Minimum km running required for diesel cars

[sumitdongerkery]

Hi Guys!!!!!!

Last month we purchased a new Skoda Octavia Rider. But before finalising on this car we had checked out many other options, of which one was ford fiesta 1.4 diesel. I had test driven the car also. It indeed is a very good car and engine response is pretty much like any petrol car but when I was discussing about the technical aspects of the car with the dealer I was surprised to hear that this car needs a minimum running of 50 Kms per day. I mean I am not sure how can someone assure a minimum running everyday. I am still not sure how can something like this be true, although I know that (infact I have heard that) volvo buses need a minimum running of 18 to 20hrs per day. I fail to understand the technical reason behind this.

All the tech gurus I just want to know whether this is true? If yes why this minimum running a requirement.

[speedsatya]

Originally Posted by sumitdongerkery

Hi Guys!!!!!!

(infact I have heard that) volvo buses need a minimum running of 18 to 20hrs per day. I fail to understand the technical reason behind this.

.

i dont think there is any technical reason for that ...volvo buses costing 60 lakhs need to continuously running so that the operators can recover the investment cost...otherwise they wont be economically viable ...i sont understand any other reason

[sumitdongerkery]

My uncle owns a Volvo bus and this indeed was told to him that the bus needs a minimum running hours. I just fail to understand the reason behind this.

[sridhar24]

I don't think its really necessary for a modern Diesel car to run some minimum Kms every day. We owened a qualis before, we didn't have any problems whatsoever even if it wasn't used for few days.

[Zappo]

Sumit, all that is a bull. Basically these sales guys are just picked up like that and given some very rudimentary training at the begining and then are left on their own. If you asked that guy to show a single technical literature from Ford to back him up he would have started stuttering. Take that from me. Almost any and every Tom, Dick and Harry will tell you that "you need a minimum no. of kms to run if you buy a diesel". So this great salesman was trying that same spiel on you. However what most people and this guy included do not know is the origin of this logic.

The fact is that normally diesel cars cost more than a petrol. In many cases they do so by a huge margin. Now to recover that extra cost you pay you will need to run some extra kms over and above the petrol car to recover your investments in say 4 or 5 years. So what that guy was saying may be true provided it works out mathematically. You need to find out the cost of the same Fiesta in Petrol avatar and its mileage and then the difference between the petrol and the diesel version (and the diesels mileage as well). Work it out whether to recover the extra amount paid, in say the next 5 years (lesser if you plan to sell it off before 5 years), whether you actually need to run those 50 kms... You may keep the difference in the prices of petrol and diesel at a steady Rs.15

[jat]

As Zappo said, it is pure economics. There is no technical reason behind it. You work out your costs and you will know immediately how much you will run to recover the extra cost of diesel car.

[revharder]

agrees with Zappo.

besides the fuel cost, cost of regular servicing and maintenance is also another factor to be calculated in this, as petrol cars need a bit lesser care. one more such factor is of resale value, diesel cars fetches less resale value.

so it has became a thumbrule for everyone to suggest for diesel cars only if the driver is going to use it for some longer KMs. else in the long run, he'll have to bear reasonable financial loss.

[kb100]

Agrees....

Though Revharder - the modern diesel's take as much or as little maintanance as the petrols... Talking from experience!!

[koooliooo]

diesel does not require maintainance as much as you people talk
firstly every full tank - consider 40 litre normally saves us 400 rs
averagely 4 full tanks a month - diesels are usually bought for business purpose and not for family and even if family , there are long trips , etc , etc due to wihc consider 4 full tanks
Rs 1600 saves every month
now just compare the cost difference of maintainance between petrols and diesels and see whether its worth having a diesel or not specially if there are 3 or mroe full tanks per month

[THE-U-]

Just wanted to revive this thread as most dealerships seem to say this (diesel cars need to be used a lot more or engine damage will result). Where did this originate from?

I would think Diesels outlast petrols because the diesels are designed to withstand higher temperature and therefore they are more rugged. Most of the naturally aspirated diesels are much more rugged generally than their petrol counter parts.

So, is this mileage requirement an urban legend? The Safari DICOR and Petrol cost almost the same, so clearly one gets to take advantage of the diesel cost savings on top of the higher mileage for the DICOR.

