Diesel Engines - Cold Start Oil Concerns?

[andreigbs]

Works with the EGR to control flow and is sometimes called an anti-shudder valve. Stops that little bit of run on that diesels tend to have.

^ This, and also helps to prevent runaway conditions if the turbo should go BANG and ingest all the engine oil in the process, revving sky-high (for a diesel anyway) until the engine also goes BANG.

 

[Jetronic]

IF the valve is actually closed by killing the ignition and not waiting for the rpm to drop low... I've never seen them close on a high rpm engine.

 

[JHZR2]

100-400´f
impossible to get rid off completely; unless you run the oil above 400´f
i guess nobody does

Is there a vacuum on the crankcase?

That changes things a bit.

Not possible in a diesel, but normal in a gas engine.

 

[OM605]

Deleted.

 

[Marcozi]

I'm pretty sure my 535d has an auxiliary heater in the HVAC - it's blowing warm air a couple minutes after a cold start. I'm impressed with how quickly this engine heats up, but there's no way the coolant is delivering that kind of heat from the heater core that quickly.

Actually, the HVAC and the cooling systems in modern BMW's are designed to route warm/hot coolant to the heater core very soon after a cold start.

 

[SteveG4]

When I was in the biz we installed diesel fuel heaters in class 8 trucks that traveled in Northern climates, especially Canada and Alaska. They were mostly installed to improve fuel efficiency but also to prevent fuel gelling. Truckers loved them.

They also used block heaters which greatly improved cold starting.

At my remote Alaskan telephone company central offices, I always specified a Pryco indoor diesel day tank for our backup generator sets. This way, they were always fed with room temp fuel or relatively close to it. It's a wise thing to do when outdoor temps can be -30 to -40 degs F!

Moreover, indoor never fuel gels, so we were guaranteed the genset would operate a good 12 to 24 hours. And if or when cold-gelled fuel was encountered, it was pumped into the warm fuel tank for mixing and a several hour warming period.

 

[Jetronic]

Actually, the HVAC and the cooling systems in modern BMW's are designed to route warm/hot coolant to the heater core very soon after a cold start.

Don't all cars do that? when the thermostat is closed, coolant is routed to the heater core, throttle body and sometimes intake manifold + header tank.

 

[gogydm]

Don't all cars do that? when the thermostat is closed, coolant is routed to the heater core, throttle body and sometimes intake manifold + header tank.

They do, yes. Maybe newer ones have smarter, electrically operated thermostats and can more efficiently route coolant. My diesel Peugeot 407 had a 1 or 2kw (I don't remember) electric cabin heater that heated the air as it passed through. It turned off when the coolant got to a certain temperature.

 

[Jetronic]

900W in those pugs. Worked as master tech for peugeot dealership until 2008

 

[Blue_Angel]

They do, yes. Maybe newer ones have smarter, electrically operated thermostats and can more efficiently route coolant. My diesel Peugeot 407 had a 1 or 2kw (I don't remember) electric cabin heater that heated the air as it passed through. It turned off when the coolant got to a certain temperature.

Not sure about my 535d diesel, but my wife's 323i gasoline 2.5L six has an electric water pump that doesn't pump any coolant until the engine reaches a certain temperature. This gets the cylinder head hotter faster and decreases cold-start emissions.

 

[edyvw]

Not sure about my 535d diesel, but my wife's 323i gasoline 2.5L six has an electric water pump that doesn't pump any coolant until the engine reaches a certain temperature. This gets the cylinder head hotter faster and decreases cold-start emissions.

BMW diesels have electric heater. They turn themselves automatically after coolant reaches 50c. And you are right, they will not route anything to heater core until certain temperature is reached.

 

[jjblbi]

My VW TDI 2014 Passat w/ ckra has an electric grid heater which is enabled when the heat is set to the hottest postion and the fresh air is set to recirc. I get some heat within a mile or two of home.