RallySport92

I believe it's time to change out the heater core on my 1992 RS 305 since I'm getting a passenger's floor full of anti-freeze. I know it will be a chore since you have to get behind the dash to change it. I have 2 questions:

1. Is there a way to bypass the heater core on this?
and
2. How do I change the heater core?

Thanks...

Slade1

This is a bitch job.. so get ready for a sore back... you can disassemble the heater box from the passenger seat dash area from underneath without too much issue. The uppermost bolt would be easier if you went in from the dash area but I managed to do it without pulling out the dash. In retrospect, I would have pulled the dash though past the ecm. Once the bolts are off the core box you should be able to expose the core. Here's the fun part.

From the engine bay, you'll have to remove some stuff in your way, take the air cleaner off and get the ignition wires out of the way if they are in the way. You should be able to see two coolant hoses go into the firewall on the passenger side of the firewall beside the engine. Loosen and slide off the clamps that hold the hoses to the heater core essentially. My core was stuck to the hoses like it was welded (it isn't, its was just really really stuck there) It took a lot of prying and pulling on the hoses for a good hour to get them off. Once the hoses are disconnected from the heater core, the core should come out real easy now. Just place the new core there, reclamp the hoses, close the heater core box and fill up the system and you're all set.

I'd make sure to run the car with heat on full for a good amount of time to ensure that its filled with coolant. Remember to bleed the system of air and you should be fine.

Because of the placement of the core and hoses, I was standing at a very awkward position for an hour wrestling with the hoses due to my height 5 10, I wound up with a very very sore back and couldn't drive for a few days lol. If you're shorter, it'll only be harder on you...

You're options to bypass the core are simply from the core itself... basically just connect the two hoses that go to the core, or even earlier... just trace the hoses to their source and connect them.. do not simply plug the connections.

RallySport92

Thanks... I got it bypassed last night so it won't give me any problems until I do change it out. I figured I'd ask here first and do it myself before paying $300 to have a mechanic put it in. Thanks again for the help.

Don Christensen

the part about being 5' 10" and the subsequent back pain, etc. I am 5' 12" and I have to change the core on my daughter's "BlackBird" before we sell it. LOL !! Oh well, it has to be done.

Slade1

Well I tried to be complete in my experience of the whole ordeal...

I remember when it happened to me... I was on the highway then noticed a coolant smell and then a pop and a flood of coolant appeared on the passenger side... very messy.. lucky it was winter so no worries about overheating. I did the job at a friend's shop and all in all, a fairly easy job minus the fighting with the hoses... if you don't have to fight the hoses and they come off easilly no worries to your health. That was the only hard part.. the other was coming in from the passenger side. Just the blood rush to my head and the nasty smell of coolant that had spilled in there.

Glad this helps!