2G How do you flush the coolant system on a DSM?

[Velmin hu]

How do you flush the coolant system proper way since I’m replace all the hoses with silicone and air as well Since hoses are old and hard. There different methods reading the forum. Also my current coolant is brownish and corroded I think .

thank you
I’m using 50/50

 

[609DSM]

To my knowledge you just open the petcock on the radiator and let it all drain out. Then fill it back up. If you want to get crazy with it you can add that Prestone radiator cleaning solution, comes in a little yellow bottle. Add that into your system and drive for 500-700 miles and then drain the system again and add distilled water mixed with the rest of your Prestone radiator cleaner. Then drive around until engine is at operating temp and have the heat going for each time you drive around btw. Then drain and add distilled water only, repeat the driving around until at operating temp and drain again, do this until the water comes out clear. After the water is clean looking fill back up with your coolant of choice and you're good to go.

 

[AWD-Tony]

To my knowledge you just open the petcock on the radiator and let it all drain out. Then fill it back up. If you want to get crazy with it you can add that Prestone radiator cleaning solution, comes in a little yellow bottle. Add that into your system and drive for 500-700 miles and then drain the system again and add distilled water mixed with the rest of your Prestone radiator cleaner. Then drive around until engine is at operating temp and have the heat going for each time you drive around btw. Then drain and add distilled water only, repeat the driving around until at operating temp and drain again, do this until the water comes out clear. After the water is clean looking fill back up with your coolant of choice and you're good to go.

That’s the proper way. Think you have to drain all the coolant though before using the cleaner IIRC. My car had brown rust water also when I got it. You want to move the thermostat, then take a garden hose and flush the system out until it’s clear. Back flush the heater core while you’re at it and 100% use distilled water.

 

[91talonts1]

You can also use distilled white vinegar instead of one of those bottled flush solutions. The vinegar is mild, some of the bottled stuff can be pretty aggressive when you've got old seals and gaskets to worry about.

 

[Velmin hu]

That’s the proper way. Think you have to drain all the coolant though before using the cleaner IIRC. My car had brown rust water also when I got it. You want to move the thermostat, then take a garden hose and flush the system out until it’s clear. Back flush the heater core while you’re at it and 100% use distilled water.

Ok also where is the heater core inlet or outlet at the back located which one is the backwards one thanks so I remove thermostat and shoot garden hose in it and clean it.

 

[AWD-Tony]

Ok also where is the heater core inlet or outlet at the back located which one is the backwards one thanks so I remove thermostat and shoot garden hose in it and clean it.

The hoses off the heater core go to the back of the thermostat housing and the other goes to the water pipe. Water pipe is inlet and tstat is outlet.

Don’t take the hoses off the heater core since the best way would be to cut them off so you don’t bend the pipes. They’re really prone to bending out of shape.

Correction.

Think water pipe is outlet and tstat is inlet for heater core.

 

[Velmin hu]

Here is the video and photos

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Is that where the thermostat is located and heater core

 

[miguelmcv]

Yes that’s the thermostat and heater core. Fallow the hose coming from the thermostat which is the feed line to the heater core and the other is the return line which goes to the inlet pipe.

 

[AWD-Tony]

Green is inlet
Yellow is outlet

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Below is the inlet off the thermostat housing

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This is the outlet

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The 2g thermostat housing is a little different. Remove the two bolts under the cap

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[Velmin hu]

Green is inlet
Yellow is outlet

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Below is the inlet off the thermostat housing

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This is the outlet

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The 2g thermostat housing is a little different. Remove the two bolts under the cap

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I like your set up I’m putting g plus hose silicone on mine was it hard to put all of them getting original clamps also. So I take out the thermostat and put garden hose there I also got distill water 3 gallons. Also heater hose I connect the hose to the upper inlet or outer hose need to do reverse

thank you so much

Green is inlet
Yellow is outlet

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Below is the inlet off the thermostat housing

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This is the outlet

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The 2g thermostat housing is a little different. Remove the two bolts under the cap

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Garden hose goes to outlet which is top above or bottom below hose

 

[AWD-Tony]

Thanks, Velmin!

