Green Prestone Coolant

[Mike Cobine]

Since there were some comments about the green Prestone disappearing and the new stuff not being so good in old systems, I ran across a bunch in the K-Mart in Port St. Lucie on St. Lucie West Blvd.

All old stuff, dated 2003.

[Duke W.]

Re: Green Prestone Coolant

The old green coolant is considered to have a useable shelf life of about two years due to silicate drop out.

This stuff is really obsolete both in terms of shelf life and technology. I would not use it if you gave it to me.

The industry consensus is that a modern hybrid blend such as Zerex G-05 is the best substitute for cars that spent most of their lives with the green stuff. It will provide equivalent or better corrosion protection, but will not leave deposits that eventually clog up the radiator and heater core tubes.

Visit the Valvoline web site and download the articles on the Zerex G-05 web page.

Duke

[Terry F.]

Off the subject

Duke,
I have read a little about front end alignment. It sounds as though a person would start out by adjusting the camber 1st, then adjusting the caster. Will caster adjustment effect camber? Is toe in measured at the outer edge of the wheel or the outer edge of the tire?

My understanding of caster adjustment is that you turn the front wheels 20 degrees and then measure the wheel angle/caster angle. I assume that if you turn the wheel to the passenger side 20 degrees, you would measure the angle on the drivers side tire or does it matter which tire. Would you reverse the process for the passenger side?

Thanks, Terry

[Bernard M.]

Re: Green Prestone Coolant

I had a hard time finding Zerex G05 at any of the local stores. I tried Wal-Mart, Advance Auto Parts, Auto Zone, Car Quest and on and on and on. Everyone had the highly advertised Prestone but no Zerex. It finally dawned on me that Zerex was a Valvoline trade name so I stopped a local Valvoline Instant Oil Change and was promptly and politely handed a couple of gallons of G05 for about $8 each.

[Duke W.]

Re: Off the subject

On most cars there is some interaction between camber and caster adjustments. On C2/3 Corvettes, the best way is to shim for camber while keeping the caster in the ball park. Start by measuring both camber and caster to see where you need to go to get to your objective. Camber is changed by adding or subtracting shims to both studs. Adding shims changes camber in the negative direction since it moves the upper ball joint inboard. Caster is affected by adding/subtracting shims to just one stud, which moves the upper ball joint forward or backward, and moving it backward increases caster. Once camber is about right you can fine tune caster by removing a shim from one stud and placing it on the other, which will change the caster with little effect on camber.

Your understanding of measuring caster is basically correct. Caster can be estimated by the arithmetic difference between camber readings with the wheels turned. I just turn them to the limit of steering travel. The important issue is to get the side to side difference as close to zero as possible.

For cars that have near zero caster, getting the sign correct can be tricky, but should not be a problem on C2/3 Corvettes since their nominal caster specs are in the range of 1.5 to 2 degrees.

As an example say you are measuring left side caster and the camber is zero degrees. You turn the wheel full left and the camber is plus one, and minus one with the wheel turned to the RH stop.

Caster = 1 - (-1) = 2 degrees.

The RH side caster measurements and computation is a mirror image.

Another way to look at this is that positive caster creates negative camber gain on the outside wheel. Zero camber results in no gain and negative caster yields negative gain. The negative camber gain created by positive caster is good since it tends to offset body roll to keep the tire more vertical relative to the pavement.

Once camber and caster are set, set the toe. With the steering wheel centered, I adjust the tie rod sleeves until each tire has just a hint of toe-in by eyeballing down the edge of the tires from the front of the car. Then I measure and adjust the sleeves equally to 1/16" total-toe in. This usually results in the steering wheel being nearly straight on a level straight road, but I sometimes have to tweak one or both tie rods once or twice to get it dead straight with about 1-2 32nds total toe-in before I'm satisfied.

If the tire has a center groove, use this to measure toe. If it has four grooves pick either the second from the inside, or second from the outside, on both sides. If the groove is a zig zag, measure from the outside apex. On the back side of the tire mark these references with a tire crayon as high as possible without a straight line between them (your tape measure) interfering with chassis components. Measure the distance, then roll the car forward to the limit of where a straight line will not interfere with the chassis and take the measurement between the same reference marks. You want this measurement to be about 1/16" less than the first measurement.

Once set up, the car should hold alignment well if the suspension is in good shape and you don't bang any curbs.

Duke

[Duke W.]

Re: Green Prestone Coolant

It seems to vary with the part of the country you're in. In So. Cal. Pep Boys and Autozone carry Zerex G-05.

You got a good price. I think the local Autozone and Pep Boys charge about $9.95.

Duke

[Terry F.]

Re: Off the subject

Thanks for taking the time to respond. I greatly appreciate it. Thanks, Terry