What exactly is normal "operating temperature"?
 

This time a year I always start to worry about how I'm probably not getting my car's temperature up high enough on my daily commute to work. It's a 15 minute drive and on cold days I only get the temp up to about 150, according to my numbered gauge. It's about half way between the first 120 tick and the second 180 tick.

I do drive the car almost every day, and I do try to take the long way home to get the temp up to 180+, but that honestly happens about 1/3 of the time.

I've read the other posts about this. I understand that not getting the oil up to operating temperature will cause internal condensation which can be bad. Is 150 well below operating temperature, or is it probably ok? What is considered operating temperature?

Thanks for your input!

Warmed up was considered by the factory to be 176F (80C) for a 77. That's the temp @ which oil level should be checked. Normal is usually considered to be anywhere from there to 220. Temps of 220 to 240 are getting warmer than normal, except for on long trips or in occasional situations. 240 is hot and Bruce Anderson always said that 250 was "too damn hot!"

Unless it's a very hot, humid day and I'm in stop & go traffic, my engine temps tend to be about 190. This afternoon, in 10-12C temps the engine was @ 180 both in town and on the highway. These engines seem to be affected by the ambient conditions much more than water cooled ones.

I have the same problem, 15 minute drive each way to work. I try to drive longer on the week ends to get the temp. up especially in the winter months.

I was having the same issue in my carrera... solution: let the car idle for 3-5 mins before driving, on the (short) drive to work stay in a lower gear, keep the rpms near 3500.

On an '83 SC, the factory says 192 F is oil-checking temperature. Whatever. I consider 180 to be "normal operating temperature."

The basic problem is that a lot of people are doing 15-minute commutes in cars that carry three gallons of oil and were never intended to be used this way. It's like buying a lightplane to make a five-minute flight. No U. S. Porsche dealer would ever have admitted this in in '70s or '80s, but I think Ferry would have. If I want to go to the grocery store, I fire up the Volvo or Boxster. I never start the 911 unless I know I'll achieve operating temp.

180 at all driving speeds and outside ambient temps. Anything more then that, you need more coolers....your thermostat controls the temp, the cooler(s) keep it there....

That's pretty extreme, to say you need "more coolers" if you exceed 180 degrees. In fact it's nonsense.

I don't think so.....when I converted to a 3.6 in my SC, it ran normally at 180, around town. Any spirited driving at the track or long trips showed elevated temps. Adding another coooler up front along with the Carrera fender well cooler fixed it. Steady 180 temps at all driving conditions and ambient temps.....

I think this proves my point....

After a long enough ride, mine stays steady at about 83C (~181F)

All of the factory t-stats keep the oil at ~180F+/- a bit. When the temps go beyond that it means that the cooling system is maxed for that state of speed & load. The faster you go the more heat is geerated and the more heat the system can offload so temps will vary up to ~ 220F+/- which is generally considered to be the max you want to run though temps to 240F +/- can and do occur for short periods.

I like to have mine run at ~190F but change oil at 2-3k mile intervals.

The lower the operating temp the slower water is to boil off. The more frequently you need to change oil.

In your shoes where max 150F is seen no oil goes through either cooler, the flow is strictly internal to the engine so you can't even block airflow to the coolers. The only thing you can do is take the long way or pop a 3.6 in there which will warm far more quickly

I think the poster's real question is not re: overheating but minimum operating temperature that will not cause problems in the long run. I'm not sure anyone really knows. There was a thread about a Carrera owner some time ago moving to Northern Canada where it was certain he would never reach operating temperature.

All very interesting. Thanks guys. I guess ultimately the answer is to drive it the long way and get closer to that 180 mark. That's not also that practical, but I will try to be more disciplined about it.

So, I know that idling in the driveway for a few minutes (3-5 was suggested) can also be bad. What is worse, letting it idle for 5 minutes so I can eventually get it up closer to 180 on a more consistent basis, or only getting it up to 150 like I am now?

Is this 150 situation really bad for my car?