This perception seems to be prevalent among all dealerships. Any of you sage auto engineers out there to throw more light on this issue?

[k_nitin_r]

Originally Posted by THE-U-

Just wanted to revive this thread as most dealerships seem to say this (diesel cars need to be used a lot more or engine damage will result). So, is this mileage requirement an urban legend?

Lately, I've only been leaving the house about once a week and that's only for a trip to the grocery store or the temple, both of which are within 1 km from where I live. With a maximum of 8km per month, I still have an old Peugeot TUD5 diesel engine running perfectly in my Maruti Esteem 2004 Di. The engine even starts on the first turn of the ignition key!

[thoma]

Originally Posted by THE-U-

Just wanted to revive this thread as most dealerships seem to say this (diesel cars need to be used a lot more or engine damage will result).

I have similar doubts. See http://www.team-bhp.com/forum/techni...ml#post2561387 (Petrol versus diesel cars - reliability)

Where did this originate from?

It was and is indeed true that the diesel engine and its associated parts are made heavier (in order to be sturdier) than the petrol counterpart. This is basically because the fuel, diesel, is compressed and ignited, as opposed to, spark ignited in the case of petrol. Also, the diesel engine have to withstand the higher combustion pressure developed. Noise and vibrations too tend to be on the higher side. Modern technological advances in accurate machining, high pressure fuel injection and other areas has transformed the diesel engine to a great extend.

As we will all agree on that the maximum stress on an engine is during starting and then comes prolonged high rpm runs, especially with the case of diesels. However advanced the diesel technologies be, I guess frequent start / stop combined with low running will affect the diesel mill more (in comparison to) than a petrol one. Thus, diesels are more suitable for longer runs rather than many shorter runs.

However coming to the question, I do not see much harm on the diesel engine, compared to the petrol one, if it remains unused.

[CANPUSH]

Originally Posted by speedsatya

i dont think there is any technical reason for that ...volvo buses costing 60 lakhs need to continuously running so that the operators can recover the investment cost...otherwise they wont be economically viable ...i sont understand any other reason

Originally Posted by sumitdongerkery

My uncle owns a Volvo bus and this indeed was told to him that the bus needs a minimum running hours. I just fail to understand the reason behind this.

Originally Posted by sridhar24

I don't think its really necessary for a modern Diesel car to run some minimum Kms every day. We owened a qualis before, we didn't have any problems whatsoever even if it wasn't used for few days.

IMO - Diesel engines run more efficiently when certain engine temperature is reached. They are designed to sustain that temperature during the run. If the engine cools down beyond certain limits the efficiency is down.

Further, the fleet owners, whose business is transport want their machines to be constantly on the run so that the investment is recovered faster. In fact, some fleet owners abroad use 1 tractor - 3 trailers combination for fixed middle distance routes where the time for loading/ unloading is also saved. i.e. the tractor takes the trailer-a to destination and on reaching starts return journey by attaching already loaded trailer-b, leaving trailer-a for loading/ unloading. On reaching origin it leaves trailer-b and attaches already loaded trailer-c to start again for destination where by the time he reaches trailer-a is ready to be attached.

It makes sense for them as well as for taxi services and buses. Not for private car owners.

[viggienomad]

Glad to see this thread which saw the last post on 2007 got revived today!

Originally Posted by thoma

... I guess frequent start / stop combined with low running will affect the diesel mill more (in comparison to) than a petrol one. Thus, diesels are more suitable for longer runs rather than many shorter runs. ...

Mahindra's Micro-Hybrid technology does that. It stops & starts the engine at almost every signal (if we use it). http://www.team-bhp.com/forum/techni...o-hybrids.html (Micro Hybrids?)

Not sure whether it will affect the engine.

[sgiitk]

imho the higher up front cost and maintenance of the Diesel engine leads to a change over point. I know many will disagree on the latter. Let me put a few points here - the battery for a diesel car costs more than twice that for a petrol car, Diesel engines being heavier will tend to wear out the tyres and front suspensions more, NVH being higher will require more and better damping. Theoretically there is no reason why one can say that a diesel needs to be run x-km per day.