19
votes
4answers
2k views

Why would I want to measure torque while loosening a bolt or nut?

An answer to a question asking about torque wrench maintenance mentions to not use a particular kind of torque wrench for loosening bolts. This got me thinking. I would think it'd be preferable to ...
18
votes
5answers
57k views

Why should the fuel petcock valve be turned to “Off” position when not using the vehicle?

It’s mentioned in the user manual of my motorbike, that when not using the vehicle, I should turn the petrol tap (the one that has three positions “On”, “Off” and “Reserve”) to “Off” position. I don’t ...
15
votes
3answers
14k views

When car is standing still, I smell Diesel exhaust. Why?

In my 2003 Opel Vectra, the cabin air smells of Diesel exhaust while stopped at e.g. a red light. The exhaust smell goes away when driving, and it also doesn't come back if I turn the ventilation off ...
15
votes
2answers
427 views

Standard Practices for Use and Care of Click-Type Torque Wrenches

Torque wrenches, while straightforward in concept, require much different use and care compared to a regular ratchet. This can be confusing to someone who has never used one before. There are several ...
15
votes
4answers
5k views

Is downshifting on hills harmful for non-trucks? [duplicate]

Possible Duplicate: Does Downshifting (Engine Braking) Cause Extra Wear and Tear? Since the days of taking drivers ed (many years back). I was told that when you encounter a steep or extended ...
15
votes
3answers
39k views

What exactly is a “burnt valve” and what causes it?

I've come across this term a couple of times in the context of diagnosing engine-related issues, but don't know what it refers to. Here is an example from an automotive forum I frequent: I gotta ...
14
votes
3answers
510 views

How does the car's ECU detect a misfire?

I was wondering what the specific mechanism used by car ECU's to detect misfires is, or are if there is more than one method.
14
votes
4answers
1k views

What makes two-stroke engines less fuel-efficient than four-strokes?

It is a commonly-held belief that two-stroke engines are less fuel-efficient than four-stroke engines, and some example BSFC figures appear to confirm this as well. But what is it that causes two-...
13
votes
2answers
202 views

How do I troubleshoot the source of oil in my coolant?

I would like to know the step by step troubleshooting procedure for discovering the source of oil appearing in coolant. There are several different points of failure that can be the root cause for ...
13
votes
3answers
315 views

Why does GM still insist on push rod engines?

GM continues to design and produce push rod (Over Head Valve or OHV) engines while most of their competitors have gone to over head cam (OHC) configurations for their performance engines. Is there a ...
13
votes
1answer
747 views

What is fish plating a frame?

When building a frame I've heard people refer to adding a fish plate. What does fish plating a frame do and what exactly is it?
13
votes
1answer
134 views

How to determine exactly what's wrong with my alternator?

My 98 Mazda 626 GF 2L uses an 80 amp fp34 A2TB0191 alternator with an internal voltage regulator. I did a little test where it I turned on the bright lights, AC, radio, rear defogger and opened the ...
13
votes
2answers
35k views

How should I remove stickers or pinstripe decals from paint?

I want to remove a dealer's sticker from my car. The sticker is on a painted surface. What is the best way to do it? Could I remove pinstripe decals in the same way?
12
votes
3answers
2k views

What are the Advantages of a Single Side SwingArm on Motorcycles?

I have noticed that Ducatis , Honda and Triumph have bikes with a Single Sided SwingArm Much like most of the scooters. Are there any advantages of following this design , if so why are not all ...
12
votes
5answers
2k views

Why nitrogen and not carbon dioxide is used in critical tire applications?

In critical applications tires are inflated using pure nitrogen (link). But carbon dioxide (CO2) is a larger molecule (will leak slower from the tire), as well as inert (will not oxidize rim and will ...
11
votes
2answers
16k views

How much power (HP) do the components on the engine belt generally use?

In general, how much power (HP) to the components on the the engine belt actually use? I'm trying to come up with an estimate of how much horsepower an engine wastes on things like the AC compressor, ...
11
votes
3answers
713 views

How to start my motorcycle when the kick-starter fails?

