Coolant testers

[Mark_T]

I'm looking for thoughts/opinions on coolant testing: specific gravity testers vs refractometers, recommended models, the RHA-200ATC in particular, yada, yada...

I have two turkey baster hydrometers, both for ethylene glycol, and they give readings about 20C apart. I'd kinda like to nail it down a little closer than that.

[DenverSteve]

The system is a sealed "lifetime" coolant system. Except for scheduled dealership maintenance, I don't add to or mess with the coolant level. They change my "lifetime" coolant when it needs to be changed.

[Mark_T]

It's only lifetime if you've owned the car from new and know without doubt that nothing but Porsche coolant and distilled water has been put in there and that it has not been compromised with polypropylene glycol, tap water, etc.

That, however, was not my question. I'm talking about checking antifreeze strength to make sure there is no danger of the coolant freezing during winter hibernation. There are a couple of ways to do this and I'm trying to poll the group to see who does what in which way and why. In other words, not interested in anyone's opinion about whether or not it should be tested, only in opinions on the method and equipment used by those who do test it.

[JFP in PA]

Refractometers a nice, and very accurate, but require more care (cleaning and handling) than the $3 “how many balls are floating” testers, which are more than accurate enough. But even the cheapo versions need to flushed out with warm water after use, or they become inaccurate over time………………

Along with freeze point, you should also monitor clarity and pH, which will tell you how well the coolant additives are doing.

[Mark_T]

Thanks JFP - I was hoping you would post something on this.