Auto-RX?

Some of you may have read my thread on some new, disconcerting noises from my engine that began suddenly around 198,000 miles.

Nobody listening seems to think it's bottom end, and I did check valve clearances and found them all to be on the tight side (ten within tolerance on the tight side, and six just-out-of-tolerance tight).

I also saw what looked like less oil on the #4 exhaust cam lobes and I'm wondering if there could be some kind of oil delivery issue. (#4 exhaust was also an area that had stuck out to the stethoscope before I took the cover off).

There's a dark brown varnish pretty much everywhere on the top deck (photo in other thread), pretty much as a thin coat that doesn't rub off easily, but I saw a few flat flakes coming off here and there, and wonder if that stuff might occlude an oil passage.

I've picked up a product called Auto-RX that I've never used before. From reading its patent I think there at least might be something to it (an ester of a fatty acid that's claimed to dissolve varnish and sludge without the other effects of more conventional solvents).

I think I might give it a try. If it improves anything, great; if it doesn't, oh well; if it trashes my engine, well, the noise already had me thinking of replacement anyway. Also, I've got before-pictures of the varnishing (and before- cylinder leakage measurements) so if the stuff has any effect on either of those I should be able to document it.

Has anybody else had experience with this stuff? Worth trying? Am I wasting my time?

Thanks,
-Chap

 

On the recommendation of the Auto-RX people (whom I invited to read and follow this thread), I put 24 ounces of the stuff in with a fresh oil change on Saturday at 200037.

On the web I had found postings by other users of the stuff, one of whom said it was so dark that it made the fresh oil change look black immediately. That wasn't my experience - poured out of the bottle, it's a dark red-brown and somewhat cloudy, with an odor incongruously like blueberries, for whatever arcane chemical reason. Mixed in with the three+ quarts of new oil, it does not look any darker than usual on the dipstick. And yes, you can notice the odor on the dipstick.

Now to put some miles on and see what, if anything, the stuff will do.

Right off the bat, I'm noticing my noise seem louder, but then the temperature has gone cold again, from 67 F on Saturday when I changed the oil, to 17 F today, and cold is always when the noise is loudest.

-Chap

 

Finished one 3,000 mile (and a little bit more) oil change interval and drained the stuff out, replacing it with straight Castrol GTX 5w-30 nonsynthetic as recommended for a "rinse". The stuff does seem to do something, as I easily wiped off the dark varnish spot at the tip of my oil drain plug, which I don't remember ever being able to wipe off before.

I have not yet taken an 'after' set of leakdown readings or gone under the valve cover for an after photo of the valve train. (I might end up under there sooner than intended anyway, if it's true that the I need the cover off to get injectors out. Whimper. There are some things I don't like about working on this engine.)

I haven't noticed any significant change in the sounds I was originally concerned with. The weather has warmed, which is going to give me fewer chances to compare. My oil consumption over the oil change interval seemed to have increased last summer/fall, but seems back to what I was used to now.

-Chap

 

I saved a small clean sample in a jar last fall, at my first oil change after I became concerned about the sounds. I haven't sent it anywhere. I have not saved samples from either the change where I put in the additive, or this most recent change where I took it out.

-Chap

 

Sure, I wasn't expecting any miracles, just figured I'd give the stuff a try and see if I could document anything it seemed to improve. Since I had fresh leakdown measurements and a valve-train photo from just before adding the stuff, it seemed like a good opportunity.

Actually nobody I've paid to listen seemed to think the sound is bottom end, so that was why I shifted to looking at valve train. It was when I saw the cams for #4 exhaust looking unusually dry that I started to think there might be an oil flow problem there that a cleaning could possibly fix. But I've yet to get the valve cover back off for an after photo.

Funny you mention the forums at BITOG because I spent a lot of time reading there. There seemed to be a period with favorable reports about Auto-RX, followed by a period of many unfavorable references to it, often embedded in discussions of a competing product. It was hard for an outsider to be sure what was going on, because a lot of the unfavorable comments seemed to suggest that the favorable ones had been made by shills. But then the unfavorable ones themselves seemed to be posted in similar wording from various accounts, leading to one of those situations where from the outside it's hard to guess who's doing what to whom.

I noticed virtually nobody on either side made much effort to offer data (besides "I put X (or Y) in my car and now it's running waay better") so I thought if I could post a couple modest before/after photos or measurements it could be my small contribution to concreteness.

-Chap

 

Umm ... in my case, I guess I'd have to say inconclusive / nothing striking. I noticed (as posted above) that it softened some varnish on the drain plug to the point it could be wiped off when it couldn't before. I did get under the valve cover again a bit later, and did not find much effect there. In that location, the varnish was still present and still not easy to wipe off. The #4 exhaust cams still looked dry-ish, and the valve train can still be noisy.

I know I intended to take another set of leakdown readings after. I see I didn't get around to posting any on this thread, I am not finding notes about them in any of the places I've just thought to look, and this far after the fact, I actually can't remember whether I ever took any or not. Last summer/fall were kind of hectic and some is just a blur. So much for my contribution to science....

Edit: yes I had posted followup readings after all, but forgot where and didn't find it until now. They did look as if they had improved some.

-Chap

 

Yes, but with side effects. Some people running MMO in a Prius have reported being able to find the timing belt.

-Chap