Safe oil temps.?

[ogrice]

Which one of the autmotive industry experts out there knows the safe upper oil temp limits are for our diesel pickups.?

I installed a mechanical oil temp sensor that reads the oil as it exits the turbo. I have not seen higher than 205 deg on my engine, but i'm sure that i'm not the only one who monitors their oil temp.

Somewhere I have seen the number 230 deg as the safe limit. I think it was during a nascar race from the inside cockpit camera view, but i'm not sure that the race car limit means much for our pickups.

Thanks for any input.

[Dvldog8793]

Howdy
I am just a simpleton not a "expert" ;)
Under HEAVY load with outside ambient temp of 70* I saw 235* oil temp. This was a continuose load of about 14,000lbs pulling level grn at about 60mph.
Normal temp for the same ambient temp is unloaded is about 150-165*
My temp gauge is in the pan so my temp readins will be different than yours.
Hope this helps!
L8r
Conley

[ronniejoe]

As I posted in this thread (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=008901), the sump temperature (measured in the pan) should not operate above 300F for any length of time. The temperature coming out of the turbo may be higher than sump temperature on hard pulls.

[ogrice]

O.k.

Isn't 300 deg close to the breakdown point for some motor oils.? I would be doing some repairs to the engine if I think the temp got this high enough times.

[ronniejoe]

Last summer after installing my new engine (and oil temperature gage), I saw sustained oil temperatures of 240F on a 95F day running solo at 75 mph. I'm quite certain that the old engine ran in excess of 300F when towing heavy.

I also found heavy sludge in the old engine when I tore it down.

That's why I upgraded my oil cooler.


Originally posted by ogrice:
Isn't 300 deg close to the breakdown point for some motor oils.? I would be doing some repairs to the engine if I think the temp got this high enough times. Yes, that's why I said not to operate above it. Why did you ask, then, if you already knew the answer?

You might be surprised at what you see in the heat of summer under a heavy pull. The later engines that have oil cooled pistons (as mine does) will see hotter oil temperatures. Based on your statement, you should get ready to make some repairs...

[Hubert]

Thanks for the real world datapoints guys.

I think you want motor oil to operate between 212F and 250F. The low temp of 212F might not be real critical with frequent changes and depending on climate. But if you are in a humid environment with regular significant temperature swings through the dew point and you can see condensate regularly on metal the 212F min is probably more important (also consider extended drain intervals or long periods of inactivity and if the vehicle sits in the weather unprotected).

Above 250F increases oxidation of chemical additives. And temperature should be considered locally anywhere in the engine. Including but not limited to pistons and turbo lubricating and cooling.

Check out this webpage.

http://www.synlube.com/sludge.htm

(scroll about half way down and read about temperature and sludge formation)

No endorsement intended for the product but it looks pretty well written. I am sure there are more informative webpages and welcome good references.

Hue

[Hubert]

Ron,

The above website estimates in excess of 320F could be seen while towing heavy. And just think they are probably not even considering the heat problems of the 6.5 redface.gif :mad: .

[ronniejoe]

Originally posted by Hubert:
Ron,

The above website estimates in excess of 320F could be seen while towing heavy. And just think they are probably not even considering the heat problems of the 6.5 redface.gif :mad: . I have no doubt at all. I did not have the oil temp gage in prior to the new engine, so I have no data. I do know that I was shocked at how hot it ran solo on a 95F day here in Indiana last August. That's why I upgraded my oil cooler.

[Hubert]

Bare with me guys. I dislike to just repeat what I have heard/read w/o really understanding and knowing the details.

The 212F minimum oil temp spec. why? Maybe more importantly one should consider blowby. Maybe the most significant introduction of "vapors" and water (or steam H2O anyway, a byproduct of combustion) to crankcase oil. If oil runs too cool (and the engine too) possibly harmful amounts of condensate will be trapped in the oil.

[ronniejoe]

I posted this in the Oil Cooler Upgrade (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=008901) thread:


Originally posted by ronniejoe:
Using these oils, the oil temp should not stay above 300F for any length of time.

As for the water vapor...I don't think that's a real issue. Bottom line, the hotter the oil runs, the hotter the engine will run. This accelerates break down of the oil and causes reduced oil pressure.

