The heat and defrost on my '92 has not been working well this winter. It just does not get hot, takes forever to defrost the windshield, and will frost back up going down the road when it's really cold. Rear heat works OK.
I'm off work today and it is unseasonably warm out, so I decided to back flush the front core. Holy crap! Twenty five years worth of sludge, it's a wonder it worked at all. It looked like mud coming out at first. After flushing it out with a water hose, I blew it out with air and filled it with CLR and let that set for a couple of hours. When I flushed it again, it looked like as much came out as the first time. I also back flushed the rear heater core.
I went ahead and completely drained and back flushed the entire cooling system. I thought it was pretty clean before since I had drained the system and refilled it last spring. The coolant I drained out looked good and clean, but I was surprised by how much rust and sludge came out by backflushing from the heater lines back through the pump and radiator. I connected the water hose to every place possible and backfushed until it ran clear.
I replaced all the straight hoses going to the heater cores and control valve. Of course no ports stores had the formed hoses in stock, so I had to re-use them. Went ahead and refilled with new coolant instead of re-using the old stuff. I did not run it very long, but I can definitely tell a difference in the temperature coming from the front vents and defroster.
I'm off work today and it is unseasonably warm out, so I decided to back flush the front core. Holy crap! Twenty five years worth of sludge, it's a wonder it worked at all. It looked like mud coming out at first. After flushing it out with a water hose, I blew it out with air and filled it with CLR and let that set for a couple of hours. When I flushed it again, it looked like as much came out as the first time. I also back flushed the rear heater core.
I went ahead and completely drained and back flushed the entire cooling system. I thought it was pretty clean before since I had drained the system and refilled it last spring. The coolant I drained out looked good and clean, but I was surprised by how much rust and sludge came out by backflushing from the heater lines back through the pump and radiator. I connected the water hose to every place possible and backfushed until it ran clear.
I replaced all the straight hoses going to the heater cores and control valve. Of course no ports stores had the formed hoses in stock, so I had to re-use them. Went ahead and refilled with new coolant instead of re-using the old stuff. I did not run it very long, but I can definitely tell a difference in the temperature coming from the front vents and defroster.
