4

Does he mean to say that my engine doesn't disengage completely when the clutch is released, if that's the case then my clutch would wear out. Am I correct in thinking so?

  • Was this advice specifically for winter? Are you asking if there's a difference between starting the car in NEUTRAL with the clutch engaged and disengaged? – chilljeet Jun 29 '15 at 13:29
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    With the clutch pressed, you'd completely remove the transmission out of the picture as opposed to leaving it in NEUTRAL , which could result in slightly lesser resistance for the starter motor. Though, this effect could be insignificant and your mechanic might have had something else in mind. – chilljeet Jun 29 '15 at 13:42
  • @chilljeet this dates back to winter when I went to get my battery check, I was having some starting trouble, so he said since in winters engines get super cooled (cooler than normal days) so the starter motor needs to run a bit longer – shabby Jun 29 '15 at 13:49
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You should be pushing the clutch pedal to start the engine no matter what time of year it is. There is a clutch safety switch which needs to be engaged in order for your ignition to work when you turn the key. It can only be engaged when you press down on the clutch pedal. This is to prevent you from trying to start the car while it's in gear. Just a safety feature they installed in cars a long time ago.

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    I know some cars have that, but I didn't think it was a common thing - the only ones I have come across are SAABs and a few Volvos... edit - and don't you mean "start the car while it's in gear"? – Nick C Jun 29 '15 at 12:04
  • @NickC - Yes, that's what I mean. And, have you tried to start a car without the clutch pedal depressed? Has to be something there keeping it from engaging the starter. – Pᴀᴜʟsᴛᴇʀ2 Jun 29 '15 at 12:11
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    @NickC - Maybe it's an American requirement? I know every standard shift vehicle I've ever driven here in the States has one. – Pᴀᴜʟsᴛᴇʀ2 Jun 29 '15 at 13:46
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    @Paulster2, yeah, it must be - all automatics here have such a thing, so you can only start them in Park. I've not driven anything with stop-start so I don't know if they have something, but a brand-new hire car I had recently didn't... – Nick C Jun 29 '15 at 15:06
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    @Paulster2: Most manual cars in europe don't have this safety mechanism. Only some of the newer model years (say > 2008) or cars equipped with start-stop or at least an engine start button have it. – user5626466 Feb 4 '16 at 16:38
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Starting the engine in Neutral (manual gearbox) without depressing the clutch means the starter will have to get the engine parts moving, but also the main (input) shaft on the gearbox. Cold temperatures affect not only the oil in the engine, but also the lubricant inside the gear box. Thus the starter motor will have to contend with the slightly thicker oil within the gearbox at lower temperatures.

As you drive, the gearbox oil heats up progressively due to friction between moving parts and also the oil itself getting into motion. As it heats up, it also thins out, giving better lubrication and making it easier for the driver to change gears (the gears enter better). Transmission oil also has the double viscosity grading system, such as "EP 75W/90": 75 when cold, 90 when warmed up.

When both the engine and the gearbox oils are at working temperature, the engine may be started in Neutral without depressing the clutch. However, as pointed out by @Paulster2, best practice is still to depress the clutch when starting.

  • +1 "lubricant inside the gear box" - very right I have observed heavy gear lever in cold mornings, either its due to low quality gear oil or what, but yes good point that might be the cause – shabby Jun 30 '15 at 6:36
  • This is the correct answer, you depress the clutch in winter to make the job easier for the starter motor. Might be the difference between starting and not when the battery is weak. – I have no idea what I'm doing Feb 4 '16 at 7:56
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I personally always start the car with my foot on the clutch pedal as a matter of good practice.

If you start the car this way then you put very slightly less strain on the starter motor as it's not having to spin the entire clutch assembly or any shafts within the gearbox.

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    some cars and motorcycles just start when you press the clutch. – AFetter Jun 29 '15 at 12:28
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When I learnt to drive in the 1960s, British engines were not as powerful and batteries were nowhere near as good. I was taught to start in neutral with the clutch out and later, as a driving instructor, I passed this on. I don't know about now, but back then, depressing the clutch put MORE strain on the motor. This was easily established by listening to the motor, or watching the tachometer. If I had the car idling in neutral, and I depressed the clutch, the engine revs would go DOWN. Of course, living in coastal suburban Australia, I did not have to deal with the kind of cold temperatures that would be experienced in the USA or Europe.

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There are two sides to this topic: 1) As you depress the clutch the input shaft is disconnected from the crank -> Less strain on the starter and the battery/electrical system.

This is all nice and dandy, HOWEVER: 2) By pressing down the clutch pedal you put an axial load on the crankshaft. This will lead to increased wear on the thrust bearing (The one crank bearing that also limits/sets the axial play of the crankshaft) as there is no or not enough oil pressure yet.

Personally, I use the clutch out neutral start. However, I never drive my cars for such short times where an increased strain on the battery can't be recharged. If the starter should at some point fail from the added stress, it is easier and cheaper to replace.

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