Author Topic: Care And Feeding Of Your Turbo  (Read 3340 times)

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Offline Brett Wolfe

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Care And Feeding Of Your Turbo
« on: September 25, 2011, 07:15:40 PM »
Care and Feeding of Your Diesel’s Turbo

Start and warm-up:
If the temperature is below 40 degrees F and convenient, use the block heater for 2 hours or so. If colder it is  more important and if well below freezing, leave it on for 2 1/2-3 hours. This makes starting easier, but as critically, makes the oil flow better (as we all know, warm oil is less viscous).

Start the engine per your engine manufacturers recommendations-- basically, on most modern diesel engines you are waiting long enough for the intake manifold heater to reach temperature.

After 30-40 seconds at low idle, use the cruise control to select high-idle-- around 1000 to 1100 RPM. Obviously, continue to high-idle until air pressure is fully built. If you have a distance to go at low speed (like a couple of blocks out of the CG, you are now good to go. If you have to pull out intofreeway traffic right away, continue high idle until the temperature gauge starts to move off the cold reading.

From the turbo's standpoint, it is important to NOT really get into the throttle until the oil viscosity has thinned out enough (about the time coolant temperature reaches normal operating temperature) to supply good oil flow to the turbo. In the real world,  drive gently and never push past light throttle in 5th gear (6 speed Allison) until normal coolant temperature is reached.

No special issues while driving.

When shutting down the engine it is really critical to allow the turbo to cool down. That means both time for it to stop spinning AND more critically for the oil that has been super-heated in the extreme environment of the turbo to continue to circulate as the housing cools so that oil is not "trapped" in the hot turbo where it can "cook"-- literally turning into coke. Coking can block oil flow through the turbo over time. Depriving the bearings of oil flow is a sure formula for killing the bearings and therefore the turbo.

However, many get carried away with this! Yes, if you just pulled a 6% grade and pull into a freeway rest area, it needs to idle for 3 minutes (a lot longer by the clock than it seems). But, if you pulled off the highway and drove at low speed to a CG and then idled into the CG and on to your site, the turbo is adequately cooled and you can turn it off as soon as you arrive in the site. And if you are the third coach waiting to check in, turn it off after 2 minutes or so.

Maintenance: Change oil per your engine manufacturer's recommendation. This means ONCE A YEAR as well as based on miles. And of course, use an oil that meets the MIL specs prescribed by your engine manufacturer (most commercially available oils for diesels are fine).

Be aware that other systems also affect the turbo (as in any engine). Over heating the engine accelerates coking (again any engine gas or diesel).

Brett Wolfe