Engine Cool Down / Idle

[bettsy Junior Member Find all posts View Profile Close bettsy]

Hi All

Just a query that some of you may be able to help me with in relation to letting engine (D4D) cool down / idle after highway running at approx 105km hr.

Scenario 1 - To work I travel about 35km at this speed, then enter "city" traffic for about 5 minutes at a speed of between 40-80km kr. Do I need to let the engine idle and cool down, or would the slower speed above be enough cool down.

Scenario 2 - Way home I travel the 35km at 105km hr, then have about 1 minute at 50km hr. Should I let it cool down / idle for longer period

Thanks for your help

Regards

[Guest Close Guest]

I wouldnt be bothered at those speeds or duration.

[IRON-PAWW Avid PP Poster! Find all posts View Profile Close IRON-PAWW]

Yeah, TP, as always, is on the money here I think.

As far as I'm aware, the real danger time is when you're loaded up with holiday gear and have been going at 110km/h up the highway for a few hours and decide to stop at a roadhouse for a coffee. You pull up and switch off. That's when you'll do damage. Particularly if you're towing something and you've made the engine work during the trip. In that case, I'd be giving it a good few minutes to cool down. At least 5 or so, and perhaps more if it was a hot Oz summer day.

If you're just hooning off to work with no load or towing nothing you should be reasonably covered. Certainly 5 mins going at 40 - 80 km/h at the end of the trip, I really don't think you'd need to worry. 35k's at 105 km/h with no load and similarly I don't think you'd have a problem. Maybe a short cooldown (1 min) if you literally pull off the highway into your driveway, but after only 35 km I don't think you'd need to. Let's say you did a 100km trip though at 105km/h. If that was me I'd be giving it a good few minutes at the end to cool down if I wasn't slowed down in city traffic before switching off.

[intens Junior Member Find all posts View Profile Close intens]

you need to take into account how heavy you are on the right foot and duration

[D4D Addicted PP Member Find all posts View Profile Close D4D]

I've had a few turbo cars and I don't rev above 1800-2000 for the last 5 mins or so of normal driving. After heavy driving, in the bush or towing, I usually let it idle for 5 mins before switching off. In the summer I usually pop the hood when I get home to let the heat dissapate quicker and not heatsoak the engine.

[lawrance Senior Member Find all posts View Profile Close lawrance]

How is the turbo cooled? Is it water cooled or oil cooled?

[clifton Advanced Member Find all posts View Profile Close clifton]

Hi Lawrance:
The turbocharger rotating assembly bearings area is water cooled and supplied with oil from the engine oil galleries.

[lawrance Senior Member Find all posts View Profile Close lawrance]

Thanks Clifton,

I'm not sure if I understand you 100% but from what you've said, this turbo is basically water cooled and of course it gets its lubrication from the motor's oil circulation system.

Looking at the Mercedes ML270 CDi motor, it too is water cooled and what's really neat about the Merc design is that even after you've turned off the engine and pulled the keys out of the ignition, the clever boffins at Stuggart have fitted a secondary electric coolant pump which continues to circulate coolant around the turbo until the heat soak condition goes away.

Now that's neat.

[McBAIN Avid PP Poster! Find all posts View Profile Close McBAIN]

hired a saab 9.3 once and it did the same minute or two of an electric motor cycling the oil after shutdown which was pretty cool.

[Guest Close Guest]

Thanks Clifton,

I'm not sure if I understand you 100% but from what you've said, this turbo is basically water cooled and of course it gets its lubrication from the motor's oil circulation system.

Looking at the Mercedes ML270 CDi motor, it too is water cooled and what's really neat about the Merc design is that even after you've turned off the engine and pulled the keys out of the ignition, the clever boffins at Stuggart have fitted a secondary electric coolant pump which continues to circulate coolant around the turbo until the heat soak condition goes away.

Now that's neat.

I'm sorry, Maybe I dont get it but just what does this have in relation to answering or providing feedback on the original question?

[waltec Senior Member Find all posts View Profile Close waltec]

TP

Watercooled Turbos usually have less issues with idle down, the old oil cooled turbos if shutdown when very hot cooked the oil and stuffed the bearings, the new water cooled tubos don't get as hot, and have more volume to disapate the heat into. The Idea of the Merc is that the water keeps circulating after the engine has stopped dumping heat into the turbo, and continues to cool it until its at a safe temp.

Matt

[Guest Close Guest]

Correct, and this I knew. But I dont see how it answers the question about if he should idle down?

Seems to be a lot of answers going totally off topic from some posters lately. :x

[Yota Advanced Member Find all posts View Profile Close Yota]

Correct, and this I knew. But I dont see how it answers the question about if he should idle down?

Seems to be a lot of answers going totally off topic from some posters lately. :x

And you have never got to the end of a conversation and wondered how it started?

No it doesnt answer the question directly, but its hardly"totally off topic" when their still talking about turbos and how they cool down.

Calm down!!

[TOPNDR Lurker Find all posts View Profile Close TOPNDR]

FWIW in the three diesel turbos I've owned, I've always planned stops. I never arrive at a stop having been highway cruising and turn the motor off. I either leave it idling with Mrs TOPNDR, or slow down to 80 kph for the last 5 km, and then turn it off. I've not had any turbo or engine problems.

1 x Mitsubishi 2.8 l diesel, 2 x Nissan ZD30 diesels.

[ntp Addicted PP Member Find all posts View Profile Close ntp]

FWIW in the three diesel turbos I've owned, I've always planned stops. I never arrive at a stop having been highway cruising and turn the motor off. I either leave it idling with Mrs TOPNDR, or slow down to 80 kph for the last 5 km, and then turn it off. I've not had any turbo or engine problems.

1 x Mitsubishi 2.8 l diesel, 2 x Nissan ZD30 diesels.

Likewise... 8)

ps. Don't forget to add your location to your profile TOPNDR