What temperature is too hot for conventional oil?

[dustyroads]

Earlier this year I traded in a Volvo truck that didn't cool the oil until it hit 246-247F and it only cooled the oil to 238-239F. Climbing those long mountain grades in the desert it would still manage to stay at 249-252F with the oil cooler remaining open the entire time. I posted a few uoa's for that truck last October.

All of my other trucks from various decades have maintained 210F oil temps under normal circumstances and climbed well into the 240's when climbing mountains. OTR trucks go way past a million miles, many closer to two million miles without trouble. It doesn't matter the brand of engine or brand of turbo. Here in North America they mostly get it done with conventional oil.

Back in the CH-4 and even the CI-4 days, my oil samples showed significant thickening in my summer oci's and labs would note that in their comments. These days it's not bad at all. I'm pretty sure my Volvo was thickening the semi-synthetic oils I used but it was still fine overall.

Sorry for always bringing up OTR trucks but that's my business. I've never had a diesel pickup to work and can't speak about them.

 

[demarpaint]

Originally Posted By: 2015_PSD
Originally Posted By: demarpaint
Originally Posted By: 2015_PSD
Originally Posted By: mbacfp
Great question and concern. I have the Cab & Chassis version of the Powerstroke 6.7 (F550 motorhome). One of my nagging aversions to trying conventional 10w-40 vs 5w-40 is driving in those occasional situations. In taking I-15 north to Las Vegas and going up those long grades with the temperatures over 105+...makes me feel better knowing Mobile Delvac 5w-40 is in the crank. However, those environments aren't the norm for me. I have seen those same temp ranges as 2015_PSD.
Heh, I-15 headed into Las Vegas is where I saw some normal temperatures, but I was not hammering it (only 65-70mph). Headed into San Diego on I-8 and in, through, and out of Joshua Tree National Park towards Vegas is where the oil was the hottest. I am thinking I will stick with synthetic oil--especially when towing since the temps will undoubtedly be higher.
Smart move using a synthetic going forward. Any idea what the coolant temps were, cruising at those speeds and moving uphill under load?
The oil temps are digital, but the coolant is analog. It barely moved up from normal on the needle.


I got it now, thanks. My Jeep has a digital readout for coolant temps but not for oil. I wish I had both. The buffered coolant gauge doesn't tell you much. The difference between 199F and 220F is about a hair on mine.

 

[dustyroads]

Originally Posted By: dustyroads
Earlier this year I traded in a Volvo truck that didn't cool the oil until it hit 246-247F and it only cooled the oil to 238-239F. Climbing those long mountain grades in the desert it would still manage to stay at 249-252F with the oil cooler remaining open the entire time. I posted a few uoa's for that truck last October.

All of my other trucks from various decades have maintained 210F oil temps under normal circumstances and climbed well into the 240's when climbing mountains. OTR trucks go way past a million miles, many closer to two million miles without trouble. It doesn't matter the brand of engine or brand of turbo. Here in North America they mostly get it done with conventional oil.

Back in the CH-4 and even the CI-4 days, my oil samples showed significant thickening in my summer oci's and labs would note that in their comments. These days it's not bad at all. I'm pretty sure my Volvo was thickening the semi-synthetic oils I used but it was still fine overall.

Sorry for always bringing up OTR trucks but that's my business. I've never had a diesel pickup to work and can't speak about them.



I wanted to add that OTR trucks are obviously climbing those mountain grades at much slower speeds. At 80K lbs or in many cases much more (overweight permits) trucks are climbing those grades at 25-45 mph, depending on power/torque settings. That is really extending the high temp time and yet survive just fine.

On the other hand...I completely understand those who prefer to use full synthetics and don't blame you. I'm just saying that conventional is still good stuff. There are many guys who make a living pulling loads with their diesel pickup's that get by on conventional oils, too.

