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Found the turbo cool down timings for the 2.8 CRD


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My recently acquired KJ is the second 2.8 CRD I have owned. The first was in a 2007 JKU that I had from new and I always cooled the turbo down before switching the engine off. However, I used knowledge that I gained from work when I was in R&D destroying stuff for the idle timings. I would give my turbo at least a minute idling before shutting down to allow the engine oil flow to cool the turbo.


I came across this chart in the KJ's factory service manual that went a lot further on recommended idle times than I had been using myself. I guess when towing the caravan I should be idling for 5 minutes before shutdown.


If you have a newer Jeep with a water cooled turbo, if your turbo spindle is rotating at shutdown at more than 150 DegC the oil film on it will coke. I don't know how well engineered the turbo oiling systems are on modern Jeeps but they would need both an electric coolant pump and an electric oil pump or pressurized oil accumulator to continue both coolant flow and engine oil flow over the spinning turbo shaft.




A ball bearing turbo will spin for longer than a plain bearing turbo.


30 seconds or more for a ball bearing turbo...



About five to ten seconds for a plain bearing turbo...



Edited by V
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