my oil cooler temp data-can oil be too cool?

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25
Location
Co
What are the risks of running oil too cool with an oil cooler? I installed an Earl’s plate type oil cooler last month. It is a 6” x 12” plumbed using 5/8 id Earl’s hose and a Canton racing sandwich adapter. I installed it on my 96 lex lx450 (same as Toyota landcruiser). My truck (with a 4.5L inline 6) is well maintained and has never gotten hot before but in june I was driving I15 in California through Baker on my way to Vegas in 100+ degrees with AC cranking, truck heavily loaded and going fast as I could (65-70) up the passes and my rig got to 226 degrees (on my self installed digital gauge) which is too hot for this motor which automatically cuts off the AC at 226. I was forced to slow down as my kids yelled “dad it’s too hot…waaaa waaa waaa.” I don’t think anything was/is wrong with my rig although I must admit that she does have 135,000 miles on her though you would never know it by driving her. This pass on the I15 was an extremely taxing situation and my rig has never before or since got to such temps. Just to be safe I changed the fan clutch.I change/flush the coolant yearly. I also went a step further and put in the above stated oil cooler. I havn’t yet had a chance to race up another big pass in the heat to test out the oil cooler. Today I tapped an oil drain plug and put a temp sensor in it so I could monitor oil temp. My fear is that the oil may not be getting hot fast enough with the oil cooler. Based on the water temp probe the water gets right to its thermostat temp of 190 degrees as always even with the oil cooler-this takes about 5 min at idle. In my brief testing today with the newly installed oil temp sender I found that it takes the oil about 10 min at idle to get to 190 and this was with me holding the rpm’s to 2000 and cranking the ac. I noticed that when I drive the car the oil temp falls fast to about 170 degrees just driving around town. The data from the oil probe may be premature-I need to do some more observations when it is hotter outside (I live in southern Colorado and today was overcast and in 70's at time of test) and if I was real ambitious I would disconnect the oil cooler and get some data without the cooler. I know I could put an oil thermostat on the cooler but don’t want to slow the system down with such an expensive piece if not entirely needed. My question is this: If the engine is at proper operating temp does it matter if the oil is not? I imagine the oil will eventually get to operating temp on the highway but my brief bit of experimenting today suggests that for day to day grocery getting my oil may not be getting hot enough with the cooler and in the winter there is may be cold oil running through the veins if my motor if i keep the cooler on without a thermostst. Is cool oil dangerous if the engine is hot enough (as measured by water temp? Note that I do reg oil analysis (which suggests engine is doing great) , use m1 5w40, and change at 6000m intervals. fire away
 
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12,385
Location
Northern CA
If your oil gets over 190F several times a week and stays there awhile, you don't have problem. I suggest you keep your oil temp gauge and if you oil runs too cool, block off part of your oil cooler with cardbard or whatever works for you. Any place between 190F and 225F will make your oil real happy. At 190F sump temp the oil is getting hot enough in other parts of the engine to get rid of any moisture. I don't care for unecessary oil thermostats either and it's not the cost. I don't like having an extra piece of crap that can fail in the oil stream.
 

laproscopic

Thread starter
Messages
25
Location
Co
thanks xs650 I will be watching the oil temp for more data. My next oil analysis may also be revealing. About oil thermostat sandwhich adapters-i returned a derale thermostst piece because it was machined like crap. i went with the canton racing sandwch adapter cause it is machined nice and has semi ported 1/2 npt ports where almost all others use 3/8
 
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988
Location
Melb, Aus
The oil setup sounds fine. I would probably look more to your coolant system. Is this up to par. Maybe it needs servicing or an upgrade.
 
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39,805
Location
Pottstown, PA
Hmm...let's take a walk to AutoGen. The cooler the oil, the longer event duration required to purge moisture. I think you'll be fine. Without an oil cooler my temps ran 160-170 in cooler weather ..even at highway speeds. If you want to assure that you're up to temp, put a sandwich heat exchanger in as well. This will bridge the coolant to the oil ..assuring a faster oil warm up and higher normalized temps. [ August 15, 2005, 07:06 AM: Message edited by: Gary Allan ]
 

laproscopic

Thread starter
Messages
25
Location
Co
thanks people Gary you have been a big help to me in the past. Concerning the heat exchanger issue: the toyota 4.5L 6 in my rig has a factory oil/water heat exchanger bolted right on the pass side of the block-i have never taken it off personally to see what is in it but I have seen pictures of it's guts in the Factory service manl. The manule shows what looks like an old water heated home heater (the ones that pump hot water through them) that is surrounded by a water jacket. I immagine the oil flows through the heater thing while the water is flowing around it in the jacket. The heat exchanger is the last thing the oil sees before returning to the pan. I wish this exchanger worked a little quicker. The weird thing about this whole issue is that I always thought the oil ran hotter than the water and it appears this is not the case. I do think my cooling system is up to snuff (at least 99% of time)
 
Messages
7,409
Location
Austin, TX
quote:
Originally posted by laproscopic: I noticed that when I drive the car the oil temp falls fast to about 170 degrees just driving around town. The data from the oil probe may be premature-I need to do some more observations when it is hotter outside (I live in southern Colorado and today was overcast and in 70's at time of test) and if I was real ambitious I would disconnect the oil cooler and get some data without the cooler.
I would do as XS650 suggested, use cardboard/tape and block off the entire cooler to gather some data. Then compare this data to that obtained when your new oil cooler is fully functional.
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by laproscopic: I do think my cooling system is up to snuff (at least 99% of time)
I'm not so sure. Overheating with 65 to 70 mph air on the front of your truck at any temperature indicates a problem.
 

