A heavy oil used in compression-ignition engines.

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7answers
7k views

What to check when buying a used car?

I'm looking to buy a used car. What do you think I should check (mechanically) before buying it (especially if it's diesel)?
40
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6answers
9k views

Why do heavy vehicles almost always use diesel engines?

I have always wondered why heavy vehicles such as large trucks and buses almost always use diesel engines, whereas in light cars there is a choice between diesel and gasoline engines. Engine ...
16
votes
5answers
4k views

Why not use gasoline on diesel engines or vice versa?

I've read gasoline engines use sparks to ignite the mixture, but diesel engines use just compression which can't be done in gasoline engines due to high compression ratios which can cause engine ...
13
votes
9answers
11k views

Diesel vs Petrol motorcars. Pro's and cons?

I realize this may be a silly question to those of you on here who are proper petrol-heads and this may even be a repeat question, but I could not find anything on it on here, so here goes: What are ...
13
votes
5answers
31k views

How to test for defective glow plugs?

On a diesel engine, how can I know which glow plugs are defective, and can I change these only?
11
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3answers
6k views

Why does diesel engine have redline much lower than petrol engine redline?

why do diesel cars redline at around 4500 rpm whereas petrol ones around 6500 -8000 rpm? Does this have something to do with the compression ratio?
11
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2answers
322 views

Diesel Engine Runaway - What is it?

I was watching some youtube videos and diesel engine runaway videos started to pop up where apparently the diesel engine runs out of control until it destroys itself. My Question What is diesel ...
10
votes
2answers
623 views

What's the cause of Diesels' typical clatter noise?

I guess it's related to their basically running off knocking, but if I were to explain it to someone like this, it wouldn't convince me neither. [Edit] From http://www.ford-trucks.com/forums/369700-...
10
votes
1answer
137 views

What are the pro's and con's of compression braking vs. exhaust braking?

My truck supports 2 types of engine brakes: Compression release brake Exhaust brake Both can be selectively deactivated using switches. What are the pro's and con's of each type of engine braking ...
10
votes
1answer
314 views

Why do diesel fuel lines have to be bled?

Background I've had a couple of situations with diesels. One in particular where I swapped a Ford F350 Powerstroke 7.8 transmission. When I was done. The truck wouldn't start. It was a painful ...
9
votes
6answers
28k views

Is it normal for the oil to be dark in color right after an “oil change” in a 10-year old diesel car?

I took my 2002 Jetta TDI wagon to a neighborhood shop about 10 miles, 24 hours ago. They supposedly changed the oil, but the color is very dark, almost black. Definitely not light-colored/transparent. ...
9
votes
2answers
178 views

How are diesel engines better for the environment than gasoline?

I understand that diesel engines have become much more efficient at controlling emissions over the last couple decades. Various websites like this one describe the technological improvements that have ...
9
votes
2answers
3k views

Modern cars and diesel warm-up time

First of all let me say that I already read this question and its answer, so it's clear to me why diesel-powered cars need a warm-up time. My question is: do modern cars need it too? I have VW Golf ...
9
votes
1answer
88 views

Ford Tractor 5600

This is a older tractor. My question relates to the fuel system. The older fuel injectors don't have any external seals? All of them seat and 3 don't leak but one does. I was looking for a seal but ...
8
votes
2answers
1k views

Why does a petrol engine need to maintain an air-fuel ratio, while a diesel engine doesn't?

This simple question has been bugging me for a while. The amount of fuel injected into a petrol engine is calculated according to the amount of air entering through the throttle valve (as measured by ...
8
votes
1answer
232 views

My car's diesel exhaust smells really bad

First of all let me say I apparently have no exhaust leak. For a long time I've been asking myself how was it possible that the exhaust of my car smells so bad. It does it when in the morning, I ...
7
votes
3answers
2k views

Why are VW recalling their cars to remove a defeat device?

As I understand it, Volkswagen had software to artificially enhance their efficiency ratings on a test rig. Since it would only be active under test, what is the point of recalling millions of cars to ...
7
votes
2answers
544 views

Two-Stroke Diesel Engine - Do they use forced induction on them?

As I have indicated before, I'm very diesel ignorant. I just know the basics, very basics. In a two-stroke diesel engine using forced induction seems necessary but at the same time I see challenges. ...
7
votes
3answers
2k views

What kind of engine oil should one use in a diesel?