Thanks again.

Low temps allow sludge build up....

Bill,

I'm wondering if there is even more to this. Here's an owner who lives near SF and on a "cold" day only sees 150 after 15 min. And even when he takes the long way home, he still usually doesn't get up to 180.

Maybe he is running not enough advance or a too rich mixture.

Today I was @ 176 after 15 minutes in about 10C weather.

butzi73,

You're right. The factory always had the position that the car should be driven right after the enginestarted to run smoothly, which is the best way to bring the temps up. I would think your engine would have to warm up while stationary for quite a long time to get to temp. I have always heard this is bad for bearings. It also wastes gas and pollutes unnecessarilly.

Have you always had this problem? Have you had your mixture and timing checked? What about your spark plugs? Are they correct for your engine?

It's sure that different engines have different warp up times, a 2.4t will take far longer than a 3.6 to reach 180F, it's been a long time but as I recall my 2.4 would not reach 180 no matter what when ambients were in the low 40s, but I didn't drive it much when it got cooler.

Warm up solution
 

I make many similar short trips on the small island of Kauai, my sc takes a good 10-15 mins to hit 180-190. I work at a fire station that is fifteen minutes from home, sometimes you need the speed hit in the AM....I have also heard that warming up at idle is not recommended , being a carpenter my solution is taking about a 40" 1x1 rip scrap and putting it between accelerator and the drivers seat, thus setting the rpm to between 2-3 grand, for a steady warm up. I usually wash her up let her warm up nicely, then punch it when ever necessary.

Regards-

JS

Yeah, a cold day for me is only in the 40's. I know that's not very cold to most people, but there is certainly a difference in how easily my oil temp goes up versus a 90-100 degree summer day.

I just had my carbs dialed in perfectly on the dyno (by John Hollerans's Performance in Pinole - He is great!). I know for sure that my mixture is correct. New plugs and wires. It's running better then it ever has. I can't say the temps are any different then they've ever been for me. By the way I have no thermal reactors. I also have an Electromotive crank fire ignition system.

Like Bill just said, on a cold day in the 40's I can drive indefinitely and it won't go past 180, and it takes a while to get there. If I really push it and drive aggressively I can get it past 180. In the summer 200+ is no problem to get to.

Right now in winter I have to extend my 15 minute commute to about 25 minutes to get the temp to 180, with normal driving. Are these normal temps for a carbed 2.7? Should I have any reason to consider the accuracy of my gauge?

Thanks,

x2...

The Quoted 180 degrees (82 Celsius) is the ideal. Bear on mind this is the temperature of the oil. Some of the internals are much hotter.

I live in a very hot climate. My 911 warms up quickly and once there stabilises without much variation.
If your cars aren't doing this then that could be an indicator of a problem somewhere.

My 78 3.0 might be running a little hot, but I'm not sure. It has original gauges with no numbers, but with much research, I have figured that straight left to 9 o' clock position is 200 degrees F, and redline is 300.

I think I'm running close to 240 sometimes, after it's all warmed up.

This is using the original trombone cooler, like it has been for the past thirty years.
But sometimes I think about changing to a radiatior style cooler, and maybe one with a fan, too.

In keeping with the thread topic, I have a short drive to work, but take the long way home sometimes just to be sure it gets warm enough.

But is it getting too hot? How is the best way to verify what the temps actually are?

LOOK at your gauge again.....on the far edge are tiny numbers. LIKELY in CENTIGRADE, BUT THEY ARE THERE....

+1

For all of those that never exceed 180 ... bring your car to Charleston, SC in the summer. Drive it hard and then report back.

Unless you have done major mods to your cooling system, you will see temps over 180. Most likely around 200 or 210.

I have a rebuilt 3.0, Elephant Racing finned lines and a carrera cooler (no fan). It is impossible to stay at 180 in my climate during the summer.

Right now with it in the 70s I will see a steady 180. In the winter I have a hard time getting my temps up to 180. But in the summer ... forget it. The high ambient temps + high humidity + afternoon radiant heat from the pavement = beyond 180.

