Thread: A myth busted! For me anyway

In very cold conditions, like bus tours through the Himalyas, they are known to leave the vehicles idling all night with a fire under the diesel tank to stop it turning to jelly. If the motor stops you have about 1 minute to get the hoses off so the coolant doesn't freeze, expand and crack the block.

This happened on a Top Deck tour once. Even the passenger's water bottles had frozen, they stalled the bus, probably from gluggy fuel and the block cracked.

You know how long most engines last in really cold places though...

In places like siberia, they mix up to 30% petrol in with the diesel. This is permitted by the manufacturers.

Originally Posted by tombraider

I then fit my belt and then drive straight to work...

How do you keep your pants up until then?

I stayed a night at Salina Utah a while back. Outside the motel (and truckstop) more than 100 rigs idled the night away; outside temp at 0600 the next day was minus 20, bleak and snowing...and windy and not fun....

I can only assume these drivers knew about diesel and diesel engines...and below freezing conditions.

GQ

I was recently driving a Kenworth T404 SAR fitted with a Catapiller C15.
This truck being fairly new had all the owners manuals including Caterpillars manual for the engine.

The truck was fitted with a selectable turbo timer. The book said to let the engine idle for three minuets before shut down.

For start up it said to not rev above idle until full oil pressure is at the gauge and if this is not achived with in a few seconds to shut down the engine.

As for idling they say to not let the engine idle for more than five minuets or the turbo can suffer from lack of lubrication.

This truck, and I know that Western Stars also have this; When stationary you can use the cruise control to increase and hold the engine RPM to about 1600. This is if you need to leave truck running.

I know a driver who pulls over for a half hour power nap and on a hot day leaves the engine running at 1600 to keep his air con working.

As for angle gear, the reason it is bad for the gearbox is that the gear box has an oil pump driven by gearbox input which means engine revs.

This is the same as an early four speed Range Rover. The oil pump lubricates the gears where they are spinning on the main shaft.
So when the mainshaft is turning at road speed (the output shaft which is directly connected to the tailshaft) the oil pump being driven at idle speed does not supply enough oil to match the mainshaft speed.

This can easily be over come by raising engine revs when in angle gear, which is what I used to do with this truck going down a big hill until I lost my licence (126kph in a 100kph zone).

Dave.

There are other issue's when operating in sub zero temperatures, least of which is the driver not freezing to death. But there can also be serious issues with various other compnents freezing

Yes, air compressors need to keep running so air lines don't freeze.
New Volvo FH prime movers with I-shift will slip in to neutral and drop to idle at highway speeds when coasting. Than pick up the right gear and engine revs if speed drops or if speed increases above set speed. Kind of spooky at first. Haven't been able to tell if it saves much fuel though.

The only reason they keep the engine running in super cold conditions is to keep everything warm. I was reading the other day about a unit they can install , some sort of heater and generator, that heats engine, cabin, load and provides power, and at the same time uses less fuel than idling the engine. Most european petrol cars will happily start in -20. Most diesels as well (as long as the fuel is not solidified).