ATF in Crankcase

[Al Powell]

On 11/20 Taka asked:

Is it safe to pour some ATF into the crankcase, run it
for about 100 miles and dump the oil and filter? I've
heard here and elsewhere that ATF, due to its high
detergent action, is good for cleaning out gunk in your
engine.

The answer - you're right that ATF is highly detergent and will clean things
out.  However, remember that it also thins the engine oil because ATF is very
low viscosity.  If you add ATF and drive it, go easy on the throttle and
don't beat it hard, as your oil viscosity will be changed.  This used to be a
pretty standard "old mechanics" trick to keep hydraulic lifters clean, and
I've used it a number of times.

This was mostly before 1977, when I switched to using only synthetic oil.
  This eliminates the problem of having ANY gunk anywhere in the engine, as
the synthetics are very high detergent, indeed.  This also does away with
noisy lifters - if they are willing to be silenced at all.

Given today's' technology, my suggestion if you want to do some engine
cleaning would be to pick up a can of Gunk or Amsoil "Engine Cleaner" (the
Gunk brand is available in most auto parts stores) and use it according to
label directions just before an oil change.  If you think you still have
deposits, repeat at the next oil change.  I've used these cleaners in a
number of cars before converting them to synthetic and never had any problems
afterwards.

************************************
Al Powell
Fort Collins, CO
powellae at home.com
cougfan1 at gocougs.wsu.edu
************************************