laproscopic

Thread starter
Messages
25
Location
Co
I will try the cardboard trick XS650-the temp outside and the speed are not the issue in the said scenario. I drive in 100+ degrees all the time at 85+ mph. (radar detector of course) The issue is that long pass on the I15 in cali going from baker into Nevada. On the day I was running this highway I had the pedal to the floor in third/2nd gear to get that 65mph. This is one heck of a tax under high heat. But I agree, there is no excuse for overheating in my book either and my cooling system is probably not perfect. for what I spent on the oil cooler project I could almost have baught a new radiator
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by laproscopic: I will try the cardboard trick XS650-the temp outside and the speed are not the issue in the said scenario. I drive in 100+ degrees all the time at 85+ mph. (radar detector of course) The issue is that long pass on the I15 in cali going from Baker into Nevada. On the day I was running this highway I had the pedal to the floor in third/2nd gear to get that 65mph. This is one heck of a tax under high heat.
It is the issue. At 65 mph the engine should cool no matter how hard you are driving it as long as it's below redline. You would be in real serious trouble on a real grade at 1/2 that speed. The grade out of Baker should be no more than 6%, I don't remember it being even that steep, but it's been awhile. I say no more than 6% because that's the upper limit for Interstates.
 
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189
Location
The cool green NW
The oil needs to get up to a high enough temp to vaporize water from it. Or sludge will form?. Don't know much about cars, but the Allison T-56 turboprop engine--as installed in C-130 aircraft--has oil temp limits 60-85*C. The oil cooler automatically controls this or the pilot if auto is inop. Backup is another valve that bypasses the oil cooler if oil temp drops to 58*C, in case the oil cooler flap fails full open. So oil temp minimum as well as maximum must be pretty important. Synthetic tuboshaft oil.
 
Messages
7,409
Location
Austin, TX
quote:
Originally posted by laproscopic: Today I tapped an oil drain plug and put a temp sensor in it so I could monitor oil temp.
Moving my lips while reading yielded better comprehension. [Duh!] Anyway, XS650 is correct. Your cooling system is limited in it's ability to remove heat from your engine. At a certain power level, the limits of the system are overtaxed and overheating results. One would assume the manufacturer has taken in account the power level needed for 6% grades with AC use at highway speeds. Your normal trips at 85+ mph may not reached this limit. Probably worthwhile to check the cooling system thoroughly to include the radiator and thermostat. Your radiator could be partially plugged or your thermostat isn't fully opening. A UOA will help check for gasket leaks. Also check for collasping hoses. Good luck.
 
Messages
39,805
Location
Pottstown, PA
This would be supported by the lack of good oil temp as well. You may be scaled up internally and not transferring very well. You'll know after you do the cardboard test. In an application like this, I would expect the oil to run hotter than the coolant in a high stress situation (extended climbing @ highway speeds). This is only because I would expect the cooling system to have more than enough excess capacity to handle just about anything you threw at it (as our esteemed contributors assert). It doesn't apparently.
 

laproscopic

Thread starter
Messages
25
Location
Co
THANKS FOR POSTS I do accept that my cooling systm may have limitations in spite of my excellent maintainance. I frequent a toyota landcruiser forum (ih8mud.com) and the cooling system on my engine is often suspect though there are many with no heating problems at all. like I shared abobe I put a new toyoya fan clutch on the rig and baught a new thermastat I need to install. The hoses less than a year old and belts are tight and in good shape. note I do reg uao's that are good Yesterday I took the truck out for a drive. it was about 75 degrres out and I let the motor warm to 180 deg before i took her on the highway where I only got her to 70mph (55mph limit) for 10 min of driving. I then went back to town and drove around a bit. the water temp maxed out at 190 (nl) but the oil temp never got abobe 140 deg! I guess I need to do the cardboard test sooner than later. I will post results.
 

laproscopic

Thread starter
Messages
25
Location
Co
herky jim shared that his aircraft oil cooler was shooting for an oil temp of 136 degrees to 185 degrees (converted from celsius to farenheit) if I consider my truck a plane the temps I am getting w my cooler ore ok. no? comments more on the temp oil must reach?
 

laproscopic

Thread starter
Messages
25
Location
Co
Herky the shell site is interseting; especially the part about how "instantaneous" temps are about 50 degrees hotter than the sump temps-cool thought. I don't like the idea that my cool oil ins't getting hot enough to burn off the water/condensation that may be in it. Ill bet there are some sick bastages on this site that would just love it if I would leave my oil running cold so I could run my UOA in a few months and post how there is now water in it...wouln't that be cool...well no such luck for you sickos. Cardboard for me-results to follow
 
Messages
189
Location
The cool green NW
These general aviation engines are air-cooled so the internals are different and the materials. If I were to insatall an oil cooler in my car, I'd have to have it thermostatically controlled, and then I'd need an oil temp gauge to checkup on the thermostat and then...and then...
 
Messages
7,409
Location
Austin, TX
I would shoot for a minimum of 160°F oil temps to both evaporate water out of the oil and to activate certain additives in automotive oils. The oil in a turbine engines "sees" a different environment and is formulated and managed accordingly.
 
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