21
votes
2answers
10k views

Why doesn't anyone ever repair an automatic transmission?

I am old enough to have had about four transmission failures spaced over about 40 years and at no time did any mechanic ever offer to “fix” it; the only diagnosis has been a complete rebuild. This is ...
21
votes
4answers
1k views

Are there requirements for building a car-PC and it's software?

I am currently rebuilding a car as a hobby. As a part of it I am planning on building in a car PC with custom software for some multimedia usage, navigation and some diagnose usage. I know there are ...
21
votes
7answers
124k 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 ...
21
votes
6answers
24k views

Is Start & Stop technology good or bad for my car? (Alfa MiTO)

I was recently in the lucky position to obtain an (almost brand new) Alfa Romeo MiTo, Progression. Like many new cars coming out these days, it has "Start & Stop" technology that turns the engine ...
20
votes
11answers
153k views

What happens if a single spark plug unexpectedly goes down in a multi-cylinder engine?

AFAIK vehicle manuals say owner must replace spark plugs every N miles. Suppose he fails to do so and a single spark plug unexpectedly dies in an engine with multiple cylinders right in a freeway. ...
20
votes
7answers
6k views

What's the point of servicing a car?

As you can probably tell from the question, I know almost nothing about motor vehicles. So apologies for my ignorance but I wasn't sure where else I might get this question answered impartially. ...
20
votes
4answers
2k views

How do you un-seize an engine?

I have an older engine that is seized. It is a 1953 Desoto Hemi. How can I un-seize it? I have sprayed Sea Foam Deep Creep down the plugs and let sit for weeks. As well as transmission fluid. To no ...
20
votes
4answers
3k 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 ...
20
votes
2answers
912 views

Difference between OBDII and CAN

What is CAN (controller area network)? What are the differences between an OBD-II protocol and a CAN setup?` How do I use an OBD-II scanner on a vehicle with CAN?
20
votes
10answers
339k views

How should I remove a paint scuff on my vehicle?

The painted edge of a side mirror on another car recently scraped the side of my vehicle, leaving a scuff of paint about half a meter long. There is no indentation or scratch, but the other vehicle ...
20
votes
2answers
966 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? ...
20
votes
7answers
73k views

What are the risks of overfilling a small engine with oil?

I recently overfilled a 4 stroke lawnmower engine with oil. It has been run for about 1.5 hours while overfilled. It smokes a lot right after being started but after 30 seconds or so the smoke clears. ...
20
votes
3answers
30k views

Is starting your car with the A/C on bad?

I was always yelled at by my father when I was first starting to drive when I left the A/C on when I turned off the car, and then later turned it back on, with the reasoning that I was ruining / ...
19
votes
4answers
3k views

Why do tyres go flat after a few weeks of non-usage?

My car is a 2007 model FIAT Albea 1.3 liter 4-door saloon. I think it might be the "fire" version. Made (assembled) in Turkey. I use it 6 months a year but 4-5 weeks at a time. When it's stored/parked ...
19
votes
4answers
1k views

What are the benefits of a dry sump?

I've heard references to dry sumps, usually in reference to racing engines. But more recently I came across an article about a 'supercar' which stated that it had a dry sump. What are the benefits of ...
19
votes
3answers
2k views

Is it ok to use a scissor jack instead of a floor jack?

I need to jack up my car to take out the front driver side tire and change the p/s and alternator belt. I don't own a floor jack but I do have a scissor jack. I was wondering could I just use the ...
19
votes
3answers
1k views

Does a carburettor engine apply fuel at high speeds when the pedal is no longer depressed?

There's a question that is pretty similar to this one except the existing question satisfies EFI engines. EFI question Let's say I roll down a hill at a considerable speed I let go of the gas. Say ...
19
votes
8answers
136k views

What's the point of the D3 gear in an automatic transmission?

My Honda Civic has a D gear and a D3, which apparently prevents it from going into 4th. Why would I want to do this? What is it good for? Does it make my fuel efficiency better or worse? Does it ...
19
votes
3answers
5k views

What differences between synthetic and dino oil?

What are the main differences between synthetic and dino oil, and is one always better than the other?
19
votes
2answers
1k views

How exactly does a differential work?

I understand that the differential (or "diff") is the thing that allows the drive shaft to transfer its rotational velocity to the front or rear axle in order to move the car. As far as I know, the ...
19
votes
7answers
19k views

How old is too old for a new tire?

When shopping for new tires from tirerack.com, the production date of the tires is listed. I'm considering tires from a 2007 production run, which would make them around 5 years old today (after ...
19
votes
2answers
165 views

Does (forcefully) overriding the self-canceling damage my indicator levers?

Sometimes I don't want my indicators to self cancel, so I hold the indicator on while turning the wheel, and it makes a cracking/clicking noise. Am I damaging anything if I do this? EDIT: To ...
18
votes
2answers
10k views

Why doesn't the engine stall out when you come to a stop with an automatic transmission?

When you come to a stop with a manual transmission you have to push the clutch in or take it out of gear to keep the engine from stalling out. What keeps the engine from stalling in an automatic ...
18
votes
6answers
1k views

Will higher octane fuel improve towing power?

According to Will higher octane fuel improve gas mileage? higher octane fuel does NOT notably improve fuel efficiency. Will higher octane fuel, increase power while towing? I looked online and ...
18
votes
9answers
70k views

What is the best way to remove a stuck/rusted exhaust bolt?

