An immediate shut down after putting a load on an engine can result in overheating the engine coolant flow stops upon shutdown and the block becomes a heatsink. Their reasoning seems to be that temperatures are uneven after hard use and by idling the engine cools off and the temperature differences arent as great.
Idling Emissions
Why idle a diesel engine before shutdown. Joined apr 8 2009 470 posts. Gasoline engines operate under high intake manifold vacuum at idle due to the closed throttle valve. He also said it isnt necessary when just running about town without the trailer. It seems to have to do with the lack of a throttle valve in diesels. The drop in turn can cause internal parts to cease fitting together as the manufacturer intended. Says to idle before shutdown.
Abusing your turbocharger can affect its longevity. I had someone tell me to let the truck idle for 10 seconds before shutting down. Rampant lion registered. But after long hauls you may want to idle the engine for up to seven minutes to allow the manifold to cool down. So a minute or two run at idle by idle i mean 1200 1500 rpm with a tractor allows the coolant to flow at no load and keep the engine cooler. Why idle before shut off.
I dont shut down my engine when its hot. And again this practice wastes fuel. But i guess a minute at high speed without a load wouldnt increase the engine temperature. Dan explained that three to five minutes is usually sufficient for cooling down a diesel engine. Discussion starter 1 aug 29 2009. With time the turbo will become less effective.
While there are a lot of valid arguments supporting the cause of idling even the naysayers will agree youve got nothing to lose by practicing the idling rule. Jump to latest follow 1 8 of 8 posts. There is always full air flow though the engine varying only with the rpm. If a diesel is left idling the internal temperatures will eventually drop a change the temperature gauge may not register. I believe that diesels unlike gasoline engines do not have heating problems when idling. An idling diesel circulates more than enough lube to keep everything well oiled and revving the engine then shutting if off can leave unburned fuel in the combustion chambers and even starve the turbocharger bearing because the turbo will keep spinning after the oil supply dies.
Turbo charged engines must be idled down to allow the turbo to spool down and even out the temperature in the turbo this is done either by using oil cooling or the engine coolant or both in.
Gallery of Why Idle A Diesel Engine Before Shutdown
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