Flushing coolant system

[James Morse]

I got Fram coolant 100% and distilled water and 195F thermostat and gasket. I think I'm ready to put in new gasket and new coolant. My question is about flushing. In my recollection, and it's been a while, I drained the old coolant, put in plain tap water, being careful to not put real cold water in hot engine, ran it until warm, drained it, maybe did that a couple times, then swapped out the thermostat and filled with good coolant, probably 60% coolant /40% water, I think that's what they say to use in the manual. Am I on target about that? Do you recommend any aftermarket flushing additives, or is that not necessary? I never used them before. Also, will I have to bleed air out of the heater core or bleed any high spots afterwards? Thanks.

 

[Dirtman]

How many times you flush it depends how dirty it is. If the old coolant comes out clean I don't even bother. If it keeps coming out nasty just keep flushing it. You shouldn't need to do anything special to bleed the air out, they bleed themselves pretty well. You should switch the heater core lined around so it flows through backwards. This keeps gunk from forming on one side of the plates.

As for the mix ratio. It's always 50/50 unless you live in an extremely cold climate.

 

[James Morse]

It nasty, that why I do it otherwise if clean like auto trans and oil then I would leave alone.

Wow that nifty about heater core hoses. THANKS.

No it hardly ever get below -10F here, if even. Usually 0F would be unseasonably cold.

Yeah ok, good, if after one flush it looks pretty clear and not gunk and particulates coming out then I'm done with the flush.

I was thinking maybe it's better to change out the 'stat before flushing but I guess it doesn't matter either way as long as I feel the engine is reasonably warm before draining the flush, if that even matters. Main thing is just get crap out of there and put in what I know for sure is good coolant. Cheap to do and then I know I have it in the best condition it can be given what I'm working with. Ah... I think... flush, then, while it's still drained, change out the 'stat, then put in good coolant. Then I don't worry about stuff running out of it at the 'stat, not that it matters that much, but just seems to make sense. Thanks.

 

[Shran]

I flush by unhooking both radiator hoses and one heater hose and running water from a garden hose through the engine, radiator and heater core in both directions several times...usually I'll plug off the lower radiator inlet with my hand or temporarily reconnect that hose and let the engine and radiator fill up, then quickly pull the hose off to dump everything.

What I do to "bleed" the system is AFTER the flush, I connect all the hoses and fill the radiator as full as possible, then start the engine with the radiator cap off. I watch the fluid level closely and add as necessary when it drops... when the thermostat opens, you'll probably add another gallon or so. At that point, have a helper hold the engine at 2-3000RPM while you top off the radiator and then put the cap back on. The increased engine speed sucks the coolant level down. Test drive it at that point and check for leaks, should be good to go.

It's always a good idea to test the coolant after this process because you always have some residual tap water left in the engine after the flush process which can mess with your 50/50 ratio, you can correct this by draining some coolant out of the radiator and adding some full strength coolant to replace it.

 

[RonD]

When you change coolant you should also swap around heater hoses at the firewall

Heater cores have no "direction of flow"
By reversing the hoses you reverse the flow thru the core, this keeps it cleaner, helps it last a few years more
And easy to do even after coolant has been changed, you would lose very little swapping around these hoses

 

[James Morse]

THANKS guys. RonD, you are saying, just periodically reverse the heater core hoses, to even out the wear, right? I assume then without looking at it that both hoses will reach either the inlet or outlet.

Shran how am I testing the coolant, with the bulb tool where you suck some in and it has a needle on it that tells you? Thanks for tips on the flush I am going to follow that.

 

[RonD]

Yes, heater core connections at firewall are next to each other so easy to swap around
Heater core passages are small, so any larger debris can clog passages, when you reverse the flow it can push that larger debris out the way it came in

Coolant additives protect the metal parts of cooling system from corrosion by continuously coating the metal parts
If flow is lower or blocked in a passage then corrosion can start, thats when heater cores or radiators get leaks
Can't reverse flow in radiators, lol, but you can in heater cores, and its FREE to do

 

[James Morse]

Thanks RonD sounds terrific, and I'll do it.

 

[Shran]

THANKS guys. RonD, you are saying, just periodically reverse the heater core hoses, to even out the wear, right? I assume then without looking at it that both hoses will reach either the inlet or outlet.

Shran how am I testing the coolant, with the bulb tool where you suck some in and it has a needle on it that tells you? Thanks for tips on the flush I am going to follow that.

Yep, the bulb tool.

Also if you are mixing yourself instead of buying premix, it's a good practice to use distilled water instead of tap water. Some tap water is OK but I try to avoid it... well water around here is even worse, it's very hard and will leave calcium deposits on everything.

 

[James Morse]

Got the distilled already this morning. Price of premixed is higher even with the cost of distilled, I'm pretty sure, but not by much. In olden days they didn't have premixed so I'm used to mixing.

Have to dispose of old stuff somehow, probably should drain into pan and put in empty containers and put in trash to landfill. It poison to dogs and I've heard they'll drink it. Not good to put down storm sewer any more, that goes into river which is not good even if it's way diluted. The flush part, probably not enough in it to affect much, but even though I'm not an eco-freak, I don't like the idea of putting poison in a place that eventually ends up in somebody's drinking water, even if not mine.

Yeah when I moved to this house, water heater was literally half+ full of deposits like rocks almost. Probably was never cleaned. It's a Merklett heater, if you never heard of them that's probably because it's like 100 years old or something. I mean really old. Replaced elements and it works like a champ. Nothing can go wrong with them you can't replace if the tank doesn't leak. Yup deposits form around faucets etc. Vinegar takes them off. You wouldn't want that crap in your truck system it could wreak havoc. Distilled water is .89/gal, not like it breaks you.

Thanks Shran.

 

[fastpakr]

You should be able to take the old coolant to any of the chain auto parts stores. I've run it to Advance several times.

 

[Dirtman]

Yep advance an autozone take it. Dunno if it varies by state but in NJ if a store sells oil, antifreeze, or batteries they are required by law to be designated drop off spots for recycling those products.

 

[James Morse]

AWESOME. Thanks. Will definitely do that then, problem solved.

I wonder what they do with it. Maybe they filter it and put it in new containers, lol.

 

[Shran]

That's interesting, I wonder if that's a local thing... I don't think any of our parts stores take antifreeze, just used oil.

I kill weeds with used antifreeze. I figure it's no worse than Roundup or whatever else gets dumped on the ground legally in huge amounts. At one point I had called the city to see what to do with it, and was told to dump it down the toilet...I guess the water treatment plant can filter it out. Sounded weird to me but pee and poop get filtered out too......

 

[Dirtman]

That's interesting, I wonder if that's a local thing... I don't think any of our parts stores take antifreeze, just used oil.

I kill weeds with used antifreeze. I figure it's no worse than Roundup or whatever else gets dumped on the ground legally in huge amounts. At one point I had called the city to see what to do with it, and was told to dump it down the toilet...I guess the water treatment plant can filter it out. Sounded weird to me but pee and poop get filtered out too......

The problem with using antifreeze like that is that animals like to drink it since it tastes sweet. Weed killer may be no less poisonous but you won't find chipmunks and birds trying to drink it...

And you uhhh don't have to tell the parts store what's in the Jug. They don't look, if you say its motor oil they will take your word for it. Plus, I mean people must take 2.9 engine oil there to be recycled and that's always at least 90% antifreeze...