Buying A Diesel Vehicle

[SLA]

How can we find the engine is in good condition when buying a diesel vehicle?

(I want to buy a Serena, cd20 engine van, but hope your advises will be very much important to all the readers who wish to buy a diesel vehicle)

[Uditha88]

How can we find the engine is in good condition when buying a diesel vehicle?

(I want to buy a Serena, cd20 engine van, but hope your advises will be very much important to all the readers who wish to buy a diesel vehicle)

1. Check the oil level & color. Bit black color oil is normal for diesel engine.

2. Check for oil leaks.

3. Listen to the engine noise. Normal that Diesel engines bit noisy than petrol. But listen for any sounds like "kata-kata" which tends to come out from repaired engines.

4. Check the exhaust smoke. No blue smoke. Note that diesel engine may have slight black smoke in cold starts.

[SLA]

Thanks a lot Uditha!!!

[SLA]

If the engine is having a slight black smoke after driving for little time ( lets say the test run... 2- 3 Km), does it means the engine is bad?

[nexus]

1. Check the oil level & color. Bit black color oil is normal for diesel engine.

2. Check for oil leaks.

3. Listen to the engine noise. Normal that Diesel engines bit noisy than petrol. But listen for any sounds like "kata-kata" which tends to come out from repaired engines.

4. Check the exhaust smoke. No blue smoke. Note that diesel engine may have slight black smoke in cold starts.

i like to add another to this list

5 after vehicle is started when take out the engine oil dipstick look if there is any steam or oil or both comes out of the engine locally this is called karen thel gahanawa then take out the oil filler cap and see any steam comes out of it.

Edited January 1, 2012 by nexus

[Ripper]

1. Check the oil level & color. Bit black color oil is normal for diesel engine.

2. Check for oil leaks.

3. Listen to the engine noise. Normal that Diesel engines bit noisy than petrol. But listen for any sounds like "kata-kata" which tends to come out from repaired engines.

4. Check the exhaust smoke. No blue smoke. Note that diesel engine may have slight black smoke in cold starts.

engine oil color is not at all a good indicator to see if the engine has any wear on it.

blue smoke in a a diesel engine means oil burn and you might be in for an overhaul.

Noises are tough one to go by unless of course it's quite clear the engine is not running well. Some engines tend to run louder and have distinct sounds.

Black smoke means partial burning of fuel, can be due to multitude of reasons. everything from a clogged airfilter to bad injectors or injection pump.

If you are not very familiar with vehicles, best bet is to get an expert to look at it.

There are minor little details that an expert will be able to latch onto very fast. And it's an acquired skill that takes years of hands on experience to develop

[Amila G]

One more thing, A good diesel engine can be started when cold without pre-heating. Especially Toyota 2C engines.

So if an engine is hard to cold start without pre heating, it could be worn out.

One trick I use is to turn the key all the way from off to start, without stopping on the "ON" position and see how easy does the engine start. A good engine usually starts within one to two revs of the engine.

[TURBOMAN]

Not only the engine you have to look for other stuff like Shocks/Interior/Corrosion/etc....

And legal things too.

Try to buy a car with a good service history..thats one of the best ways

Ave

[Dhanu DaGreat]

Please inspect vehicle registration documents and avoid buying from people who are not the registered owners of the vehicle. Go early in the morning and try to do a cold start yourself. Remove the deep stick and see the density of the engine oil. If it's too thick the owner has used a thick oil to fool you so that the engine smoke wont come out from the oil chamber. If any smoke or oil coming out from the oil chamber avoid buying that vehicle. Inspect any visual leaks from the top engine seals and other seals. If the engine is re built ask for a bill and see whether it's a reputable place and whether it's done properly. It's better to build the engine yourself after buying the van. Also don't buy the first van that you are going to inspect. Go to see several vans so that you can compare engine noises and other stuff. Avoid buying high deck ( just low) vans as it's very hard to re sell them. If you see the engine heating a lot it's normal for Serena it's made for long runs ( highway ) don't make it a problem this is a good choice. The problem is that most of the vans are sold by very cunning people so be aware.

Edited January 4, 2012 by Dhanu DaGreat

[terrabytetango]

One more thing, A good diesel engine can be started when cold without pre-heating. Especially Toyota 2C engines.

So if an engine is hard to cold start without pre heating, it could be worn out.

One trick I use is to turn the key all the way from off to start, without stopping on the "ON" position and see how easy does the engine start. A good engine usually starts within one to two revs of the engine.

I always pre-heated our Townace (2C powered Lotto) if it hadn't been used for over 8 hours. The glow plugs actually remained powered on for about 10 seconds after the glow indicator on the dash went out; you could hear the 'click' of the relay when the circuit switched off. That mantra served us well for over 13 years and 300k+ kms with only one rebuild.

Edited January 4, 2012 by terrabytetango

[SLA]

Thak you all for your valuable advices and information.

[Amila G]

I always pre-heated our Townace (2C powered Lotto) if it hadn't been used for over 8 hours. The glow plugs actually remained powered on for about 10 seconds after the glow indicator on the dash went out; you could hear the 'click' of the relay when the circuit switched off. That mantra served us well for over 13 years and 300k+ kms with only one rebuild.

