Flushing a neglected cooling system

[dlundblad]

Happy Sunday BITOG.

With a neglected cooling system, it can take quite a bit water to get everything looking clean. Typically, I just use distilled, but I know folks use a garden hose too.

I live in the country with a well and hard water. Would I create issues by flushing with a garden hose until clean water starts pouring out? Would soft water be better or worse?

When I'm done, I could fill the system with distilled, run the engine a bit, drain, and then top off with 50/50.

 

[Vern_in_IL]

Honestly, if it is not overheating, or not heating inside. I would just drain and refill. If you really want to get the buildup out, it might be better to replace the radiator.

....and if you do a flush, drain from the lower radiator hose, not the peacock drain. Material could get into the peacock and may not close properly and leak.

 

[krismoriah72]

Distilled Water is $1/gallon just about everywhere.. so for about $3 you could drain all old out, install distilled water..circulate well for an hour or so...then dump.. Install the best antifreeze you can find and mix yourself at 50/50 or higher concentration depending on your climate with distilled water.

Use the leftover distilled water to make yourself a pot of coffee or give it to your critters in their drinking bowl.

 

[69GTX]

I've always used and heard the term "petcock" drain.

 

[Donald]

OP - what are the indications of a neglected cooling system you are seeing?

Unless it's pretty bad I would fill with as much distilled water as you can get in the system, run for an hour and drain and refill with 50/50.

Best if you can get the block and radiator drains open.

 

[CourierDriver]

I always take our cars/truck to a radiator shop in town. Never a problem and it is whistle clean. Been down the road of do it yourself, or those oil changing places that clean out your radiator and engine, not a good idea imho.....you dont see a GP doctor to get your heart worked on do you,,,you go see a heart specialist,,,no brainer...

 

[SHOZ]

I use some citric acid based cleaner. Drain, add the cleaner, and refill with distilled or demineralized water and drive for a day. Then drain and fill again with distilled. Heat up the engine a bit drain and fill again with antifreeze, best to start with 70% to account for the water you can't drain out.

 

[dlundblad]

Lets just say the water looked like something from inside the Titanic wreckage. $3 worth of distilled won't cut it.

The car is a 1971 Datsun 240z. Dad and I are going over it and finally replacing the thermostat (with the correct temp, PO installed a 160*F rather than the OE 180*F), all hoses, clamps and antifreeze. With everything disconnected, we dumped about 6 gallons of distilled through the block and radiator last weekend until it looked clear.

Yesterday, with the housing back together, but without the thermostat, we ran 2 batches of distilled though the system with the engine on. It looked just about as bad as before.

 

[Kira]

Sounds like you're just swishing distilled water through a heavily soiled system. Too bad you didn't attack the crud while the system was still buttoned up with its old parts.

A citric acid cleaner (or whatever you used) could have been allowed time to clean.
1)Dump out old (as much as will exit via lower hose disconnection).
2) Add cleaner and garden hose water to fill. Run to warm or even hot.
3) Drain (when safe etc.) and access repetition of process. 3a) Changing cleaners-or using more than one-might attack crud better.
4) Nearing clean, switch to distilled for rinses.
5) Do your coolant mixing with residual water in the block in mind.

An earlier post regarding going to a real radiator shop is a good one especially if you're going to generate 30 or more gallons of poison waste water.
That post inspired me to go to a radiator shop in Hackensack and ask if they do that there. I always see their El Caminos and Rancheros with radiators piled high.

Best of luck with that 240Z....one of my favorite cars of all time....soooooo cute. Kira

 

[Olas]

Drop a dishwasher tablet in there, drive till hot, drain and repeat.

4 or 5 dishwasher tablet drain & refills will have it like new, flush with distilled then 50/50 and you're done

 

[barkingspider]

Keep doing drain and fills with hose water and cleaner of your choice until it starts to come out clear, then move to distilled water, then move to 50/50 distilled/coolant of your choice. It appears you maybe doing the DnF for while, but it is what it is

 

[JHZR2]

Use the Daimler citric acid flush process. A site called diesel giant has a good DIY.

I'd flush with plenty of hose water. But the last one or two flushes I'd do with distilled, and I'd probably even do a radiator drain and refill a few times a few hundred miles into it if really neglected.

 

[CharlieBauer]

Once it's done, consider installing a coolant filter.

 

[dlundblad]

We did 2 more drain and fills and it wasn't cutting it. Broke the hose out and flushed the block, radiator and heater core. More crud came out then it turned clear. Had enough distilled for 2 more drain and fills and called it good.

Today was probably the first time the poor thing got to temperature in years.

Oh and the engine got a steam bath today too.

 

[DoubleWasp]

It's going to come back very soon.

Been there, done that.

The safest and most correct way to handle this?

1. Drain radiator, block.
2. Remove thermostat, reinstall thermostat housing without thermosstat.
3. Disconnect all hoses, and separately rinse everything with a garden hose.
4. Put system back together and fill with "Shout!" for degreasing, and run the engine for 20 minutes.
5. Repeat 1 and 3.
6. Fill system with water and Citric Acid cleaner.
7. Put system back together and run the engine for 20 minutes.
8. Repeat step 1 and 3.
9. Fill system with water and baking soda, to deactivate any remaining acid, run engine for 5 minutes.
10. Repeat 1 and 3.
11. Reinstall thermostat, fill with appropriate coolant and distilled water.

There's no need to attempt any flush with distilled water. Your cooling system is and always will be contaminated with more heavy minerals than 100 gallons of tap water contains. Flushing with tap water won't make things any worse.

 

[dlundblad]

We are planning on another flush sometime next year and will give the Shout and citric cleaner a try next.

Thank you for the detailed reply.

 

[CourierDriver]

I am not a radiator professional systems cleaner person, but some of these previously mentioned ways of cleaning up your radiator ,engine and heater core are really something...

So, with that said, how does / do the radiator shops clean out radiators and heater cores,,,I do not know. I have heard the term boiling the radiator out and pressure testing them,,,,