" In the late 60's I worked part time in a Chevy dealership in a small town. The service manager would occasionally add a small Coke bottle (6.5 oz) worth of ATF to a car's crankcase. This was usually done to try to unstick a hydralic lifter without resorting to surgury. He would then let the car idle for 15 min's then change the oil."
When I was just wee lad
I saw my grandfather do the same thing. Back then the oils were 10W40's, barely Group I's, with weak DD additive packages (compared to today), but had loads of VII's that sheared and sludged. Grandpa always used the ATF as only a flush, since the ATF was expensive back then, relatively speaking. Sperm whale oil was used to supply the ester friction modifiers back then, so this stuff wasn't cheap.
A thinner oil like ATF would mix with the old thick cruddy oil and still provide some lubrication while doing minimal cleaning. The DD package in the ATF added some measure of cleaning additives to the host oil while thinning it. Since the DD package in the circa '60's oils was weak, hydraulic lifters often failed to pump up or got stuck in their bores, so running a thinner fluid through them with a slightly higher level of detergent/dispersant addditves, would clean the lifter so they could pump up and reduce valve lash.
Todays oils are additized and on the thin side of SAE 30 weights, so putting in ATF would bring down the viscosity toward a 10 weight or less, since many ATF's are 0W20 weights.
There are better products for engine cleaning than these ancient shade-tree mechanic cures.
[ September 23, 2003, 12:23 PM: Message edited by: MolaKule ]
