General internal combustion engine questions.

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23
votes
9answers
33k 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 ...
17
votes
5answers
16k 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 ...
16
votes
3answers
5k 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 ...
15
votes
11answers
116k 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. ...
15
votes
7answers
63k 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 ...
15
votes
6answers
53k 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. ...
15
votes
2answers
20k 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 / ...
14
votes
2answers
8k 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 ...
13
votes
4answers
19k 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 ...
13
votes
8answers
20k views

My car's coolant temperature reaches almost 100 C / 212 F in a fast pace

Today, after a very hot day, I saw that my coolant was almost reaching 100C/212, I pulled over, stopped and took a look over the hood. The very little water that remained in the coolant tank was all ...
13
votes
4answers
24k views

Is it OK to mix oil of different viscosity?

I have a Mazda RX-8 (with a Wankel rotary engine). Mazda advises North American owners to use 5W-20 oil. The engine was just replaced 200 miles ago by the dealer so it currently has 5W-20 in it. ...
12
votes
1answer
152 views

What is the difference between a 180° V4 and a true boxer motor?

Reading this thread which talks about V4 motors, I am wondering what exactly is the difference between a 180° V4 motor you'd find in a Subaru and a true boxer (or horizontally opposed) flat 4 ...
11
votes
9answers
10k 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 ...
11
votes
1answer
2k views

What is happening when a two-stroke engine is said to be “four-stroking”?

Many years ago, I was involved in a hobby of building and flying model aircraft. The aircraft used alcohol-fueled 2-stroke engines with glow plug ignitions. When these engines ran rich (and always at ...
11
votes
4answers
40k views

What would be the most likely cause of engine sputter?

Most of the time my 2001 Honda Civic sounds like this... Vrooooooom. But some times when I start driving it sounds like this... Vrooom putt pa putt pa putt pa vrooooom. When it's in the "putt pa ...
11
votes
1answer
697 views

Changing Firing Order in a 4 Cylinder Car

Backstory In motorcycling you can get cams that change the firing order and time from a traditional 1,3,4,2. It's was very common in American roadracing in the 1990's to hear 4 Cylinder engines that ...
10
votes
3answers
4k views

Why (almost) all dirt bikes have single cylinder engine?

Every dirt bike i know has a single cylinder engine. I myself ride a Yamaha XT660Z which has a huge 660 cc cylinder. What are the characteristics of those engines? what are the benefits of such ...
9
votes
2answers
380 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 ...
9
votes
4answers
25k views

Why does a Turbocharger only produce boost when the engine is under load

As per the Title. Why does a turbocharged car only produce significant boost whilst the engine is under load. Is is something to do with how much exhaust is being produced or is there some kind of ...
9
votes
6answers
13k views

Do I need to torque my spark plugs?

I have never torqued them before on several vehicles that I do tune ups on. I just apply a bit of anti-seize lube and get them "snug" and everything seems to work fine. Should I be using a torque ...
9
votes
5answers
2k views

How to properly change out spark plugs?

I am looking into how to change out my spark plugs on my 4 cylinder 2005 Mazda 3. All I know to do is: 1: Open each cylinder. 2: Use a spark plug socket (with the rubber insert) to remove the old ...
9
votes
1answer
6k views

Is this what is making my car sound like a racecar?

Recently, my car (2000 Mercury Grand Marquis) started sounding like a racecar: the engine became very loud. There's clearly something going wrong with the exhaust system. I'm trying to understand ...
9
votes
4answers
4k views

2000 Jetta runs rough, shutters on cold start only on wet days.

This is an issue I've had off and on for, embarrassingly, at least a year: On misty or wet mornings, everything starts out fine but, a few minutes into the drive (like clockwork. I even know the ...
8
votes
5answers
4k views

Car crash: when does a car catch fire?

Which kind of crash does it need for a car to catch fire? I'm asking because I was discussing about an accident where a car crashed into a full-grown brown bear. Is it realistic under normal ...
8
votes
2answers
4k views

Why might I experience a power falloff after starting my car with the AC On?

I have a 2000 Chrysler Neon which generally runs well. I have noticed that if I start the vehicle, turn the AC on and reverse out of the driveway, the engine seems to struggle/sounds like it is going ...
8
votes
1answer
857 views

Why does diesel engine need a warm-up before the start-up?

When starting up, diesel engine needs approximately 5s before turning the key for ignition. Why is this neccessary and what can be damaged if you don't do that?
8
votes
2answers
432 views

Can you stop fuel delivery to one cylinder of a 2003 Ford F150 with 5.4L Triton Engine?

Can you disconnect a wire so gas will not pump into the cylinder? I have a spark plug blown out and need to get my 2003 F150 5.4 Trition engine home without paying another tow charge.
8
votes
3answers
1k 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 ...
8
votes
2answers
9k 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, ...
8
votes
3answers
6k views

How to begin learning engine tuning?