Hell, my water cooled jeep's normal temp is 210.

Follow Mike's lead and check the actual numbers to get a true read on your temps. However, most would agree that the trombone is inadequate for a 3.0 and a radiator style cooler, preferably with a fan, should be installed. Given that you are in a hot climate, I'd say switch out to a more efficient cooler as soon as possible.

I have a 1988 Carrera without numbers on the temp gauge. In normal driving the needle doesn't make it into the "normal" range. Even after 20 minutes on the track the indicator barely gets up there and I have never seen it in the center of the red range. I was told by the PO and by a Porsche mechanic that this was the normal way these gauges display, but I'm beginning to wonder. It this true?

My '88 runs just above the second tick mark no matter how long it runs for. Once over the summer in heavy stop and go it got almost to the third mark. I think if I ever saw it climb above there I would pull over and let it cool for awhile. My commute is 1+ hour each way with good traffic, I think that day it took me almost 3 hours one way.

I found my answer on this thread
http://forums.pelicanparts.com/porsche-911-technical-forum/231988-temperature-86-carerra.html
Looks like my car is normal.

Exactly. Normal op. temp. is when all the engine component temperatures are normalized and dimensionally accurate. That's around 190-220ºF. The lower in that range, the better.

However, the oil must be warm enough to burn off condensation from the combustion process.

If the temp. gauge reads 180ºF, you're probably okay.

It may be unavoidable to bring the vehicle up to op. temp. at every cold start. In that case, change oil more frequently to remove harmful deposits and acids from the lube oil.

Sherwood

I'm a little confused by all this. These cars are made in Germany. It gets cold in Germany. Whats the difference in the way the cold/operating temps/time it takes to get to operating temp, etc..... affect these cars? Why do they have to get to operating temp everytime you drive? Is it just the condensation issue? If that is as harmful to the engine as it being implied in this thread it seems like a serious design flaw on Porsches part, no? Did they continue to make these cars with the intent to drive them until they reach proper operating temp in order to boil off water in the oil for the entire time they made them?
I have a 5 mile drive to work everyday. I'm not sure if I'm not getting to to operating temp (it gets to just shy of the second white mark) but I think I do. But it seems awfully silly to make a car that shouldn't be warmed up at idle yet needs to be driven hard to reach operating temp everytime you drive. It's only gonna get colder over the next few months and I may have made a grave error in buying a 911 as my daily driver.

Any engine, Porsche or not, will "suffer" by continual use in very short drives--ie. five minute jaunts to the market--unless maintenence schedules are changed. Nearly all engines are designed for long duration running under a wide variety of conditions and most driver manuals offer alternatives if the car is operated for extended periods outside "normal" conditions. Short, below warm-up running is definitely outside the normal condition, but is not harmful on occasion. An engine which is run for only a five mile daily trip is one, IMO, that should be given special service--more frequent oil changes--to keep it healthy and happy.

210 boils the cheese off the oil.

"I may have made a grave error in buying a 911 as my daily driver." You may have. Repeated cold running has the same effect on whatever car you drive for 5 miles at a time. It's not that a 911 is any more susceptible, it's that most people care more about preserving their Porsches than their Accords or Camrys. In the past 40 years I've been through half a dozen daily drivers, but I still own the same Porsches. Daily drivers are vehicles I sacrifice to my interest in Porsches.

Basic difference: Porsches are not "cars."

Maintenance book says to change oil and replace filter every 15K.
Also under Severe Condition Maintenance
More frequent maintenance than specified in the Maintenance Schedule is required if you drive under severe operating conditions. They include:
More frequent engine oil and filter changes for extended idling or low speed operation.
More frequent engine oil, oil filter and air filter replacementsunder severe dust condition, driving on unpaved roads or off road.
Frequent cleaning of radiator grille and core to prevent debris from restricting the cooling system (928, 944)
Cleaning and bleeding of fuel system may become necessary if contaminated by water, foreign matter, dirt or residue.
Owners Manuel says Oil Temperature has an influence on the service life of the engine. After starting the engine, drive at moderate speeds until the oil temperature gauge needle has reached the end of the white field. When the needle has blimbed to the first white line of the scale, the engine has reached operating temperature (194 F/90 C). etc.....

