Another Oil Temp Question
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From: Gemantown, TN
Another Oil Temp Question
My oil temps seem to be a little higher than they should be, both on the track and the street. Since oil is the lifeblood of our engines, I figured I should do some investigating. So lately I have been paying more attention to the temp gauge while driving, and here's what it does: it climbs slowly to just above the 194 degree mark (8:45 or so) and then drops to just below the 194 degree mark when the valve for the front oil cooler opens. If I have the high speed bypass switch on, it drops just a little further. Now for the question; according to what I've read, the oil cooler valve should open at 181 degrees, so is there any way to tell if my oil cooler control valve is opening at 200 degrees or my oil temp gauge is just a little off? I suspect the later, because I changed my gauge faces shortly after I got the car, and may not have put the needle back on just right. On my 84, I put the oil temp sending unit in boiling water, so I could tell exactly where 212 was on the gauge. I know this car has an oil temp sending unit, but I'll be darned if I can find it. It sure would be nice to know exactly what my oil temps really are. Thanks for the help.
Drifting
Joined: Sep 2002
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From: La Jolla, CA
Bob, I think each car is slightly different and may be calibrated the same or not. I do not know if you can figure out when it opens but I just listen for the oil flow. In my car it is pretty easy to hear when it begins. Of course this does not help you with the calibration of the gauge. I have to say though, since I put the additional oil cooler on the left side by the AC, my oil temps have been below 8 o'clock even sitting in traffic where there is just small movement in traffic flow. I have my fan wired to a switch so I know when the fan is on since it will not come on otherwise. I also tested the air conditioning in a 95+ temperature day and had no issues with cooling the interior with the engine fully warm. I am going to the california speedway this weekend where the temps will be in the mid 90's so I will get a good track test and report on that as well.
Sorry I wrote so much without any real answer to your question ;-(
Sorry I wrote so much without any real answer to your question ;-(
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From: Gemantown, TN
Surely someone out there knows how to check the accuracy of the oil temp gauge. What if I let the car get to temperature and then measure the temperature of the oil tank with a pyrometer? This may not be perfect, but it should give me a pretty good idea of what the gauge is reading unless I'm missing something. Thanks again.
Bob
Bob
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From: North West
I don't know about the 993, but on most other cars, you take the sender (sensor) off and put it in a liquid with a known temperature and then measure the resistance on the sensor, then reference the reading to a chart in the service manual.
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I took the oil temp sensor out and jumpered it so that I could still see the reading on the in car gauge. I then put the sensor in a beaker with oil and a thermocouple which I then heated to 225F. I noted the needle position on the gauge as the temp dropped. Took about 30 minutes start to finish
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From: Gemantown, TN
Alan & Hatchy - that is exactly what I want to do, but I can't find the freakin oil temp sensor! I have factory a service manual on CD, but I can't find it either! Anyone know where that silly thing is? (the oil temp sensor, not my service manual - but if you know where my service manual is, that would be ok also)
King of Cool
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Bob,
It's on top of the crankcase in front of the engine, that's why you don't see it. It's shown on the manual (at least in my paper manual).
Without "snake hands" you pretty much need to take the intake off in order to get it.
It's on top of the crankcase in front of the engine, that's why you don't see it. It's shown on the manual (at least in my paper manual).
Without "snake hands" you pretty much need to take the intake off in order to get it.
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Joe Kucinski
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From: Solana Beach, CA
Living in Memphis, if you want cool oil in the summer, you are probably never going to be happy until you do what Kary did, install a secondary oil cooler. Kary is too polite to tell you this, but not only did he install the Cargraphics cooler in the left fender, Kary, a Rennlist sponsor, is also a Cargraphics dealer. Check out http://www.group9motorsports.com
The naysayers say (cute twist of the language), the Cargraphics cooler can't work...and if it does happen to cool the oil, it will severely compromise your air conditioning. I for one am very interested in the Oil temps Kary sees at California Speedway this weekend. And if Kary is a real sport and wants to put the naysayers to bed, once and for all, he will do a run session with his air-conditioning on...come on Kary, do it! Let us know how it goes. Personally, I will sacrafice a little air conditioning for cooler engine oil...but then again, my 993 is not a daily driver, and I live in San Diego with pretty mild weather.
At Streets of Willow 2 weekends ago, with a Turbo S cooler helping out in the oil cooling department, and ambient air at about 95 degrees F, I was seeing 10:00 o'clock on the oil temp gauge. I would rather see below 9:00, just as the old SC with an auxiliary cooler would run on hot days at the track. The SC oil temps would get up to about 215 degrees F, max! And that is at Willow Springs in the Cali High Desert with ambient air at about 100 degrees.
I may weaken one of these days and at a minimum, get the Cargraphics dual Turbo S system. Stay cool!!!
The naysayers say (cute twist of the language), the Cargraphics cooler can't work...and if it does happen to cool the oil, it will severely compromise your air conditioning. I for one am very interested in the Oil temps Kary sees at California Speedway this weekend. And if Kary is a real sport and wants to put the naysayers to bed, once and for all, he will do a run session with his air-conditioning on...come on Kary, do it! Let us know how it goes. Personally, I will sacrafice a little air conditioning for cooler engine oil...but then again, my 993 is not a daily driver, and I live in San Diego with pretty mild weather.
At Streets of Willow 2 weekends ago, with a Turbo S cooler helping out in the oil cooling department, and ambient air at about 95 degrees F, I was seeing 10:00 o'clock on the oil temp gauge. I would rather see below 9:00, just as the old SC with an auxiliary cooler would run on hot days at the track. The SC oil temps would get up to about 215 degrees F, max! And that is at Willow Springs in the Cali High Desert with ambient air at about 100 degrees.
