Decoking, the Click and Clack Method?

[Dave@Moon]

In this Sunday's newspaper, Tom and Ray Magliozzi's collumn had a method for removing carbon deposits for the combustion chamber by pouring 8 oz. of water down the carburator at 1500-2000 rpm over about a 30 second interval (obviously being careful not to stall or hydraulically lock the motor). My nailhead has a habit of carbon fouling spark plugs over about 1000-1500 miles, probably due to valve seals (the motor has excellant compression, and there is no noticable blue or black color to the exhaust).<P>Has anybody tried this as a short term fix? Does it work?

[NTX5467]

I remember the recipe of a 50-50 mix of water and atf poured through the carb at the rpm range mentioned. Was supposed to do the same thing and smoked things up pretty good.<P>GM Accessories and other additive manufacturers (i.e., Shaler Rislone) had pour through additives. With some, you killed the motor at the end of the can amd let the vehicle sit overnight. The softened deposite were supposed to burn out when it was run the next time.<P>Some people used to put a gallon of diesel in their tank when they filled up to leave on a trip. Supposed to do the same thing.<P>It always seems like that after a long, sustained interstate highwy trip of about 200-300 miles, the vehicles run better just from the sustained combustion heat and moderate load. Just my observation with several vehicles<P>Almost any modern fuel cleaner additive (if they say they clean the combustion chamber) will now do the same thing with less fuss. It might take two treatments, though, and then you might want a fresh oil change.<P>Just for good measure, you might make sure the air filter is not dirty and the choke is at its leanest setting and is not sluggish in operation.<P>There are probably as many shade tree fixes for this situation as there are cars.<P>Enjoy!

[Don Caithness]

I've used the water method to "steam clean" the combustion chamber over the years. Be careful to pour the water very slowly. If badly carboned up you will hear the chunks as they exit the tailpipes. Works better than any cleaners on the market!<P>------------------<BR>Don Caithness<BR>Technical Advisor<BR>1967&1974 "A" Body<P><BR>

[Guest]

the water method ive read about. they used a vacuum line long enough to reach the interior of the car, a bottle with a hole in the cap to put the vacuum line into the water, a passenger to pinch off the vacuum line and yourself to drive the car down the highway. the hose gets teed-off of an existing vacuum line make sure its not ported-vacuum but manifold vac. as you drive the passenger periodically will let the engine take a little sip of water as your driving and you watch the black crap come shooting out the tail pipe. This is basically the description given out of an automotive repair shop "trade type magazine"

[Guest]

Could this be 'safely' used on an engine thats never had anything done to it? 1971<P>Only thing I've ever tried was a bottle of some kinda carb cleaner or somethin..<P>TIA<BR>

[Don Caithness]

I wouldn't recommend having the engine under a heavy load while doing this. Too much water will hydralic a cylinder and crack a piston at the very least. Pour the water very slowly from a bottle using your thumb to regulate the volume directly into the carburetor. If you've ever had a head gasket leak into a cylinder you know how clean the piston and cylinder head appear. Water will give the same results but again, CAUTION must be used!<P>------------------<BR>Don Caithness<BR>Technical Advisor<BR>1967&1974 "A" Body<P><BR>

[GSMAG]

My buddy did this to his most excellent '64 T-Bird convertible. His car is so smooth running it's incredible. He tried this after reeading the Click and Clack column and said all sorts of crap came out of the exhaust. He used a 409 bottle and sprayed a constant stream in. Seems like a pretty conservative way to inject the water. Now I have to try it on my cars!<P>Mike

[BUICK3001964]

I've used the spray bottle method and had good results,1500 - 2000 rpm agood spray occasionaly crack the throttle.<P>------------------<BR>Sean Etson

[GSMAG]

OK Guys, tried it on my '69 Sportwagon with 215,000 original unopened (except timing chain) miles. The car kinda chugs, so I knew something was weak. A compression test revealed 6 and 5 at 120 PSI while all others were about 150 PSI. Since 6 and 5 are right together in firing order, this amplified the problem. Tried the water thing and the car idled noticably smoother, not perfect, but a lot smoother. Did a quick compression test on number 5 and it was up to 140 PSI! Must've been carbon on the valves. It sure worked for me.<P>Mike

[Sled]

Hi Guys<P> I have to agree with others posting here, BE CAREFUL about putting water down the throat of the carb, water wont compress so something will give! But I used this method 15 years ago on my 62 electra and it did work, I raised the idle to about 1000 rpm, then dribbled some water in the carb, repeating slowly. If you watch the tail pipe and rev the car you can see black come out of it! I have to do this on my 65 Electra convert, it has a bit of carbon in there Im sure. Good luck all!<P>Jim