I know how to flush and replace my coolant in my radiator, but I was wondering how to flush the coolant from the engine block and heater core.

I saw that Prestone makes a backflush coolant kit which flushes out the coolant through the heater core. But I don't like the idea of slicing my heater hose an installing a permanent T-valve in there. It sounds good in theory but I can see it leaking.

And I don't think the coolant flush solutions do any good. I think water does the job just fine.

Any suggestions?

 

Unless your interested in taking the heater core out (Have fun) then you are most likely going to have to cut the hoses.

Use a clamp and make it tight I have had the splits on alot of cars in the past and they dont leak. Check them often and if they start to you prolly need new hoses anyway.

Yeah I use water also not the flush liquid that is out there.

 

Mark, I had the kit on a couple of older cars, but i don't think I would do it on either of mine now. What I do now takes a bit longer, but hey, good way to stay out in the garage and drink a few cold ones.

Park on a downhill slope, or just jack the rear end slightly. Open the drain valve or pull the bottom hose, crack the rad cap, drain and refill, run engine 3 min or so, drain and refill. Run it to temp with heater on, let cool, drain and refill with antifreeze. This is gonna get probably 95% or more of the old stuff out.

Hey, I said it takes a while. And yes, I dispose of it correctly, I have people...lol

 

I really would like to try the backflush kit, but on my car (1999 Mercury Mountaineer V8), the heater hoses are really crammed in there and it would be tough to find a straight enough section of the hose to get the T-valve in.

I think I'll go with Gunguy's suggestion of drain, refill, run the engine with the heater on, drain, refill, repeat, etc.