 

[Panzerman]

I have yet to see any coal truck tri axles using synthetic oil when I was in trucking. I can't imagine a more grueling environment. Dusty conditions, vertical hills in PA, heavy,heavy loads and long hours idling. Conventional oil is alot tougher than alot of people think.

 

[Dodgetracker]

2015_PSD, Sir, Just wondering if you noticed any difference in engine noise after being up to temp say like after stopping for fuel and such. More rattle or less? Also while driving at speed. Any difference?(between this oil and your last)
Thanks for your time.

 

[CT8]

Delo 400 is 238*c or 460*f will there be any difference Delo data sheet. So many misconceptions these days.

 

[CT8]

Originally Posted By: UncleDave
This is my normal towing area, and many guys go from LA to the desert rivers and lakes through this route.

Ive seen ambient temps at 125 on these routes.

This is why j2807 tow standard uses the Davis dam grade as one test route, and eisenhower as another, although eisenhower gives you nice cool air towards the top where Mojave/ Davis remains brutally punishing inlet temps the whole time.

Id say sustained temps of 250 and up is where conventional oil starts breaking down.
I like to keep trans temps under 220. Not all that hard to see those temps towing a 7500 LB boat through there, or a motorhome towing a boat.

The brutality of towing through here is why many boat guys are losing their engines altogether around the 100-150K range. Especially chevy and ford 5-6 liter engines.

The mythical Bitog "forever" truck engine that actually sees rated capacity towing is a fantasy in these parts of the US.

UD



They run the hill at the pedal to the metal wot all the way.

 

[CarbonSteel]

Originally Posted By: Dodgetracker
2015_PSD, Sir, Just wondering if you noticed any difference in engine noise after being up to temp say like after stopping for fuel and such. More rattle or less? Also while driving at speed. Any difference?(between this oil and your last)
Thanks for your time.
No difference in noise (it is pretty quiet as diesels go), but the Kendall felt smoother than the M1, not that it means anything. I will have to see the M1 UOA to see if there are any differences.

 

[CarbonSteel]

Originally Posted By: dustyroads
Sorry for always bringing up OTR trucks but that's my business. I've never had a diesel pickup to work and can't speak about them.
No worries about that, but I am guessing we are not comparing apples to apples especially with the OTR systems and capacities overshadowing the light duty ones?

 

[bdcardinal]

Originally Posted By: bullwinkle
Your F-250 should have synthetic ATF already, should be Mercon SP in the TorqShift. I'm a pretty big fan of Delvac 1 5W40-not sure if it's 249C/480F flashpoint can be beaten!


The Torqshifts have not spec'd SP for a few years now. The OP's truck should have come with Mercon LV. They actually back spec'd all the Torqshift transmissions to Mercon LV.

 

[CarbonSteel]

Originally Posted By: bdcardinal
Originally Posted By: bullwinkle
Your F-250 should have synthetic ATF already, should be Mercon SP in the TorqShift. I'm a pretty big fan of Delvac 1 5W40-not sure if it's 249C/480F flashpoint can be beaten!
The Torqshifts have not spec'd SP for a few years now. The OP's truck should have come with Mercon LV. They actually back spec'd all the Torqshift transmissions to Mercon LV.
It is Mercon LV; nearly all (if not all) current Fords use LV in their transmissions.

 

[bdcardinal]

Originally Posted By: 2015_PSD
Originally Posted By: bdcardinal
Originally Posted By: bullwinkle
Your F-250 should have synthetic ATF already, should be Mercon SP in the TorqShift. I'm a pretty big fan of Delvac 1 5W40-not sure if it's 249C/480F flashpoint can be beaten!
The Torqshifts have not spec'd SP for a few years now. The OP's truck should have come with Mercon LV. They actually back spec'd all the Torqshift transmissions to Mercon LV.
It is Mercon LV; nearly all (if not all) current Fords use LV in their transmissions.


Pretty much except for the terrible dual clutch monstrosities and manual transmissions. The only assemblies that call for SP now are the 6 speed ZF automatics that were in the Explorer, Expedition, Navigator, and Mountaineers for a few years.

