The following is a thread excerpt found on Bob is the Oil Guy online forum.
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Posted July 12, 2005

I have a 1991 Subaru XT6 with the 2.7-liter flat 6 and ~100,000 miles on it. I ran a compression check the other day (see thread in Maint. tips forum) and found 1 low hole and 1 at the factory minimum. From talking with folks on XT6.net, I think the most likely suspect is a stuck hydraulic lash adjuster on the low-compression cylinder. Stuck fully extended, that is. So, I put in the bottle of ARX that I had intended as a maintenance routine. We'll see what happens. I didn't take any pictures, but here are the compression numbers:

#1 155 psi
#2 125 psi
#3 90  psi
#4 160 psi
#5 140 psi
#6 155 psi

The oil in the car is a mix of John Deere TorqGard Plus 50 15W40 and the evil empire's SuperTech 10W30. I just finished a Neutra treatment on this car a couple hundred miles ago. I did not change the filter on account of it being new.

Wish me luck!

Posted January 16, 2006

**UPDATE** WITH NEW COMPRESSION NUMBERS

Thought I'd update this thread since I've finished my Auto-RX clean/rinse cycle. I started this just barely over 100,000 miles, so going strictly by the label, I'm supposed to put another bottle in and do another clean/rinse cycle. At this point I haven't decided whether I'm going to or not because CHECK THESE RESTORED COMPRESSION NUMBERS OUT:

#1: 156 psi   (~the same)
#2: 153 psi     (up 28 psi)
#3: 146 psi     (up 56 psi)
#4: 159 psi   (~the same)
#5: 135 psi (down 5 psi??)
#6: 165 psi      (up 10 psi)

You can see that the two cylinders that were borderline and outright low are now right up with all the rest and right where they're supposed to be. I'm so happy! I can't explain the 5 psi decrease on #5. Perhaps following the directions and doing a second bottle would bring it back; I can't say. I have no idea whether this was a ring cleaning or something to do with the lifters. I have never had lifter noise on this car apart from on the occasional single-digit cold start on straight 15W40 oil. Also, looking in the oil filler cap where there used to be a nice varnish color (not sludge of any kind, just a nice varnish color), it is now sparkly-clean white metal.

Auto-RX has worked really well for me in this application (in contrast to almost every other junk of whatever kind I've put in an engine, including various 'restore'-type products) so I thought I'd share.

Posts authored by bulwnkl.