Is it bad to start without pre heating ? I too noted that the glow plugs remain active for a couple of seconds after the engine is started. I never pre heat my corolla (with a 2C engine) but starts without any issues and currently have ~200k.

So am I doing any harm by not pre heating ?

[Watchman]

From my limited knowledge I think if your engine starts up without an issue there's no harm in not heating the engine. The problem comes if your engine CANT start without heating and hence the starter-motor needs to crank the engine for longer. This obviously is bad on the starter motor and could even drain your battery out.

Having a coupleof diesels I know the difference. Our 4DR5 doesnt need any heating, it just comes to life with a single crank. On the other end of the scale our w123 will NOT start without heating. Another couple of diesels we had needed heating, but were able to start with about 4-5 cranks. So yeah it can vary a lot

Edited January 5, 2012 by Watchman

[terrabytetango]

Is it bad to start without pre heating ? I too noted that the glow plugs remain active for a couple of seconds after the engine is started. I never pre heat my corolla (with a 2C engine) but starts without any issues and currently have ~200k.

So am I doing any harm by not pre heating ?

Only if your engine starts easier with preheating than not, and if there's a significant difference with and without. The more you crank, the more you wear you engine, because there's no oil circulation in the 2C engine till the engine catches.

[Amila G]

Only if your engine starts easier with preheating than not, and if there's a significant difference with and without. The more you crank, the more you wear you engine, because there's no oil circulation in the 2C engine till the engine catches.

ah.. good point. Mine starts about half a second faster with pre heated so guess it's not that different than without the heating. But anyway our townace never starts without pre heating and is suffering from under compression.

I think more engine wear = need for more pre heating and so you can use the cold start ability to check for engine condition.

[nexus]

I think more engine wear = need for more pre heating and so you can use the cold start ability to check for engine condition.

afaik nissan CD20 engine must preheated before starting it so your theory isn't going to work on serena.

[Amila G]

afaik nissan CD20 engine must preheated before starting it so your theory isn't going to work on serena.

Oops at least for toyotas it'll work

[Sylvi]

Members,

Diesel engines some start without preheating in the morning. some need to heat once or three times. This happens due to low compression.

The compression build up inside the cylinders are not enough to ignite diesel.

Some members will have a different opinion what I post under.

I know a person who used to inject Kerosine oil 3 CC into the air intake with a injection syringe in the morning for a quick start.

That worked till he sold his Peugeot car. That car had after 40000 miles cold morning start defect. Due to low compression.

Sylvi Wijesinghe.

[Amila G]

Members,

Diesel engines some start without preheating in the morning. some need to heat once or three times. This happens due to low compression.

The compression build up inside the cylinders are not enough to ignite diesel.

Some members will have a different opinion what I post under.

I know a person who used to inject Kerosine oil 3 CC into the air intake with a injection syringe in the morning for a quick start.

That worked till he sold his Peugeot car. That car had after 40000 miles cold morning start defect. Due to low compression.

Sylvi Wijesinghe.

Good explanation. Goes with what I have experienced. Out of 4 diesels I've experienced, the one with the best compression was always the one that was easiest to cold start.

I have first hand experience that when an engine is wearing out it is getting harder to cold start(well atleast for toyotas )

[SLA]

Bought a Diesel Serena yesterday!!! Our mechanic confirmed its in good condition.

Thank you all !!!

[maheshw]

My Congtrtz on yur buy

[SLA]

Thanks maheshw !!!

It is a better van than I thought of it before... drove over 500km including a travel to Kandy without any issue. Good fuel consuption too

[The Don]

Thanks maheshw !!!

It is a better van than I thought of it before... drove over 500km including a travel to Kandy without any issue. Good fuel consuption too

Which version of the Serena is it?

[SLA]

It is a LX, replaced with FX doors (so having the fx look). Manual gb.

[Lalith Prasad]

i am planning to buy unregistered nissan vennet diesel. i prefer auto. my current vehicle is toyota vits ksp 90 2008 model but its too small. tell me about nissan vennet reguarding fuel consumption,pickup,maintainance and comfortability.

[Ripper]

Members,

Diesel engines some start without preheating in the morning. some need to heat once or three times. This happens due to low compression.

Sylvi Wijesinghe.

gotta disagree here. low compression is one reason for poor morning starts but not the only one.

it can be anything from poor heater plugs, poor ignition timing (retarded ignition at the pump), bad fuel filter etc

for instance...on my ford diesel

recently replaced all four injectors, air-oil-fuel filters after i start noticing a bit of black smoke and somewhat poor starting in the morning.

Truck used to start without heating the moment you crack the motor up. Later i had to crank 2-3 times even after heating up.

heater plugged checks out ok, fuel filter was replaced with one with a manual pump cos originally it didn't come with a manual pump

Even with new filters, injectors...still it doesn't start the first go in the morning.

engine doesn't burn oil and had been rebuilt at 200k. its less than 40k over that figure at the moment

I too am quite foxed why i still have morning starting issues.

leaning towards ignition being a bit retarded.