This morning I tried to start my motorcycle but the kick-starter failed. It was idle for about a month but it was riding fine before that . My motorcycle doesn't have an electric starter function. ...
11
votes
3answers
2k views

How do you get the carburetors out of a 1983 Kawasaki KZ1000 P?

It's a 4-cylinder engine, and the carbs are really wedged in there. The best way I know is to loosen the boots on both sides, pull the carbs back, and try to slip them out sideways, but what a pain! ...
10
votes
3answers
112k views

Sloshing Sound Under Dash

I have a 2011 Suzuki SX4 Crossover AWD with MT. Sometimes when I start it up, begin moving forward, or quickly decelerate I can hear what sounds like water (or some other liquid) moving from one ...
10
votes
10answers
3k views

How can I detect vacuum leaks without access to a smoke machine?

In the course of helping my friend sort out a lean condition with his Mercedes GLK280 we have to pinpoint the source of a vacuum leak in the intake plumbing. The interwebz tend to recommend having ...
10
votes
2answers
235 views

Proper Jack Location

In general, where is the best place to put a jack to prevent damage when lifting?
9
votes
4answers
2k views

Finding a possible vacuum leak

One of our cars has a bit of a rough idle which disappears at about 1,000 RPM. After eliminating everything else I concluded that this is due to a minor vacuum leak. This was confirmed by the use of a ...
9
votes
3answers
2k views

Car won't reach operating temperature

Here's a seemingly simple problem - I noticed that the temperature gauge of my mother's 2004 Opel Meriva 1.7CDTI won't ever climb above minimum. I checked the OBD readings to see if it was a defective ...
9
votes
3answers
26k views

Can I use lower octane fuel at high elevation?

Here in Colorado, gas stations sell "regular" gasoline which is rated at 85 octane ((M+R)/2). In most of the rest of the US, 87 octane is the lowest grade available. (As noted previously, higher ...
8
votes
3answers
151 views

Buying Car Parts Online

It's clear to me that car parts are cheaper when purchased online rather than through the mechanic. I've been buying tires and brake pads online for years with few problems. Now the wheel bearings on ...
8
votes
2answers
520 views

Fiat Punto Wont Start. Fuel Light & Three warning lights flashing

My Fiat Punto 1.2 Year 2000 MK2 (I believe) will not start. The engine turns over but the car won't start. The fuel light is flashing and petrol gauge says empty which isn't the case. There are three ...
8
votes
7answers
8k views

Fuel efficiency and Shifting/RPM

I was reading a thread in a car forum where someone wrote: The lower the RPM, the less fuel you use, the less strain you put on everything.. Another person then replied, stating: Not true. ...
8
votes
2answers
76 views

Can I only get an alignment on new tires or is the salesman just being pushy?

When purchasing new tires, the salesman is quick to recommend getting an alignment as well to prevent premature tire wear. I've even been told that you have to get the alignment done when the tires ...
8
votes
5answers
14k views

Doing my own fuel induction service - how to, and how difficult?

I was recommended to get a fuel induction service for a 2002 V4 Camry, and am considering doing it MYSELF. The reasons for considering this are: My car idles a bit rough, especially when the AC is ...
8
votes
3answers
686 views

What do these compression figures mean

This is a follow up question to What are the causes of fluctuating intake manifold vacuum I have a 2005 Honda CBR600 F4i which suffers from occasional hesitation at low rpm when accelerating. After ...
8
votes
3answers
306 views

What do the terms “combined port” & “direct injection” mean?

I heard these terms recently as part of the description of a new car. I know that there are intake and exhaust valves in the engine that are controlled by cams on the camshaft (if that helps you ...
8
votes
4answers
2k views

What are the “1” and “2” or “L” gears used for on an automatic?

In a car with an automatic transmission, we are normally greeted by the acronym PRNDL, or in some cases (older cars) PRND21. I know that the L, 1, or 2 will cause the transmission to stay in a (L)...
8
votes
3answers
556 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 ...
8
votes
2answers
5k views

What is overboost?