I may weaken one of these days and at a minimum, get the Cargraphics dual Turbo S system. Stay cool!!!
Drifting
Joined: Sep 2002
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From: La Jolla, CA
Martin,
You propose an interesting test. I am perfectly willing to run the air conditioning in a perfectly warmed up car in the grid, but as I understand it running the air conditioning at high engine RPM's for 30 minutes is not good for the air condition parts. This is just something I was told by some racing folks that saw someone run their car's air conditioning on the track with some less than optimal results in the engine compartment.
I have many bench marks written down for California Speedway with varying outside temperatures/oil temp readings so I will be able to match my test conditions up with this new CG oil cooler. It will be interesting to see the results this weekend, but as I said just doing basic tests on the street and driving school show significant improvement.
You propose an interesting test. I am perfectly willing to run the air conditioning in a perfectly warmed up car in the grid, but as I understand it running the air conditioning at high engine RPM's for 30 minutes is not good for the air condition parts. This is just something I was told by some racing folks that saw someone run their car's air conditioning on the track with some less than optimal results in the engine compartment.
I have many bench marks written down for California Speedway with varying outside temperatures/oil temp readings so I will be able to match my test conditions up with this new CG oil cooler. It will be interesting to see the results this weekend, but as I said just doing basic tests on the street and driving school show significant improvement.
Banned
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From: San Diego
This is something I've been wondering about as well...During normal cruising, I will see my temp guage between the first and second hash marks - 8 and 9'oclock. If I am really getting on it, the needle moves up to the 9'oclock or 9:30 postition, almost to the 10'oclock position. I spoke with the guys at Hergesheimers who did my valve job and they said this is normal...The day I was really driving it hard, it was in the high 80's to low 90's and I had the motor running no lower than 4000 revs for at least 30 mins. During this period I was at redline in second and third, nonstop.
Drifting
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From: La Jolla, CA
Agro1,
That is somewhat normal if you have the stock oil cooler only. Since I installed the additional oil cooler cruising in town or on the freeway never gets above 8 o'clock. I can't wait to try it on the track this weekend! Will you have time to come up to the speedway this weekend to visit?
That is somewhat normal if you have the stock oil cooler only. Since I installed the additional oil cooler cruising in town or on the freeway never gets above 8 o'clock. I can't wait to try it on the track this weekend! Will you have time to come up to the speedway this weekend to visit?
Racer
Joined: May 2001
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From: Chicago
Two comments:
First, this is probably not as much of a help for high-speed track use, but for street situations I am extremely impressed with the results of the manual oil cooler fan switch mod as per Robin's site. Flick on the factory-looking 944 switch in the center console, and within 60 seconds or so the oil temp gauge reading is back to 8:00.
Second, anybody familiar with Thermostrips? They are "irreversible temperature indicators" which record the highest temperature reached on a given engine surface. This might be a quick way to get a sense of maximum temperature with minimal hassle--just stick it on and go.
First, this is probably not as much of a help for high-speed track use, but for street situations I am extremely impressed with the results of the manual oil cooler fan switch mod as per Robin's site. Flick on the factory-looking 944 switch in the center console, and within 60 seconds or so the oil temp gauge reading is back to 8:00.
Second, anybody familiar with Thermostrips? They are "irreversible temperature indicators" which record the highest temperature reached on a given engine surface. This might be a quick way to get a sense of maximum temperature with minimal hassle--just stick it on and go.
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From: Ann Arbor, Michigan
Well, I don't think it is a fair test, but here is my recent experience. With Kary's help, I now have a Cargraphics cooler mounted over the AC condenser. I also put in vents where the fog lights were. I was driving with the Windy City BMWCCA a few weeks ago at Road America, and was at Grattan the weekend before with the Michigan ACCNA. I drove several hard 30 min sessions at each track. The temp was cool, at or below 60 degrees. As the engine warmed up, the temp guage would slowly rise to about 8:00, the second mark. When the thermostat opened, the temp would drop to the first mark, just above stone cold. It stayed there, and never would bump until the cool down lap, when the spoiler would come down, and the temp would get to about 8:00.
Now you might say that the ambient temps were so cool that this experience is not relevant, but I'll tell you that I drive frequently in cool weather as well as in 90 degree weather (which is why I needed the Cargraphics cooler in the first place) Even with these cool ambient temps, I've never seen ANYTHING like this level of cooling. It was amazing, and I have no doubt that this cooler will make a huge difference. I am also eager to see what it will do to my AC function, but for me, this is secondary.
I'll also report through the upcoming season, but as has been reported here before (and the reason I slid further into the abyss), this is the answer to oil cooling.
Chuck
Now you might say that the ambient temps were so cool that this experience is not relevant, but I'll tell you that I drive frequently in cool weather as well as in 90 degree weather (which is why I needed the Cargraphics cooler in the first place) Even with these cool ambient temps, I've never seen ANYTHING like this level of cooling. It was amazing, and I have no doubt that this cooler will make a huge difference. I am also eager to see what it will do to my AC function, but for me, this is secondary.
I'll also report through the upcoming season, but as has been reported here before (and the reason I slid further into the abyss), this is the answer to oil cooling.
Chuck
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Bob,
Here's wealth of information:
http://p-car.com/diy/fan/
Also, have you verified your fan resistor if it's working properly? Most common problem is a dead resistor which prevent the cooling fan from running it's slow speed. It is designed though to still work in the fast speed, for safety, but at that point your temp indicator is already at 930 position.
Here's wealth of information:
http://p-car.com/diy/fan/
Also, have you verified your fan resistor if it's working properly? Most common problem is a dead resistor which prevent the cooling fan from running it's slow speed. It is designed though to still work in the fast speed, for safety, but at that point your temp indicator is already at 930 position.