[Jaggu]

If the vehicle stalls by any chance and sucks in water, the next crank would mean... an expensive engine overhaul. Water can get sucked in, when the engine stalls (reverse pulse). And engine can stall, especially after a nice wet shower! Catcon cars can fry their cat con with sudden moisture on the hot cat con metal.

Most of the commercial vehicle guys do this to remove the soot, either to avoid the horrible black soot that they leave behind while lugging engine OR thinking this will help them pass the emission test easily. Both are placebo effect.

Easier thing to do is to drive around at higher rpm say 3k RPM for about a minute or so, so that all the loose soot is thrown out, once every week. Cars that do long highway trips typically would have cleaned up the exhaust automatically.

In short definitely not worth it!

[SS-Traveller]

LOL... the TATA Indicas / Indigos, with their unique jugaad servicing methodology. At one time they used to remove the exhaust system completely and do the water flushing separately. Then they figured this out, and no, there's absolutely no harm done unless the engine stalls (pretty unlikely, with the revs held high). The soot needs to be removed before the car goes for a PUC check, else it would never pass the test.

A check will reveal that most of these cars have had their catcons fouled up with soot anyway, and totally ineffective, so what happens when a little water comes in contact with the catcon mesh is quite inconsequential.

[Aroy]

Originally Posted by Jaggu

If the vehicle stalls by any chance and sucks in water, the next crank would mean... an expensive engine overhaul. Water can get sucked in, when the engine stalls (reverse pulse). And engine can stall, especially after a nice wet shower! Catcon cars can fry their cat con with sudden moisture on the hot cat con metal.

In short definitely not worth it!

. It is a recipe for disaster as the water can get into the engine in case of a restart after a stall, and then you are in for an expensive engine job. That is the reason why you always keep the engine at a very high revolution while crossing deep water. As long as the exhaust pressure is there you are safe, but if it is lost the water can be sucked back.

http://www.smartdriving.co.uk/Drivin...ies/Floods.htm

[dass]

Mine is a 2006 Indica DLG Turbo and it does have a cat convertor. This procedure was done couple of times when I had given the car for washing, but it dint seem to have any impact, except for the soot coming out. Did it make the car any smoother? I dont think so. But I dont see this procedure being done of late in any of the washin centres.

[swiftdiesel]

The damage done by inadvertent revving of engine is greater than the damage created by soot. For starters, diesels aren't rev happy engines like petrol and it puts a lot of metallurgical stress on the piston and other engine components. Getting water sucked into the tail pipe due to flood is one thing and unavoidable but deliberately shooting water into the exhaust is another! Just because it happens during at an unavoidable flood crossing doesn't mean it's a good practice!

I've never revved my earlier Swift and my current Ertiga at idle! Some would argue that soot builds up and we need to redline it once a while - no, I don't subscribe to that theory! Once a while I do some spirited driving (not redlining mind you!) on an open road and let the engine and turbo loose. Normally I change gears at 2000 RPM but when driving hard I change at 2300 RPM. Never had black smoke problem in my earlier Swift or my current steed, Ertiga. The engine delivers what I demand, be it sudden acceleration, unavoidable lugging (rarely), normal sedate driving.

Do some highway driving once a while, even take a short 50 or 60 kms trip and that's all your engine needs to keep its insides carbon-free. The added bonus is you get to enjoy a picnic with your friends and family!

[sanyal779]

Dear Sirs,

I have been following this very interesting thread.

I would like to add the following based on what I have observed and what I can reason out.

Request views of all members on this.

a) Exhaust gas leaving the engine gets its first obstruction at the catalytic converter box, where maximum deposits of soot occur, together with sticky lube oil vapour. Over prolonged low speed city driving this creates substantial resistance to free flow of exhaust.

b)This catalytic converter box operates at high temperature and eventually some deposits evaporate and part gets oxidised. This mixture of loose carbon and gas then pass over to the silencer box at the outlet end and a parts of it deposit as loose soot due to relatively cooler temperature.

c) when the mechanics at the workshop inject water jet into the exhaust pipe they are able to only reach the silencer box, from where black water comes out by washing the loose carbon. But the catalylic converter box situated much upstream hardly receives any water wash.

d) When the engine is raced up [ in idle mode] after the water injection, there is not much exhaust flow generated as there is hardly much load on the engine to drive away stubborn carbon deposits, only the soft deposits in the silencer box [ already washed with water] comes out. The major blockage at the catalytic converter is not affected much.

e) This water washing method, which is very common treatment by the workshop mechanics, is a placebo effect at best.

