PH of Coolant

According to the material safety data sheet for a 50/50 mix of Dexcool and water:

-------------------------------------------------------------------------------- SECTION 9 PHYSICAL AND CHEMICAL PROPERTIES

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Appearance & Odor: Orange liquid Substance Chemical Family: Ethylene Glycols Appearance: Orange liquid

Boiling Point: 226 ºF

Flash Point: 260 ºF [Pensky-Martens Closed Cup]

Freezing Point: -34 ºF

Odor: Mild odor

pH: 8 - 8.6

Specific Gravity: 1.06 - 1.09

NOTE: The freezing and boiling point values reflect a 50% solution in water at atmospheric pressure.

So, it appears that the spec is from 8 to 8.6

I was about ready to post 8.3 myself. :) I was in the middle of reading=20 an interesting editorial I found in a Google search. I never thought to=20 check the pH in a msds.

does the ph change over time or would the ph have been high from the beginning?

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When doing a flush and fill, it is common to use a "radiator flush" solution. The normal process is as follows:

1. Drain radiator and block of old coolant .
2. Refill radiator with clean water and run engine for 5 minutes to circulate.
3. Let cool. Reflush radiator to get more of the remaining coolant.
4. Refill with clean water and add radiator flush.
5. Run engine 5-10 minutes after reaching normal operating temp and with heater on full hot.
6. Repeat steps 1 through 5, but without adding flush.
7. Backflush system with clean water.
8. Refill system using appropriate amount of antifreeze per desired mix and system capacity.
9. Crush and add sealant pellets from GM/Saturn dealer if specified for your vehicle.

I'm speculating here, but it sounds to me like someone used the flush, but then got lazy and failed to get it all out of the system before adding coolant. If the flush solution was very caustic (basic) and started with a high PH then this could account for the high PH in the current mix.

If it was me, I'd do the job over again to make sure it was done right and to assure you don't cause long term damage to the radiator, and block. This is especially true if any of the system is Aluminum.

Good luck!

Bob

Forgot to add that some of the most aggressive chemical flushes actually require use of a neutralizer after use... Another possibility here is that they did not use it or used it incorrectly. In any event the solution is the same. Do the job over to make sure it is done right.

Bob