912 Temperature Sensor Resistance Range

[nicholasjcraig]

Does anyone know the range for the standard sensor - e.g. 20degC = 75ohms, 50degC = 150ohms, 75degC = 225ohms.

I'm trying to troubleshoot the temperature gauge/sensor issues I'm having and I want to confirm the sensor it operating as expected. If I know the range, I can also simulate a resistance and test the gauge.

Thanks in advance,

N

[Jaems]

I think it is one of those senders that work or don't work.

Your optimum temp for normal driving is 176 degrees F. or 80 degrees C. On a 912 temp gauge the would be 1/4th of the way up from cold. Anything over 176F or 80C you start loosing the longevity of your engine. You will want to let your engine cool down; if you hit 100C or 212F, about half way up.

Mine will rarely get above 80C, even in the hottest weather. However, I have a front oil cooler, remember the key work is engine longevity

If you do not comfortable with your temp sending unit. Then I would purchase a new one. They are not that expensive compared with other items.

[nicholasjcraig]

Originally Posted by Jaems

I think it is one of those senders that work or don't work.

If that's the case, I think the gauge is kaput.

I've taken a baseline when the engine is cold and after 15mins of running at approx 70degC (using a point & shoot temp gauge). The resistance definitely changes across those two points, so it appears to be working to some degree.

Good to know where the engine operating range should be on the gauge. Looks like I should start looking at putting a cooler in and keeping an eye on the (new - to be bought) gauge. Never know how it's going to react during the summer months here in Aus.

Cheers,
N

[Jaems]

Depending on what part of Australia you are living or how warm it gets there. You may never need a front oil cooler.

With a 912 air cool engine, the internal and exterior heat will be different, also the #3 cylinder will be hotter, yet.

There are three ways to keep the heat down in the engine. One is to keep the internal oil cooler clean and or use one of the new aluminum internal oil coolers. Two, install one of the free flow oil filters, or both. For most this is enough. Third, you can install a front oil cooler or a combination of all three.

With all three and if you live where it gets quite cool during your Winter months; then the oil temp may not get pass 60C. If in the Summer your ambient temps get up to 35- 40C or higher, a lot. Then you may want a front oil cooler.

If after some spirited driving and there is not any movement on the oil temp gauge. Then I would say the oil sender is Kaput. If the oil temp goes to max when you turn the key on then the sender is wired wrong or kaput. Finally, you may have the wrong sender installed. It's been a while since I look at one. However, I think it should say 140C on the sender.

In the Winter, my gauge will just make it above 60C even after some spirited driving. Since I really do not drive in the Winter this will not make much difference. In 30-40C Summer driving my gauge will still show just 80C, even with a lot of spirited driving. However, I have both the free flow filter system and a front oil cooler.

I would just replace the temp sender and see what the running temp is. Then decide if I will need one of the upgrades or a combination of the three.