Oil Temp in Owners Manual

[matt gineo]

I've been reading various threads on this forum regarding Oil Temps and most everything I've read said 220 degrees F is way too hot. I just downloaded a Porsche Owners Manual online and it says that anything under 300 degrees is ok.

I was running on the highway a few weeks ago at 70 degree ambient air temp, 70-80 mph and my oil temp was in the 220-225 range. I have a 1976 2.7 C.I.S with an 11 blade fan, no thermal reactors, Mobil 1 Synthetic oil and new head studs.

Any thoughts on this info in the Porsche Manual?

[Trackrash]

Do you have a front cooler? You probably should consider one if you don't. That being said, 225 is probably an ok temp for synthetic oil.
At 300 degrees, your valve guides will wear out in a few months.

[matt gineo]

Originally Posted by Trackrash

Do you have a front cooler? You probably should consider one if you don't. That being said, 225 is probably an ok temp for synthetic oil.
At 300 degrees, your valve guides will wear out in a few months.

Gordon, I don't have a front cooler yet but it's in the budget for next year. I figured 300 f sounded a bit warm but was wondering if 230-250 is ok? From all that I've read on this forum I started to have a mild heart attack when I saw the needle approaching 220-230. I actually pulled over, shut it down and opened up the hood to let it cool down.

[db_cooper]

220-230*F is OK. 250*F is getting into the nervous zone. I would not think 300*F would be acceptable and would be cause for investigation..like a broken fan belt or low oil level. I don't recall that 300*F in the 911 owners manual was considered a normal oil operating temp. I would think your oil pressure would be very low with your oil at 300*F

Older 911 engines without the oil cooler up front ran over 100k miles with oil temps at 230*F in the summer. My 73.5 911T with A/C and no front oil cooler would run 230*F or maybe a little more in traffic. On the open road the oil temps would go down to 200*F more or less with the A/C on.

Remember water boils at 212*F. You want to rid the engine oil of condensation and that happens best when the oil is at 212*F. If your engine runs at 180*F it takes awhile to cook off the H2O..oil temps are higher under the pistons, ring packs and cylinder heads. Thats where the H2O steams off when the oil is colder and that takes a while driving. Short trips are a killer in a 911 with 10+ quarts of oil.

Thats why I would not worry about oil temps at 220*F more or less.

When I rebuilt the 2.4 engine at 120K miles..the bottom end, rockers, camshafts and bearings were fine.

Valve guides were shot..as usual. Not lubrication related. High copper content in the valve guides and no lead in the fuel wore out the valve guides. Porsche figured that problem out much later.

[gamin]

Could you be more specific? What Porsche owners manual did you download, what year/model? I've never seen anything about 300 degrees being ok. If I were to get to 250 I would be looking for a problem.

[schumicat]

mobil 1 is ok up to high 200s, even 300, but that doesn't mean the engine likes being that hot.... but most people wouldn't use it in 911 engines. i wouldn't worry about 220.

new vintage usa website has overlays that show you the temp in degrees. the hashmarks vary greatly in what they mean in different years (3 different unumbered gauges were used). 300 is definitely getting hot and into the red.

[ejp]

I hope that I'm not hijacking this thread, but what *is* a safe oil temperature?

I was running on a short track last weekend (Shenandoah Circuit @ Summit Point, WV) on a hot day (90F), and my '88 Carrera was just touching the bottom of second hash mark (248F). It was steady there during every session. Is this too hot for dino oil (VR-1 20w50)?

Thanks!

[Reiver]

That seems hot for the mph.
Yesterday ran my '83 SC 930-10 in 107 degree ambient (Arizona Phx summer) for 1 hour at 70-72 mph and some stop/go. Never got above 205.
I do have a Carrera oil cooler/fan/block off unit and that makes a diff.
220 is not way too hot...240 is hot. 220 is probably ok but seems a bit hot for 70 degrees...at 70 degrees I stay at 194 or just at the first tick, sometimes below.
Timing, CO, plugs...and, clean your motor/oil cooler...dirt oil mix will 'encase' your air cooled deal and raise the temps.

[Reiver]

Originally Posted by ejp

I hope that I'm not hijacking this thread, but what *is* a safe oil temperature?

I was running on a short track last weekend (Shenandoah Circuit @ Summit Point, WV) on a hot day (90F), and my '88 Carrera was just touching the bottom of second hash mark (248F). It was steady there during every session. Is this too hot for dino oil (VR-1 20w50)?

Thanks!

That's prob not uncommon if you were running at wot. Tracking is hard work on the machine. Especially at that ambient.
Most guys I know change the oil right after a track day for that reason.

[Jerome74911S]

The original owner's manual for my '74 states 285 F as a max, not 300, so I wonder what manual that figure came from. Anyway, I have not run over 212 F so far this year, on synthetic oil. No worries.

[matt gineo]

Originally Posted by gamin

Could you be more specific? What Porsche owners manual did you download, what year/model? I've never seen anything about 300 degrees being ok. If I were to get to 250 I would be looking for a problem.

I got the info from the 1977 911s Porsche owners manual. On page 21 it says, The oil temperature gauge registers degrees Farenheit, the oil temperature should not exceed 300 degrees F (150 degrees C) If the temperature should exceed the limit, stop, check the oil level or, if necessary, consult your authorized dealer. Improper ignition timing or a slipping V-belt also cause too high oil temperatures

I'm wondering where everyone else is coming up with their figure for too high oil temps.

Schumicat, what's wrong with using Mobil 1? my mechanic is Daniel Jacobs in CT, one of the most well respected Porsche Shops in the Northeast. He uses it in all the 911's he works on.