Quite simply, I want to begin tuning and modifying automotive engines for hobby. I have always been fascinated with cars, and I want to become knowledgeable in as many aspects of car tuning as ...
8
votes
2answers
2k views

Low power, bad gas mileage, smelly exhaust after engine work

My 92 Civic has had low power (need to use at least one gear lower than usual to get the same power) and has been getting bad gas mileage (15-25mpg vs 32-42 mpg usual) since I replaced the head ...
7
votes
4answers
658 views

Why did V4 engines never take off?

I read that Ford Taunus (not to be confused with Taurus, it was a small model for German market) used to be made with a V4 engine but that's about it. How come V4 never became more used in modern ...
7
votes
4answers
10k views

How reliable is a second-hand Subaru 2.5 RS 04-05?

Basically, I've been a Subaru enthusiast for a few years but never been able to purchase one because I'm still a student. However, this summer I will be able to. The issue is that I need a reliable ...
7
votes
5answers
11k views

Is it all right to clean a car radiator with vinegar and chlorine?

I got the idea from this article, where it suggests cleaning your washing machine using chlorine bleach and then vinegar. I have successfully used this method to clean my household washing machine ...
7
votes
5answers
24k views

How to get a motor to Top Dead Center

I'm not sure how specific to my car this is or not, so I will include my car information just in case: It's a 1991 Honda CRX, base trim(the motor is the d15b2). On to the question: How do I go about ...
7
votes
5answers
696 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 ...
7
votes
4answers
16k views

What colour should power steering fluid be?

Recently started shopping for first car, so want to know as much as possible when going into a sale. Car I looked at recently has a brown dirty colour in the power steering reservoir, but the stuff ...
7
votes
2answers
953 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 ...
7
votes
4answers
57k views

Cold start squeaking noise in engine

I just purchased a used 2010 Corolla 3 days ago. I've only now noticed that when I start the car, there is a squeaking sound coming from the engine. It lasts no more than a second. Sounds like it ...
7
votes
2answers
1k views

2004 Ford Focus engine cover would not budge after all screws are removed

I have a 2004 Ford Focus SE 2.0L. There’s some oil leak on the engine. A mechanic told me it could be the engine valve gasket being cracked (the car is pretty old and never had a valve gasket change). ...
7
votes
1answer
378 views

Put Stop leak into engine. Can I reverse the process?

I accidently poured Barsleaks stop leak for the radiator into the engine oil compartment. Is there any way I can reverse the process? The stuff is hardening already. This a 2004 Volvo S80.
7
votes
2answers
6k views

WHY does an engine stall? (manual transmission)

Before you write off my question as one that's been answered a million times already, I want to clarify. I understand that the engine needs to go a certain rpm and when you try to engage the clutch ...
7
votes
1answer
844 views

Car Suddenly Decides To Not Crank

Today I turned the key to start up my car and all the lights (headlights and instrument panel) came on bright and normal, but the engine made absolutely no sound. It wouldn't start, it didn't even try ...
7
votes
2answers
1k views

What is the likelihood that my crankshaft is warped?

This may be an involved question so bear with me. :) I have a 1998 Honda Accord EX (4cyl) with 281xxx KM, and last week I was told by my mechanic that the harmonic balancer is warped. And in fact, ...
7
votes
1answer
346 views

Why does an engine's idle RPMs take time to settle from a cold start?

I've noticed my car's (healthy) engine will idle at a slightly higher RPM for a few moments after it's been started from cold/not run for a day. I also noticed that my (somewhat less healthy) other ...
7
votes
1answer
7k views

Why would my engine temperature raise from normal to high and drop back down again?

I have a Nissan Micra (UK, 51-plate, 2001 model) that I have been using to drive to work on a daily basis - 10 miles each way a day on a variety of roads - streets, main roads, main roads in traffic, ...
7
votes
1answer
367 views

Ants in my lawn mower engine

Related questions: Are small engines on topic? (meta) Reviving a vehicle that has been idle for a long time. With the arrival of Spring, I went to dust off my riding lawn mower. It had been sitting ...
7
votes
1answer
953 views

What do i need to know when replacing a valve cover gasket

I have an oil leak from a cracked valve cover gasket that i want to replace myself. I bought the gasket nearly 6 months ago and i am apprehensive at doing it myself without sort of feed back as to ...
7
votes
3answers
269 views

Will I be okay running thinner oil with a minor oil leak on an older car?

Recently when I had some work done I was shown a minor leak, I believe he told me it was the oil pan. It doesn't drip out onto the ground, but if you look closely you can see condensed oil drops on ...
6
votes
8answers
7k views

What would cause motor mounts to go out on a factory engine?

I got my factory motor mounts replaced on my 2000 eclipse at 175k miles. I am now at 189k and the mounts blew again. I can hear the same rattling and squeaking. I had the spark plugs and valve cover ...