TinMan

Within the last few weeks I have back flushed both of my heater cores, then the entire coolant system, then added prestone coolant system cleaner to regular water, ran it for 10 hours, then back flushed the system again. After each time I let it run for almost 45 min without the rad cap off to let the air burp out. The truck is not over heating at all.

When I turn the heat on in the morning it will gurgle around in the heater core for a while. The heater will heat up but not to the heat that it was after I flushed the system. Then after a while it blow out just luke warm air.

I have also noticed that when I go around a hard corner, it will gurgle around in the heater core.

I have let it run many times with the cap off the radiator. but get little to no air burping out. Even have let it run on a hill with the nose pointing up.

What can I do to get the air out of this thing?

theAuthority

Raise your front end to burp and let the air out. Or pull the exit hose from the heater core and fill it up with antifreeze. You just have air trapped in there.

TinMan

I'll try filling the exit hose in the morning. Do I need to take the inlet off to let the air escape while doing it? I have raised the front to burp a few times but just cant get the air to burp out.

Thanks

DeathCougar

iTrader: (23)

Sounds like your heater core is starting to clog. My 4Runner did the same thing, and the heat worked so-so. New heater core fixed it, but if the core is clogging, be sure to check the rest of the system for corrosion

theAuthority

I just thought that same thing DC said. If you've flushed it out that many times all the particles could have impacted themselves into the Heater core.

I wouldn't risk the possability of overheating my engine, i'd just replace it.

theAuthority

Yah if you've already raised it, sounds like it's clogged.

You keep the inlet hose on while the truck isn't lifted and fill the outbound hose of the heater core.

TinMan

When I flushed the system I did it because the heat was not working at all. So I started by un hooking the heater inlet and outlet. Then put the prestone tee into the outlet of the heater core and clamped off the free end. turned on the hose. Gobs of rusty gunk came out by the tons for about 5 minutes. then a good flow of clear water. Got so much out of the main heater core that I decided to back flush the rear core before back flushing the entire system. Got the same out of it. Then hooked everything up and back flushed the whole system. More gobs of rusty gunk out of the radiator for about 5 mins. After that the heat blew hotter than fire for about 3 weeks. No gurgling or heater problems until the beginnin of this week.

Do you think that back flushing and cleaning the system may have broken more stuff loose after I refilled it with antifreeze and clogged the heater core. If so would back flushing the heater core again flush out any gunk that got forced back into the heater core.

TinMan

sorry for the miss spelling, my keyboard is acting up.

theAuthority

I'd keep doing that flushing to make sure you have it all out. At some time this issue is going to move from the heater core to your radiator which will cause your motor to overheat.

You're doing the right steps, just keep doing them until you get it to work

or replace the heater core.

TinMan

Right on, I'll price a heater core. Autozone or dealer? Already can tell the rad needs a good proffesional cleaning. First back flush made it look a lot better.

Thanks again for the help.

aalan

Not trying to hijack here. But is there a thread that explains the proper procedure for replacing the heater core? Or does anyone know the procedure or maybe some good pointers? Looks like you dang nearly have take the dash apart just to get to it! I would love to replace mine as after several flushings it only blows out marginally warm air. Hey, it's been in there since 1984 so I think a new would be the ticket. I am also loosing a small amount of coolant somewhere and I wouldn't be suprised if the heater core was leaking slightly.