[sumeshmani]

For my Maruti 800, the service supervisors at Mandovi Motors, Bangalore always pushed me for carbon-cleaning @ 20k interval services.
I always refused, because i had doubts about the benefits. My car is still running smooth with 80k KM on the odo.

[SS-Traveller]

Originally Posted by avasekeh

On the same note, how about decarbonising for bikes? Is that also not necessary? At about 40k kms mark the service centers recommend a decarb process and the amount is non-trivial as well.

The comments in the first posts of this thread apply to any four-stroke internal combustion engine, whether carburetted or fuel-injected, whether petrol or diesel. Two-stroke engines, by the sheer nature of their lubrication method, will continue to need decarbonisation at specified intervals, but they are probably easier and cheaper to decarbonise mechanically than by the use of chemicals.

In any case, I wonder how many two-stroke engines continue to be used in automotive applications today, if at all.

[SPIKE ARRESTOR]

Originally Posted by Jeroen

I doubt very much if knock would remove carbon deposits. Knock is just poor ignition really (too early).

That means before TDC right, what if it is after TDC?

Although, I must say this is not THE way of removing carbon deposits, but it definitely helps in breaking up the dry powder kind of residue sticking around the combustion area. How efficient it is, that I need to probe further.

Spike

[Sahil]

My 525d has clocked 75,000kms and I find an increase in the amount of black smoke it is emitting under hard acceleration or down shifts.
What product can I use to clean-up the system?

[akshay4587]

Originally Posted by Sahil

My 525d has clocked 75,000kms and I find an increase in the amount of black smoke it is emitting under hard acceleration or down shifts.
What product can I use to clean-up the system?

Rather than going in for Some additives on a premium car,i would recommend that you get in touch with BMW,and she might have to go through EGR/Intake Manifold/Intercooler cleaning.

[ACM]

Thanks SST - Rated 5 Stars.

Had gone in for Decarbonising of my Safari TCIC at 24,000 kms in year 2002 within 2 years of buying the car - was a novice at car stuff then and taken for a ride. It was too early and not repeating the same for the next 150,000 kms did not seem to have an impact. Yep did use premium Diesel (Turbo Jet) at lot later, and did also flush the engine a couple of times with STP post 100,000 kms. But the first and only decarbonization attempt then costing about Rs. 4000 was a waste of money, didn't see any improvement in performance. Was told it was to get the vehicle to clear PUC.

Actually dread to think of the damage to the Laura or the Aria by doing the procedure, now a days even TATA ASS does not seem to suggest it on the newer age vehicles.

[SS-Traveller]

Originally Posted by Sahil

My 525d has clocked 75,000kms and I find an increase in the amount of black smoke it is emitting under hard acceleration or down shifts.
What product can I use to clean-up the system?

Broadly speaking, Sahil, the usual reason for black smoke emission in a diesel is incomplete combustion - this again can be because of either too little oxygen, or too much fuel, going into the cylinders.

How's the FE?

IMO the biggest culprit here is poor quality of diesel, which fouls up injectors, with incomplete atomisation. I am assuming that you've had no check-engine-light issues. Before subjecting the car to more elaborate work, I'd suggest

- put in fresh engine oil and a new air filter, if either is more than 5000 km old;

- completely empty the tank (at 75k km your car deserves a tank cleaning too);

- fill it up from a super-reliable pump, pour in an additive (System-D, Bardahl, Wurth, Cyclo, BG and many others have such products) to clean up the fuel injection system, and

- go for a non-stop fast cruise for a few hundred km (a round trip to Pune and back, maybe? )

If this doesn't help reduce the smoke, then you need a technician to carry out a scan, and take a look at the EGR system, TC, MAF sensor etc. as akshay4587 mentioned.

[sanyal779]

Good day Sirs,

Thanks for the informative posts. I have one query as follows: does the the cleaning chemical have any damaging effect on the rubber /teflon seals of the fuel injectors? Any known problems ?

