Cooling system flush before overhaul question


Fortzen1305

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All the parts for the cooling system overhaul have arrived and I want to make sure I've got this down and my thinking correct.

Is it okay to drain the radiator, pull the thermostat and then reinstall the housing, refill with distilled water and prestone flush, and then keep filling and draining until it's clear before I start the overhaul?

I've never done a cooling system and have been a little lost in the weeds with adding T's to the heater core hoses, reverse flushing the heater core, draining the block using the plug etc.

So I guess my question is if I can drain, pull the stat fill, add the flush chemical, drain, fill until the water is clean and then take the parts out and reinstall the new rad, water pump, stat, etc.

NOTE: I also know I'm likely overthinking this but the steps to all this with the flush and then taking the parts out and reinstalling I'm going through a mental checklist putting the steps together without having any experience on a cooling system yet. No doubt it'll make more sense when I start doing it.
 
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sycboi

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You’re on the right track. I’ve done similar myself before installing new parts in the cooling system. My thinking was to get all the bad out before installing all the good…
 

TJ Starting

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I'm putting a ear in here to. Getting ready to do the same and had questions.
 

Rubicon88

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Do you have cooling issues at present?

If not...just flush it. You don't need fancy chemicals this and that. Just flush the thing until you get clear water exiting.

#1 distilled water is a bad idea. Distilled water has been stripped of impurities and will try to rebalance itself by robbing the metals in your cooling system. Use the garden hose.

#2...if #1 wasn't true (it is) why are you using distilled to flush the system then drain it anyways?

We never use distilled water and not one cooling system problem on hundreds and hundreds of automobiles over the years. Not one.

Good luck
 

TheBoogieman

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Water will NOT get the years of crap out of your cooling system when flushing it.
Thermocure.jpg
 

Thunderhead

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I changed my radiator, upper and lower hoses, 2 weeks later then my water pump started weeping.
The same process all again.
2 different fluids came out of the radiator and the block
 

Rubicon88

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Water will NOT get the years of crap out of your cooling system when flushing it.
View attachment 258381
Do you have a cooling issue?

If your cooling system is working properly then go buy some amazing potion....if it tickles you.

Now if you're talking about neglect as in never changing your coolant but once every decade, using brown stop leak pellets and goo to band aid a cooling leak....

Well that's different and that's just asking for troubles.

It's silly to do all this hoop jumping through if your cooling system has been properly maintained....as in changing it out just like any other petroleum product on the vehicle. It breaks down over time and loses it's effectiveness.

Do you remove the oil pan and do an engine tear down on a properly maintained engine with scheduled oil changes?
Sure it has a filter but don't think for a second that 100k plus engine is completely sludge free.
Sludge is kept to a minimum by doing proper routine maintenance of changing out the broken down oil and adding fresh....

thus the cooling system with proper maintenance is kept in good working order as well******
Again...if properly maintained
And that's the key
 

TheBoogieman

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The PO of my Jeep changed the antifreeze every 3 years (20,000 miles). He was the only owner before I bought it and gave me every service record from the first oil change. I flushed it and still got rusty water coming out. 🤫
 
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Fortzen1305

Fortzen1305

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What I'm gathering is that products such as thermocure and superflush are controversial products.

I am planning to use one of these products because the cooling system has not been properly maintained. These are all original parts on the jeep. I can smell coolant when I drive, the overflow is dropping slowly, it's its a 15+ year old jeep with >100k miles so in my opinion it's probably best to replace the cooling system anyway and get the maintenance on track.

But the original question is how to quickly and efficiently flush. Can I run the cleaning/ flush product with the stat removed, cycle water through until its clean, and then reinstall parts?
 

qslim

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But the original question is how to quickly and efficiently flush. Can I run the cleaning/ flush product with the stat removed, cycle water through until its clean, and then reinstall parts?
If you're going to use that Thermocure product you'll just add some to the radiator, drive it around for a few hours, then drain & flush everything. I've never used it on any of my cars, but that's what the instructions say.

What all parts are you replacing for your overhaul?
 

qslim

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If you are smelling coolant when you drive have you checked the passenger floorboard for coolant? That would be a leaky heater core. My heater core leaked the day after I put thermocure in.
Yeah, I was smelling faint coolant for about 6 months, it would come & go. I finally replaced my heater core and it was leaking just enough to evaporate before it spilled onto the floor. It is a telltale sign.
 
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Fortzen1305

Fortzen1305

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If you're going to use that Thermocure product you'll just add some to the radiator, drive it around for a few hours, then drain & flush everything. I've never used it on any of my cars, but that's what the instructions say.

What all parts are you replacing for your overhaul?
Replacing the radiator, fan clutch, water pump, t stat, upper and lower rad hoses.
 
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Ericict

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When I did mine, I used the Prestone flush. Drove around with it in the system for a few days and then drained. I did have overheat issues and once I was all done Ive had no problems. Dont forget to replace all the hoses and clamps when you do this. After teh flush, I replaced the pump had the radiator flushed and checked at a shop and bak flushed the heater core since I wasnt having any issues with it.
 

Ericict

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Replacing the radiator, fan clutch, water pump, t stat, upper and lower rad hoses.
OEM parts? I had bought non oem water pump and it had an internal crack thru a bolt hole. I knew it was leaking but could not locate it. Had to rent a system pressure check tool and pressurize the system to find it with the fan off. In the future, I will just add that step to the job prior to installing the fan. qslim is correct about the heater hoses. Dont forget them.