This car had 227000 miles on it when I bought it; previous care history is unknown.
After correcting the camshaft timing, replacing an extremely weak fuel pump and correcting a jury-rigged crankcase vent system, the engine was runnning smoothly but it was sadly lacking power. This is a 172 hp SOHC 12 valve V6 pulling a nearly 2 ton AWD vehicle ('93 Audi 100 quattro Avant) so the perceived low power was not terribly surprising.
Furthermore, I replaced the leaking cam cover gaskets and the valve guide seals, which had become quite hardened. No sludge was found on the cylinder head. The undersides of the cam covers had some accumulation of vapor induced deposits which came off with solvent.
This engine was obviously an oil burner, emitting plenty of blue smoke both at startup and while driving, no doubt affecting performance as well.
At 227710 miles I performed an oil and filter change and added 1 bottle of ARX. I used whatever conventional motor oil I happened to have on hand.
Only 375 miles later it was down a quart at which time I upgraded to the Heavy Oil Burning/Sludge application by adding another 10 oz. of ARX to the 5 qt. sump.
We drove it a total of 3000 miles, changing the filter at around 1000 and again at 2000 miles. Consumption ranged from 400 to 800 miles per quart and blue smoke was still evident, but less than before. Also, several hundred miles into the application, improved power output was very obvious, confirmed by my wife who drives it more than I.
Compression tests were done before and after the first cleaning phase, the results being:
227710 miles:
1) 115 2) 115 3) 110 4) 100 5) 110 6) 100
230950 miles:
1) 170 2) 175 3) 170 4) 150 5) 175 6) 170
Wow! Can you say "tangible results"? (Frank, if I could, I would give you a big hug!)
Specs for this engine (new) are 131 - 203 psi with a difference of no more than 44 psi between cylinders and a wear limit of 109 psi. I wonder how many engines are rebuilt or tossed due to wear when all they need is an easy and inexpensive ARX cleaning!
I don't think the crankcase was terribly sludgy but the rings were obviously very dirty. This engine has most of a rinse cycle to go, plus a second clean/rinse, so my money is on even further improvement.
I cut open the filters but saw nothing except oil soaked media; perhaps debris will be evident during rinse (or perhaps not, I would not be bothered either way). The oil was dark in color but so is any used oil drained from my engines so I cannot accurately comment on that.
Oil consumption didn't improve much, if at all; perhaps that will come later, or perhaps too much metal has worn away for good oil control. However, it no longer smokes. I'm not complaining!
I don't drive this car much so it is taking me a long time to get through the cleaning/rinse cycles.
I dumped the rinse oil 600 miles early, as the oil pan gasket was leaking and I needed to fix it before winter made it's arrival.
I performed another compression test, now at 233,125 miles:
1) 170
2) 180
3) 175
4) 155
5) 205
6) 145
As you can see, cylinders 1 - 4 made only slight additional gains, which did not surprise me. Notice that cylinder 5 made a significant gain while cylinder 6 suffered a significant loss. I wonder what's up with that?
As seen in the photo, the pan had a bit of sludge remaining but clearly, the areas where oil flow was the greatest are free of sludge. I believe that had I not manually removed that remaining sludge since I had the pan off anyway, one more clean/rinse cycle would have removed any remaining gunk.
As always, steady as she goes!
-- Edited by oldgoat on Friday 27th of October 2017 10:13:45 PM
-- Edited by oldgoat on Friday 27th of October 2017 10:16:18 PM
