46
votes
6answers
171k views

Why does my A/C blow foul smelling air when it first turns on?

Most of the time when I first turn on the A/C in our 2008 Toyota Sienna, the air that blows out has a very distinct chemical - nasty smell. After a while it seems to go away. I'm not sure if I just ...
36
votes
4answers
34k views

Reviving a vehicle that has been idle for a long time

Some related topics: How to maintain a sometimes-used vehicle? How long does it take for gas to go bad? The first related topic addresses preparing a vehicle for long-term disuse, and maintaining ...
21
votes
4answers
4k views

How do I test my car battery?

My car still starts fine but when I turn off the car (just the motor . . the key is still in and "on") I noticed the headlights dim to almost off. It's and older car and the headlights don't turn off ...
26
votes
4answers
52k views

How far can I drive with 1 gallon too much oil?

I have way too much oil in my Acura TSX. Do I need to take care of it without turning it on or can I drive it to a service station? If I need to do it in place, I don't have the ramps or a pan or ...
71
votes
17answers
110k views

Does Downshifting (Engine Braking) Cause Extra Wear and Tear?

Does the act of downshifting to slow your vehicle down have any negative side affects? I don't downshift more than one or two gears at a time and I let out on the clutch slow enough that I don't rev ...
64
votes
9answers
27k views

What are the benefits of premium (high octane) petrol?

Here in the UK it's common for petrol (gas) stations to offer both regular and "premium" unleaded petrol. The premium stuff is (naturally) more expensive, and I've often wondered what the actual ...
11
votes
2answers
9k views

Lugging the Engine (Manual Transmission)

So...lugging the engine obviously isn't something that is good. But why? For example when you feather a clutch to get the car moving, it lugs for a quick moment when you hit the catch point (When ...
11
votes
4answers
487 views

How can I tell if I have bad cats?

No, not that cat! Catalytic converters - or "cats" - have a nasty habit of failing with age. What are the symptoms associated with a cat that's gone bad? Are there any tests that could ...
47
votes
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)?
23
votes
3answers
5k views

Will engine braking damage my transmission? How can I tell?

I drive a manual transmission '08 Honda Fit. On my daily 17 mile commute to work, there are three long hills that I can coast down, each about a half mile long. Going down these hills, I've done two ...
12
votes
4answers
29k views

Engine power specification at different rpm?

Car companies advertise power of an engine at different rpms. Car 1: 80 PS at 6000 rpm Car 2: 85 PS at 6500 rpm What does the power at different rpm mean? Does it mean Car 1 has better power than ...
10
votes
5answers
33k views

Can coasting in neutral damage an automatic transmission?

When I drove a manual transmission, I got in the habit of shifting to neutral on long, shallow grades to save fuel. Now I'm driving an automatic (specifically, a recent Corolla) and still doing it. ...
8
votes
3answers
44k views

Oil in coolant - how much trouble am I in?

I have oil in my coolant reservoir. Could it just be the head gasket or is it almost certainly the entire engine or might it be something else entirely? Thanks in advance...
15
votes
4answers
62k views

Symptoms of Lean or Rich carb settings on a motorcycle

I have a 1981 Yamaha XS650. I recently put in K&N stock replacement filter (ie, they are in the airbox and conform to the size of the original), however they may be leading to a leaner mixture ...
25
votes
3answers
7k views

Static vs. Effective compression: Why does higher effective compression not require higher octane gas?

Background I've been trying to do a lot of research on boost lately because I'm planning on running a moderate turbo setup on my daily/light-duty-autox car in the future. I'm trying to get into the ...
21
votes
7answers
132k views

Running with straight water as coolant in the summer. Is it fine?

I grew up flushing the coolant twice yearly. In the Spring, you drain the antifreeze and fill with straight water for the summer. In the Fall, you drain the water and put in a 50/50 antifreeze/water ...
17
votes
9answers
48k views

Battery drains by itself when vehicle is parked (parasitic draw)

A 1998 Jeep Grand Cherokee has gone through 3 batteries in the last 3 months. While they have all been replaced by warranties, it'd be nice to get the problem solved permanently. I've tested the ...
32
votes
9answers
43k views

What actually happens when there is not enough oil in a car engine?

