Replacement heater core - Aluminum

M

Merle Nelson

Been here much more than a while
Location
SF Bay Area, CA
Don't do it. I let my mechanic put one in because, 'there would be less issues with electrolysis.' There is also less heat, like 40% less or so. Not workable.
 
There is something else wrong. 99% of new cars and trucks use aluminum heater cores. When you consider the internal corrosion that is inevitable, and the oxidation that occurs to external exposed copper the aluminum transfers more heat than copper. You can paint the copper on the outside, but that limits the thermal transfer too.

One of four things are the root cause now.
Air still in the system after the repair. Sometimes the air stays in the core, so you have only a little cabin heat.
T-Stat not allowing full warm up. Some dash gauges lie, find out the real warmed up temp. It should be over 190F.
Temp doors in the dash not allowing full air flow through the core. Most direct any air through the AC when not going through the heater. Since many vehicles use AC for defrost, if the air is mis-routed, it can be very cold.
Bad coolant flow through the core. Valve and line problems are the most likely.

Why did your mechanic deliver a vehicle with poor heat after a heater core job? Does he not own a thermometer?
 
Welcome to TreeBuzz adaycj.

My mechanic delivered it that way because I'm not a highly enough skilled consumer of mechanical repairs. I wish I could have someone like you managing all of that for me.

It is on a 1990 F350 that was heating fine and I started smelling a sweet smell in the cab and the window fogging from heater. Had it replaced which I assumed would get it back to original function level.

Given your info about new cars using aluminum I will use it more and or see if I can check for air in the system. Then check a few of the other things you mentioned in order of problem solving.

Thanks for your info and input. Again, welcome.
 
I agree. More than likely an air bubble in the heated core

Many ways to burp it out. One is to open the radiator cap to the safety stops and drive for a day or so

Another is to have the engine up to temp and then take off the highest hose going into the heater core. This can be messy because hot anti freeze comes out. The mechanic should really have done this...no charge
 
I think the sweet smell is close to a 100% diagnosis that you needed a heater core. On that truck the control cable is right above the heater core access door. Improperly re-clipping during installation can cause the heater to not heat properly (the temp door I suggested in another post). It is at 14:50 in this video.
Anyone can fix the cable if you are tying to avoid a service appointment. No tools are required.

I can send you a link to a Ford truck forum where there is a thread about fixing this cable to resolve the issue. I just can never remember the rules about other forums on the forum I'm on. Maybe a PM?
 
Go ahead and post the repair link here. Lots of Fords out there doing tree work

As far as cross posting Mark and I are pretty loose with linking. Over the years there has been very few attempts to hustle traffic away to other forums. And if people leave well...such is life
 
The years and attachment on the other end of the cable vary a bit. The HVAC box diagram and temp door remain the same as well as the general termination of the cable at the door surrounding the year of your truck.

I hope it helps, the weather is only going to get colder.
 
Merle Nelson said:
Yeah, great info, thanks. I will check that this weekend and do my six mile drive to and from a job tomorrow with the radiator cap loosened to the stops.
Click to expand...

I don't want to challenge another forum user, but I don't agree with that advice. The cap seals in the coolant until it expands enough to make it to the overflow tank. Leaving it loose allows air to get in as the system cools. It will also make a mess since the expanding coolant mostly won't go into the overflow tank like it is supposed to. Plus boiling is much more likely without pressure in the system. Granted I can't imagine boiling in only 6 miles. It would work if the truck was a 1960 with an air gap above the coolant in the radiator, but on your more modern ride it will do the opposite of let the air out.

For the record I also would never open the system once it is warmed up. It is just asking for burns, and it not a proper service procedure.
 
I have an 89 F350 myself and have had to replace the heater core. I had no issues at all like you describe. I'd make sure the heater hoses aren't pinched somewhere. Another thing you can do is make sure they are both hot when the engine is warmed up. If that's the case, then you most likely have a temperature blend door problem.
 
@adayjc

Good details there, thanks.

I've burped out a bubble by opening the radiator cap
Tonthe stops. This was in a 2000 crown Vic. While the cap
Was loose I didn't load the engine and I watched the temp gauge. No freeway driving. It took about ten miles for it to work. I felt the heat output change. I stopped and tightened the cap and that was it
 
Well Never Mind, as Gilda Radner used to say. It did seem to be air in the system. It worked out between use a few more mornings and leaving the cap loose for the short drive to work and back one day. I can imagine air getting in there now that I think about it since my mechanic didn't drain the system and refill as in youtube video adaycj put up. He just pinched heater supply lines took them off old core while replacing with new one.

Thanks for the help everyone.
 
Thanks. Yeah I could see your points of concern after the fact but had already done it.

I just understand the very basic principles of cooling systems and didn't think it would boil hard on a short drive, cool weather.

Nice to have it back working.
 
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