1992 22RE

The truck has been parked since April in the garage. As soon as I put it back on the road again a few weeks ago, I started getting the smell and fogging windows. It seem to come and go and is most noticeable when I start moving again after sitting at a traffic light. Heat coming from the vents is lukewarm. No signs of coolant on the passenger side floor. This was not an issue when I last drove the truck in April. I did a coolant flush in June of last year. I have a gut feeling that the heater core is not shot. How do I tell if the core is plugged? Could air in the cooling system cause this? Is there anything else it might be?

Thanks.

 

I'm thinking its leaking. If it was just plugged up, you wouldnt be getting the coolant smell or the window fogging.

 

I would make sure the hose connections are on well at the firewall and not leaking there. Inside the bottom of heater core assembly, there is some area that can hold some antifreeze and keep it contained inside and keeping it off the floor.

When you did your coolant flush, did you pull the hoses off of the firewall and flush the core itself? I run a water hose right to the core and flush both ways.

 

I didn't touch the core when I flushed the coolant.

 

By running a water hose right to the core, you can flush the core out that way. You may see chunks of rust come out of it. Also what I have done is take an air hose and blow the water out of the core and then pour some CLR into the core and let it sit for 30-45 minutes and then flush the core. I have gotten some cores to heat that way as well without having to change the heater core.

 

Im getting low heat on my 1986. ( it was built aug 1985) To day im pulling the heater control valve. They were metal back before 1989 ( I think) and can become corroded. If mine is good im planning on doing the air compress flush thing too.

 

Thanks. I will give that a shot.

This morning there was heavy frost on the windshield. The defroster was able to melt it all and I only noticed the smell a couple times for a few seconds each time.