3.5 turbo let run ?

[XLT22]

The issue is oil to lubricate the spinning turbo.

Look at how the turbo oil feed lines are routed. There's enough there to gravity feed for a bit.

We had a spate of oil feed line replacements on the last gen 2.7 due to smoking on startup. Even after sitting cold a good bit of oil would always run out. Sure let it idle a minute on the scenic overlook after climbing an 8% grade at 75mph but other than that it doesn't need it.

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[adaycj]

Just no. The turbo is oil lubricated, and coolant cooled. It's not like an old turbo that wasn't cooled, and even the bearings are different. And it was never about "spinning down". Even if the turbo was going 100k rpm it spins down pretty quickly because it has a turbine and impeller on both ends of the shaft with air resistance. A fast running engine has lots of coolant flow from the water pump, idling just heats the turbo with minimal coolant flow. Engines also have less oil flow at idle too. If the turbo is all nice and hot the best way to shut it down is to remove the heat source by shutting down the engine and let the coolant in there cool it slowly. Plus start stop in many cases also pretty quickly shut off the engine with no ill effects on the turbo. And even the weird argument "if you were towing" isn't really anything. How often are you boosting at 10 or 15 psi and just lift and shut it down? Expressways, gas stations, rest areas all have a ramp down that takes a bit of time. It's not a pit stop.

 

[adaycj]

The issue is oil to lubricate the spinning turbo.

The turbo is done spinning in a few seconds. It used to be about the oil cooking (coking) at the bearing from heat. But now there is coolant in the center section of that keeps it cooler.

 

[Gros Ventre]

Relying on residual oil in the feeder lines is not a good idea... Being water cooled is a nice feature but again relying on that to reduce or eliminate bearing damage is not a good idea... Spin down does occur quickly since if the compressor is spinning its compressing but without its driving force it'll low down quickly... Still all of these are betting it'll be OK... Rather take some kind of positive action to ensure the rotor is at rest.

 

[XLT22]

Relying on residual oil in the feeder lines is not a good idea... Being water cooled is a nice feature but again relying on that to reduce or eliminate bearing damage is not a good idea... Spin down does occur quickly since if the compressor is spinning its compressing but without its driving force it'll low down quickly... Still all of these are betting it'll be OK... Rather take some kind of positive action to ensure the rotor is at rest.

Ecoboost engines have been in trucks for well over a decade now with no issues caused by parking them hot. I think it's time to let that idea go.

 

[Ricksc]

This subject just like all are subject to personal preference. To each their own.

 

[Gros Ventre]

Ecoboost engines have been in trucks for well over a decade now with no issues caused by parking them hot. I think it's time to let that idea go.

Ignorance is bliss...

 

[v8440]

He's not ignorant because he disagrees with you.

 

[Goldeneye36]

Honest question because I don't know: Do modern diesel engines have turbo timers from the factory? Those trucks work their turbos a lot harder so I would imagine if the issues some people mention here were still a thing it would show up in those applications for sure.

I've owned a 3.5L truck of some sort for over a decade and never had a turbo issue. I don't baby my vehicles, either.

I personally think it's silly how many people think turbos in general are complicated/unreliable. They have been used in various types engines going back to at least WW2 and at their core are actually quite simple mechanically. The most complicated thing about modern engines are the electronics and computers, which are present regardless of being NA or FI.

 

[powerboatr]

Honest question because I don't know: Do modern diesel engines have turbo timers from the factory? Those trucks work their turbos a lot harder so I would imagine if the issues some people mention here were still a thing it would show up in those applications for sure.

I've owned a 3.5L truck of some sort for over a decade and never had a turbo issue. I don't baby my vehicles, either.

I personally think it's silly how many people think turbos in general are complicated/unreliable. They have been used in various types engines going back to at least WW2 and at their core are actually quite simple mechanically. The most complicated thing about modern engines are the electronics and computers, which are present regardless of being NA or FI.

Hmmm
My previous 22 eco
It idled a minute
While I log off Pandora
Gather my stuff
My 250, same thing. By time its nestled in its parking spot I shut it down, its been idling a few minutes
Both..if it was a hot mother of a day pulling working it
Same same
My super duty om
Suggests after heavy towing at speed I am paraphrasing
To let it idle a few minutes to let some heat dissipate not just for turbos, but the whole ppwer package
Use the guidance in the OM

 

[Gros Ventre]

He's not ignorant because he disagrees with you.

He's ignorant because he doesn't understand the lubrication issue for a shaft spinning as much as 100,000 rpms that is involved.

 

[Gros Ventre]

Unless Ford designed in a "drain down reservoir" for oil to keep the bearing lubricated, relying on residual is a crap shoot. The issue of cooling is nice and helps but the key is a hot bearing that has a spinning shaft with no or little oil to keep it lubricated and cool. The coking happens inside that bearing.

 

[DT444T]

Ah the good ol’ days of boosted imports and turbo timers

Still got the turbo timer in my Z, lol

 

[Gros Ventre]

Keep in mind that part of the issue on a PowerBoost is the engine cycling off when you crest a slope where you were on the turbos in the climb. In my case there is a coffee & snacks place just over a healthy ridge. I go in there with some regularity. If you're staying at highway speed after the crest there' no problem. Consider, there's a stretch of I-64 in Virginia/West Virginia with a steep 7 miles climb. At the crest there's a pull off. If you're towing and heavy on the turbos climbing, then go into that pull off... you need to keep the engine running and cool off & spin down the turbos. Or keep going to the next rest area...

 

[TheGoatman]

Keep in mind that part of the issue on a PowerBoost is the engine cycling off when you crest a slope where you were on the turbos in the climb. In my case there is a coffee & snacks place just over a healthy ridge. I go in there with some regularity. If you're staying at highway speed after the crest there' no problem. Consider, there's a stretch of I-64 in Virginia/West Virginia with a steep 7 miles climb. At the crest there's a pull off. If you're towing and heavy on the turbos climbing, then go into that pull off... you need to keep the engine running and cool off & spin down the turbos. Or keep going to the next rest area...

How long does it take the turbo to cool after a long hot pull? I bet the answer will surprise you.

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