There was a recent posting about a de-carbonizing agent known as “X-66”, made by A.C. Delco. While I agree strongly with Stevebfl about the effectiveness of this stuff, serious attention should be paid to the cautionary statements as well as the directions for its use.

While it is sometimes difficult to find, (at least around here) it should be known that it is available as either a can of liquid or an aerosol spray. The directions for use vary for each, and it should be determined which is going to work best for your particular application.

I can attest that it works extraordinarily well, but is comprised of VERY nasty chemicals which you do not want to contact your skin AT ALL. People using it should be aware that it seems to be able to penetrate through latex gloves, and even the thin nitrile ones. I would strongly suggest using gloves that are intended for use with furniture refinishing products; they are usually made from a very thick nitrile rubber. Also wear a long sleeve shirt. Eye protection is important. If you are using the aerosol type, a respirator isn’t a bad idea either (for those that are truly paranoid).

A note of caution: Unless you really want to piss of your neighbors, check the direction of the wind when you intend to use it. When you run your engine after it’s use, (if your engine is very dirty) it will produce a huge cloud of noxious, dense smoke that the guys at the Pentagon would be envious of .

Boy, have you been there, done that. On the S500 that I thought I bent a rod on, the smoke continued for about two miles as I sneaked around the back streets of the industrial district. I sure didn't want anyone to see me and even though I have five acres in downtown Gainesville I sure couldn't leave it all there.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Hi guys,

I've been reading up on all the posts on MotorVac and X-66, and it does seem like a good measure to take before I bring my car in for an engine overhaul in the not-too-near future.

Does anyone knows where I can get the X-66? I've searched the internet for online stores selling this product, no to no avail. Tried AC Delco's website too, but no luck. Made several phone calls to local chemical companies with no luck too.

And Steve, I've read your instructions pertaining to the use of X-66. So does that mean that it is certainly a DIY job?

Thanks in advance!

Mervyn
1983 W126 (280SEL)

[Edited by Mervyn on 06-28-2001 at 07:57 AM]

Where exactly on a 103 engine (300E) do you introduce the X66 into the system?

Take off the air filter unit and dump it into the fuel injector intake?

Thanks in advance for any advice


~~Paul

Ok, the X66 goes into the main plenum, but where is this? Sorry for the newbie ignorance here.

Is this the hose leading from air filter to the middle of the head unit? (M103 engine)

I really want to try this stuff, but don't want to blow up my engine in the process

Thanks!

~Paul

Would this X-66 stuff be worth it for someone who drives hard, usually long drives, and therefor has hardley any carbon build up? Or would I still benefit from it?

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

I also did some research, and from what I was able to find out, AC-Delco doesn't make this stuff, and it isn't called "X-66". The only product I could find was made by GM, sold only at their dealerships, and is called "Top Engine Cleaner", GM part # 1050002.

If anyone knows otherwise, please correct my findings...

__________________

Scott Longston
Northern California Wine Country...
"Turbos whistle, grapes wine..."

Scott,
Your findings are similar to mine! I thought I was losing my way when somehow AC Delco's website doesnt seem to be carrying any engine cleaners, let alone something called X-66.

And yes, there IS this GM product called "GM Top Engine Cleaner".

So are we talking about the same product here? Gee....this engine cleaner is getting really elusive, must be some kind of "magic" potion.......

Mervyn
1983 W126 (280SEL)
PS. so far still no luck with online stores carrying this item.

Yes, there is a number on the cans that reads X-66. Yes, it is made by A.C. Delco. I am sitting here looking at a can of the aerosol version. Note that there is X-66A, which is the aerosol, and if my memory is right, X-66P is the liquid.

There is also a (part?) number below the “X-66A” which is 12302498. The label also reads: “Carburetor Tune-Up Conditioner” (remember, this is the aerosol can.)

Nowhere does it say anything about GM or “top engine cleaner”. Note however, that I did not source this at a GM dealer. I called A LOT of places and found the liquid was carried by one of the few remaining Gen-U-Wine auto parts stores left. Not a national chain store. The only reason THEY had it was because one of the owners was a long-time GM tech, and he knew about this stuff. They special ordered me some of the aerosol.