I got an 1987 Toyota Land Cruiser with a 2H diesel engine. I never changed oil on a diesel engine prior to this truck, so I'm a little confused. Toyota Factory Shop Manual recommend API CC oil type, ...
7
votes
2answers
8k views

Why do head gaskets fail in diesel engines?

I'm considering the purchase of a 2001 VW Golf TDI "mechanic's special", so named because it apparently has a failed head gasket (white smoke). I'm not a mechanic but I'm fairly handy with tools and ...
7
votes
5answers
17k views

How to extend the life of the dual mass flywheel in a diesel engine?

I am looking for ways to improve the life of the dual mass flywheel (DMF) in my 2005 Ford Focus tdci. I have heard that they can wear out quite quickly on the Ford Focus if they are driven in city ...
7
votes
3answers
137 views

How did they start diesel engines before the glow plug was invented?

According to this Bosch page, their glow plug was developed in the early 1920's. Yet the diesel engine was around for at least 20 years prior to that; the French used it in a submarine in 1904, for ...
7
votes
3answers
454 views

Why don't all diesel engines have throttle plates?

I learned recently that many older and some newer diesels don't have throttle plates to control airflow. I was also quite shocked to learn about a condition called diesel engine runaway. Apparently ...
7
votes
1answer
99 views

Does free revving a diesel engine to 4000 rpm (1.6 crdi- hyundai) cause any damage?

It's a Hyundai CRETA/ ix25 model... clocked 1800kms on the odometer, diesel spec engine 1.6 crdi unit, manual transmission! It has redline at about 4800rpm in the tachometer. When i took it for ...
7
votes
4answers
183 views

2002 Ford F350 Superduty 7.3L Turbo diesel using a quart of oil every 43 miles

This Diesel engine has been rebuilt and it didn't use any oil till the HPOP went out. I replaced the oil pump and then I noticed my turbo when going up a hill and the Turbo would sound like a sneeze ...
7
votes
1answer
158 views

Car can't start after rocker gasket change

I have a 2008 BMW 120d LCI with N47 engine. Recently was diagnosed with some oil leak on the rocker gasket near the injector area. Were advised to change the rocker gasket seals. So I did change the ...
7
votes
2answers
315 views

'83 Mercedes 300D will not start when warm

The car runs great when first started, great pickup, etc. However, if I stop and shut off the engine, it will not start back up. At times I can pump the accelerator 5 or 6 times and then it will start ...
7
votes
2answers
173 views

Hyundai i30, 1600 cc Difficulty starting

Hyundai i30 model 1600 cc Auto. diesel, now done 60,000 miles. About 10 months ago, I had difficulty starting the engine from cold. The temperature would have been in the 50 to 60 degree Fahrenheit ...
7
votes
1answer
436 views

Intermittent starting trouble with new battery

I sometimes have problems starting my 2003 Ford Fiesta Diesel. When I turn the key it'll either start normally or just start to kick over then die. If I try again, the same thing happens. My battery ...
7
votes
1answer
83 views

How will diesel engine perform with air in fuel line?

I recently replaced a fuel filter in my 2005 Dodge Ram 3500 Cummings (5.9L). I'm now getting performance issues: at low speed, and especially starting from a stopped position, I'm getting low power. ...
7
votes
2answers
60 views

Proper glow plug operation

Are glow plugs supposed to stay on after the engine has started to help with the firing of the first few revolutions?
7
votes
0answers
76 views

1983 Mercedes Diesel - Loses Power Over Time

I picked up this car as a gift, and on day one drove it the 370+ miles home. After the first 160 miles or so I noticed that the car was struggling to maintain highway speeds. So I pulled over into a ...
6
votes
2answers
365 views

Would a non-turbo diesel perform better in high altitudes than a comparable gasoline engine?

I live close to the Rocky Mountains and drive into them quite often. I have a small naturally-aspirated four-banger that tends to lose a very noticeable amount of power getting into the higher ...
6
votes
1answer
68 views

What is DEF and how is it used?

I keep hearing about DEF ... what is it and why is it used in conjunction with diesel engines? I know it is a more recent thing (last decade), but don't know much about it.
6
votes
6answers
6k views

what can be the reason my old diesel Mercedes won't start?

