'Decoke in a can' with head still in place. Fact or fiction?

[Dr. Dub]

I've been reading online about the pros and cons of 'Decoke in a can'. Has anybody on here (the only online source of info that I trust) used a product such as Ecotek powerboost? Does it do anything or is it a waste of money.

Also some folk swear by firing a mist of water into the air intake, thus creating super heated steam in the combustion chamber that loosens carbon build up, or that's the theory at least. Not convinced about that.

I must add that this isn't for the Scirocco. Our 1999 1.0l AER engine Polo 6N is running like crap but I can't complain after 150k+ miles. Done all the usual things to sort it. Funds are tight and it's an old car so a cheap remedy would be good. The low value of the car rules out a major overhaul.

The compressions are down anyway, whether this is poor seating valves due carbon build up I don't know. It's not burning any oil so I'm hoping it's not the piston rings. Maybe worth a shot if the engine is on it's way out anyway?

Opinions please guys?

Obviously any thoughts on the pros/cons of such products will apply to Sciroccos too. All knowledge is money in the bank. Thanks in advance

[Nate]

They do work, bit no where near as well as the mabufacturer would have you believe

[james butler]

When my head gasket was weeping water into chamber number 1 it steam cleaned the internals really well.

[DannyH]

the old trick was to put a small amount of brake fluid into the carb (thimbleful ish) but i believe that's now illegal??

always iffy anyway.

[Nate]

the old trick was to put a small amount of brake fluid into the carb (thimbleful ish) but i believe that's now illegal??

always iffy anyway.

Same idea as using redex. Great fun blowing all the smoke out once you'd put it in :D

[MikeH]

I use a cold water decoke / steam clean on engines that I think need it.

How to do it:

Warm the engine up… get it properly warm so the fan is coming on, and let it idle.

Get a pint (ish) of clean water in a bottle, pull one of the narrow vacuum lines off that goes to the inlet - ideally to the throttle body, not through the bigger breather pipes. The dizzy vac line is good on cars with a vacuum advance dizzy, if it's been routed correctly to the connection on the throttle body.

Put the car on fast idle (about 2000-2500ish RPM) and stick the vacuum line in the bottle so it starts to suck the water up slowly. Make sure you keep the revs up so the engine doesn't stall on the water. Using a small vac pipe minimises the chance of sucking up too much water and hydraulic locking the engine, but as long as you keep the revs up it'll be fine, and if you find the engine struggling, just pull the hose out of the bottle till it picks back up.

Once it's sucked all the water up you should be good to go. If you have the car a foot or two in front of a wall, you should see if there's a load of muck coming out of the exhaust.

It's a lot cheaper than Redex!

[McMad]

MikeH is right about this.

I got this tip from a drag race friend of mine in the States who knew his engines (World Record holder Super Stocks) and he "tuned up" his customers cars by reving them to 5k and pouring a 2 gal. watering can of water straight into the carb! The first time I saw him do this I could not belive it and what was more unbeliveable was what came out the exhaust!

When I told my bother about this a couple of years latter he told me that this was rot (we were both engineers but he has "better" qualifications) and disappeared indoors to find his slide rule. After about an hour latter he came out the house with a full watering can, took the air cleaner off his wifes Fait 127 Special T ( Hi perf twin cam1430cc?), got me to rev it to 6k and poured the contents into the carb. Did not even hick but blew out a ton of gloop out the exhaust. I have since made a lot of money taking bets on this one.

Now if you try this and blow your motor - dont blame me but if you want to put money down to see me blow mine, you are on

John

[McMad]

Just to state the obvious - DO NOT try this on a car fitted with a cat.

In fact putting anything in your petrol becomes debatable on a car so fitted.