Heater Core - Replacement vs. Flush

[A4orce84]

Hello Everyone,

Yes, I know we have a few active threads (recently) around heater cores. Linked below for ease:

Links:
1. Heater Core Flush DIY - http://www.audizine.com/forum/showth...Core-DIY/page5
2. Old Guy's Heater Core Post - http://www.audizine.com/forum/showth...1#post12092558

Question:
To all of you that FLUSHED your heater cores, how many of you are still having good heat after the flush? Or was it a temporary fix (like old guy and a few others) and you ended up spending the $$ on a new core down the line?

I have noticed last year my heat was pretty weak during the winter months. Not zero heat, but pretty low heat in terms of warming the car up quickly. I know I need to get this heater core issue addressed in the next 2-3 months, so trying to understand what is the better / cost-effective approach. Trying a flush and seeing how that goes first obviously sounds like the more logical approach. But if everyone is just replacing their cores anyway, maybe that's the better long-term solution.

Any thoughts, feedback, or opinions are welcome. Thanks in advance!


Thanks,
Asif

[ADCS]

From my experiences...

Flushing just the heater core: temporary relief. Could be a day could be 6 months. This depends how much crud is in your cooling system as it will migrate from your engine/rad back into your heater core quite quickly. Or if the core is just so plugged with junk you will not be able to remove it with just a flush.
Flushing rad, engine & heater core: Nearly as good as a replacement depending how you do it. It is still better to replace it. Same with the radiator as you will never be able to remove the thin film on the inner surfaces which hinders the thermal resistance.

How I flush the engine/rad: Warm up engine. Drain coolant from lower rad hose. Fill with straight distilled water. Warm up engine. Drain coolant from lower rad hose. Repeat distilled water several times until it drains clean (5-6 times). You can add some rad flush if you wish...be careful with it. And I would only add it to the first or second drain/fill. When you are ready to refill the system use straight coolant as you will already have about 4L of straight distilled water still in the block.

How I flush the heater core: I do this with the engine flush so the coolant is already drained. Disconnect heater core hoses near battery. Attach 6ft long 3/4" heater hose to each connection. Put one heater hose line into a drain bucket and use my garden hose to flush water into the other hose. It helps to hold the hose you are adding water to up high using a small step ladder or similar. Alternate hoses several times. After a ton of shit comes out I then fill the core with water from the hose again and use my air compressor to force the water through the core quickly. Tons more shit will come out. Again do this in both directions multiple times. Once you are satisfied the junk is out flush the heater core again using straight distilled water in both directions a few times to remove the tap water and air. Re-connect everything. Bleed the system (cold) and enjoy your heat.

[seanf86]

I flushed my core 4-5 times maybe more since I had terrible heat, it would work for a few weeks to month then go back to terrible, I finally sucked it up and spent $100 on a new core, why I didn't before is beyond me, it took me an hour to change which is pretty much how long I would spend every time I would flush the core.

I bought the all alum Spectra premium from rock auto, its been 3 years so far so good.

[Willënskraft]

In addition to either flushing or replacing I recommend removing the coolant expansion tank and flushing that as well. Since there's old debris and stuck crud in there. Or replace with a new one and you'll have a nice tank of pink coolant.

[Pothole]

Don't waste your time flushing.
The heater core replacement isn't that bad on these cars.

[Chris M]

replace it. its easy. make sure to purge the air out of the hose on the engine side of the firewall.

[old guy]

replace it. its easy. make sure to purge the air out of the hose on the engine side of the firewall.

Easy you say?

I'll just leave this here......Clicky click®

[A4orce84]

Easy you say?

Fletcher,

What are your thoughts sir? Flush first?

[old guy]

Fletcher,

What are your thoughts sir? Flush first?

I flushed mine numerous times. Each time the interval between good heat and poor heat decreased. If you have never flushed yours I would say go with a flush. Once you start with the diminishing returns go ahead and replace it.

[Chemmie]

I flushed mine and it worked well for 3-4 days. Heater core replacement looks relatively straight forward on these cars, and the core is comparatively cheap.

The last heater core I did was on a Jeep Grand Cherokee. By the time you get to the core, there is nothing between the driver/passenger seats and the steel if the firewall. Steering column, entire dash, nothing is left.

[Chemmie]

I flushed mine and it worked well for 3-4 days. Heater core replacement looks relatively straight forward on these cars, and the core is comparatively cheap.

The last heater core I did was on a Jeep Grand Cherokee. By the time you get to the core, there is nothing between the driver/passenger seats and the steel of the firewall. Steering column, entire dash, nothing is left.

[2000blk1.8t]

after many flushes for me I also replaced mine. It really isn't that bad of a job. I did it in like an hour and a half.