Engine/Transmission (1998.5 - 2002) How hot is the turbo oil back to the filter?

[rweis]

In trying to plan a really good gauge set I am thinking that there are a lot of members that monitor both pre & post pyro, but I don't recall anyone monitoring the turbo oil temp as it goes back to the filter (at least that is the way I think it flows).



Would it give you any more useful information? There are a lot of discussions about cokeing the oil because the turbo is too hot prior to shutdown and to cool the post turbo to 300 degrees. If the oil being too hot is a concern, why not monitor its temperature?



Just a thought / question



Absolutely think these forums are the totally outstanding!

 

[Whitmore]

great question

I have wondered that myself ??? I would think that the oil from the turbo is the hottest spot in the motor and yes you are right on about coking the oil there from premature S/D , actually you are right that we do monitor the EXHAUST but that does not mean that the conduction heat transfer is getting thru the mass of the steal to cool the oil to 300 degrees, seams to me that the oil from the turbo would be the last to cool , not only is the oil there for lubrication but it is also there to pull the heat away from the components too !!!



Cheers , Kevin

 

[jbone]

I have oil temp out of the top of the filter--as I recall?? the turbo dumps in on the side of that same mount--so I read steady running or towing temp of 190--hope to lower that soon to 180--have my new Cummins thermo read to install... ... R, J. B.

 

[slo-ryde]

Actually, I think the oil leaves the filter and goes to the turbo through the stainless steel line at the top of the filter housing. There's a large tube from the bottom of the turbo that dumps the oil into the sump (oil pan). If you wanted to measure the oil temp after the turbo you would want to mount the sensor in the tube underneath the turbo. Unless I'm completely confused about how the turbo gets lubricated.

 

[Mundgyver]

If your are running a synthetic oil, then coking of the oil is not a major concern. Coking take place more with regular Hydro-Carbon based oil. The heat just cooks it. Synthetic will withstand hotter temps than regular oil. Reason is that all the molecules are the same size which promote greater cooling from the tumbling action as they flow. Regular hydro-carbon oil has different size molecules and they tend to stratify into layers as they flow. The stratification prevents the oil from cooling as efficiently as it could. This is also the reason why synthetics are superior to hydro-carbon oils for wear protection and over all cooling of the engine. The oil is also going through an oil to water cooler just before it goes into the filter. Normaly your oil temp will be about 10 degrees higher than the water temp which is what you want so that any H20 moisture in it will become vaporized and be dumped over board via the vent.

It would be interesting to see what the temp is on the return line to the pan from the turbo though. I look forward to your post update.