When a car is topped up with oil, it clear to most people that you are supposed to fill it to the recommended amount as specified by the manufacturer (normally on a dip stick). What exactly are all ...
11
votes
3answers
168 views

Multimeter - Basic Functionality and Howto

Multimeters I'm looking for some responses regarding multimeter basics for the site tag-wiki to point OP's at when we want them to use one. The question is; What are the basic functions of a ...
8
votes
2answers
3k views

Why should I connect the red/positive terminal first when jump starting?

So, it's fairly popular consensus online that it's red/positive clips to the positive/red posts, then the black/negative clip to the frame One site mentions sparks, but you'll still get a spark when ...
8
votes
1answer
54k views

I lost my Mercedes smart key, how do I get a new one?

If I lose a Mercedes smart key fob, how do I get a replacement? Is there anything I should do to prevent the old key from being used if it was stolen?
6
votes
3answers
2k views

Rough Low Idle and Engine Shakes, Hesitation and Lack of Power

On a 98 Mazda 626 GF 2L I'm working on the engine seems to shake / wobble for about a second / second and a half when going to WOT from any starting rpm. It also almost sounded like maybe one of the ...
57
votes
16answers
256k views

Should I resurface or replace my rotors everytime I replace brake pads?

I have heard it is proper practice to replace or resurface your brake rotors every time your do a brake pad replacement. Does this need to be done every single time or is it overkill? Maybe it is ...
13
votes
1answer
4k views

how to optimize fuel consumption by changing the rear differential ratio?

Is it possible to improve the fuel consumption (decrease it) in my van by changing the rear differential ratio? I would like to optimize it for low-speed driving about 40 km/h (25 mph). Is it true ...
5
votes
1answer
1k views

What are some Seafoam Alternatives

I read this procedure for using Sea Foam ( also listed on their website ) to clean the intake manifold, injectors and crankcase. I think this would be useful for my vehicle, however Sea Foam isn't ...
7
votes
3answers
3k views

Squeaky Brakes: How much of a concern are they?

I recently bought a 1998 Jeep Grand Cherokee from a dealership. When we bought it, I noticed that the brakes were not working very well, and the dealer fixed them before we finalized, putting in a ...
23
votes
8answers
65k views

Will higher octane fuel improve gas mileage?

I've heard from some people that high octane fuel will increase gas mileage. Around here, we have the basic unleaded(87), mid-grade(89), and premium(93 or 91). I've been using the basic 87 unleaded ...
12
votes
1answer
8k views

Do I have to rely on wire color to correctly wire up an O2 sensor?

It seems that everyone and their grandmother has a different color-code convention for 4-wire O2 sensors, which complicates matters when one is trying to wire up a replacement "universal" O2 sensor. ...
7
votes
4answers
33k views

Is engine braking harmful? [duplicate]

Possible Duplicate: Does Downshifting (Engine Braking) Cause Extra Wear and Tear? My wife and I have a disagreement about a practice of mine--engine braking. When I'm driving her manual ...
18
votes
3answers
51k views

Must I Replace All 4 Tires on an All Wheel Drive (AWD) vehicle?

I have a 2005 Subaru Legacy 2.5i Wagon. I just destroyed the passenger-side rear tire. The tires have approx. 6/32" tread remaining, per an informal measurement with a coin (I used this guideline ...
9
votes
1answer
297 views

A most intriguing cold-start misfire mystery

I'm trying to help a friend out with a CEL on his 2009 Merc GLK 280. Hooked it up to an OBD2 reader and retrieved a single code: P0300 - 'Random/Multiple Cylinder Misfire Detected', via the 'OBD ...
6
votes
2answers
2k views

What bolt extractor will remove a broken motor mount bolt on a 2004 Subaru WRX?

Things were going slowly but well on my install last night until I sheared off the passenger side motor mount bolt while putting everything back together (at about midnight - sigh). Here are the key ...
4
votes
1answer
252 views

What is a stress riser?

What is a stress riser and why is it important to avoid them during engine construction or rebuild?
3
votes
2answers
115k views

Honda Accord radio anti-theft code not working…what am I doing wrong and what should I do?