[Reiver]

Originally Posted by matt gineo

I got the info from the 1977 911s Porsche owners manual. On page 21 it says, The oil temperature gauge registers degrees Farenheit, the oil temperature should not exceed 300 degrees F (150 degrees C) If the temperature should exceed the limit, stop, check the oil level or, if necessary, consult your authorized dealer. Improper ignition timing or a slipping V-belt also cause too high oil temperatures

I'm wondering where everyone else is coming up with their figure for too high oil temps.

Schumicat, what's wrong with using Mobil 1? my mechanic is Daniel Jacobs in CT, one of the most well respected Porsche Shops in the Northeast. He uses it in all the 911's he works on.

and the same manual says using a liter of oil or more in 600 miles is 'normal'. Porsche covers it ass litigation/warranty wise with such comments.
Look into any serious engine builder and ask if 300 degree oil is good.....the optimum temp for oil is about 210 degrees.

[Reiver]

BTW, at this point in time Porsche was trying to figure out how to deal with emissions.....thermal reactors, using fans with less blades...all kinds of things to raise the engine temp to burn off impurities.
It helped them pass emissions laws so they could sell cars.
It was the wrong thing for engine longevity....look at all of the 2.7 heat, expansion, pulled studs issues......that was ok as long as they could sell cars in our major market.

[matt gineo]

Originally Posted by Reiver

and the same manual says using a liter of oil or more in 600 miles is 'normal'. Porsche covers it ass litigation/warranty wise with such comments.
Look into any serious engine builder and ask if 300 degree oil is good.....the optimum temp for oil is about 210 degrees.

Optimum may be 210 but it doesn't mean you can't drive it safely at 220 -230
I agree, I think 300 is way too hot, but 220 - 240 doesn't sound as bad as many people make it out to be on this forum. I'd like to get my temp down to 200-220 and as soon as I can afford a front oil cooler I'm going to go for it.

[Jerome74911S]

Originally Posted by matt gineo

I got the info from the 1977 911s Porsche owners manual. On page 21 it says, The oil temperature gauge registers degrees Farenheit, the oil temperature should not exceed 300 degrees F (150 degrees C) If the temperature should exceed the limit, stop, check the oil level or, if necessary, consult your authorized dealer. Improper ignition timing or a slipping V-belt also cause too high oil temperatures

I'm wondering where everyone else is coming up with their figure for too high oil temps.

Fascinating that my '74 manual has the exact same wording in it (page 16), except that it specifies 285 degrees F. Maybe as the engines ran hotter for emission reasons, they upped the temp recommendation. And, my manual pictures an 11 blade fan, not the dreaded five.

[Ronnie's.930]

Originally Posted by matt gineo

I got the info from the 1977 911s Porsche owners manual. On page 21 it says, The oil temperature gauge registers degrees Farenheit, the oil temperature should not exceed 300 degrees F (150 degrees C) If the temperature should exceed the limit, stop, check the oil level or, if necessary, consult your authorized dealer. Improper ignition timing or a slipping V-belt also cause too high oil temperatures

I'm wondering where everyone else is coming up with their figure for too high oil temps.
Schumicat, what's wrong with using Mobil 1? my mechanic is Daniel Jacobs in CT, one of the most well respected Porsche Shops in the Northeast. He uses it in all the 911's he works on.

Most of the "too hot" figures you see quoted on the oil temp threads are simply misguided, emotional reactions to pre-conceived notions of "heat" (probably based on what so-and-so knows about the boiling point of water). I've often read on this forum that 180-185 is the sweet spot and anything over is a cause for concern, and this is just plain false.

[Reiver]

220-230 ok, some of the higher compression cars have had issues at higher temps (blown rings due to detonation) etc.
Running at 240 or higher for extended periods isn't doing anything for your oil or engine longevity. It is acceptable for track time.
Even in 100 plus degree ambient with a 225k mile unopened 930-16 I'd run at under 230...

[schumicat]

mobil 1 is excellent and I've used it in many cars, but the conventional/board wisdom is that the old 911 engines like thick dino oil like VR 20w-50 for hard driving. there are innumerable threads about the technical reasons...high zinc or something.

on temp I trust Porsche and as long as it isn't getting in the red the car and oil should be fine.... I have a mocal cooler and even on track on hotter than hell day it doesn't get anywhere close.

Originally Posted by matt gineo

I got the info from the 1977 911s Porsche owners manual. On page 21 it says, The oil temperature gauge registers degrees Farenheit, the oil temperature should not exceed 300 degrees F (150 degrees C) If the temperature should exceed the limit, stop, check the oil level or, if necessary, consult your authorized dealer. Improper ignition timing or a slipping V-belt also cause too high oil temperatures

I'm wondering where everyone else is coming up with their figure for too high oil temps.

Schumicat, what's wrong with using Mobil 1? my mechanic is Daniel Jacobs in CT, one of the most well respected Porsche Shops in the Northeast. He uses it in all the 911's he works on.

[Reiver]

Making Sense of Synthetic Lubricants
Just an opinion but I've heard the same from most engine builders...conventional oil can 'start' breaking down at 230-250 degrees and oxidizing.
Semi syn and synthetics have higher temp ratings but even a semi syn is pushed at 250.
Many of us use semi syn oils like B Penn etc for the higher zinc for our flat tappet motors.
In a newer car with hyd tappets and a fully syn oil you'd be ok I suspect.

[Wilhelm]

Where in the oil system loop does the oil temp sensor measure temp. ? Like is the oil temp sensor measuring temperature right after the oil passes through the cooler ?
In other words, is the oil temp measured at the hottest point or coolest, or somewhere in between ? Seems to me like it should be measured at the hotest point in the loop.