Oil cooling
- Thread starter super diesel
- Start date
Well this thing definitely works but I can still use more 
.
Ran 70mph with about 7k on the back. Rolling hills and flat, never saw over 210 on oil temp. Hit the hills and with slowing/accelerating back up to 65-70, I’d hit 230* oil temp. Wayyyyy better than I’d do before. I would have been running 220 up these rolling hills and 240+ on the grades.
Hit the big 7%+ grade on the way back (apparently they changed it from a 6 to a 7% grade now). Started at 70 at the bottom and held it till the top. 5th gear the whole way and 40-45lbs of boost. The last 1/2 mile, oil temp finally hit 240 and the moment it did and kept creeping, coolant started going with. Got up to 235* coolant and 245* oil. Again, miles ahead of what I’d do before but still not enough and the big trailer will mean I’ll have to slow way off. Probably won’t ever see this route again though
I’m debating putting the external oil cooler back on. She literally has one last trip in her to deal with these temps though and the hills aren’t near as bad... hmmm
.Ran 70mph with about 7k on the back. Rolling hills and flat, never saw over 210 on oil temp. Hit the hills and with slowing/accelerating back up to 65-70, I’d hit 230* oil temp. Wayyyyy better than I’d do before. I would have been running 220 up these rolling hills and 240+ on the grades.
Hit the big 7%+ grade on the way back (apparently they changed it from a 6 to a 7% grade now
). Started at 70 at the bottom and held it till the top. 5th gear the whole way and 40-45lbs of boost. The last 1/2 mile, oil temp finally hit 240 and the moment it did and kept creeping, coolant started going with. Got up to 235* coolant and 245* oil. Again, miles ahead of what I’d do before but still not enough and the big trailer will mean I’ll have to slow way off. Probably won’t ever see this route again though I’m debating putting the external oil cooler back on. She literally has one last trip in her to deal with these temps though and the hills aren’t near as bad... hmmm
Well this thing definitely works but I can still use more
Ran 70mph with about 7k on the back. Rolling hills and flat, never saw over 210 on oil temp. Hit the hills and with slowing/accelerating back up to 65-70, I’d hit 230* oil temp. Wayyyyy better than I’d do before. I would have been running 220 up these rolling hills and 240+ on the grades.
Hit the big 7%+ grade on the way back (apparently they changed it from a 6 to a 7% grade now
I’m debating putting the external oil cooler back on. She literally has one last trip in her to deal with these temps though and the hills aren’t near as bad... hmmm
Glad to hear this thing works as well as it does!
What were the EGTs? Be interesting to see how oil temp plays if you put some more heat in the exhaust. I wouldn't be worried about oil temps at this point, but like you said, it'll only go up with the big trailer
Well this thing definitely works but I can still use more
Ran 70mph with about 7k on the back. Rolling hills and flat, never saw over 210 on oil temp. Hit the hills and with slowing/accelerating back up to 65-70, I’d hit 230* oil temp. Wayyyyy better than I’d do before. I would have been running 220 up these rolling hills and 240+ on the grades.
Hit the big 7%+ grade on the way back (apparently they changed it from a 6 to a 7% grade now
I’m debating putting the external oil cooler back on. She literally has one last trip in her to deal with these temps though and the hills aren’t near as bad... hmmm
I don’t have an approximate weight on my camper loaded but GVWR on it is 6k. So let’s pretend for simplicity it was only at 5k. The truck got weighed the other day at a certified scale and they handed me a ticket for 7500 lbs. So pulling the camper over rolling hills and flats, manually shifting it 90% of the time and keeping it out of 6th gear the whole time. I kept it at 60mph the whole time (just local highway driving), oil never went above 200* the whole trip. Coolant never went above 195. Engine fan would come and go mostly when going through small towns with low speed limits. I was grinning ear to ear with the difference in the way it pulled this time from when I had just bought the truck stock. Man the turbo brake is just the bees knees when pulling this camper!
In 5th, I saw 1250 max. In 4th I saw 1100 max all holding 70mph. 5th gear is 2150rpm and 4th gear is 3000rpm. That idea sounds right till I get too high with egts on the big trailer. 60-65 is about all I’ll get with the big one as rpm in 4th is high. I’d love a 10 speed in there
As far as I can tell, the L5P still does not have an actual oil temp sensor...oil temp is just calculated by the ECM.
The LML ECM also has the ability to calculate oil temps too, but GM didnt turn it on for some reason.
Apparently they turned on the "calculated oil temp" function with the L5P ECM.
Or maybe the schematics on the service manual are wrong, and the L5P does have an actual oil temp sensor?
Either way, the LML ECM definitely has the ability to read a physical sensor.
No idea about earlier ECM's. LBZ/LMM...probably. LB7/LLY...doubt it.
The LML ECM also has the ability to calculate oil temps too, but GM didnt turn it on for some reason.
Apparently they turned on the "calculated oil temp" function with the L5P ECM.
Or maybe the schematics on the service manual are wrong, and the L5P does have an actual oil temp sensor?
Either way, the LML ECM definitely has the ability to read a physical sensor.
No idea about earlier ECM's. LBZ/LMM...probably. LB7/LLY...doubt it.
Started on an adapter for the sandwich adapter (hmm adapter for my adapter ). I figured I might as well try it and put the external oil cooler on if I can before Labor Day weekend. Cheaper than a new sandwich adapter and still keep -12 stuff. I just don’t like the large void between the adapter and sandwich. Maybe overthinking that?
