Engine pre-heating

[twosmoke300]

Saab 9-3 2.2 tid's had a fuel powered heater too

[Squire_Dawson]

I have also seen a sump heater:

 

http://engineheaters.co.uk/description.html

 

From a technical point of view, the starter motor is struggling to turn the engine with the weight of the cold, tar-like oil, to the point which, on a compression stroke, it stops entirely for a fraction of a second. The starter motor itself is actually in good health, as is the battery. The ignition timing is not so far advanced. I have observed, in the past on a similar car, that the oil pressure gauge takes quite a while to move when starting from cold. So the cold, thick oil is naturally taking longer to circulate.

 

I will report my findings.

[pshome]

"Tar like oil"?? Sorry thats total BS.... "So the cold, thick oil is naturally taking longer to circulate." More BS.

If your starter can't turn your engine properly, check it, your battery and the cabling, but leave the poor oil alone.

[Rusty_Rocket]

I must admit, my A-Series engined cars fire first crank, whether it's hot or -5.

 

Having said that, during a cold winter, I also remember having to pour boiling water over the block in a 1970 Mini I was running in the early 90s.. so maybe that was the same thing.  That car had a dynamo though, so I always put it down to the starter not having enough grunt to spin the (very) cold engine.  It was a pretty knackered motor by then too!

 

Are you sure the starter isn't just weak?

[sierraman]

I've never heard of a car struggling to turn over due to the oil it's running on. I've heard of plenty with fucked starters, dying batteries and generally worn out engines. I mean Christ what have you filled it up with? Marmite? Or possibly that gloop they call 'Irish Meadow' in Iceland.

[Des]

I think someone has procured a drum of pre war monograde, pre WW1 that is.

[twosmoke300]

Or has done an oil change with Landrover swivel grease

[Squire_Dawson]

"Tar like oil"?? Sorry thats total BS.... "So the cold, thick oil is naturally taking longer to circulate." More BS.

If your starter can't turn your engine properly, check it, your battery and the cabling, but leave the poor oil alone.

 

It's a fact, I'm afraid. The colder it gets, the less free-flowing it becomes. By all means attempt to re-write the laws of physics, but don't call me a bullshitter.

[forddeliveryboy]

Different engines are affected differently in cold conditions, I've known some which are much slower to turn over with gloopy oil at -10C, others for which it makes little difference other than a few seconds rattle from the top end before oil reaches it. Like for like that is, not condition of battery or starter-motor dependent. 

 

I think anything modern would turn over almost as fast on a straight 60 grade in the cold, just ruin its bearings in the process, everything's so powerful today. 2cv owners are advised to 'unlock' their engine in extreme cold by turning it on the starting handle a few times before turning the key.

[Dave_Q]

Have been having a quick google about this and it does seem that the viscosity of 20w50 does increase (decrease? whichever is thicker) sharply below about 0 degrees C, the axis isn't labelled on this graph but I'm guessing it's temperature in degrees F.

 

 

If the axis is as I think then the 20w50 should be twice as hard to pour at 0C as a 10w40.

 

Not sure about tar like though.

 

Squire, fancy leaving a bottle of oil outside overnight and doing a pour video for us?

[Dave_Q]

Here it is at -20C, looks like the sauce in a Maccys caramel sundae.

 

[holbeck]

Years ago I worked at a manufacturer of diesel engines, to pre-qualify for some sort of military contract we had to do a witnessed cold start test at -30C ( I think) .

The engines had been cold soaked for 24 hours in a fridge. The engines were air cooled -so no coolant to worry about but the oil was just treacle and wouldn't pour from a jug.

 

The only way we could do it was to dilute the oil with diesel. That made it sufficiently fluid that you could crank the engine. However at very low temperatures the engines still wouldn't fire.  How they got round it was to devise an oil injection system where a plunger would give a shot of (pre warmed) oil directly into the cylinder to raise compression during cranking. And with this contrivance we could get the engines away.

 

All of this had nothing to do with what the engines were expected to do, just the hoops you had to go through to be on the tender list.

 

Apologies to the OP as none of this is relevant, but hey-ho!

[artdjones]

In the North of Canada many vehicles have three plugs hanging out the front grille. One to hook up the block heater, one for the sump heater,and the third one for a little heater that is fitted in the water pump.When I say the North I don't mean up where the polar bears live,but where there are still towns and people.

[Squire_Dawson]

No, it is all relevant as there's more to oil than meets the eye. I will do a video but it will take me a while. Here's an old one, but note that here the sump was filled with Halford's Classic 20w50. The Miller's Classic Mini Oil I use now is the same grade but, like I said, still thicker.

 

Note the oil pressure gauge reading.