Heater Core Flush

[lexiechitty]

Following this thread to get some insight into why my heat is lukewarm. I have already replaced my heat sensor valve and servomotor since they were both giving me trouble. But, still don't have total heat coming from the front vents. Great heat coming from the backseat vents, though.

So this leads me to believe the issue is within the heater core. I don't want to pay an arm and a leg for a flush, so is this something I can easily do myself? If so, anyone who can link me to a step by step video I would be forever grateful. What I've seen so far on youtube doesn't show me a before or after, just during. Not willing to risk it without full viewing.

 

[JBurt]

I had a similar situation. It's nice that the rear heat is a completely separate system, so it's easy to isolate. I used a Blue devil product at home. It couldn't be easier. You can buy it at any parts store. The big trick is you've got to have a way to collect and dispose all the old coolant after you drain the system. All you do is add the flush through the radiator cap, let the system run for however long the directions say, and then drain it out of the petcock at the bottom of the radiator. Then fill it up with distilled water and new (Toyota Red) coolant

 

[19963.4lsr5]

I drain enough out to put the coolant level below the heater core lines then carefully remove the hoses from the heater core and first run water from a garden hose backwards until it’s clear water then repeat in the forward flow direction.


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[diverscale]

I used CLR (pure) to unblock 2 heater cores that could not be only flushed.

Use at your own risk, but it needs to stay in there longer than you think.

 

[Romeo1]

Don't fight a guys. Go get the OTC backflush gun hook it up and flush everything there is on that vehicle forward and backwards. It's gonna take you at least an hour or two to do it. And a huge mess. Definitely do it outside lol.

You'll have to flush the main cooling circuit, and the secondary heater circuit for the rear floor heat. The amount of garbage I got out of mine was silly. Pull the thermostat, flush bottom up and top down. Don't stop until everything pushes clean water.

My 4runner runs so hot in the cab now for heater that you can fry eggs in that thing. Heats up almost as fast as my old Subaru did. I swear that Subaru, blew hot air in 45 seconds.

The OTC gun lets you do pulsating action with air and water. There's other methods out there for sure. But just using a garden hose is marginal the best. Do it right the first time and be done with it. I did mine when I replaced the radiator a couple years ago. Junk for days came out of that thing. Rust crap goo, you name it. A true testament to the durability of Toyota. Most vehicles would've met untimely demise with a compromised radiator and plugged exchanger circuits, and probably a lifetime of an empty de-gas bottle.. Not the 5VZ. It don't care.