes, best is if you open the block drains so everything that might be trapped in the block has a way to escape. Change the heater hoses back to where they belong. Refill with fresh Dexcool in the proper mix. Replace the radiator cap, fill the overflow to the "HOT" mark.
I've had 100% success doing this on S and T trucks with blocked heater cores, and it beats the hell out of pulling the dash and changing the heater core.
Naturally, if you're going to do this, you'll want to make absolutely certain that the intake manifold gaskets haven't failed (i.e., has it had a history of coolant loss?)
I have had to add a small amount of coolant now and then but really don't know how much. If it needs a new heater core, and A/C is also not working. My thinking is try the flush if still no heat its time to replace the car.
BTDT. If the engine temps are OK and you don't see any junk in the rad when you remove the cap, just flush the core with a garden hose in both directions.
Reading paraphenalia with my new heater core replacement mentions voltage in the coolant itself causing electrolysis. Little as .1+ volts is all that needed. The worst of it will be where the ground is located in the cooling system. IE radiator or heater core.
Where the heater core integrated pipes enter the firewall from underhood, there's a bracket (metal) that separates and contacts the two pipes and is bolted to the firewall. And the two bands that hold the heater core proper are metal, use two metal screws each and are bolted to the firewall inside the passenger compartment. 94 Chevy Blazer S-10, V-6 4.3L Vortec engine, w/AC.
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