All Questions
1,852
questions
71
votes
6
answers
390k
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 ...
- 813
51
votes
4
answers
88k
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 ...
- 2,591
43
votes
4
answers
157k
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 ...
- 665
16
votes
3
answers
14k
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 definitively ...
- 39.1k
27
votes
4
answers
16k
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 ...
- 1,041
104
votes
17
answers
272k
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 ...
- 1,193
14
votes
1
answer
107k
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.
...
- 39.1k
68
votes
7
answers
23k
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)?
- 1,021
62
votes
6
answers
311k
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 ...
- 2,591
33
votes
8
answers
421k
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 ...
- 695
25
votes
4
answers
466k
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 ...
user460
66
votes
9
answers
810k
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 ...
- 7,927
31
votes
9
answers
359k
views
Is it okay to leave a car for 5 months without driving it?
I need to travel to the east coast and work from there for a duration of 5 months. I can leave my car in covered parking here and ask a friend to start the car for a few minutes every week.
What ...
- 649
26
votes
4
answers
506k
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 ...
- 7,927
19
votes
3
answers
58k
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 ...
user4822
82
votes
10
answers
46k
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 ...
- 1,053
9
votes
3
answers
228k
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...
- 205
5
votes
1
answer
6k
views
What is a stress riser?
What is a stress riser and why is it important to avoid them during engine construction or rebuild?
- 153k
16
votes
3
answers
2k
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 ...
- 33k
13
votes
5
answers
148k
views
Tire SideWall Damage. Replace?
Yesterday I bumped into a curb and my tire has sidewall damage. Is this tire safe to drive on? or do I need to replace this tire?
- 131
46
votes
4
answers
26k
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 ...
- 768
21
votes
9
answers
103k
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 ...
- 858
21
votes
4
answers
775k
views
Will Putting An Extra Quart of Oil In My Car Ruin It?
I put too much motor oil in my car's motor. About a quart - have I ruined my car? I've been driving it. I know I need to get the oil drained. But I'm worried that I've ruined my car which has been ...
- 211
21
votes
6
answers
335k
views
I drove with my Parking Brake on for 30 mins: should I be worried?
Yesterday, I was driving my car for about 30 minutes on the highway at speeds of up to 60 mph. I felt my brakes weren't really working and looked down to notice my emergency brake had been on the ...
- 211
18
votes
2
answers
5k
views
What is a leak down tester and what can I do with it?
Background
There are quite a few head gasket related questions on the site. Coolant or water in the oil, oil in the coolant or water in a radiator, etc. I'm thinking that some instruction on howto ...
- 33k
29
votes
9
answers
128k
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 ...
- 927
24
votes
4
answers
8k
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 ...
- 347
23
votes
3
answers
156k
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 ...
- 414
18
votes
11
answers
31k
views
What's the best gear to leave a manual vehicle in when parked? [closed]
I've been told that reverse is the "strongest" gear, so in a manual transmission vehicle you should park your vehicle and leave it in reverse in the event of a parking brake failure. Others have said ...
- 651
16
votes
6
answers
98k
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.
...
- 265
14
votes
1
answer
4k
views
What exactly are fuel trims?
What is meant by the term "fuel trim"?
Why are they so important in diagnosing engine operation issues?
How do short-term fuel trims differ from long-term fuel trims?
- 39.1k
11
votes
10
answers
103k
views
Will different tread depths hurt my 4 wheel drive?
I have a Ford F150 4x4. The front 2 tires treads measure 12/32, one rear is 6/32 and the other is 10/32. The dealership told me I should replace the rear 2 tires because the big difference in tread ...
- 211
38
votes
3
answers
374k
views
What does a water-like drip coming out of the exhaust of the car signify?
Sometimes while driving in the traffic, I come across a car or two which would be dripping water-like drops from its exhaust steadily in 4-5 second intervals. I tried to ask a couple of people at the ...
- 685
19
votes
6
answers
122k
views
Engine power specification at different rpm?
Car companies advertise the 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 ...
- 407
14
votes
4
answers
75k
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 ...
- 522
8
votes
4
answers
84k
views
What is the proper way to extract a broken sparkplug?
When dealing with a car with aluminum head(s), what is the proper way to extract a broken sparkplug?
- 2,902
8
votes
3
answers
95k
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 ...
- 15.7k
7
votes
1
answer
15k
views
I drove with the handbrake on for 1000 metres
I left my handbrake on for about 1000 meter when driving this winter. I smelled something burning when I opened the front door.
Since then there is often a burning smell back right wheel after ...
- 71
29
votes
3
answers
14k
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 ...
- 643
20
votes
2
answers
81k
views
How is engine load determined?
I'm struggling to find information on how engine load is defined. Is it really just a fancy word for torque demand?
There are three parts to this question:
Is there a theoretical equation that is ...
- 39.1k
14
votes
2
answers
4k
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 ...
- 15.7k
12
votes
1
answer
87k
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 ...
- 257
11
votes
2
answers
5k
views
BSFC (Brake Specific Fuel Consumption) - How is this a beneficial measurement?
Brake Specific Fuel Consumption or BSFC
Measuring various attributes of an ICE (Internal Combustion Engine) and how it performs certainly gives a greater understanding of how a particular ICE ...
- 33k
11
votes
4
answers
67k
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 ...
- 213
11
votes
4
answers
2k
views
Starting a 2 stroke jet boat after several years
The parents in law gave me a jet boat, it hasn't been started in 5 years. The boat resided in NH on a trailer on their yard for 5 years, so it has seen freezing temperatures frequently. From what I ...
- 489
9
votes
1
answer
692
views
Excessive Coolant Expansion: Part 2
This is a continuation of my excessive coolant expansion question regarding my 98 Mazda 626 2L. When I drained the coolant I noticed this black sediment which settled to the bottom of the container I ...
- 15.7k
8
votes
3
answers
134k
views
Can I reprogram a used Mercedes smart key?
I want a new key for my Mercedes Benz and I've heard that you can get a used smart key for much cheaper than a new one from a licensed Mercedes mechanic.
Can I reuse an already programmed Mercedes ...
- 626
8
votes
1
answer
21k
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 ...
- 15.7k
6
votes
1
answer
2k
views
How does a torque converter work?
I am still in the learning process and I am okay with torque converter but there are some things I can't understand very well:
Why does the impeller and turbine have vanes in opposite directions?
...
- 977
76
votes
16
answers
525k
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 ...
- 2,096