I had to remove the battery so I can replace the driver's side low beam headlight. I didn't bother to buy a settings saver because I found the security code in my Honda's packet (I bought this car ...
1
vote
3answers
2k views

Fast Idle and High Fuel Consumption

I just bought a Manual 97 Mazda Lantis 323 1.8L DOHC 16 Valve BP and I was amazed that it went through 1/4 tank gas ( about 12.5 liters or 3.3 gallons ) in one day after about 60 kilometers / 37 miles ...
10
votes
5answers
922 views

Second hand car - Engine/Tyres/Etc

I am looking into buying a second hand car from a reputable Mercedes-Benz dealer (not just some dodgy salesman by the side of a road lol....). Anyway, there are a few maintenance/mechanical things ...
31
votes
9answers
45k views

Is it necessary to 'burn in' or 'break in' a new car?

I've just bought a new 2011 plate car. I've heard stories of people 'burning in' engines for the first few hundred or couple thousand miles using methods such as: Not driving above 50 mph. Varying ...
28
votes
3answers
11k views

Jump starting a dead battery: Connect black wire to negative pole of battery or grounded metal?

Most of the advice I've seen for jump starting cars instructs to connect the black wire to a bare piece of metal on the car with the dead battery. However, I've always just hooked up both poles to the ...
20
votes
2answers
979 views

How To Read Car Tires

On my VW Passat B5 tires, there is a marking that reads "195/65R15 91 V". What does this mean? Do I have to get replacement tires with this exact marking on the side of the tire in the future or not? ...
18
votes
1answer
5k views

How do I know when to change my spark plug

I ride a Piaggio scooter with a single cylinder engine. Recently I broke down and the engine wouldn't restart. It turned out the spark plug was stuffed. How can I ensure that doesn't happen again?
23
votes
9answers
228k views

What is the difference between normal, platinum, iridium plugs?

What is the difference (besides price) between normal, platinum, and iridium spark plugs?
7
votes
4answers
98k views

Is it okay to replace one tire (of four matched tires) with a completely different model of tire?

I have a 2011 Ford Focus, and while the car itself is good quality, I have now ruined two tires in three months by merely driving over a screw. Ford offers no road hazard on their tires, so I am ...
5
votes
1answer
2k views

How can I get rid of door dings?

Wife parks too close to my white car. Would love to get rid of these door dings as her car is only 3 years old.
42
votes
5answers
117k views

How long does it take for gas to go bad?

Approximately how long does it take for unleaded gasoline in the tank and fuel lines to become unusable in a car that is not being used? What causes this, and what can be done to prevent or remedy ...
17
votes
2answers
913 views

What does a flywheel do and what is it connected to?

I understand roughly how an engine works and that there is a crankshaft which is able to turn the flywheel using internal combustion. I have just realised that I have got absolutely no idea how the ...
10
votes
3answers
2k views

What actually happens when there is way too much oil in a car engine?

I saw the answers to a question I posted recently highlighting the disadvantages of having too little oil in an engine, but that got me wondering what if the complete opposite were to occur! I know ...
8
votes
1answer
15k views

Is it normal for stop distance to be long on brand new brake pads?

I just had the brake pads replaced in my car. As I left the shop I noticed coming to a complete stop took longer distance or needed a fair bit more force on the pedal. Is this normal? Will the ...
6
votes
2answers
906 views

Should one fit the least-worn tires to the rear wheels?

According to the Owner’s Manual Saab 9-3 M2001 (front-wheel driven cars): WARNING When fitting just one new pair of tires, these should be fitted to the rear wheels, as these are more ...
6
votes
2answers
26k views

Accidentally poured engine oil into the coolant reservoir

My 1990 Mazda 626 leaks oil like a sieve, so I regularly top up the oil. In a moment of stupidity, I opened my radiator cap instead of my oil cap while topping up my engine oil, and poured about ...
5
votes
2answers
11k views

How to understand different engine oils?

When I went to shop for engine oil, I found many types as such: 5W-30 A5 5W-30 A1 5W-20 SAE 5W-30 10W-30 Also I see other information such as: Fully Synthetic Semi Synthetic Oil Synthetic ...

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