ATF to cure noisy valve lifter?

Since I acquired my 1947 Packard Super Clipper with the 356 CID engine 2 years ago it has a loud tapping sound once the oil gets hot.. I am assuming it is a stuck valve lifter as it is coming from the area of the valves. I tried using a stethoscope with inconclusive result so I am open to other suggestions. The car has been driven probably less than 50 miles per year for at least the past 30 years. I removed the oil pan and cleaned out the sludge and ran some engine flush in two oil changes. the engine valve gallery is very clean now but the one lifter persists in clattering ( unbecoming of a Packard IMHO). A couple of people have suggested putting a quart of ATF in with the oil as a possible cure assuming of course it is a sticking lifter which is the problem. I know this is an old mechanics trick but have never tried it myself but was wondering what the members of the forum think?

[Jim Bollman]

I have never tried ATF, but have had good success on several engines with Marvel Mystery oil. Use it in the crankcase for lifters and in the gas for valves.

Thanks Jim, Marvel isn't available in Canada at least where I live but there are other things like CD2 and Rislone but maybe ATF is just as good?

[critterpainter]

I bought an 87 ford pu that the prior owner had NEVER changed the oil on. I removed the oil filter and cranked the engine to drain it as it would NOT pass through the drain hole. refilled it with 4 qts ATF and 1 qt oil. ran the engine for one hour. drained and refilled with 4 qts oil and 1 qt ATF. changed oil after 100 miles.
After that it got oil changes every 3K miles. 50K miles later I had to pull the pan to replace a leaky gasket. the pan was SPOTLESS.
ATF is very high detergent and will clean sludge

Bill

[Ron Green]

I have used a quart of ATF to quiet lifters several times with success. I remove a quart of engine oil and replace it with a quart of ATF. Run the engine a couple of hundred miles and then change the oil and filter with no ATF. I have found it seems to work better if you run the vehicle on longer trips rather then shorter ones when the ATF is in.

[De Soto Frank]

If you've already cleaned the sludge out of the sump, I would try the ATF, up to two quarts (my MoToR's says the 356 has a 7 qt crankcase), and drive it a bit - some nice long drives in the country...

I don't think the ATF will do any harm...

The biggest fear of running high detergent stuff in old engines is that the detergents "will suddenly break-up all the gunk at once, which will then block-up oil passages, etc...."

You've already removed most of the crud, so the ATF is certainly worth a try...

Good luck!

[Mrbuick714]

Alemite CD2

[Coley]

I have always been intrigued by the notion that ATF is high detergent. Just what is the detergent for in an automatic trans? There is no combustion to form acids, dirt etc.....just wondering....