Idling engine before start up and shut down 2.0

[Linda z.]

Do you guys let your turbo idle before driving it and before shutting it off?

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[BDinTX]

After starting and before putting it in reverse and backing out of the garage, I watch the gauge cluster. Once it’s done doing its thing, I go so maybe 15-20 seconds. I’m also going pretty low speed exiting the neighborhood, then 35 mph side roads. All of that, I think, sort of lends itself so a nice easy warmup.

Shutdown is the same in reverse. Side roads, neighborhood, garage, idle ~15 seconds.

On road trips where I’ve been driving freeway speeds for a while I’m more careful with a cooldown. Similarly, if I was going from cold straight to the freeway I’d let it idle longer.

All that said, I think I’d do the same with a normally aspirated engine. Haven’t had one in a long time.

 

[NWJeepr]

Yes.

I like to let idle for 30 seconds- 1 minute when it's stone cold to let the water temp come up. Then, easy driving during warmup until the oil comes up to temperature.

For shutdown I try to follow what's in the owner's manual. Although the engine has systems to prevent baking the turbo and running it dry, the recommendations about letting it idle before turning it off are easy enough to follow.

What's written in my Jeep's owners manual about operating a turbocharged vehicle isn't that different from what's written in the Cummins engine manual for my motorhome.

Here's the idle recommendations as outlined in the owner's manual. It follows several sections of information about the diesel engine, but such headings are labeled diesel or gasoline engine. This heading is not specific, so I take that to mean either engine with a turbocharger (2.0 included). Following the practice certainly can't hurt.

 

[jadmt]

we have a CX5 turbo and Mazda recommends a short warm up before putting your foot into it which is no problem and also recommends a minute idle after highway driving which is hard to remember to do for some reason. I think that is the reason Mazda does not do the stop start on turbos.

 

[Reinen]

You don't necessarily have to idle at start or stop. You just shouldn't drive it like a bat out of hell immediately after starting or immediately before stopping. Keep a light foot until the engine warms up to normal temperature and don't shut off the engine until the engine cools to a normal operating temperature after a workout.

Unless you live immediately adjacent to a highway on/off ramp or at the top of a mountain you wouldn't need to be concerned about this. For the vast majority of people, casually driving through your residential neighborhood is more than enough time to regain normal operating temperature.

 

[Erievon]

In the early days of old school import turbos, when people were still using dyno oil, coking in the main bearing was an issue. I remember on my Eclipse I even had a turbo timer to let it idle down for 1-2 minutes on it's own.

These days with Synthetics it's far less of a concern. Unless you're drag racing on your little side street before you pull into the driveway, your ride though the neighborhood should cool it just fine. The only time I let it idle a minute is if I'm on a road trip and we immediately hop off the highway to a rest stop, I'll let that cool down for a minute at idle.

 

[Reinen]

The only time I let it idle a minute is if I'm on a road trip and we immediately hop off the highway to a rest stop, I'll let that cool down for a minute at idle.

Exactly.
I'll also add the following situations where I'll idle until I reach normal operating temperature range before proceeding or shutting off.

• On a rough trail in the mountains, as soon as I reach the top of a big hill.
• When leaving a campsite and will immediately proceed on a very rough trail or up a big hill.
• In extreme temperatures. Greater than 100F and lower than 0F on anything more rugged than a residential paved road.

You get the idea. Idling before driving and shutdown is really only for extremes.

 

[VKSheridan]

A) Don’t kill the oil supply (shut off the engine) when the turbocharger is still rotating at 20,000 R.P.M. That’ll weld the shaft to the bearings.

B) Don’t kill the oil supply (shut off the engine) when the turbocharger is glowing hot from pulling a hard load. That’ll coke the oil which will etch the shaft, bearings and sealing rings into leakage and failure.

C) Don’t just fire up and go when the engine’s cold. The cold, less viscous oil could open the filter bypass valve to prevent filter burst from high pressure which will send unfiltered oil into your system. That’ll put contaminants where you really don’t want them.

D) Use the specified grade/type of oil for your region. Just because [insert brand/blend] worked in Uncle Harry’s flat head V8 doesn’t mean it’ll help your turbocharged, emissions choked, lean burning 4 banger.

 

[Linda z.]

A) Don’t kill the oil supply (shut off the engine) when the turbocharger is still rotating at 20,000 R.P.M. That’ll weld the shaft to the bearings.

B) Don’t kill the oil supply (shut off the engine) when the turbocharger is glowing hot from pulling a hard load. That’ll coke the oil which will etch the shaft, bearings and sealing rings into leakage and failure.

C) Don’t just fire up and go when the engine’s cold. The cold, less viscous oil could open the filter bypass valve to prevent filter burst from high pressure which will send unfiltered oil into your system. That’ll put contaminants where you really don’t want them.

D) Use the specified grade/type of oil for your region. Just because [insert brand/blend] worked in Uncle Harry’s flat head V8 doesn’t mean it’ll help your turbocharged, emissions choked, lean burning 4 banger.

So how long do you idle at startup? I give it about a minute

 

[Gregj]

And all of this good advice is completely ignored by the 4Xe when the ICE kicks in because the battery is depleted or the driver floors it.

Gregj

 

[VKSheridan]

So how long do you idle at startup? I give it about a minute

It depends on the ambient but a minute or two usually does the trick. Up in Canada, a bit longer…..

 

[NWJeepr]

And all of this good advice is completely ignored by the 4Xe when the ICE kicks in because the battery is depleted or the driver floors it.

Gregj

2.0's may live a gentler life in the gas-only models.

That's also not to say the driver can't take reasonable precautions to not WOT a cold 2.0 in the 4xe.

 

[running_man]

I let mine idle at start up until the temperature rises and the RPM's drop before I put her in reverse. I try to let it idle before shutdown as well, but I'm not as consistent with that one.....

 

[WI_Sarge]

Sorry, maybe I am misunderstanding. I dont see this page in my 2024 owners manual. I have to 2.0 turbo gas only. Is the chart posted in this thread for a different model?

 

[BDinTX]

Sorry, maybe I am misunderstanding. I dont see this page in my 2024 owners manual. I have to 2.0 turbo gas only. Is the chart posted in this thread for a different model?

Hey Matt, if you're referring to this chart:

There is a freeway near me with a 70mph speed limit, about a mile long with a decent grade. My turbo inlet temp is over 1000*F for the entire climb. At the top It becomes slightly downhill for 1/2 mile, then my exit ramp to a stop sign. At that point, after light throttle and coasting, it's still reading over 600*F.

So they can get pretty hot, significantly hotter than either oil or coolant temps, especially under load. That heat then takes some time to be carried away.

Granted I'm watching temps an EcoDiesel but I think the temps are similar. Lacking a gauge, I'd say those idle times are sound guidance for anything turbocharged. I have the Banks iGauge and try to let mine idle until the turbo inlet temp is under 450*F. Which, by the time I get to the house is between 30-60 seconds depending on air temps (it has been ~100* outside lately).

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