Running a 160 thermostat with 0-40 oil, doable?
#21
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If the engine doesn't get warm enough for the moisture to be dispelled it will stay in the engine. Yes it will evaporate at temperatures below 212. It will eventually evaporate at ambient temperature provided the humidity isn't too high. Short drives in the winter with an engine that never warms up is bad for the engine in more ways than just moisture. If the coolant is only getting to 160 I'll bet the oil is less than 150. Engine clearances will be tighter as well and you could have a failure simply because the oil didn't warm up enough. Too hot or too cool is bad.
#22
Melting Slicks
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right, but now back to the tollerances which is what i was addressing in my first post... and my last one to Jstewart, wouldnt a 0 40 oil behave similar to a 5 30 oil if it is 10 degrees cooler than the recommended 170?
#23
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Many times the lower viscosity oil is recommended because that's what was needed to meet the fuel mileage figures. That doesn't mean that 5w30 is necessarily a better oil for our cars just that to meet the mileage and emission standards that is what they used. I'm not an engineer so I can't tell you if it would be better, worse, or the same. That said you don't want things too cool or too hot. I'd be more comfortable on track with my oil temp at 250 than I would at 150.
Last edited by badhabit_wb; 03-19-2019 at 01:47 PM.
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Mikec7z (03-19-2019)
#24
Melting Slicks
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i see, well, im still looking for answers. To me the 0 40 oil is the way to go, and i cant imagine that 160 with 0 40 is worse on a motor than 170 with 5 30.
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The only issue I see is that the engines are designed to work in a certain temperature range. Above or below that range can cause issues. Too cold and rings don't seal and clearances are too tight. Too hot with these engines and the bearings will seize.
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Mikec7z (03-19-2019)
#26
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I want to ask this question from a slightly different angle. I installed a 160 thermostat (C6 style) and new housing last summer. On hotter summer days the coolant temps and oil temps ran in the mid 190's at 70 to 80 MPH on the interstate and 200 + in traffic in town. No real problem but no improvement. This winter with temps in the 30's the coolant temp never gets above 160 and the oil temp never gets to 160 F. Trans fluid temp on my A8 never got out of the 120 to 130 F range. Now for reference I have only driven the car in these conditions 4 or 5 times this winter but one trip back from Cincinnati to Louisville was 125 miles on the interstate. Just wondering if the low oil and trans temps are OK in these conditions. I ordered a second 175 degree tstat that I am thinking about switching over to for year round use since 99% + of my driving will be street use.
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Mikec7z (03-19-2019)
#27
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he said trans fluid is 130... which is fine. He said coolant is 160's and oil never gets past 150, in the cold on the hiway that is.
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Mikec7z (03-19-2019)
#29
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Higgs I want to revise my original post. The coolant temps came up to 160 maybe 165 on the gauge on the interstate at a constant 70 to 75 MPH over the 125 mile trip, steady speed on a 28 degree day. The oil temp ran slightly under 160 degrees. The A8 trans temp never got out of the 120's. Not only is the low oil temp a concern because of moisture accumulation but I was surprised the trans fluid was running so low. I do not run the car hard during cold weather because of the traction issues but I am curious about whether running these low fluid temps is good for the motor and trans. As far as I am aware there are no reliability issues with the older design C6 thermostats like I am running on my car but in any case I am changing it out for the higher temp stat from LPE.
#30
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i was concerned about cold trans fluid myself since we are about to release a way to cool them down further, but to my surprise, it does not do harm to the trans to be at those cooler temps.
There is a statistic that every 20 degrees increase in trans temp HALVES the transmission's life. So to keep one cool, is of no negative consequence, quite the opposite.
There is a statistic that every 20 degrees increase in trans temp HALVES the transmission's life. So to keep one cool, is of no negative consequence, quite the opposite.
Last edited by Mikec7z; 03-20-2019 at 12:45 PM.
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jstewart (03-21-2019)
#31
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Higgs I want to revise my original post. The coolant temps came up to 160 maybe 165 on the gauge on the interstate at a constant 70 to 75 MPH over the 125 mile trip, steady speed on a 28 degree day. The oil temp ran slightly under 160 degrees. The A8 trans temp never got out of the 120's. Not only is the low oil temp a concern because of moisture accumulation but I was surprised the trans fluid was running so low. I do not run the car hard during cold weather because of the traction issues but I am curious about whether running these low fluid temps is good for the motor and trans. As far as I am aware there are no reliability issues with the older design C6 thermostats like I am running on my car but in any case I am changing it out for the higher temp stat from LPE.
the oil temp at 160 is also fine, part of the reason you are supposed to change the oil more often if you take short trips, it's considered hard usage. do you wait 10k miles for your interval counter to get to 0%? I don't. I change the oil every 5k miles, in fact, my 17 has 5k miles and I changed the oil at 500 miles, 2000 miles, and at about 4000 miles, and it was changed when I put the cam in also sometime in between there, lol.... you aren't going to damage the engine if you change the oil on a regular basis. oil doesn't turn into ball bearings circulating in your engine below a certain temperature. even 15W50 flows and protects at 0 degrees. don't worry about it.
#32
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Is there anything that can be done about that annoying Warm up Tach Red line. After i installed the 160 stat it fluctuates as the Temperature slowly rises.
#33
Melting Slicks
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thats a question for higgs
#34
Burning Brakes
Thanks Higgs & Mike. Since I drive 99+% of the time on the street is there any need to go to a heavier than specified oil for the drag strip in the summer? Have a lot more HP & TQ than stock but don't use much of it often in normal driving. I no longer have any cats so I don't need the factory spec oil to protect the cats. Would like to just stick with the 0W 30 or 5W 30 Mobil 1.
Last edited by jstewart; 03-21-2019 at 09:48 AM.
#35
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I run the 15w-50 year round. I spend a lot more time on the track than I do the street and I change it regularly. I have something over 14,000 miles on the car and I've probably changed the oil 8 or 10 times. I also change the rear end oil and transmission oil yearly.
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Mikec7z (03-21-2019)
#36
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Thanks Higgs & Mike. Since I drive 99+% of the time on the street is there any need to go to a heavier than specified oil for the drag strip in the summer? Have a lot more HP & TQ than stock but don't use much of it often in normal driving. I no longer have any cats so I don't need the factory spec oil to protect the cats. Would like to just stick with the 0W 30 or 5W 30 Mobil 1.
#37
Melting Slicks
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does the 15 part of that 15-50 oil's number indicate it is rough on cars during cold startup? Jstewart is in kentucky ohio area, gets pretty cold.
Last edited by Mikec7z; 03-21-2019 at 01:47 PM.
#38
I'm also trying to figure out what tstat to get with my aftermarket oil cooler running 15w-50. 180 or 200. Coolant will be at 170 tstat.
180 sounds good as that's when it starts opening and 195 ish it will be fully open. So doesn't seem bad at all.
Last edited by BrunoTheMellow; 03-21-2019 at 03:48 PM.
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Mikec7z (03-21-2019)
#39
Melting Slicks
Higgs Boson walks into a church, priest is immediately happy, 'cause now they can have mass................
Seriously though, am enjoying the technical reading. Thanks for sharing the info!
Seriously though, am enjoying the technical reading. Thanks for sharing the info!
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Mikec7z (03-21-2019)