For information, the helicopter engines that used to work on used oil in conformance with MIL-L-23699. Mobil Jet Oil II and Aeroshell 555 are two oils that conform to that spec. They are both fully synthetic. Max oil temperature was limited to 400F. Any hotter localized temperatures result in coke formation. Typical oil inlet temperatures (after cooler) were 180F. I've never seen any evidence that this is a concern.

[ogrice]

Thanks for all your input guys. I've learned that the health of the oil in the engine will directly effect its lifespan. This is true for all the vehicles that that we operate and not just our trucks.

Currently, I run the pre-luber aux oiling system. For anyone reading that doesn't know what these components do, this is what it does.
Its a 12V, electric driven pump that is connected between the sump and taps into the oil galley. A one way check valve is provided to stop back flow when it is not energized. It cycles for about 20 seconds when the key is turned to the "on" position and circulates oil before you startup the engine. It also cycles when you turn the engine off to circulate oil to cool down the turbo.

#1 Does anybody who has responded to this topic know of anyone else who runs this system with a long range degree of success.?
#2 Are there any real life success or horror stories out there about the use of this aux system.?

[ronniejoe]

I have not used it, but it sure sounds like a good idea. This system will eliminate the need to idle the engine to cool the turbo down...as long as it will circulate long enough after shut down.

[tommac95]

>>a long range degree of success

I think most stationary engines use something comparable....that's the way it is done for a substantial installation; ideally everything is warmed up before ignition, too.

If concerned about failure of such a system :
--How well was it plumbed? any sharp bends , excessive vibration , abrasion potential, or high heat in/at hose locations??
--The only obvious vulnerability [assuming plumbing remains intact] would be leakage back thru the (one way) check valve. An obvious cure/solution would be a second check valve in series with the first , possibly with a tee (to a low oil pressure switch/relay-alarm) in between, to warn of leakage from first valve. If second valve failed first, this would be useless; a third valve in series would probably keep probability on your side....

[ogrice]

tom mac:

I see where you are coming from. The plumbing is soft lines and to my best ability i've avoided sharp bend. I do get a few drops of oil on the pavement, but that's only overnight when I shut off the truck for the day. Same for a couple other spots on the high pressure side.
I've mounted the electric pump in place of the washer fluid reservoir. No excessive vibration concerns. The high pressure side lines up parallel to the main electrical wire loom on the firewall. It taps in to the same spot where the oil pressure switch taps in to with a brass tee fitting. It's clear of sharp surfaces to rub on. I've went thru ceramic coating the exh manifolds, x-over pipe, and turbine housing. No high temp problems here. My underhood temps have dropped about 30 deg maybe more. This is without a hood scoop or vents added.
I will definitely be looking into fabricating a double/triple check valve assembly. Currently my only indicator is a mechanical oil pressure gage that connects downstream of the check valve. I watch that gage like a hawk and i believe its more reliable indication than just the factory gage.(I wouldn't have to watch it so close if i did it right in the first place)


I appreciate you guys for input and ideas, and i hope that i have done the same.

[JohnC]

I had one on my (ford) It worked well as far as function goes. did what it was supposed to do. After about 50K I had to replace it. The motor had failed and the installation had vibrated itself to pieces. Don't know how long the second one lasted. I bought a kit for my '93. Still have it (the kit) somewhere, in the box...

[Kent]

There is no reasone for the oil temp to go above 225. The oil cooler in these things stock is inadequet. 300 deg is rediculis, not that the oil wont take it, it shouldent be that high unless some components are substandard.

Kent

[ogrice]

Kent:

What kinds of oil temps did you see w/ stk. oil cooler.?
How about w/ the larger one.?
I've read your last thread with the pressure increases, but what did you see as far as temp.?
I've went under the grill and put a shroud around my stk. oil cooler to make sure that air passes thru it and not around it. Still running stock, but surely not for long.

[HH]

Where are you all measuring the oil temprature, pre cooler, post cooler, at filter, pre or post turbo, in the pan? I am measuring in the line before the cooler, because I figured that would be worst case. I am seeing 220 - 230 on a summer day.

[ogrice]

HH:
I measure temp post turbo at the return line to the crankcase. Unloaded temps stay below 200 even in mid day traffic. Don't know about towing temps. My brother has my truck right now and he has yet to do any towing or hauling.