Tell me I'm correct (or wrong if I am!)

[Fastpedeller]

Unsure whether to put this in braking or engines/drivetrain. Consider the latter to be correct but mods please move if you wish.
Anyway, to subject. Bought new car, in handbook it says:-

Parking Brake:- If you park your vehicle on a hill and facing downhill select reverse gear and turn the steering wheel towards the kerb.

I have always understood if a vehicle was to roll away in gear the engine compression will stop it, also the engine should NEVER be turned backwards, as it's not designed to do that. Therefore if facing downhill the car should be in a FORWARD gear, and if it rolls it will be prevented by the engine compression.

Am I correct? or is the vehicle manufacturer correct?

[Fastpedeller]

sunbeam alpine said:

Happy Jim said:

You are wrong :-)

The engine only turns in one direction....that's why you have a reverse gear ;-)

Surely this has to be the correct answer?

It only turns in one direction WHEN IT IS RUNNING.... but if it's forced (by gravity pulling the car downhill) to turn in the opposite direction because the car is in reverse gear what then happens?

[Fastpedeller]

Max_Torque said:

It's got nothing to do with the engine being turned "backwards" and everything to do with what happens when you jump back into thr car, and go to start it, forgetting it's in gear, back when cars let you do that sort of thing!

(if you'd put it in first, start in gear would, fire up, and zoom off down the hill. but in reverse, either the starter wouldn't be man enough to fire it up, or having to lift the car up the hill would just stall it out straight away)

No that's not the reason because this car won't crank unless the clutch is depressed!

[Fastpedeller]

Max_Torque said:

Hugo a Gogo said:

Max_Torque said:

It's got nothing to do with the engine being turned "backwards" and everything to do with what happens when you jump back into thr car, and go to start it, forgetting it's in gear, back when cars let you do that sort of thing!

(if you'd put it in first, start in gear would, fire up, and zoom off down the hill. but in reverse, either the starter wouldn't be man enough to fire it up, or having to lift the car up the hill would just stall it out straight away)

wouldn't they just tell you to park it in neutral if that was the case?

Not on a "steep" hill. Being in gear gives you extra security if the handbrake is a bit crap! (well, at least in theory, ime, whilst being in gear will prevent the car running away at speed, on really steep hills, even in 1st, there is enough force to slowly turn the engine over as the compression leaks past the ring pack, and the car very slowly inches down the hill without the h/brake applied

In which case, if you are facing downhill with the car in reverse then the engine is going backwards! It would seem wise if 'relying' on the belt and braces approach and putting the car in gear, that you also take the safer approach and put it in forward gear if facing downhill or reverse if facing uphill so that the engine will A)hopefully stop the car if it rolls and B)only turn the engine in the direction it's clearly designed for rather than one it may not be designed for.

[Fastpedeller]

KiaDiseasel said:

What a silly thread. The handbook says X. Do X. End of story. What other engines do when they're turned backwards is neither here nor there.

Until it's your engine that's mashed due to following the incorrect instruction from the person you are fighting with to get a repair under warranty?

[Fastpedeller]

S0 What said:

I suppose it depnds on if the engine is chain or belt and if it has an oil pressure fed or sprung tensioner, in the old days with a locked tensioner (like a pinto or Xflow) turning the engine backwards would not damage it and as reverse is the lowest gear the compesion would be most effective in reverse, in say a BMW 4 pot with the oil pressure fed tensioner where just turning it over with a flat battery (IE to slow) causes the chain to jump, i wouldn't advise it.

As always dealers staff (both sales and service) didn't know much about the oily bits. They did say it's got a belt (rather than chain). I know it VVC timing on both inlet and exhaust, but as to the finer details?????