Anyhow, It’s 1/2” thick, 7075 aluminum. Just need to cut the slot for the o-ring and put an inner lip to center up into the oil cooler. Was thinkin of using the oil filter o-ring from my last oil change, just not sure how I’ll cut that slot since it’s square. Then I’ll make a new threaded extension from some 4140, tap inside threads for 22x1.5 and the external threads will go back to standard 13/16 for the old style oil filter. All sounds good in theory and looks like it won’t be an issue. We will see
). I figured I might as well try it and put the external oil cooler on if I can before Labor Day weekend. Cheaper than a new sandwich adapter and still keep -12 stuff. I just don’t like the large void between the adapter and sandwich. Maybe overthinking that? Anyhow, It’s 1/2” thick, 7075 aluminum. Just need to cut the slot for the o-ring and put an inner lip to center up into the oil cooler. Was thinkin of using the oil filter o-ring from my last oil change, just not sure how I’ll cut that slot since it’s square. Then I’ll make a new threaded extension from some 4140, tap inside threads for 22x1.5 and the external threads will go back to standard 13/16 for the old style oil filter. All sounds good in theory and looks like it won’t be an issue. We will see
Someone make an adapter for the 22x1.5 to 13/16-16 and we will be golden! I am going to see what I can find to adapt the 20x1.5 plug to npt for my temp sensor to keep it in the original location. Coller is mounted in the LBZ, just need to find some longer bolts. 
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Someone make an adapter for the 22x1.5 to 13/16-16 and we will be golden! I am going to see what I can find to adapt the 20x1.5 plug to npt for my temp sensor to keep it in the original location. Coller is mounted in the LBZ, just need to find some longer bolts.
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What do you mean by that? like for a sandwich adapter or for just an oil filter? the sealing diameter is an issue as well.
https://www.glowshiftdirect.com/m20-p-1-5-male-to-1-8-27-npt-female-thread-adapter/
This M20 to NPT adapter works perfectly for my temp sensor on the LBZ. Put a small oring at the top of the threads and used blue Loctite. Let the Loctite set just long enough to provide a tad bit of restriction to get a good seal. Not sure if the oring helps or not, but it is better than nothing.
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This M20 to NPT adapter works perfectly for my temp sensor on the LBZ. Put a small oring at the top of the threads and used blue Loctite. Let the Loctite set just long enough to provide a tad bit of restriction to get a good seal. Not sure if the oring helps or not, but it is better than nothing.
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Havent made it far enough for the adapter. I think James is going to make a fitting for us though.
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Havent made it far enough for the adapter. I think James is going to make a fitting for us though.
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I’ve been keeping an eye out but hadn’t seen an update. Thought I’d ask! I don’t need any additional cooling at this time. Pulling my camper at 75 mph the highest I’ve seen yet is 215. Normal cruising with the camper behind us loaded, it rarely even reaches 200 the cools down to about 185, 190 whenever it’s flat ground and 60 mph and below.
Any local hydraulic fitting/hose shop should stock a M20-1.5 Metric to -6 or -8 JIC adapter. Trying to find the M20 to 1/8NPT is very hard.
Take the M20x1.5 to JIC adapter home and cut the male JIC fitting off flush with the top. Drill out to 21/64 and tap it with a 1/8 NPT tap. Works perfect and actually leaves the temp sensor protruding into the oil gallery as much as possible. Cost should be around $2.00 for the fitting.
Take the M20x1.5 to JIC adapter home and cut the male JIC fitting off flush with the top. Drill out to 21/64 and tap it with a 1/8 NPT tap. Works perfect and actually leaves the temp sensor protruding into the oil gallery as much as possible. Cost should be around $2.00 for the fitting.
Havent made it far enough for the adapter. I think James is going to make a fitting for us though.
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That’s the plan. You gotta send me that info though!
Massive difference. Oil cooling is by far the least of my issues now. I don’t see over 230* no matter how hard it’s pushed up the hills or rpm ran.
Overall, from the exact same trip as last year with NO tracker in the trailer (4-5k less weight), I pulled the hills about 5-10mph faster and stayed cooler even at those speeds and the tracker inside the rig. Which was great till I lost a boot up the last hill into flag (pos Chinese PPE boot).
On the way back, I got dicked over by a guy in a car and lost momentum up verde hill. Slowed to 50 but got back up to 55-60 and oil temps held 200-210 (amazing as they have NEVER stayed that cool unless it’s 50* outside). Coolant stayed the same. By the top of the hill I got screwed again and was down in 3rd gear, 3k rpm and oil temp hit 225-230 and coolant just started to climb to around the same but never went higher. Best I’ve ever seen the truck stay cool before. Usually I’m at 230-240 on coolant about 1/2 way up the hill. I literally had my eye glued to the coolant temp waiting for it to move and it just held steady. My smile kept getting bigger every time I glanced down lol
Unless there was a large grade coming, I actually never turned the fans for the oil cooler and aux rad on. Oil temp would hold right with the coolant the whole time around 190-210 depending on the little grades I hit. Again, coldest I’ve ever seen as usually I’m holding steady at 220* under the same conditions on the old oil cooler and fan running the entire time.
This cooler rocks and the external with it makes oil temps a thing of the past no matter the temp outside. Coolant heat capacity becomes the new name of the game as I expected. It was nice never seeing oil pressure drop under 60psi the entire hill with the better pump.
Also one thing to mention, since I am running 20w-50 in the truck, that will heat up oil faster than 15w-40 and it still could keep it cool.
I’m going to monitor oil temps with my same auto meter gauge in the 2020 when it comes in and I might put my external oil cooler on it as well if it’s hotter than I like. I also want to see if I can find an actual temp sensor for oil temp factory or if it’s just an algorithm like Ben was thinking.
In the end, buy the cooler, put an external on with a good fan as well and never worry about oil temps, just watch coolant temps