When do I know when to flush my antifreeze?

[donaldbc]

And how hard is it. Does anyone know anything about those prestone "do it yourself kits"?

Thanks

 

[jimmiecakes]

Rule of thumb would be every three years though you can either use litmus strips to test the Ph of your coolant or even a voltmeter (one lead in the filler neck and one on a good engine ground - s/b 0v or very, very close).

The only real problem with the DIY kits is in the disposal of the old coolant. Here in Alberta I'm hoping that we soon have a facility much like waste oil collection.

 

[astrochimp]

what should you be looking for when using a voltmeter?

 

[jimmiecakes]

Antifreeze and voltmeter

You should see a reading of 0VDC (volts DC) but some voltage will be "almost" expected. Use a decent quality DVOM (Radio Shack has some good hobby meters as well as others - we sell Clarke at work - I don't have one but they seem OK). set on the 2Volt scale - lower is better with a half a volt getting pretty darned high.

I've seen almost 4 volts on systems that have been badly neglected - bear in mind computer sensors work on a 4.5 volt power supply and figure out the confusion there 8^).

As metallurgy and composites change in modern cooling systems, we are seeing problems we never even thought of 20 or 30 years ago.

Notice that I haven't said "Boo" about opacity or colour of the coolant....... dirty coolant is prime for changing but "clean" coolant isn't necessarily good coolant.

 

[KEbert]

I think it is a good idea to change coolant about every 35 thousand miles. If the coolant has calcium deposits in it, use some flush. If that does not work, take it to a radiator shop and have them rod it out. I also think a new water pump every 60 thousand miles is good too.

 

[jimmiecakes]

It can be difficult to pin a mileage figure to something so drastically affected by climatic conditions - where I live we have 90+° all the way to -40°. Three seasonal changes should be about enough. "Thermocycles" are an intrinsic and decisive factor in motor vehicle maintenance. In the winter, my motor goes from -40 to +200 a couple/three times a day.

It's tough to put a mileage factor to water pumps - some exhibit premature pattern failures, some last the life of the vehicle, and some just bite the big green wiener. Water pumps "generally" (note the quote) give plenty of warning when failure is imminent - but we have to heed these warnings.

Water pump failures can include the seal/bearing (allowing coolant to escape through the "weep" hole), impeller failure (loose on shaft), impeller failure (vane erosion due to chemical reaction), among many others.

While we're on cooling systems.... specific gravity (antifreeze content) of the coolant will have an effect on coolant temp sensors. Antifreeze not only modifies the freezing point of your coolant, it also modifies the "boiling" point, corrosion properites and flow (viscosity) all without changing the Ph properties of your initial water content...... which may or may not be chock full of calcium, potassium and/or other minerals/chemicals (some of which will be added by your local water authority - they like calcium and such to plug the pinholes in old, leaky water mains).Calcium, et al, will also seal off those pesky leaks in our cooling system....like the ones between our header tanks and the rad core....

 

[Bill Kemp]

Prestone SuperFlush and Prestone green anti-freez every two years. I've used it for ten + yrs. in all veh. and have had no problems or failures.
If I buy a veh. over 5 or 6 yrs. old and the anti-freez looks bad I'll take it to the mechanic and have them do a power flush.
Other than that just follow the directions on the the Super Flush container.