Good Hunting!
RTH

Sorry to bother again, but....

Would this X-66 stuff be worth it for someone who drives hard, usually long drives, and therefor has hardley any carbon build up? Or would I still benefit from it?

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

David,

My opinion (for whatever it’s worth) is that if there is very little carbon build up, then don’t bother. There will always be *some* carbon in an engine, but the question should be: Does the amount of carbon in a (that) particular engine affect the it adversely? Others may disagree, but “if it ain’t broke…..”

I should take my own advice sometimes .

Well I picked up a can of this Top Engine Cleaner today, and followed the instructions, except that I let it soak for an hour rather than 15 mins.

Started car up and ran around the neighborhood pissing neighbors off with all the smoke. Pulled into my driveway and popped the hood, and heard a very disturbing sound -- that of metal to metal clanking coming from the valve cover.

Is this sound normal after using this stuff, and will it eventually fade away? I also noticed that I blew about a quart of oil in that plume of smoke. I sure hope I didn't damage my engine.

~Paul

Well I hate to say it, but there IS a reason that I have been warning people that this stuff is nasty, at least from a chemical & personal safety standpoint. Come on people – think about it here; this stuff is removing CARBON! FYI Carbon is a very stable element - It isn’t exactly easy to remove from surfaces via chemical reaction.

X-66 should NOT be thought of in the same light as typical over-the-counter type products. It was never intended for use by anyone other than professionals. You don’t exactly see this stuff marketed like the latest snake-oil ‘miracle in a can’ on late night TV. When the directions state a given time period for this stuff to sit in your engine, FOLLOW THE DIRECTIONS. Or better yet, if anyone is contemplating using it, and you have ANY doubts whatsoever as to what to do or how to do it, the best advice is DON’T use it.

As far as damage to your engine, pmizel, I can’t tell you what has happened. Did you really blow “about a quart of oil in that plume of smoke”? Burning a quart of oil in a quick jaunt around the neighborhood is NOT a good sign. I do know that X-66 should not be left sitting on aluminum for extended periods of time. Some alloys may be O.K., others may not be O.K., but do you really want to push the envelope?

Sorry if I am sounding harsh here, and I truly hope that your engine is OK. People learn from both their experiences & mistakes, as well as those of others. That is where this forum is an invaluable resource. I would just hate being in the shoes of the person that *makes* the mistake, although others will benefit.

Best Of Luck to you
RTH

Pmizell,
Sorry to hear about your engine. I think 1 hour is far too much to let the X-66 soak in it. But what's done is done, I would suggest you do an oil change now. Flush the old oil thoroughly, fill with new synthetic oil, replace filter, and voila, maybe the metal clanking sound will be gone! Just don't drive around too much with that old oil in there, I'm guessing pretty much of your carbon deposits is gone, but the extended soak has perhaps stripped away much of the protective lube coat.

Nevertheless, we all learn from mistakes. Thanks to Runningtoohot also for your advice. Like what you said, to anyone who is contemplating this job, please follow the proper instructions religiously.

Me? Should I count myself lucky that I couldnt get my hands on this nasty stuff?

Mervyn

[QUOTE]Originally posted by pmizell
[B]Ok, the X66 goes into the main plenum, but where is this? Sorry for the newbie ignorance here.

Even if this would be the right place, you need to be VERY careful with how much you allow to be sucked in at a time. I've tried a similar product on my '95 Miata and the Miata technical service bulletin has a reducing oriface to insert into a small hose so that too much isn't added at a time. Too much and your crankshaft bends from "water lock," as the liquid won't compress like air.

Granted the 1.8 liter Miata engine is half the size of my 3.0 1989 300E, but I'd be using locking plyers or soem other mechanism to insure that the can empties VERY slowly.

For what it's worth, Miata says to empty 1/2 the can while revving the engine and then allow the engine to stall at idle, sit for up to 24 hours, and then run the 2d i/2 thru. Worked verey well. Mazda sells the product as a top engine cleaner too for about $2.50.

Just my 2 cents worth.