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clean-out just heater core

chrlsful

Bronco Guru
Joined
Oct 21, 2009
Messages
1,448
as per Subject line.
I just machined/assembled/installed a new motor, radiator, plumbing, etc.
Broke in, changed oil, got running/idleing well, etc.

I forgot to flush the coolant system (read: heater core) and now have a new system
anda ol core. Any ideas on how to flush w/o running crap thru the new system? I wuz
tinkin B4 I plumb-up the core to the rest of the system just run a loop w/a ele fule pump. But...
that’s no good. I guess I could run it thru another vehicle (heat the juice, have a pump to run the
cleaner/water solution/mix, flush w/H2O). That core is old, not flushed in decades, dont wanna take
the whole thing apart and 'boil out' at the 1 radiater guy’s left around. Just wanna get the rig on the road.

I guess it wont hurt my new system to clean this out in it. I’m @ a place pretty secluded so short on water too.
I’m just imagining cloging my new radiator w/the ol back flush from the rotten heater core. Thnx~
 

mdainsd

Contributor
Full Member
Joined
Mar 16, 2025
Messages
263
Loc.
San Diego
Plumb an old garden hose to one side and leave the other open and blast it with the hose? No chemicals or heat, but how much crud could there be in there?
 

bronco italiano

Contributor
Bronco Guru
Joined
Feb 1, 2004
Messages
2,593
I took mine out of the heater box and had my radiator just hot tank and pressure test mine because it was copper/brass
 

Timmy390

Contributor
Bronco Guru
Joined
Jan 1, 2011
Messages
5,946
Loc.
Conway, AR
If it needs a flush....it needs replacing.....You're just kicking the can down the road. I mean I get it....but summer is the time to do this. Remove the heater hoses and connect them together. That way you can drive around this summer with no heat and work on it as you can. It's not that big a deal. I did mine years ago....Since then swapped engines and never hooked the heat back up. That's one of the many advantages of being in the south.....for the most part....mild winters.....

Tim
 

bmc69

Contributor
Bronco Guru
Joined
Jun 11, 2004
Messages
12,015
as per Subject line.
I just machined/assembled/installed a new motor, radiator, plumbing, etc.
Broke in, changed oil, got running/idleing well, etc.

I forgot to flush the coolant system (read: heater core) and now have a new system
anda ol core. Any ideas on how to flush w/o running crap thru the new system? I wuz
tinkin B4 I plumb-up the core to the rest of the system just run a loop w/a ele fule pump. But...
that’s no good. I guess I could run it thru another vehicle (heat the juice, have a pump to run the
cleaner/water solution/mix, flush w/H2O). That core is old, not flushed in decades, dont wanna take
the whole thing apart and 'boil out' at the 1 radiater guy’s left around. Just wanna get the rig on the road.

I guess it wont hurt my new system to clean this out in it. I’m @ a place pretty secluded so short on water too.
I’m just imagining cloging my new radiator w/the ol back flush from the rotten heater core. Thnx~
Dang...been a while since I've seen you post! I've got more than a few 1" shaft orbit motors lying around.....going to run the Koenig on my '69 EB that way also.
 

serial car restorer

Yes, I'll restore almost anything...
Joined
Aug 27, 2024
Messages
742
Loc.
Western Oregon
New heater cores are cheap for Broncos ($22-33 at RockAuto, for example), and not difficult to replace. I'd just buy a new one in your situation.
 
OP
OP
chrlsful

chrlsful

Bronco Guru
Joined
Oct 21, 2009
Messages
1,448
thnx 4 all the responses. Specially as I do not have great written communication. Most 'got it’ tho~

* dont wanna create lots of ‘poison water’ (the flush chem) I pay for the removal or truck it out myself,
* yes, -0- running water here, havent needed any for the 20 yrs here,
* will not rip the core (or put in 1 of several in prts bin) out of the system if possible. Avoid all labor I can, use head instead, Y the post for ideas here.
The bronk is a spare-a-second, here/there ‘project’ type of deal. I'm an antique myself and busy w/other stuff...

What type of "orbit motor" do U use? Want something hi pressure/low volumn. I have a sump pump I bring in the rain water with. (Hammer on and pressure wash under carriages then dry’n spray fluid film or other coating needed so badly here in the 'salt-belt'. 200$ a sm job, mostly lght/medium duty truck work here). One fitting only (like above guy’s comment, itsa ‘garden hose’ type fitting). May B it has enuff pressure? to throw the pump in my rain tank, screw the garden hose on, run the other end onto a transition of some sort that necks down to heater core sz input line... a sump pump is typically very low pressure (15/20 psi max?) and hi volume. Thnx again, room for more if ya got any...
 

4xfun

Jr. Member
Joined
May 16, 2005
Messages
128
If you don't want to get into ripping out the heater core and only want to do a flush with limited water, unhook the heater core hoses and connect them to an electric transfer that has the intake hose in a bucket and put the discharge hose from the core into the bucket.. Probably cheaper to replace the core, but this is the answer to the question for a situation where water is limited. Keep your intake off of the bottom of the bucket to keep from sucking up debris.
 
OP
OP
chrlsful

chrlsful

Bronco Guru
Joined
Oct 21, 2009
Messages
1,448
yeah, that sounds like re-cycling it, but no problem. After ten min or so I’d change out that water. Do several cycles.
May B less and less caustic solution pumped around each cycle so near end I’d B able to just dump on ground here
as almost pure water...
Leave it to the guys w/2 fewest posts I all ways say ( 22 & 121 ) aahahahaa
 
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