 

[userfriendly]

This summer I'm running SAE40 & 25% SAE50, flash point 265C, KV100C 15.8, HTHS 4.6< in my LML.
The object is to keep oil pressure high for piston cooling.
I've made thick 20W40s by spiking 15W40 with CF-2 SAE50.
I no longer mix multi-grades together, only a mono-grade with a multi-grade,
or two mono-grades, always of the same brand and HDEOs only.

 

[dustyroads]

Originally Posted By: 2015_PSD
Originally Posted By: dustyroads
Sorry for always bringing up OTR trucks but that's my business. I've never had a diesel pickup to work and can't speak about them.
No worries about that, but I am guessing we are not comparing apples to apples especially with the OTR systems and capacities overshadowing the light duty ones?


Certainly, we are talking about very different capacities...but we have the same concerns. We are both hoping to keep the turbo bearings functional and we want to keep the piston rings free. Severely oxidized oil could cause problems with those things on either size engine.

A pickup truck is going to get three gallons of oil into the 240's or 250's and my heavy truck is getting 10-12 gallons up to the same temps, and keeping them there for much longer times. That's why I brought it up. If I'm overlooking something that still makes it an unfair comparison, I'll be willing to concede but it seems reasonable.

Pickup trucks have a lot of power compared to their overall abilities. You guys can run up the mountains at full GCVWR at a high rate of speed and make a quick climb. Heavy duty trucks are a different story. At 40K-50K lbs, a class 8 rig is a blast to drive with the ability to fly up the mountains but add 30K lbs and well...

I welcome everyone to straighten me out. I'm not an engineer or anything close but when talking about oil temps, aren't we all sharing the same concerns... The turbo bearings and piston rings? I have seen HD diesels (built and operated in the 1980's) with some sludge in the valve cover after nearly a million miles but not since then. Oil has come a long way. As long as we all use proper cool downs, I see no need to worry about conventional oils (at least in HDDEO's).

 

[CarbonSteel]

Originally Posted By: dustyroads
Originally Posted By: 2015_PSD
Originally Posted By: dustyroads
Sorry for always bringing up OTR trucks but that's my business. I've never had a diesel pickup to work and can't speak about them.
No worries about that, but I am guessing we are not comparing apples to apples especially with the OTR systems and capacities overshadowing the light duty ones?


Certainly, we are talking about very different capacities...but we have the same concerns. We are both hoping to keep the turbo bearings functional and we want to keep the piston rings free. Severely oxidized oil could cause problems with those things on either size engine.

A pickup truck is going to get three gallons of oil into the 240's or 250's and my heavy truck is getting 10-12 gallons up to the same temps, and keeping them there for much longer times. That's why I brought it up. If I'm overlooking something that still makes it an unfair comparison, I'll be willing to concede but it seems reasonable.

Pickup trucks have a lot of power compared to their overall abilities. You guys can run up the mountains at full GCVWR at a high rate of speed and make a quick climb. Heavy duty trucks are a different story. At 40K-50K lbs, a class 8 rig is a blast to drive with the ability to fly up the mountains but add 30K lbs and well...

I welcome everyone to straighten me out. I'm not an engineer or anything close but when talking about oil temps, aren't we all sharing the same concerns... The turbo bearings and piston rings? I have seen HD diesels (built and operated in the 1980's) with some sludge in the valve cover after nearly a million miles but not since then. Oil has come a long way. As long as we all use proper cool downs, I see no need to worry about conventional oils (at least in HDDEO's).
I totally agree we have the same concerns, no worries there. I was simply thinking (which could be totally wtong) that OTRs have more reserve capacity than light duties do. I am just not sure about using a conventional oil at 240F over a prolonged periods of time. Varnish, sludging, and bearing coking are my concerns.