I've had my car for 4 months (4k miles) and have changed the oil and fitler twice. Being that it's recommended to change every 15K is it save to say I'll be OK changing every 3-5K?
It's not that I only drive it 10 miles a day but more often than I'd like I am running around town. I get it out on the highway or through the back roads about once a week. I'd really hate to not be able to enjoy my car. As much as I really (REALLY) like driving on the highway and back roads I still like driving my car all the time regardless.

As an afterthought - I still can't wrap my head around the "getting the car to operating temp" thing. How can it be an issue if you don't always get your car to 194F when driving? Regardless of how long you drive the car if the car starts cold (needle at the bottom of oil temp gauge) you still have to get it up to operating temp. So doesn't the engine have to run "cold" until it gets to temp? How is it starting a cold engine and getting to temp is anymore beneficial? Whether you reach operating temp or not the engine still has to run cold for awhile, no? Why is always getting it from cold to 194F important? What if you drive in a place where the temps are bitter cold in the winter and regardless of how long you drive the car can't get to 194F? Are you not supposed to drive? I'm confused as to why Porsche (Germany, where it gets cold) would make a car that can only be driven in fair weather climates. I know I may sound dumb asking these questions but it doesn't seem right to me. I'm sure I'm missing something here. The wear and tear physics of it don't seem to make sense if you're always starting cold.

i have the gauge with no numbers on it on my 77. when it is warm outside, it gets about 1/16 to 1/8th above the white. so i just went and looked for the hidden numbers on the left of the gauge. they are there, very hard to read though. it seems the top of the white is 99 degrees C ??? my car has never gone above 1/16 or 1/8th over the white, even on a 90 degree F day. now it is 40 degrees F. if i drive it hard for 15 miles, it is just getting into the white. i change the oil every 2000 miles..... subscribed :) PS, does anybody know what those tiny nubers to the left of the gauge are? looks to be 4 of them at different spots on the gauge. really hard to read.....

Apparently those numbers are the Deg C readings. My guages were covered by the PO in white so whatever marking mine had are gone...

Temp in Celsius.

Here's a pic of the numbers exposed with Fahrenheit conversion:

http://forums.pelicanparts.com/uploa...1258007461.jpg

hum, my gauge is a little different, but it seems mine runs around 190 if the second number is 90 Centigrade.....that is where my gauge goes to, the second little number.... it has trouble getting there when it is cold outside!

It's an issue because running the engine creates combustion byproducts (some corrosive) that won't be fully burned off if you don't reach full temp. Start a typical engine and notice how much water comes out of the tailpipe until it's hot. That's not distilled water.

Another example: when you grill outside and shut down your grill after cooking, it's full of grease and gunk, right? But if you close it up and let it keep burning, eventually the crap burns off into soot. Not only is it easier to clean, but the grill will last longer.

Getting the engine oil hot "boils off" contaminants such as water vapor that condenses in the crankcase and fuel that gets past the rings. If you seldom get the oil hot enough to cause contaminants to evaporate, they build up to levels that are significant enough to damage the engine. A few short runs are fine, but the oil needs to be thoroughly warmed up occasionally. I'd say once a week at least. It's the same for every engine. Porsches are not especially susceptible to this. Porsche owners just care more.

http://forums.pelicanparts.com/uploa...1258041136.jpg

"Porsches are not especially susceptible to this."

Actually, they are, because their cooling medium is for the most part oil, and 911s carry three gallons of it. Our Volvo V50 brings its few quarts of coolant up to operating temperature in about five minutes of gentle driving even in winter temps, and our Boxster takes only a minute or two longer.