any leaks after changing to rotella t6 5w40

[wearl]

not trying to start a best oil post but i use mobil delvac 1300 15w40 now and have had no problems. but last week in chicago it got a little cold and my car would not heat up all the way. i felt my oil lines to cooler and they were cold after a 80 mile highway run.. i am sure this is not a problem because i have drove it in winter with 15w40 but got to thinking i should go with a 5w40 for winter for low temp oil flow at startup . the rotella t6 is a synthetic and i was wondering if anyone developed oil leaks using it. i do drive my car if the streets are clean in winter.

[DRACO A5OG]

Hmmmm, synthetic will most likely leak but if it is not leaking now you may be okay.

If you engine does not reach 194 degrees your thermostat will not open up to allow flow to your cooler.

[wearl]

i agree it is not getting warm enough to open thermostat .which i believe is not a problem, but my question is since it is not getting to full operating temp would the 5w40 hdeo synthetic oil flow better than the 15w40 hdeo in this situation plus cold start and warmup.

[db_cooper]

I use Rotella T6 5w40 in a 1986 3.2 owned since 38k miles with no leak issues (did do the triangle of doom this past summer.. thermostat "O" ring, breather cover gasket and leaking oil pressure sender). If anything the T6 seems to be easy on seals and gaskets. No complaints.

[db_cooper]

Cold starting will flow better. Warm it has a SUS@210*F of 73.3..a good 40w.

[boyt911sc]

Originally Posted by DRACO A5OG

Hmmmm, synthetic will most likely leak but if it is not leaking now you may be okay.

If you engine does not reach 194 degrees your thermostat will not open up to allow flow to your cooler.

Jim,

Don't want to contradict your statement but OEM SC/Carrera auxiliary thermostats operate below 194 deg. F. Tests and experiments showed an average of 186 deg. F. I would say that initial opening of the aux. thermostats could be observed to commence in the vicinity of 185 - 187 degree F based on a dozen units tested.

Tony

[wearl]

think i will try the rotella t6 today. dbcooper do you use it year round. i see you are in the south. hows your temp gauge in summer. i was told to use 20w50 but car ran hotter than using 15w40 hdeo.

[db_cooper]

I use Rotella T6 5w40 year round. The virgin oil analysis from bobistheoilguy.com above shows strong ZDDP numbers and a solid 40w at high operating temps.

Here in Atlanta with A/C on in traffic..the temp needle will run at about 8 o'clock. If the engine gets very warm..9 o'clock. Right in the middle of the operating range.

In the cooler weather we are having now..the engine thermostat keeps it at the first mark on the normal range..about 190*F.

My oil cooling system is stock without the extra oil cooler fan up front.



A good 40w oil works fine in the summer. If I was in the high desert and saw 100*F+ outside on a regular basis..I might go up to a 50w. Just don't think 50w is needed for regular street use.

The cold start 5w helps the engine run cooler. Internal friction cold with 20w50 is pretty high. Modern oil chemistry is much better than 30 years ago.

Just take a quart of your favorite 20w50 and a quart of 5w40 T6 and place them outside when the overnight temps fall to 50*F/40*F.
Go and try and pour them in the morning..the 20w50 will be very, very slow. the 5w40 will flow much better. Then think of your oil pump trying to move that 20w50 on cold starts. It is generally agreed that most engine wear occurs at cold start up and early cold running.

[spuggy]

Heh. I run Rotella T Heavy Duty year round, and was concerned my first winter because the temp gauge would never go over ~180, except under prolonged boost - and then it dropped back immediately you got out of throttle..

At first I worried my thermostat might be stuck open and over-cooling the oil - but finally realised that the external feed line was actually slightly warmer than ambient, but the reason the return line was the same temperature as the outside of the car was the big old FMOC.

The external thermostat only opens to send oil through the front cooler if necessary - and it's cold enough outside, it will regulate to the set temperature without any overshoot due to shortfalls in the cooling system.

Only concern is that 186 degrees isn't boiling point - and this means that you're basically just gently steaming water out of the oil. Just make sure to run it long enough every start and you should be fine. Or partially block off the oil cooler if you want it to run hotter. I considered this briefly, but never did.

[db_cooper]

186*F is fine. The temp sender is in the block upstream and is measuring oil temps as it is pumped up to the heads, fresh from the oil pump and tank.

The oil temp is much higher under the pistons, around the cylinder walls and in the rocker covers. I recall a study done years ago..they indicated a 30* to 50*+ in oil temps under the pistons and upper cylinders. Makes sense, it is very hot up there. Oil plays a big part in keeping the pistons cool.

That is where the H2O burn off is occurring when your gauge reads 180*F.

You are correct too..don't drive short distances or the H2O will not boil out. It takes a while for our 10 quart plus oil capacity to get up to operating temps. If you don't get the engine warm..it never blows off the H2O..and you get goo under the oil filler cap..a sure sign.

[dshepp806]

I'm looking to run 15W40 BP this wnter , for the first time (from my religious 20W50 BP,) ..

BEST!

Doyle

[DRACO A5OG]

Originally Posted by boyt911sc

Jim,

Don't want to contradict your statement but OEM SC/Carrera auxiliary thermostats operate below 194 deg. F. Tests and experiments showed an average of 186 deg. F. I would say that initial opening of the aux. thermostats could be observed to commence in the vicinity of 185 - 187 degree F based on a dozen units tested.

Tony

No worries, I stand corrected

I should have worded it as being fully open at 194, I agree it does start to open in the mid 180's

[wearl]

since i bought my 911 i have done more research on oil than i care for. i keep it simple now and use the name brand hdeo 15w40 oils, delvac,rottella,delo exc. plus you can get a quart any where if you need it and the price is good. i have a 5 gallon pale of delvac 1300 15w40 in my garage after rebate i paid 35.00 for it. the rotella t6 is a bargain at 21.95 gallon at walmart plus you can get it anywhere.