Warm regards
S.Sanyal

[Jeroen]

Originally Posted by sanyal779

Good day Sirs,

Thanks for the informative posts. I have one query as follows: does the the cleaning chemical have any damaging effect on the rubber /teflon seals of the fuel injectors? Any known problems ?

Warm regards
S.Sanyal

It shouldn't, especially on modern cars/engines but I've seen owners reporting problems after using these cleaning chemicals. Check what your own manufacturer advises and whether there are any restriction listed on the the chemical itself.

Personally, I think the biggest risk is particles getting dislodged, not completely dissolving and getting stuck in a different place where they could do more harm.

Typically the older car/engine you have the more prone they might be. It just that the rubbers/gaskets/etc used on cars over the last couple of decades have become much better and resilient to all sort of influences.

Jeroen

[Naetik30]

Took my i10 to Trident HYundai Bangalore on 3 days back for the 30000 km service. Especially told the service advisor not to perform anything other than what is mentioned in the service booklet. And he agreed.

Went back in the evening to pick my car up and found Engine Decarbonizing (Rs. 1650) mentioned in the bill. FYI - this is not mentioned in the service booklet.
Had an argument with the SA but ended up paying the bill anyways.

I guess the best way to fix this problem is to specifically tell the guys - DO NOT perform so and so jobs on the car.

[anandjha]

Went for 10th service of my Wagon R (~75,000 kms) yesterday. Thanks to you saved money on Decarbonising. But when I also refused on Flushing, he said it was important. I had to concede.

[SS-Traveller]

Originally Posted by Naetik30

...found Engine Decarbonizing (Rs. 1650) mentioned in the bill. FYI - this is not mentioned in the service booklet.
Had an argument with the SA but ended up paying the bill anyways.

Originally Posted by anandjha

...saved money on Decarbonising. But when I also refused on Flushing, he said it was important. I had to concede.

You can refuse to pay for any high value work that a service centre performs, for which you have no specific complaints, and which is not part of the service schedule as printed in the owner's manual, unless specifically sanctioned by you.

And if you refuse to have any work carried out that is not specified in the owner's manual, and for which you have no specific complaints, the company or its ASS cannot void warranty.

[Naetik30]

Originally Posted by SS-Traveller

You can refuse to pay for any high value work that a service centre performs, for which you have no specific complaints, and which is not part of the service schedule as printed in the owner's manual, unless specifically sanctioned by you.

And if you refuse to have any work carried out that is not specified in the owner's manual, and for which you have no specific complaints, the company or its ASS cannot void warranty.

Thanks SS Traveller. I have read in a number of threads on the right to refuse pay. But some how in the heat of the moment, I only shouted at the SA for having done the job. But did not utter one word about not willing to pay for it.

Will be ready and extra vigilant the next time.

[satish_tns]

Hello all.. I have a swift vdi (ABS) and I do my regular 10k km service in Vishnu Maruti, Chennai. I had been pushed to do engine decarbonization every 10k km and I had been gracefully letting them do that thinking that it is going to keep my car good. Now after reading this thread, i am like - .. If I am not wrong, i recall the bills reflecting around Rs.2000 + odd for each time they did the engine decarbonization. I won't regret for what has happened because i cannot change the past. Now i have reached 60k km and ready for 60k km service next week. Last engine decarbonization was done at 50k km.

Can someone tell me whether to stop doing engine decarbonization from this 60k km service onwards till it is required any time in future or start doing after another 20k km so that the next decarbonization will be done after 30k km from the last time? or even stop doing it untill i run into a situation where I have to do it ?

May be this would help someone to answer my above question more clearly - I do 65% highway driving and 35% city driving and this city driving is 25% bumper to bumper traffic and 75% open strech with less traffic.

[rajeev k]

^^^ Forget the past and forget about any decarbonising for the next 50K KMs, whatever be your driving cycle.