mce993

Hi all,

My oil temp gauge has been acting kind of funny lately, and I'm wondering if
any of you have experienced this in your cars. I've got a '96 C2 with about 46,600 miles on it. The oil was changed at 45,000 and I'm running Mobil 1 15w-50. Unfortunately, I don't know what viscosity oil the previous owner was running in it.

When I bought the car back in July it seemed like once it warmed up and the needle dropped it would stay down around the second line with minor fluctuations. Now, as the engine warms up the temp gauge goes up to just under the third line (194 deg) and then drops back down to just over the second line (122 deg) like usual, but then as I continue driving the needle will creep back up until it approaches the third line again and then it drops back down to the second line. And then the process starts all over again. The car also smells like it is running a bit warmer than usual, but not like it's really hot. Other than that the car is running like a fine "german" watch. On the road the oil pressure is at the fifth bar where it's always been.

Could this be the result of colder weather? It's been in the 30's and 40's around here recently. Could it be related to heavier viscosity oil?? Could it be that my oil bypass valve starting to go out??? Thermostat????

I'm at a loss as to what is going on so any advice you could provide would be greatly appreciated.

Regards,

Mark

BobbyT

What you are seeing is typical. As the engine warms up, the oil cooler thermostat opens, allowing cool oil to circulate, so the temperature drops, and the thermostat closes, oil temperature rises, and the cycle repeats. At certain ambient temperatures, I see this repeat over and over. If your oil level is in the mid-range (engine hot), you will also see the oil level gauge go up and down too.

mce993

Thanks for the reply BobbyT. I thought this was somewhat normal, but it just seems to be much more pronounced now than when I first got the car. This is the first winter I've had the car and I'm still learning its little quirks. I guess we'll see what happens when the weather warms up again.

Regards,

Mark

Leander

Huh? I thought the oil level gauge only registers after the car is warmed up AND only when it is at idle on level ground?

It should register zero when you're in motion and rise when the car's at rest.

Slow Guy

I may be way off base here and my experience is only with my current '97 993 and a previous '88 911 but it sounds to me that considering an ambient temp. under 50 deg. your car shouldn't be running that warm.

I don't have access to my manual right this min. but I'm assuming when you refer to the "3rd line/194 deg" you're talking about the line at the 10 o'clock position. If that's the case it really sounds warm for under 50 deg weather.

As a ref., in my car I can see it climb to the 8 o'clock mark, then the t-stat open and it drops about 1-8 in. and then climbs back up but never gets anywhere near the mid way (9 o'clock) point.

If the ambient temps were closer to 90 deg. I would think your readings were closer to normal but at 40 deg., not so much.

JMHO

vjd3

I think he means the "second" line, which is 194 ... the third is 246.

Maybe it's better to say X lines below the red ... LOL

jimbo3

Bill- The third line (194 degrees) is at about the 8 o'clock position and the fourth line (248 degrees)is at about the 10 o'clock position. (First line is "Off", second line is just a tick above the first and is ~122 degrees.)

Normal oil temp function on this vehicle at this time. Wondering how it ran so cold before, though- 122 degrees is chilly and not good.

Yes, the oil level gauge rises and falls. After thoroughly warmed up, at idle on a level surface it goes up to max height, then it goes down (mostly doesn't read at all) when above idle and/or on unlevel ground, then back up when returning to idle. Height will vary with "levelness" of the car when it is stopped on the street.

-Jim

Slow Guy

OK Jim, that makes more sense. I was starting the "first line" as the one that is at about the "7:30" position. That explains why I thought it was reading warmer than it is.

Slow Guy

I'm curious in which manual it states what the temp. reading is for each marking on the gauge? I've looked in my owner's manual and in my Workshop Manual (993) but can't find any mention of what the actual temps are.

I have no doubt that Jim is correct, just wonder where the info is.

Yes VJD3, I would have called the 194 line the second line, not that I would have been correct.

jimbo3

It's most commonly found on <p-car.com>. Excellent resource.

mce993

Well, it sounds like my oil temp is running about right according to what you guys are saying. It just seemed that during warmer weather the needle swing wasn't quite as pronounced as it is now that it's cold out, but maybe I just wasn't paying as close attention to it as I am now.

To clarify the "line" conundrum I created, the third line I was referring to is the 194 degree mark, or the 8:00 position as shown in the photo I found on p-car.com. My needle lives between the 122 & 194 degree marks and I have never seen it go above that. With the exception of a few days a year, it really doesn't get all that hot here in Washington.

I'll keep my eye on it and see what happens when it warms up outside. I didn't mention it in my earlier posts, but I have the engine tray on now. I plan to remove it this spring.

Well, I better sign off. It's time to take the 993 out for a spin to Marzano's, the best Italian restaurant in Tacoma. I'll have some chicken gorgonzola for you all.

Mark

Slow Guy

I had thought about asking if the tray was on but knew that would stir up a hornet's nest you probably didn't want stirred.

Personally I think you're doing the right thing.

During the cooler days I do notice it's much easier to see when the t-stat opens....

Enjoy.