flushing heater core off shbox site.

This is the #1 cause for a no heat complaint on a 4th gen f-body.
Remove the heater hoses at the water pump. This allows flushing of the hoses and the core.
Orient the hoses to keep all moisture off the optispark.
Using a garden hose, flush into one heater hose allowing the water to come out the other.
Do not use high pressure. The cooling system is only rated for 18 psi. Full hose pressure can be over 50 psi.
When the water looks clear, swap hoses, flushing into the other one.
Reverse a couple of times to help ensure a good flush.
Re-connect the hoses and refill/bleed the system.

 

 

Wow, ask for direction and get great directions! Thanks so much! This will be my weekend project..

 

Huh. I guess only the V8 94s have the flow control valve. I forward flushed and backward flushed my 94 V6 repeatedly and got lots of nasty stuff out of the heater core. I had no trouble getting water to flow in either direction.

 

not sure but i think the flow control vavle only lets a certain amount of coolant to go through, that way its not pushin all the coolant to the heater core and not so much to the radiator when idling, thats when it needs to go to the radiator the most.

 

These hoses are not the easiest to get to...but I see which ones they are. In regards to bleeding the system...don't I just add water and warm it up? Anything else?

 

there are bleed valves on the therostat cover, inline on a coolant hose and at the bottom of the tb, there a little flathead brass screw valve. losen screw to bleed.. bleed it while u fill the system with coolant (50/50 antifreeze/water)start motor with rad cap off and bleed again filling the radiator as needed. if u can, park the car on a incline with the front of the car up while i do all of this. after all this drive it a mile down the road and back, let cool and bleed/check for air and fill to top.

 

I disconnected the heater hoses at the firewall and ran water through both valve stems. Could not get any water to flow out of either one..using the garden hose I only turned it on part way so as not to blow out the heater core...wonder if it's just that clogged or if I should have given it more pressure.

Anyone had one so clogged that it just wouldn't un clog?? Wish I knew how much 18 psi was...

 

not very much, i bet you have at least 40 lbs pressure in the garden hose. i would say you found the problem. could be whoever owned it before mixed the green and orange antifreeze and it gelled up then had time to set up and get harder. can you see in there or stick something in there to see if you can retreve any gunk without hurting anything. dont know why that would matter,,, it seems to be a gonner.

 

Yeah....at least I gave it a shot...I'll bet this is going to be a tough job...need to call the mechanic for this one...

Thanks for all the help, I learned a lot!