ATF to the rescue!!

So I had all but given up any hope of resurrecting my collapsing lifters when I talked to my dad and he recommended that I try everything possible in the crankcase to see what would happen. I had considered just replacing the lifters, but a combination of low oil pressure and neglect by the previous owner had me concerned that there was some serious wear on the bearings not allowing enough oil pressure to build to the top end, and that I'd just be stuck with the same clattering sound after repair. Basically I was convinced the engine wasn't worth repairing so I was set on buying a rebuilt for around $1500.

Now, I had tried many many solvents and had even done a 5 minute flush with ATF in the oil before draining to no avail. On my dad's recommendation, I added a quart of ATF and drove it hard for the last few days. His reasoning was that since I was already set on replacing the engine, even if I wiped the bearings by putting it under load with the ATF in there I'd at least only be out the cost of a bottle of ATF, not the end of the world if it tanks since I was so set on replacing it anyways.

Anyhow, I drained a quart of oil and substitued the quart of ATF and took it for a drive. At first, I was alarmed because the noise returned far worse than ever before and I was actually worried I wouldn't make it home without seeing a pushrod burst through the hood. Out of frustration I took it up to redline a few times on the way home to see what would happen and voila, the noise has been diminishing for the last few days. Every day I now drive it get's quieter and quieter, and today was actually the first time I havn't heard the familiar "tack-tack-tack" of the failing lifters throughout a 60 mile drive. What was even more amazing is that my oil pressure rose around 10PSI across the board, and now sits very comfortably at the higher-end of the factory specs. Before, I was always within spec but after driving for a while it would slowly begin to drop off until it was barely within allowable specs.

My theory is that the lifters themselves were not actually plugged up, but instead the oil passage galleries were clogged and not allowing proper oil flow/constant pressure to the top end. The oil "flushes" I had done were either not severe enough or not left long enough to do the job. Now, I'm not planning on leaving the ATF in there much longer, in fact I just bought a change of oil and new filter, but the bottom line is that the 5 minute idle in the driveway with ATF that so many people recommend just wasn't enough for my case.

Will the noise come back? Who knows, but for now I'm a happy camper. I'm leaving to go travelling in a few days and the prospect of having an extra $1500 to spend on strippers and booze in Mexico is very appealing...

[assume Borat voice] VERY NICE!!

I had a similar issue with an old Scout years ago. I tried a proprietary engine flush without improvement. The, rather than ATF, I went out and bought the cheapest and thinnest available high detergent oil (I think it was straight weight SAE 10, back before 5W-x was common) and a cheap filter, ran it hard for about a hundred miles, then drained it hot. The stuff came out black. Then I put a premium filter and the right oil in. The lifters quieted down and stayed that way for 13 years.

I had a noisy metro that I drained the oil filled with diesel let it idle for 30 min drained it put a new filter and oil 5-30 and in my short 5 mile drive the tick tic tick went away and never did come back

Like number 2, I ran ATF hard for 100 miles in my Neon a couple years back. Worked very well...

Liquid wrench in the oil fixed my '71 429 Mercury with very nasty lifter clatter. Completely fixed it.