antifreeze type and concentration

[Drake57]

While changing my fuel rail, I found one of the water outlet castings had a hole eaten through it in the clamping area. These parts are no longer available new, I had part glass beaded, then repaired it w JB weld.

The corrosion makes me believe that a coolant drain and replacement is in order. Question is: what type of coolant is good or best, and what if any dilution to use? Conventional wisdom is a major brand name, mixed at 50% coolant 50% water, but I also know that Q45s are not conventional in all respects, so please let me know what is recommended.

Thanks!

[Wiggler]

I think everything up to '01 FGY-33 should be ok with the universal green stuff. I used just the Wal-mart brand in my '99 and seems to be ok...someone else might have a different opinion... but the most important thing I can tell you is ALWAYS, ALWAYS, ALWAYS dilute with DISTILLED water only...unless you want to fix more corrosion problems never use tap water. Especially stuff treated from the Edwards Aquifer... Austin tapwater is bad... San Antonio is just as bad..

[Drake57]

Thank you, that is helpful. It must be that the plentiful dissolved minerals in ground water around here must neutralize the corrosion inhibitors in the coolant.

For a certainty, in years past I've used tap water for dilution, now I'd like to remove as much as possible, and start over.

The procedure from the FSM for draining the coolant specifies a repetitive process where engine is warmed up, diagnostic mode is used to open heater core, block and radiator are drained of coolant, then refilled w water, repeated until drained fluid is clear.

That said, sounds as I need many gallons of distilled water, for drain procedure, and refill

[maxnix]

Zerex in the Gold case is OAT. in Texas, one can run 35/65 distilled water/coolant. Use a bottle of water wetter also. New OEM cap is nice.

[Wiggler]

If you can get your hands on it.... De-ionized water is even better than distilled water. Although some might say it's overkill, given the abundance of distilled water at most grocery shops.

[maxnix]

De-ionized water is even better than distilled water.

No, deionized just means it is Ph7 despite having contaminants.

Distilled water is just water, nothing else.

[Wiggler]

No, deionized just means it is Ph7 despite having contaminants.

Distilled water is just water, nothing else.

Actually Maxwinch, deionized and distilled water are BOTH stripped of all minerals and contaminants. The only difference are the methods used to get the end result.