RE: Replacing coolant...

[Z51JEFF]

Originally Posted by tomtom72

Jeff, what kind of corrosion? Flakes & scale...kind of white to ashen looking stuff? Most of the time that is the results of "galvanic Action" = two or more dis-similar metals in water. The condition makes a battery. The current causes the salts in the coolant to percipitate out of soloution, scale. You can look up "Electrolytic Corrosion" also, same thing. Make sure all the grounds on the motor are clean, tight & have liberal di-electric grease coatings....I might add that all the connectors in the harness could use the same grease.

Using steam distilled water in the cooling system will mitigate the galvanic action, no salts like tap water. Flushing using plain tap water repeatedly and then drain and then use distilled for a few flushes after the drained tap water comes clear should work for most normally contaminated ZR-1's. Then just fill with 1825-M spec coolant to 50/50 mix & make sure every two yrs at the most you repeat. The FSM says not to use any of the caustic flushes sold at the parts stores. If the flakes are really bad you can take out the T-stat and reassemble the housing so it leaks fairly well. Stick a hose in the upper fill tank and then idle the motor till the run-off comes clear. I doubt that your system is really scalled up as most people heed the warnings in our owner's manual about the two yr interval. The issue is that they use tap water every two yrs and you get the small amount of scale build up. Try just flushing and see what happens.


Tom

Thanks for the info Tom,the corrosion is white powder residue,very minor traces but want to eliminate any future problems.I dont want to completely drain the system and take a chance of getting air in the system so thats why Im draining off the fluid a little at a time and the topping of with the distilled water.Would the distilled water be better that tap water?Thanks again.

[jonszr1]

yes , dot use tap water if you can help it . but its no bigge draining it .just ake your time filling it and pull the hose going to the t body and it will fill 95 percent . then just fill the overflow all the way up .start the car warm it up . ,have the heater on high(90) then shut it off . come back in a couple of hours and you will notice that the overflow tank has gone down a bunch . now you are ready to go. fill the over flow to mark if need be

[tomtom72]

Jeff, the white powder is the minerals in most tap water. If you heat a pot on the stove & it boils off all the water you usually have a white powder, the disolved minerals that are common in tap water...well water can be worse!

Have no fear to drain & refill an LT5....it's a snap and no burping like the L98/1/4's. Just empty the system using the pet **** on the rad. refill w/tap water to full and run car till T-stat opens, idle a bit after opening of stst and shut down and drain at ****. Repeat till run off comes clear. Drain and use steam distilled H2O + coolant and fill upper tank tillfull. Start motor w/tank open and continue to fill to bottom of neck, cap it and pour rest into overflow to the hot mark. Run till stat opens(upper hose hot), turn heater on, check overflow & add if needed. Shut down and come back when cooled off and check level in top tank and at overflow, add as needed. No burping, we are self-burping.


Tom

Oh, you will eventually get all the powder out if you are religious about coolant dumps every two yrs....Do Not use any flush chemicals!