Additionally it causes acid corrosion by dissolving the dry sulphur oxides present in the deposits.

But the owners are shown the black wash water as a mark of good cleaning.!!

f) I have seen the mechanics trying this gimmic on all my diesel cars, but never actually observed much improvement in the exhaust flow. This method is not really effective.

g) If however the exhaust pipe is removed and the catalytic converter box is washed with high pressure water, the effect is much better. But this is a cumbersome extra work, and very difficult to convince an average mechanic to agree to carry out.

h) One effective alterntive solution that I have tried out is to take a city driven diesel car on a highway trip and run 5~6 hrs at full speed. This is very effective, because the the higher load gives a much higher exhaust flow through the cat-converter box,which is now working at a sustained higher temperautre.

One highway trip would clear up the exhaust good enough to stay clear for about next three months of city driving.

I would like to learn from the experience of other members on this observation. Thank you all.

[joybhowmik]

Shoving water into any part of the exhaust is not really going to help clean out the system. Now for the catalytic converter cleaning, CataClean is a formulation sold by PepBoys in the US. You add it to the tank, and like other engine decarbonizers, it claims to flush out the resins, gum , soot etc from the engine all the way through the exhaust. Here's the

you-tube link

Having said that, the source of all the dirt in the exhaust system is the engine. So it is worthwhile to have a proper engine flush done also
I have always thought the engine flush done at the main dealers in India, is rather ineffective - was wondering if anyone has seen anything like the terraclean system in action?

[ACM]

Have:

For the the TCIC Safari (BSII with catcon) Over the years:

1) Driven at high speed and run the engine at high RPM at both idle and while driving - upshifting at 3000 rpms.
2) Sent water down the Exhaust and given hard throttle at the same time. (Actually water does not go in at all unless one lets the engine idle while one sends the water in for a bit and then revs the engine later)
3) Removed the Catcon to clean it up as the engine was real low on power. The mess was so bad that I just threw out the catcon & voila the engine was seemingly as good as new at 150,000 kms.
4) Did engine flush a few times.
5) Did Carbon Cleaning of the engine a couple of times.

Could never make out which of these works better but I guess trying out different things at different times does not hurt. Why bet on just one measure. Sure Water down the exhaust is not a proven benifit but seeing the black muck coming out sure feels good and it comes for free at the petrol pump service centre. The catcon is well past it's prime at 100,000 kms - it might just be better (for the car and the environment) to do without it than to manage with it. Not really heard of anyone getting their Catcon replaced. One can drive hard on one of the outstation trips (I do so by default) but would not make a trip specifically to clean up the engine.

The 2001 year Safari would not pass PUC even as while as new as 1 year old and so also had to get the service centre guys to do a combination of carbon cleaning and some other stuff to get it to pass PUC a their own center.

Hey do as you wish. The Catcon does have a life and it does get spoilt in time. It is expensive to replace - Rs. 7000 - 25,000 - depending on brand and type. If one really wishes to do good to the environment then possibly using the car a bit less, switching it off when stationary and for that matter living a life less driven by materialistic pleasures would help more.

[alpha1]

Why would someone do such an idiotic thing as cleaning the exhaust?
For looks?
In any case, the moment you start the diesel engine all the soot will start depositing again!

[SS-Traveller]

Originally Posted by joybhowmik

...have a proper engine flush done also
I have always thought the engine flush done at the main dealers in India, is rather ineffective - was wondering if anyone has seen anything like the terraclean system in action?

There's a difference between 'engine flush' and what Terraclean does. Terraclean is a chemical decarbonisation system for upper cylinders, i.e. it is added to the fuel and is said to decarbonise the fuel lines, cylinder heads, valves and exhaust. Engine flush is a chemical/oil (it could even be kerosene) added to the engine oil chamber, and is said to clean out carbon and other residues, wherever the engine oil flows and lubricates.

Terraclean is just one of the many decarbonising systems that are now available in the market, like there are many brands of engine flushing oil.

[akshay4587]

Sorry for gojng slightly OT but what are the PUC parameters for a diesel vehicle?
I recently got a pollution test done for my diesel vehicle and the machine was showing reading of 21,which according to the guy was fine and it should be below 65? What exactly is 21 and 65 and is 21 a good reading?