Idling turbo diesel before shutting down?

[krazykat]

Hi,

Just wondering if anyone knows how long to idle the NL series 4M40 for before shutting down. In hard sand driving, I'll idle for 2-3 mins but not sure how long to idle after driving around town or freeway.

How much is the turbo boosting driving around town changing gears around 2500rpm? What about sitting on the freeway at 3000rpm? How hot does the turbo get with those driving conditions?

I've heard that modern turbos with oil and water cooling jackets around the turbo don't need idling before shutdown (the thermal siphoning action of the water keeps the turbo cool after shutdown). Is the NL series 4M40 of such a design?

Thanks.

[hensby]

turbos cool down

No one answered this guys question back then. Have been wondering what is the opinion now for DID's?

[peter92]

when i had my landrover i did it for 5mins just to cool it off, should be plenty. if you like buy a turbo timer
regards perer

[Taboo]

I have owned both petrol turbo cars and diesel turbo cars,
and have never used a turbo timer with nil problems, the only
time you need to let it run for a bit is maybe after you have given it a
hard time. Regular oil changes are more important for a health turbo.

[David Anderson]

I give mine about 30 seconds at idle before shutting down.
Maybe a bit longer if I've just come off the freeway.
I figure it can't do any harm.

Given the 10 year warranty on the driveline, I bet Mitsubishi would have a standard turbo timer if it was important.

[oyamum]

mitsubishi dont put on a turbo timer because its another cost... simple as that there are plenty of things that would be of benefit or helpfull on your car that arnt fitted because of cost... i would say 1min is ok for the most part maybe a bit longer if given a hard time but honestly just spend $100 on a turbo timer its worth every $

[osca4x4]

sorry guys but idling a turbo is not neccessary, think about it, the vehicle is not moving, no air flow, whats going to cool down?

you drive slowly into your drive way or parking lot, thats all it needs.

our fire trucks don't need idling before switching off.

[Dion]

sorry guys but idling a turbo is not neccessary, think about it, the vehicle is not moving, no air flow, whats going to cool down?

you drive slowly into your drive way or parking lot, thats all it needs.

our fire trucks don't need idling before switching off.

The idea is to let the turbo cool down by letting oil/water circulate while it idles.

On both my turbo vehicles (petrol and diesel) I let both idle. Usually it's just the time it takes me to unbuckle seat belt, grab wallet etc and hop out - grab key is the last thing I do. If I've been working it hard I'll give it a bit longer.

[peter92]

it depends on the size of the turbo to wether it needs to idle down as the fins inside the turbo do the cooling. if it wasnt nessasery then why do all big prime movers all idle down. the 4x4 may no need to idle down but it wont hurt to do so. the ones that do need to these days turn off by timer
hope this helps
regards peter

[Aussie_Dan]

The Paj is my 2nd turbocharged car.
The only time I will really let the car have a while to idle down is either when pulling straight off the highway (into a rest stop or the servo?) or if i've been working the car hard offroad (on the beach for example). 90 seconds would be plenty of time.
In the city, my drives always end with me either crawling through a car park for a short time or getting out of the car to open up my garage to drive the car in. In both of these scenarios the car has already spent plenty of time at near idle. Letting the car idle any longer is only a waste of fuel....
Dan.

[mineclearer]

some interesting comments re the idle down on a turbo diesel.

I idle down after working it hard but I suppose that is because I was taught to do that on Caterpillar Equipment. It was not so much the cool down but the slow down of the turbo. On Cats the turbo is spinning at phenominal revs and the idea is to bring it down so that you do not create hydrostatic or air locks on restart

That said small diesels are different and I find that 1min seems reasonable after hard work.

Mineclearer

[Dazza.]

Yeah I figure it's just cheap insurance.

If you've been up it a bit and pull up to a sudden stop then it's worth letting it idle for 30 seconds to a minute. For just poking around town I personally just let it go 5 seconds or so and shut it down.

[Pajenaro]

Hi guys,

I have an EGT gauge with the sensor installed immediately after the turbo in the dump pipe.
Temperature sometimes gets as high as 550c for example on long uphill sections whilst towing. Hard low range slog through sand etc etc.

Normal idle temp for me is around 160c. When it comes to shutting down I let the temp drop back down to around 180-200c. This usually takes no more than 60-90sec. Which is pretty much how long it takes me to pull up to the gate, get out, open it, get back in, close it.....

Scott

[epitrochoid]

I mainly idle my 2.5 tdi NH paj down for about 3 - 5 mins after a freeway drive. I find that is when the turbo works hard for the longest period of time and the NH turbo's are only oil cooled.
Around town, about 10 seconds then turn it off. 30 seconds on hot summer days with the a/c on.

Regards
epitrochoid