Radiator Flush Question

[bennyG]

Hi,

Apologies if this has been covered but I could not find the info I'm after. Also, no response from Liqui Moly.

We have a can of Liqui Moly Radiator Cleaner and would like to know the correct procedure. Should we add the can to the current 3 year old coolant in the car? Or should we drain the old coolant, fill with DI water, and then add the Liqui Moly cleaner? (The latter being what we have done previous)

Thank you for any help and this is our first thread since joining,

Benny

 

[rob1715]

Drain, refill with distilled water and run it until warm, cool down, drain, refill and then add the cleaner. D/F until the water runs clear and the cleaner in the system is purged. If you can, it's good to change the thermostat.

 

[Falcon_LS]

Unless your system is dirty, odds are you do not need a flush

If the thermostat is easy to access, drain the radiator and take out the thermostat. Refill with distilled water, turn the heat on full blast and fire up the engine until it reaches operating temperature. Let it cool off and drain the radiator once again.

If the upper radiator hose attaches to the thermostat housing, reverse flush the system by filling distilled water from the thermostat housing with the radiator petcock open, the refill the system and run the engine with the heat on once again.

If the system is dirty, this is when you add the flush and with the heat on, allow the engine to reach operating temperature. Rev the engine to 2,500 rpm for 10 minutes, occasionally blip the throttle. Once it cools off, flush and back flush again and refill with distilled water. This is a good time to thoroughly inspect all your radiator hoses, heater hoses and replace as necessarily, along with the thermostat and radiator cap.

 

[bennyG]

Thank you for the replies.

System components are in overall great shape, water pump, hoses, t-stat, etc. right at around 3 years old. Volvo coolant they say to change every 2-3 years.

Reason for the flush is piece of mind. Car is from the 80's, we've driven since 200k miles, and the radiator is a junkyard score (it looked new but never know)

We'll go ahead with the cleaner with DI water only, change over to the Amsoil Low toxicity PG coolant after many "rinse" cycles, and let y'all know how everything goes.

Edit: new summer t-stat (190*F) after the flush as well

Thanks again

 

[SHOZ]

When it comes time for a coolant change I add the cleaner, usually citric acid and drive a day . Then drain, flush with distilled or demineralized water, then drain and fill with the new coolant.

 

[bennyG]

Thanks again for the input gang.

After a few weeks Liqui Moly wrote back saying to add their Radiator Cleaner to the coolant mix which is to be drained and discarded.

That was our initial thought after reading the label but it didnt seem right to us. Any other thoughts with this new info?

Thanks,
Benny

 

[GON]

Thanks again for the input gang.

After a few weeks Liqui Moly wrote back saying to add their Radiator Cleaner to the coolant mix which is to be drained and discarded.

That was our initial thought after reading the label but it didnt seem right to us. Any other thoughts with this new info?

Thanks,
Benny

Not sure if you response was from a seasoned technical support engineer or a call center generalist at Liqui Moly.

I put my money on the above process listed by Rob1715, the second post in this thread.

 

[SHOZ]

It's an acid with another cleaning chemical. So it works whether in water or coolant.

 

[Donald]

Keep in mind all low tox coolants are just not as efficient at exchanging heat as the normal coolants. They work, just not as efficient. I would use a decent brand G-05 or maybe the Peak Global or similar.

I am pretty sure its only low tox out of the container. Once its been in your cooling system for any period of time I think its probably toxic. Older radiator with lead soldering.

 

[bennyG]

So we ran the Liqui Moly radiator cleaner in water and a bit of remaining coolant for 30 minutes. A whole lot of sediment and dirty water came out for the 10 gallons worth of water we ran through.

I've never had a flush work this well and we've used the Prestone kind a few times. Thought that was pretty neat.

Also, the low toxicity Amsoil coolant is doing very well. We drove around 200 miles in about 90*F heat and I've never been more comfortable with where the water temperature is showing on the analog gauge. Though we're guessing this is more due to cleaning out the cooling system.

Thanks for the help and replys

 

[Kira]

Is there a commonly accepted lifespan for radiator caps?

 

[kschachn]

Also, the low toxicity Amsoil coolant is doing very well. We drove around 200 miles in about 90*F heat and I've never been more comfortable with where the water temperature is showing on the analog gauge. Though we're guessing this is more due to cleaning out the cooling system.

Normal?