I've heard the term overboost quite a lot. What is "bad" overboost? What is an overboost problem? What will happen to my turbo engine if I don't fix it? Edit: apparently there is a good type ...
7
votes
2answers
7k views

Carburetted motorcycle stalls when accelerator is applied

My father has 1995 Kawasaki VN 800 Vulcan with low kilometrage (18 000, 11 000 miles). We had installed new Vance & Hines pipes on it (in hindsight, way, way too loud, but that’s beside the point, ...
7
votes
1answer
1k views

Clutch dragging and making squeaking/grinding noise

My motorcycle clutch (Yamaha Diversion) has recently started dragging extremely badly; I need to rev-match up and down gears and shifting from neutral into first requires me to rev the engine, pull ...
7
votes
1answer
110 views

Battery tender vs trickle charger

I understand battery tenders are used to keep batteries charged for long term storage, and trickle chargers are.... also used to charge batteries? What are the differences between these two devices, ...
7
votes
1answer
4k views

What does a healthy spark plug look like?

The spark plug pictured here: Has some black carbon on the underside of the ground electrode and has black carbon on the "base" area below the centre electrode (not pictured). Is this normal and ...
7
votes
3answers
2k views

How should I prevent my battery going flat when I leave my car alone for a month?

I will be leaving my Focus alone for around a month in (scottish) winter weather. Ordinarily I would make sure to take the vehicle out at least once a week to prevent the battery going flat in the ...
7
votes
1answer
9k views

What is seafoam? What does it do? How do you use it?

Mech's seem to get a real rubbery one about Seafoam. Is it just fuel additive, like something similar to Lucas Oil? Do I just pour it into my gas tank as a gas treatment? What will it do/help ...
7
votes
1answer
5k views

Engine revs up when braking

Background: 2012 Honda Civic EX, 5-speed automatic, with no mods except a non-stock tire (ran over a large bolt). I keep it maintained per the manufacturer's manual and always see the Honda dealership ...
7
votes
4answers
16k views

How to know if timing belt failure will result in immediate engine damage?

I own two cars: a 2003 Acura TL and a 2005 Volvo S60. I've been told that depending on what car you drive, a failed timing belt can result in immediate engine damage. I would like to know (not just ...
7
votes
3answers
19k views

What is a rod knock?

What is a rod knock? What causes a rod knock, how bad is a knocking rod, and how can I tell if a rod is knocking?
7
votes
1answer
70 views

Breaking in a new catlytic converter?

I read somewhere you need to break in a new catalytic converter. To that end: Is this accurate? What is the purpose of breaking one in? How do you break it in?
7
votes
3answers
275 views

How to know if I need new tires?

For the first time in my years of driving, I slid pretty badly the other day. I've slid before a little bit, but this is the first time I slid badly-- I nearly went off the road. Granted, it was ...
7
votes
2answers
3k views

What would cause a clutch master cylinder to go bad?

I have a 1980 Honda Prelude and have only driven it a few hundred miles per year for the 10 years I've owned it. Redid the clutch when I got it, with new cylinders and everything. Last week I got in ...
6
votes
1answer
3k views

What do the numbers in 195/60/R15 mean? [duplicate]

As far as I know, each type or size or whatever of tyres has its own set of numbers which presumably mean something. In the instance of my last car these numbers were 195/60/R15. What do each of ...
6
votes
1answer
128 views

Starting using a deep-cycle battery

This weekend, during a camping trip, the starter battery on my 2001 VW Eurovan camper started to show signs of weakness - cranking was much slower than usual and took about 5 attempts to get the ...
6
votes
1answer
794 views

After brake bleed, pedal goes to floor

2005 Toyota sequoia. Brake pedal was fine most of the time but occasionally it would sink to the floor while stopping and it would be hard to stop. I bled my brakes and now the pedal goes to the floor ...
6
votes
1answer
332 views

OBD2 and CAN-bus

Do all vehicles with OBD2 have a CAN-bus? Otherwise, what are the alternative buses used? Are there special versions of the buses for trucks and school-buses than for cars/suv/vans?

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