Replacing all the hoses isn’t too bad. Some are just a pain to get off. For the heater core, cut is off because the pipe bends easily. I replaced all the hoses when I had the head and turbo off so it was much easier.

For flushing the heater core, I like to remove both hoses (on the other end of the heater core) and flush it that was but not completely necessary.

Don’t use the hose clamps that came with the kit, they’re garbage.

 

[CKOPOCT]

Flushing your coolant system and using addatives is really about trying to ensure you get rid of as much crud and corrosive crap as possible, and do so in a way that doesn't leave you with a pocket of old coolant trapped and that remains unflushed. This is why you remove the thermostat. By pulling the lower radiator hose or opening the petcock, and then using the heater core feed hose as your water in supply, you are effectively pushing all of the coolant out of the system.

The method of using the additives is so they break up any deposits that may trap crud or make your system prone to being corrosive or impede coolant flow. Flush your system with the gardren hose for as long as it takes to have the discharge run clear.

While I don't suggest or recommend it, I usually taste the discharge after it runs clear. This is because coolant has a sweet taste and I can also taste some corrosion due to the metal content. So I flush until I am satisfied that the clear color isn't deceptive. Coolant is poisonous, so I also rinse and spit after tasting, and only taste a drop from my finger. Again, not a recommendation for you - just a method I use.

As mentioned earlier, vinegar works great to flush your system. But as a mild acid, vinegar will also negatively react to some metals and can degrade some seals. You can witness this by dropping a hardened bolt with its lock washer into a cup of vinegar and leaving it sit for a few weeks. You'll see the lock washer begin to dissolve and the threads on the bolt will become serrated as the vinegar eats the metal.

Vinegar as a flush, because you dilute it with water and use it for a short period of time, can work very well.

 

[motomattx]

You can neutralize the vinegar solution afterwards by mixing some baking soda with water and flushing with that.

 

[ishnish]

While all of this is great advice, if your luck is anything like mine, your coolant will come out brown as sh*t no matter how many Preston's radiator flush & clean you use. Ask me how I know..

By the time I was on my fourth bottle of that radiator flush & clean and like my 4th gallon of distilled water, I was so fed up that I changed my approach as my fourth time draining it resulted in almost just as brown water coming out as the first drain.

So, here's what I did that worked AMAZINGLY for me.

From scratch:
Drain coolant completely, remove the thermostat, fill the car up with Prestone radiator flush/cleaner and top it off with distilled water. Drive that car like that for a a few days. This will loosen up a lot of the gunk. Heck do it twice if you want to be anal about it.

Then, finally on another day you're ready to work on the car (and have plenty of time to put aside), drain all that crap out, close that petcock, and fill that sucker up with hose water. Yes, you heard me correct, hose water.. everybody don't get all crazy on me now, it gets worse..

Then turn on the car and let it run. Keep that radiator cap open though so you can see the water flow through until the level starts to drop, once it does start filling it up with more hose water. At some points it may overflow but that's okay. Now, while that car is still running and all that water is circulating, open the petcock and let it drain while the car runs. Told ya' it gets worse. You'll notice the water is, unsurprisingly, coming out brown

Just when you thought that miracle flush got rid of everything ayy? Keep that petcock open and let it drain. While it's draining, keep an eye on the filler neck of the t-stat housing. As the level gets lower, keep topping it up. Every now and then look down below the car at the water draining out of the petcock. You'll notice it getting clearer (yayy!!) But not really...

Buy one of those cheap foil trays from the dollar tree, I think people usually bake turkeys with them or something, they're a decent size. Anyway, I like these trays because they're not black and they let you see the true clarity of the water. Remember how I said earlier that you'll notice the water getting clearer? HAH! Yah right! Put that motherf*ckin' foil tray under that petcock, let it fill up like a 1/4 way and you'll start seeing that beautiful orange/brown rusty color come back .

