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Chuck Rine (Chuck348ts)
| | Posted on Monday, January 28, 2002 - 9:55 am: | |
Nev,
Check out this link (excerpt below)
http://www.babcox.com/editorial/us/us109624.htm
Looks like performance is the same between PG nd EG, but they should not be mixed for the reasons indicated.
The "Other" Antifreeze
Another type of antifreeze that's appeared in recent years is one containing propylene glycol (PG) rather than ethylene glycol (EG). Safe Brands/Arco Chemical markets a PG-based antifreeze under the "Sierra" brand name and Prestone under the "Low Tox" name as a safer, less toxic coolant. PG-based antifreeze is not safe to drink, but is significantly less toxic than EG. It also has an unpleasant taste, which reduces the risk of accidental poisoning of pets and small children.
In terms of freezing and boiling protection, PG performs about the same as EG. PG provides freezing protection down to minus 26 degrees in a 50/50 mixture, and boilover protection to 257 degrees (these are a few degrees less on both counts than EG, but can be offset by simply increasing the percentage of PG in the coolant). A 60/40 mixture of PG and water will protect down to minus 54 degrees F.
Though some auto makers initially said they did not approve of using PG antifreeze in their vehicles, GM said it does approve PG as an acceptable replacement coolant.
If you're adding PG to a customer's vehicle, you must first remove all ethylene glycol from the cooling system by flushing or completely draining all the old coolant. PG should not be mixed with EG because the freezing and boiling points are different, making it impossible to determine accurately how much freezing/boiling protection is in the coolant. An ordinary antifreeze tester cannot measure the concentration of PG in the coolant, so you need a second hydrometer, test strip or refractometer that's specially calibrated to read PG. |
Neville Pugh (Nev_Pugh)
| | Posted on Saturday, January 26, 2002 - 11:37 am: | |
Can you mix Mono propylene Glycol and normal Ethelene Glycol antifreezes ? |
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