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
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