So yeah, you'll be here a while.. make sure you periodically close the petcock and top off the t-stat housing to let that water in the block circulate WHILE the car is running. If you don't, then you'll have clear water draining out of the petcock, fooling you into thinking your car's system is completely clean when it is NOT! Ask me how I know.. again.. It's possibly because you're not letting that water circulate, get hot, and clean out the crud that's really baked into the block. I went through ALL this trouble waiting for a day like this to pass on the info and greatly help someone else in life.. ahh it feels good to be of some use now . So yeah, close the petcock, let the car run like that and circulate that water for a few minutes, then open that petcock again, same process, while it's draining, top up that t-stat housing. If you don't do it this way, you'll drive around for a few days and then when you drain all that fluid out, it'll come out brown and you'll just get frustrated. We wanna prevent ALL of this. I spent over an hour easily doing this until finally, that fluid was coming out VERY nice, almost clear! This is after letting that car sit at idle circulating that water for 10 minutes or so with the closed petcock. That's how I knew I was golden!

FINALLY, after all that, drain everything and fill it up with distilled water and coolant flush/cleaner, and drive that car for a day or two more, drain one last time, and install your thermostat, then fill with your 50/50 mix to top it all up and you are GOOD, like GOOOODDDDDD, to go..

 

[Jimmy Edwards]

That’s the proper way. Think you have to drain all the coolant though before using the cleaner IIRC. My car had brown rust water also when I got it. You want to move the thermostat, then take a garden hose and flush the system out until it’s clear. Back flush the heater core while you’re at it and 100% use distilled water.

Just saw you're in Cincy. Me too!

 

[Kryndon]

I've found that the brown goo that often forms in the cooling system and at the bottom of the overflow tank, looking like clay almost, is very thin particles of loose rust mainly from the insides of the block. The older the block, and the more air it has seen, the higher the rust area within it will be. No matter how many times you flush it with fancy chemicals, the rust spots will keep developing and keep releasing into the coolant. Eventually you can still get fairly clean coolant, but there will always be traces of rust in it. Unless you find a way to completely inhibit all rust formation on the insides of the block's water passages, or grind them down, which would be near impossible.

It gets me thinking further. The way ishnish is doing it would mean the car would need to idle for a very long time. Has anybody ever thought of pulling the water pump belt off and trying to spin the water pump only without running the engine at all? Of course you'd remove the thermostat and fill the block with hot water to activate those chemicals. I just feel it would be less noisy and less needless idling on the engine as well as wasting fuel.

 

[AWD-Tony]

Just saw you're in Cincy. Me too!

Cool. I'm in Amelia neighbor. Do you have a silver 2ga fwd from Florida?

 

[AWD-Tony]

I've found that the brown goo that often forms in the cooling system and at the bottom of the overflow tank, looking like clay almost, is very thin particles of loose rust mainly from the insides of the block. The older the block, and the more air it has seen, the higher the rust area within it will be. No matter how many times you flush it with fancy chemicals, the rust spots will keep developing and keep releasing into the coolant. Eventually you can still get fairly clean coolant, but there will always be traces of rust in it. Unless you find a way to completely inhibit all rust formation on the insides of the block's water passages, or grind them down, which would be near impossible.

It gets me thinking further. The way ishnish is doing it would mean the car would need to idle for a very long time. Has anybody ever thought of pulling the water pump belt off and trying to spin the water pump only without running the engine at all? Of course you'd remove the thermostat and fill the block with hot water to activate those chemicals. I just feel it would be less noisy and less needless idling on the engine as well as wasting fuel.

My car had rust water when I got it too. I've put about 2k or 4k miles on it in two years. It's finally somewhat clean and what really helps is my mishi radiator having a magnet on the drain plug. Think I've drained it two or three times since I installed the radiator and there's a decent amount that sticks to the magnet. I'm sure it'll be that way for a long time though.