 

[CT8]

Originally Posted By: 2015_PSD
Originally Posted By: dustyroads
Originally Posted By: 2015_PSD
Originally Posted By: dustyroads
Sorry for always bringing up OTR trucks but that's my business. I've never had a diesel pickup to work and can't speak about them.
No worries about that, but I am guessing we are not comparing apples to apples especially with the OTR systems and capacities overshadowing the light duty ones?


Certainly, we are talking about very different capacities...but we have the same concerns. We are both hoping to keep the turbo bearings functional and we want to keep the piston rings free. Severely oxidized oil could cause problems with those things on either size engine.

A pickup truck is going to get three gallons of oil into the 240's or 250's and my heavy truck is getting 10-12 gallons up to the same temps, and keeping them there for much longer times. That's why I brought it up. If I'm overlooking something that still makes it an unfair comparison, I'll be willing to concede but it seems reasonable.

Pickup trucks have a lot of power compared to their overall abilities. You guys can run up the mountains at full GCVWR at a high rate of speed and make a quick climb. Heavy duty trucks are a different story. At 40K-50K lbs, a class 8 rig is a blast to drive with the ability to fly up the mountains but add 30K lbs and well...

I welcome everyone to straighten me out. I'm not an engineer or anything close but when talking about oil temps, aren't we all sharing the same concerns... The turbo bearings and piston rings? I have seen HD diesels (built and operated in the 1980's) with some sludge in the valve cover after nearly a million miles but not since then. Oil has come a long way. As long as we all use proper cool downs, I see no need to worry about conventional oils (at least in HDDEO's).
I totally agree we have the same concerns, no worries there. I was simply thinking (which could be totally wtong) that OTRs have more reserve capacity than light duties do. I am just not sure about using a conventional oil at 240F over a prolonged periods of time. Varnish, sludging, and bearing coking are my concerns.
It is a non concern. You are thinking conventional oils from the 1970s. there is not enough difference between the high temps capabilities of the conventional and syn oilsthese days to make a difference. Below Freezing temps starting I would put my $$$ on the syn oil

 

[dustyroads]

Well light duty diesel engines aren't my thing as I have limited experience in them. I still believe the oil gets the same treatment in either size engine but there's just more of it in the bigger one.

I have always had my truck engine valves and injectors adjusted every 100K miles and the cylinder heads are always bright and shiny. Granted, I don't do extended drains; mostly 20-30k miles depending on the engine. I don't think there's any chance of varnish or sludge in an engine like yours unless you went crazy on the oci's.

The glaring difference between the small diesels and large, is engine speed. I don't know if that is a big deal when it comes to oxidation concerns or not. We're still dealing with the same oil temps in either size engine and the big diesels remain at the higher temps for much longer periods so I remain convinced that it's fair to compare them in that respect.

I'm still willing to concede if my thought process is all wrong.

 

[userfriendly]

I don't think bulk/sump oil temperature tell us much, other than the point heat generated is equal to the heat dissipation rate.
If your oil pressure is good, HTHS on target and the engine oil meet or exceeds your OEM specification, your good to go.
Mixing engine oil or using additives, in other words playing home chemist, to achieve a real or imagined benefit,
voids both the warranty and oil performance guarantee.

 

[roadrunner1]

Everything in your truck is thermostatically controlled (same as mine) you have nothing to be concerned with. Your turbo is coolant cooled as is almost everything else built this century, so no concerns with over heating turbo bearings. The thermostats are set in the 6.7 so not to overheat anything using CJ-4 specced lube.

Check one of my UOA's with 10w-30 in my 6.7, I have seen regular temps at the thermostat in/out temp and I run to the IOLM limit.

If it makes you sleep better at night switch to a syn, but quite honestly your truck could care less, Ford engineers spent countless hours ensuring that a CJ-4 lube and the 6.7 would be just fine together, not a syn CJ-4, any oil meeting CJ-4 spec.

 

[JustinH]

I might consider a transmission cooler to keep the temp of the trans fluid as low as you can.