Chris Johns
  • Member for 6 years
  • Last seen more than 1 year ago
Why is engine displacement frequently a few CCs below an exact number?
16 votes

Until relatively recently road tax (in the UK at least and presumably in many other countries as well) was based on engine displacement. As this worked in bands and engine which was slightly less than ...

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Brakes make a "POP" sound and then I can't brake
11 votes

It sounds like the brake pads have either completely worn through or otherwise failed, your car is not safe to drive at all. In this case you will certainly need new pads on both sides and possibly ...

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Did I toast my caliper?
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8 votes

Any sort of brake fluid leak is a serious issue which needs to be fixed for several reasons. Any fluid leak means that air is also getting into the system which will accumulate and degrade braking ...

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Welding sheetmetal
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8 votes

A useful technique with MIG on thin metal is to create the weld by a series of overlapping tacks rather than a continuous run ie strike the arc, create a puddle then release the trigger and repeat, ...

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Aluminium engine vs Cast Iron engine
8 votes

In terms of material properties an aluminum casting will tend to be lighter for equivalent strength and should be easier to cool. A lot of the disadvantages of aluminium come down to manufacturing ...

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Rear window shatters after closing door
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7 votes

Rear and side windows are generally made from tempered glass which has been heat treated to set up residual stresses in the plate which put the interior under compression. This is what causes it to ...

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Stainless Steel Fasteners
7 votes

The most immediate issue is galling. Stainless steel typically contains a lot of suspended carbides ie very hard particles in a soft matrix. This means that stainless threads are prone to galling and ...

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Why do we mostly use fossil fuel instead of a more reliable and larger sum fuel?
7 votes

You absolutely can use ethanol instead of gasoline and disregarding some fairly minor technical issues they are more or less interchangeable. The issue is one of supply. We have the capacity to ...

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When is remote start unsafe?
6 votes

One obvious example would be if the bonnet (hood) is open and someone could be harmed by contact with fans, belts etc. I would guess that there is an interlock to prevent this happening accidentally ...

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How do car cooling systems cool the engine? Won't the air flowing through the radiator flow over the engine (as it exits the car) making it hot again?
Accepted answer
5 votes

The difference is that a radiator is constructed to have very high surface area it is this contact area between the surface of the radiator and the air which allows a high rate of heat transfer. The ...

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If my wheel bearings are freshly replaced, what could still be causing a loud whining sound?
5 votes

Fist thing is to check that the bearings have been torqued properly, over tightening is easy to do and a common problem on newly replaced bearings. Also if one bearing goes it is sensible to ...

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How is vehicle speed calculated?
3 votes

The speedometer is generally connected somewhere after the gearbox eg the driveshaft. So in normal circumstances this is directly proportional to the angular velocity of the wheels, depending on the ...

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Will a manual vehicle stall at low RPM without being on the accelerator?
3 votes

Obviously in a manual car with the clutch engaged there is a direct connection between the wheels and the engine. Also while switched on most engines have an idle setting designed to keep them running ...

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Why do dealers seem to prefer to replace parts instead of repairing?
3 votes

One reason for this is to simplify and standardise maintenance. Replacing a part with like for like can be a known and understood process which also allows traceability. This is of particular ...

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What's the point of servicing a car?
3 votes

Servicing usually applies to the replacement of items which are consumable or have a limited life and need to be routinely replaced at regular intervals, including things like lubricants and filters ...

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How should I modify a car to live in it? How risky are used cars?
2 votes

For a vehicle to live in you would be much better off with a van. Even a fairly large estate car will have much less internal space for an equivalent floor area. Another key consideration is that ...

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Why do race cars need suspension?
2 votes

Racing cars, especially single seaters do indeed have very stiff suspension with relatively little travel, in an F1 car something like 50% of suspension travel comes from the flex of the tyres. ...

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Brake pedal spongy after pad/rotor change and bleeding
2 votes

One fairly common issue is that the brake pistons can get corroded as the pads wear and they extend further out. In this case when you re-compress the pistons the corroded area comes back into contact ...

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What is gasoline used for in an engine?
2 votes

An internal combustion engine is a type of heat engine as defined by the Carnot Cycle, specifically a gasoline engine uses the Otto Cycle. In essence gasoline is burned in the cylinders, releasing ...

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Can I use a car wash to de-ice my car
2 votes

You really need to get the car sufficiently warm that the ice melts. the real danger with using any other method is that any residual film of water can re-freeze very quickly, especially once the car ...

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Understanding Car Servicing for a second hand car
2 votes

Generally speaking servicing means replacing consumable items after a specified interval (either miles, years or both) this can include things like engine oil, oil and fuel filters, brake fluid, spark ...

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Is WD40 a penetrant?
2 votes

WD40 is specifically designed to disperse water (hence WD). It is useful as a penetrant, lubricant and solvent and this versatility if one of the reasons why its is so popular and useful and versatile ...

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'89 BMW 525i E34 - Starting problems if car not driven for a day
2 votes

If it is not even trying to turn over it is most likely an electrical problem ie either starter motor or battery. If it sat for a long time without being used this could have damaged the battery so ...

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How do I reinstall the floor mats on a Renault Kangoo
2 votes

Sometimes the floor mats are held in place with the same screws which hold bits of plastic trim in place. Even if there aren't actual screw holes you may need to loosen bits of trim to get them back ...

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Motor Industry reliability data - is there a source?
2 votes

In reality, for modern cars, there won't be a lot to choose between similar models in terms of whole life reliability. Rust used to be the big thing which limited the life of cars but modern ...

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

Regenerative braking is only really useful on electric or hybrid cars for the simple reason that they have a way to make use of the energy stored. Also once you have an electric motor as part of the ...

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How to find out if my non-fuel injected car has a rev limiter?
2 votes

I would expect a mass market car from the 1990s to have a rev limiter of some sort. But...as other posters have stated a rev limiter won't prevent over revving due to downshifting. Having said that ...

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Why don't rubber tires burn due to friction heat when the vehicle is moving
1 votes

In normal driving conditions tyres are only subject to rolling friction in the forward direction and static friction when accelerating, braking and cornering. Unlike say brakes which are operating ...

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What are the dangers of driving a repaired car that was in major accident?
1 votes

The underlying issue is that major accident damage is likely to cost more to repair properly than the vehicle is worth so there is always a risk that repairs have been done on the cheap and are ...

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Why don't all welders use auto-darkening hoods?
Accepted answer
1 votes

There are a few reasons. Firstly the first few generations of auto lenses had several drawbacks: they were expensive, had a restricted field of vision, and in some cases didn't give such a clear ...

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