thermostat temp?

[mhagie]

I have a dual stat set up on my 6.5 with 180* t/stats.
Penninsular 6.2 hi flow water pump.
Also running a remote oil cooler fed direct, bypassing radiator.
I was cautious about trying 195* stats because I am not sure of my cooling capacity,with the old body style the radiator is way narrower than the 82-up.
I have 6.2 tanks on a 1980 454 modine replacement radiator core,Modine says their 3 row will out cool a original 4 row, but I won't bet on it.
Water temp has been staying right on 180-85*, oil temp has however been a challenge as it struggles to reach 160*
BTY it does have a deep sump pan,Dr Lee bypass oil filter, oil capacity with the HD two Qt oil filter and everything full, dipstick right on the full line is 14 Qt.
Should I have used 195* instead to heip bring up oil temp?, I never once gave it a thought that the oil would run so darn cool.
Electric oil temp sender mounted 1 1/2 up from bottom on back of pan.
Oil wt 15-40

Merle

[Hubert]

I don't think so. As long as it doesn't take excessively long time to reach temp. I used to think oil had to exceed 212F so moisture would "boil" off but a while ago I read a good bit of stuff and thought about what I read and now think oil temp should remain under 180F. Oil is suppose to be cooling the bottom end of the motor: the pistons mostly but also all the bearings too (especially the turbo).

IF the oil gets hotter than the thermostats then well it won't remove much heat from the bottom of the engine.

Oil will still get hot enough at a few local hot spots to "dry it enough" I believe and as long as you run good filters and change the oil regularly it will do what it is suppose to. And the blow by vapor will stay hot enough to get out of then engine as long as run time is decent and it gets to full operating temp. IF you just drive less than 5 miles at a time with long sitting spells then moisture may be a concern but I don't know many people that have to worry about that.

Mostly you should worry about the time at high temperature. The life of Dino oil shortens as the temperature rises. Its not a linear curve. It will last a long time at 180F but over 212F it shortens appreciably and above 220F even more. At 260F it shortens significantly. I can't remember time intervals and don't want to exagerate but I think its something life 1/2 the life expantancy at the 260F which would be a lot of oil changes. And at the turbo and around the piston rings I think it gets really hot more than what your oil temp guage reads so don't think 260F is out of reach momentarily especially if oil temp gauge was higher.

[mhagie]

Thanks, I am old school myself, I always thought oil had to be in the 200* range to rid itself of moisture.
Taking this a step further will increasing water temp to 195* affect combustion/power/economy?
If temps follow a curve even at 195*water temp oil temp would be at 175* which would still be acceptable.
My problem is I don't know what the limit is of my oddball radiator, I can be running on cruise @ 70mph and climb a hill of decent grade about 1/2 to 3/4 mile long and watch the temp climb about 5-8*, makes me wonder what it would do under load.
Temp gauge is mechanical sensing temp right out of t/stat housing to heater core hose.
Merle

[Hubert]

I am interested in others opinions too.

I googled again to find some sources and reread info again as my memory is awful sometimes and better tech articles come up. One sources says 200F and above stresses oil. I assume thats sustained oil temp at the sump and not local temps. I did not see proper engine oil temperature recommendations for modern diesels. Perma cool says 180F is ideal temp for oil but think thats biased for gassers. Diesels are different especially turbo diesels. I don't see a definative article on diesel engine oil temperature recommendations but I did read turbo diesels can expose oil to temps in the 500-600F range at the upper rings regularly. Wow thats hot! Probably depends on EGT's which blowby temp will be related to. I imagine "in the wind" on the interstate with EGT at 800F and up to 900-1000F towing the oil near the piston crown is getting cooked literally at least momentarily. Just another reason to use only "C" designated API oil.

As long as you have a bypass on the oil cooler and flow is not restricted at start up I feel oil temperature should be a little cooler on a diesels than a gasser so it can cool the piston and turbo some. So 160F sounds ok to me at the sump for an IDI TD.

What do others think and ever seen anything published?

[DmaxMaverick]

Your oil temp is moot. It is important to get it up to a reasonable temp, but it would be catastrophic if you got it up to 212°F and it still had any water moisture in it. Can you say spontaneous steam expansion? As soon as the oil was no longer under pressure, the remaining moisture would explode when the pressure was reduced to atmospheric (if the temp was at or above the boiling point). Water will vapor off at any temp, just faster if it's warmer. Any moisture in the oil is gone by the time the engine comes up to operating temp (unless you have major contamination). Spot temps can and will reach 250°+, but the average temp should be less than about 140-180°. And, it will show less if the sender is in the pan, as the hot oil coming off the engine mixes with oil in the pan, which is cooled by contact with the pan surface.

If you are seeing 150° at the pan, you are in the "normal" range. A higher capacity will further reduce the average temp.

[mhagie]

In my younger days I had 426 wedge plymouth, the oil temp on it mirrored water temp thats why I was courious as to why this one was so low, it was my guess that it was caused by the deep sump pan.

Merle