Heater core flush
#11
11-08-2015, 07:24 PM
Checked the air temp coming out of my dash vents Friday. It was 73 outside, and on full hot the heater core was delivering 119. Didn't sound too bad to get a 46 degree gain, until you consider a 30 degree day and needing warm defrost.
So I flushed the core today using CLR (not sure I really needed to use it), low pressure water, a little lung power to put air pressure on the line, and finished by flushing it with distilled water and adding mixed coolant back into the line. Got a fair amount of crud out of the line, including something that looked like what a small dog might leave in your yard.
It was 54 outside when I did this, and when done I got 160 at the dash vent. So now the heater core is delivering a gain of 106 degrees.
I don't smell anything leaking in the cab so I think I avoided flushing a leak. I'll drive it to work tomorrow and see how it goes. Wish I'd done this a couple years ago!
Thanks to everyone for the instructions and guidance.
So I flushed the core today using CLR (not sure I really needed to use it), low pressure water, a little lung power to put air pressure on the line, and finished by flushing it with distilled water and adding mixed coolant back into the line. Got a fair amount of crud out of the line, including something that looked like what a small dog might leave in your yard.
It was 54 outside when I did this, and when done I got 160 at the dash vent. So now the heater core is delivering a gain of 106 degrees.
I don't smell anything leaking in the cab so I think I avoided flushing a leak. I'll drive it to work tomorrow and see how it goes. Wish I'd done this a couple years ago!
Thanks to everyone for the instructions and guidance.
#13
12-29-2015, 09:19 PM
I did the same heater core flush on my BIL's '97 today. Same plugged up hose at the same exact place.
And to think the only reason I did these myself is that my mechanic did not want to touch it for fear of flushing a leak. It was a piece of cake; a couple of hoses, low tap water pressure, flush with distilled water, then replenish with antifreeze.....
And to think the only reason I did these myself is that my mechanic did not want to touch it for fear of flushing a leak. It was a piece of cake; a couple of hoses, low tap water pressure, flush with distilled water, then replenish with antifreeze.....
#14
01-04-2016, 08:19 PM
I've heard that CLR strips the oxide layer of the aluminum core if left too long. How bad that is, I'd only be speculating. Who knows, you may never see an adverse effect. I just used the stuff that was made for flushing radiators.
A big caution, is to avoid the core lines where they exit the firewall. They are quite fragile and can deform easily, resulting in leaks. I follow the hoses where they connect at the engine and pull from there.
One final word. Worm screw clamps are okay to use on metal lines, but not plastic. Strong spring clamps are always best, because they expand with heat expansion. Use worm clamps on plastic like radiator inlets and outlets and the plastic will eventually crack.
A big caution, is to avoid the core lines where they exit the firewall. They are quite fragile and can deform easily, resulting in leaks. I follow the hoses where they connect at the engine and pull from there.
One final word. Worm screw clamps are okay to use on metal lines, but not plastic. Strong spring clamps are always best, because they expand with heat expansion. Use worm clamps on plastic like radiator inlets and outlets and the plastic will eventually crack.