I'm trying to disassemble the exhaust system on a 2000-2003 nissan maxima and I'm having trouble removing one last bolt.. its got a 14mm head and its just plain STUCK. I've tried soaking it overnight ...
18
votes
7answers
102k views

Is idling bad for your engine?

If I sit in my car for 30-40 minutes with the AC and the car idling, does that "hurt" the engine, or does it simply waste gas and pollute the air? Would it be better if I turned off the car? A ...
18
votes
3answers
876 views

What does under-square and over-square mean?

When building an engine, the terms over-square and under-square come up. What do these terms mean? How do they apply to engine building? Which is better for what purpose? Can you give examples ...
18
votes
6answers
8k views

What damage does a car suffer if not regularly used?

Sometimes I use the car on daily basis, but there are months when I don't use it at all, and it sits parked outside for 5+ weeks, with the battery disconnected. (Main reasons: working from home that ...
18
votes
2answers
1k views

What possible causes for the “check engine” light can I check for myself?

The "Service Engine Soon" light came on yesterday and isn't going away on its own. The car drives fine, no weird noises, smells, or other symptoms. The manual is not very helpful, just directing me to ...
18
votes
2answers
1k views

Why do we need to cool air after it leaves a turbocharger?

When we are using a turbocharger to compress the incoming air, the air gets hotter. Usually this hot air is cooled by using intercooler before it is passed to the engine. But what is the reason ...
18
votes
4answers
193k views

What causes an engine to burn oil?

What are the different problems that can cause an engine to burn oil and in general how difficult / expensive is each one to repair? How do you diagnose each potential cause? I found this article ...
18
votes
1answer
564 views

What does pie cut exhaust mean?

As the title says, when looking at building a custom exhaust system I've heard the reference called pie cut exhaust but I was unable to find any definition or terminology so I was curious to know what ...
18
votes
3answers
1k views

What is the proper way to bleed brakes and replace the fluid?

What is the proper way to replace the brake fluid in a car? What tools are required? I want to make sure I do not get any air or bubbles in the system as this is something that needs to be done right ...
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?
18
votes
3answers
163 views

What's the most environmentally responsible method of car parts cleaning?

I'll be the first to admit that this one has been hard for me. I clean cylinder heads, axle bearings, calipers, crankcases....the list goes on. I want to be clear here. I am not talking about ...
18
votes
3answers
617 views

What are good features to look for in an OBD-II reader

I recently took my car in for the engine light. It turned out to be a minor problem (crack in gas cap let water in). It would be nice to have a low-cost OBD-II reader to be able to find out for ...
18
votes
3answers
49k 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 ...
18
votes
1answer
421 views

Vibration at idle, much worse after warm

My car is a 2001 Pontiac Firebird with a V6 (3800 Series II (L36)) and a manual transmission. These are all at a stop: When the car is cold, I don't feel too much vibration when sitting in it. (I ...
17
votes
5answers
2k views

How to raise the car higher than the jack stands will allow?

So it's time to raise the car onto jack stands, but for whatever reason it needs to go higher than the stand height allows. How can I safely raise the height of the car? What I have done in the past ...
17
votes
12answers
53k views

Should I pull my wipers away from the windshield when parked during a winter storm?

When we are expecting snow storm and the vehicle is parked, do we pull out the wipers so they don’t touch the glass to avoid the freezing to the windshield? Or would that hurt the springs in the wiper ...
17
votes
10answers
53k views

How can you tell the oil needs to be changed?

I know oil should be changed every 3000 or 6000 miles (depending on the car and conditions) but I'm not all that great at keeping track and I've let the car go for 10,000 miles before and it still ...
17
votes
9answers
46k 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 ...
17
votes
7answers
1k views

Seized nut & bolt - difficult to access

Last year I added crash sliders to my aging Honda CBR 600F (1998) Recently whilst trying to remove the fairing for other work, I found the nut and bolt were "seized". Actually, by using a spanner at ...
17
votes
7answers
3k views

Are manual transmission cars disappearing? [closed]

You don't have to be an expert to notice that over time, the percentage of manual transmission cars has lowered. Automatic cars are not only more popular, but more comfortable, easier to use and ...
17
votes
7answers
50k 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 ...
17
votes
5answers
49k 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 ...
17
votes
12answers
85k views

Is Prestone “All Makes/All Models” coolant *really* compatible with all models?

My car's manual says to use the blue Honda coolant: Always use Honda All Season Antifreeze/Coolant Type 2 [MSDS]. This coolant is pre-mixed with 50 percent antifreeze and 50 percent water. ...
17
votes
4answers
840 views

What is regenerative braking and why don't we use it?

I know that many electric cars use regenerative braking to enable the car to become more efficient by converting what would otherwise be lost heat energy in to a more useful, reusable form of energy. ...
17
votes
4answers
28k views

Driving in second gear at 65+ mph

I accidentally drove my 2000 Grand Marquis on second gear on the highway. I was going 65 for like 5 minutes and tried to get it to 70mph but the car was shaking, when I realized I put it into regular ...
17
votes
3answers
6k views

Can a vehicle be harmed with bad inputs via an OBD-2 port?

I bought a cheap (sub $10) ELM 327 Bluetooth clone OBD-2 diagnostic adapter on a local "ebay-style" market where the seller specializes in car diagnostics and has several thousand positive reviews ...

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