Coolant Hydrometers

[doitmyself]

After this post by Mori:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1188553#Post1188553

I thought it might be fun to start a discussion on the topic of coolant testing. Why? During a recent coolant change, my gypo Prestone hydrometer showed mixed readings. I mixed some new G05 at 50/50 (in a jar)and the tester read -50F. I tried conventional new Zerex at 50/50 and got about -25F. HMMMMMMM!.

This article says hydrometers can be way off without careful calibration. He recommends a refractometer:

http://www.asashop.org/autoinc/feb2001/mech.htm


Comments or discussion????

 

[tom slick]

I agree completely with a refractometer being more accurate. the problem is refractometers can be expensive for just occasional use. they are very easy to use though.
as you noticed the specific gravity of the two coolants were different by their formulation. that hydrometer was calibrated for conventional coolant so it has no relevance when measuring GO5 other then just for reference. the "protection level" certainly doesn't apply.

 

[pickled]

Just don't buy your refractometer from the Snap on or mac guys and you'll do fine. I've seem them go for as low as $9 on Ebay...you just have to hunt a little. I love mine and I will never go back to turkey baster and balls again (LOL).

 

[benjamming]

Good topic start doitmyself.

Does anyone have a refractometer mfg & model that they would recommend?

 

[tom slick]

The ones I've used were generic and came from a machinist's supply. i.e. mcmaster-carr, grainger, J&L type places.

I'd just buy one on Ebay or from Amazon if I were looking to buy one. you have to make sure it measures the correct range for coolant. They are usually listed for coolant and battery acid.

 

[doitmyself]

Benjamming,

I did some internet Detective work and came up with some manufacturer info about 5 companies.

Reichert (formerly Leica) http://www.reichertai.com/products.html?productID=29
U.S. made?/German ties?, GM OEM, seems to be a "standard of the industry" imo , ASTM 1deg. accuracy,ATC (Auto Temp Compensate) Water proof/resistant, Simple, clean design (equals bullet proof, IMO) $125 List

MISCO http://www.misco.com/ U.S. made, illuminated, ATC, water proof, seems very high quality. $149 List

VEE GEE http://veegee.thomasnet.com/item/coolant.../43064?&seo=110
Washington Co. (Pablo), import product. Unique features and apparent high quality. $97 retail

ATAGO Non ATC except in more $ new models $150+/- retail

Asian Generic models: Extech, Viper, Robinair, ATD... http://www.extech.com/instrument/products/alpha/RF40Refract.html

Many models look like this. The cheaper (less than $50+/-)ones "seem" to lack ATC. Extech ($52-$89)is ATC

These are not water proof/resistant....they recommend not getting wet. $10 to $90 retail

SNAP ON ($190) AND MATCO SEEM TO BE IN THIS LINEAGE, BY APPEARANCE????



There are bargains to be found on ebay....it requires some digging with the right words.

FYI......hydrometers have more or less been "banned" as an accurate method of coolant testing by auto related manufacturers.

 

[pickled]

I believe that the reason they have been out of favor is because of the multiple formulas available at retail (EG, PG, OAT...etc). Each one of these offers different freezing and boiling point modifications per dilution level. It's tough for the OEM's to keep up with the evolution of coolant products and fill up 10 more pages of documentation in a manual. Coolant isn't like API oil where there is a minimum spec related to performance and anything that has met it is good to go. Granted there are some ASTM standards out there for coolant, but there isn't a coolant mix chart available that can cover every combination. FWIW the Class 8 manufacturers (Cummins, Caterpillar...etc.) site both coolant analysis and periodic hydrometer readings as valid ways to set up coolant system mixes.

 

[doitmyself]

Originally Posted By: pickled
I believe that the reason they have been out of favor is because of the multiple formulas available at retail (EG, PG, OAT...etc). Each one of these offers different freezing and boiling point modifications per dilution level. It's tough for the OEM's to keep up with the evolution of coolant products and fill up 10 more pages of documentation in a manual. Coolant isn't like API oil where there is a minimum spec related to performance and anything that has met it is good to go. Granted there are some ASTM standards out there for coolant, but there isn't a coolant mix chart available that can cover every combination. FWIW the Class 8 manufacturers (Cummins, Caterpillar...etc.) site both coolant analysis and periodic hydrometer readings as valid ways to set up coolant system mixes.



I agree that different chemistries might make the hydrometer less accurate. Although, OAT, HOAT, and IAT are all ethylene glycol based.

Temperature differences also are cited as causing huge errors with hydrometers.

The refractometers ability to measure both PG and EG with temp. compensation is their shining feature(s).

I disagree with your comment that Cat and Cummins/Fleetgaurd recommend hydrometer use.

This Cummins service bulletin favors and only mentions refractometers:

http://www.cummins.dk/fileadmin/dokument...Maintenance.htm

"Test the coolant twice a year for freeze protection and additive levels. Refractometer measurements provide the most accurate freeze protection measurements. Test strips, although less accurate than a refractometer, will also provide an indication of freeze protection and additive levels. See Section 6 - Coolant Testing for further information and test strip part numbers.

This CAT reference also recommends refractometers:

http://www.cat.com/cda/files/87058/7/elcfaq.pdf

"Test the freeze point with a glycol refractometer"


I have other references about hydrometer use, but don't have time to find them. I remember one saying that their use should be dropped because they are too inaccurate and do not meet ASTM standards.

Here it is: http://www.fluidinfogroup.com/technical/shop.htm

 

[pickled]

I agree if you don't have ATC you're going to shoot a poor group with a refractometer. From the provided link (it's a nice read) it stated that the hydrometer should be avoided and the refrac should be favored...

"Hydrometers sold for antifreeze testing have been reviewed by ASTM, and the performance thereof was so poor that ASTM has withdrawn the hydrometer test method from the books. In its place, a method employing a refractometer has been established. This is a good method, and definitely the method of choice check the coolant freeze point."

All and all a great post...I can't understate the importance of periodic analytical testing of coolant in high use systems though. It's inexpensive and can help you spot cylinder liner issues, microdieseling, contamination and a whole host of other problems.

 

[doitmyself]

An addendum to my manufacturer info above, per conversation with Reichert Company (not that anyone cares):

Reichert is the "manufacturer" of their glycol refractometer and also the similar looking MISCO one. I thought they looked too much alike, but from the web sites, I thought MISCO was the manufacturer.

Neither is made in the U.S. anymore....... farmed out to India, but supposed to be the exact same quality. Sigh.

 

[benjamming]

So, there's not a single one mfg in the USA with ATC? Bummer.

 

[pickled]

Sometimes the global economy just sucks that way. If you can find a good old used one made in the USA it's probably the better bet.

 

[D-Roc]

If you know a plumber, they might have one. I borrowed one from a plumber here at work, to check mine after the change. Doesn't really need to be anymore than one or two checks a year if there are no chagnes made to the cooling system.