The vehicle is a Mercedes-Benz T1 model 308D. The engine is an old Mercedes-Benz OM601.940 4-cylinder indirect injection 58 kW (79 hp) 2299 dm3 diesel engine from year 1992. It's not a turbodiesel! - ...
6
votes
1answer
169 views

Two-Stroke vs. Four-Stroke Diesel Engines - What is most commonly used in heavy vehicles?

I am not well versed in diesel engines. To prove my point, I've learned in the last month that a two-stroke diesel engine actually exists. My Question. What kind of diesel engine (four-stroke or ...
6
votes
1answer
229 views

Can diesel engine be harmed as easily as gasoline engine by over-revving?

There is an excellent Q&A about why diesel engines have lower redline RPMs (about 4500 RPM) than gasoline engines (about 6500 RPM). The reason is related to the combustion of diesel fuel. However,...
6
votes
1answer
64 views

Why is there no drop-in biogasoline like there is drop-in biodiesel (e.g. NEXBTL)?

I have always wondered why there is no drop-in biogasoline like there is drop-in biodiesel. For example, NEXBTL by Neste can be run at 100% mixture in conventional diesel engines. It is different from ...
6
votes
2answers
2k views

Diesel engine starting / first start of the day problems

I’m new to the forum, and no mechanic, so please be kind! Vehicle in question is a 1999 T35 Renault Master 2.5 D. It has had first start issues since I’ve owned it, with white smoke (un-burnt fuel ...
6
votes
1answer
6k views

Re-programming injection pump on French Ford Focus TDCi

I replaced the engine on my 2003 Ford Focus (French TDCi) and I plugged it to clear the error codes. Now it starts ok but stops after 10 minutes. I read that when a new injection pump is installed, ...
6
votes
1answer
135 views

Volvo S80 II 2.4 D5 DPF (Diesel Particulate Filter) regeneration conditions

What are the conditions required for the DPF (Diesel Particulate Filter) regeneration? Is it only exhaust temperature or speed and RPM also? I'm wondering if DPF can regenerate while car is at ...
6
votes
2answers
3k views

BMW 530xd e60 2008 diesel engine turns but won't start

I have a problem with my BMW, just bought it, previous owner hasn't been facing such problems. When the engine is cold for e.g.: after night. Outside temperature is about -4 to +1 degree, engine won't ...
6
votes
0answers
39 views

Additives in Engine Oil

As engine oil is been used in the engine, it gets aged and therefore oligomers are formed. Is there a way that we can separate these oligomers without affecting the additives in the oil???
5
votes
1answer
195 views

Are there any modern diesel engines that require electricity to continue running?

I was reading this question about an owner checking the alternator by disconnecting the battery, which is an easy way to validate on a gasoline engine. The single answer assumes that the OP is ...
5
votes
4answers
2k views

RPM bouncing when in idle, especially when AC in switched on

I have a diesel common-rail 1.5l engined car. Lately I am facing an issue where the RPM needle is bouncing in the tachometer when the car is idling. The normal idling RPM is around 820. When idling, I ...
5
votes
2answers
1k views

Petrol vehicles, what are the advantages and disadvantages of a turbo charger?

Diesel vehicle often use turbo chargers. Petrol vehicles frequently do not. What are the advantages and disadvantages of using a turbo charger on a petrol engine?
5
votes
2answers
665 views

Does the a gasoline or diesel engine supply fuel at high speeds when not pressing the pedal and more

Let say I directly connect a small engine to my bicycle, and that I'm superman who can overcome any force. Then I start cycling (using my legs...) - the engine starts to rotate, even though I haven't "...
5
votes
2answers
2k views

BMW 330D 2001 E46 Turbo Charger not working as expected after changing

I have a problem with my car. My car: BMW 330D, 135kw, 2001 year, E46. A week ago my turbo charger got broken when I was driving. There was a lot of white smoke going out of exhaust and there was ...
5
votes
1answer
393 views

Ford Focus engine cuts out at 3000+ RPM

I should provide a little background to this issue as I believe the two are most likely related. The car is a Ford Focus 2008 1.6 TDCi Diesel (UK) which this year has had a brand new battery and ...
5
votes
1answer
82 views

How much to get an old restomod running?

potentially a difficult question here. It's looking like I'm going to be moving out of state for a new job here in the next few months, which is throwing a big wrench into projects I have going on. ...