New guy trying not to be paranoid
 

Hey Guys -

Please bare with me, I know there are probably many threads on this but none are simplistic or exact enough for my paranoid mind. The car in question is a basically stock drivetrain 1980 SC coupe.

1. Where should the temp guage read during normal driving? It was 80 degrees on the way to work today and the needle made it to the top of the "box" on the guage. Doesn't seem like it's reading right.
2. The oil level guage reads REALLY low but then bounces around for a bit and settles almost in the middle. Then while driving goes low again. How simple (and shoudl I even attempt to) replace the sensor for this?

Thanks for the help.

-Scott

The temperature guage sounds a bit high, were you stuck in traffic and does your car have a secondary cooler in front of the the right passenger side wheel.

The oil sounds okay. The guage only really works at normal operating temperature while idling on a flat surface. They it will stop somewhere in the middle. Oterwise it does actually bounce around at described

Scott,

I'll look at my temp guage to see what you mean by "top of the box."

As far as the oil level guage... that needle does "bounce around" between idle and higher rpm. Reason: When returning to idle from higher rpm, the oil tank is filling with oil and so the needle will rise. On acceleration, the needle will drop because the engine is now drawing oil from the tank. So movement of the oil level needle up and down is normal.

If the oil level system is operating correctly, and you are at idle and the needle remains pegged to the bottom... the tank needs oil.

I suggest you check your oil dip stick with a warmed up engine at idle (on a flat surface) and see how that reads compared to your oil level guage. Chances are there is nothing wrong with your guage.

I would think it's running quite low. See the picture below, that area outlined with a white box, it rides on the top border when "warmed up"

http://forums.pelicanparts.com/uploads/oiltemp2.jpg

How long is your commute? What speeds?
My oil temp gauge takes about 5 minutes to get out of the box, and my max temperature on long drives in hot weather is dead horizontal. What sort of oil cooler do you have?

Regarding the oil level gauge - many of them are nearly meaningless after all these years. Always use the oil dipstick to measure your level. As noted do so on a flat surface, warm engine, engine running.

From your temp guage... I would say you're doing mild stop and go traffic. If you were on the highway at a constant speed... that would look high to me.

My normal reading temp is at "top of the box."

If an engine idles long enough... it will reach red box.

http://forums.pelicanparts.com/uploa...1374673167.jpg

Thanks Everyone.

Karl - that picture wasn't mine, just one I stole from the internet. From your picture mine is at the top of the box.

My driving this morning was about 5 minutes on the highway going 70 then about 30 minutes of back road driving with speeds varying from 20-35 with some traffic lights.

I didn't think I was overheating, just making sure the temp guage was actually working. My old Miata would read pretty low then sky rocket to red if there was a problem, I was hoping this wasn't the case with the 911.

The oil level gauge should be ignored entirely both while driving and before the engine's completely warmed up. It should only be consulted when the car's at operating temp AND the car's sitting on a flat, level surface. As indicated above, the gauge isn't a substitute for checking the oil with the dipstick (when the car's running and warmed up on a flat level surface)

The t-stat opens around 180-190F. It stays there unless your driving starts to exceed the oil heat transfer capacity of the coolers OR you are in stop and go traffic.

Air flow/ambient temp and driving conditions dictate oil temps.

Ignore the oil lvel gauge, it's eye candy like the equally useless clock. Rely on the dipstick and only when the engine is running, warm and on level ground.

I don't have an SC but it looks like those guys have you covered on the oil temps.

Oil level gauge: sounds like yours is working as intended. I don't find mine completely useless, just completely useless while the car is in motion. I have found that my gauge is calibrated very closely to the dipstick. That's to say that with engine at full operating temp, car on level ground, idling for more than 30 seconds my gauge matches my dipstick. I trust it enough not to be pulling the dipstick every time I fuel up.

I check my gauge a long lights and when I pull into the garage. Let the car sit for 30 seconds and if the gauge is reading anything above the lower line I'm confident my oil level on the dipstick is over the minimum line there. -J

Hey Scott,

Good to see you on Pelican. You "daughter" is very hot.

The oil gauge usually settles at the lowest point and bounces around often depending on throttle. The temp gauge on a day like today should be just about at the border of the top of the bottom white box.

Have you checked the oil level yet? The oil should be check on a level surface at idle when the car is fully warmed up. The sweet spot is in between the low and high mark on the dipstick. If the car is low on oil it should run hotter than usual so make sure you check that out as well.

Yup, have to agree with everybody else. Mine gets to the top of the box and stays there unless it very hot out, then it just barely gets out of the box.

i remember reading or hearing something about "if the oil level guage(at temp on flat ground, running) is at the top its good. once or if it drops anywhere under the white section at the top the oil level should be properly checked and topped up." could this just be their particular adjustment or it is a general rule?

i also noticed once i had cleaned my oil cooler and did an engine wash, the car seems to run a tad bit cooler. of course digital gauge would help to truly determine this but logically it makes sense..

if working correctly the oil level gauge should match the dipstick, i.e., center point of two lines on dipstick should be about middle of gauge's range. it does not need to be at the top and if it is you are very close to overfilled.

I've heard the same as Shumicat from an old 911 mechanic. Oil at the top line on the dipstick means too much oil --- mech advised filling to mid way between the dipstick markers.

Bare? Might want to adjust your spelling a little.

They it will stop somewhere in the middle. Oterwise it does actually bounce around at describedhttp://www.camj.info/7b.jpg

I was inviting the forum to undress with me.... SmileWavy

I was always under the impression that "bear" was reserved for the animal, I guess you learn something new every day!

I took the car out for a long drive last night with some spirited driving. The temp guage rose a bit above the box so I know it's at least working. I'm comfortable with the temp guage now.

After my drive i let the car idle for about a minute in my driveway (flat surface) and checked the dip stick, it measured exactly half way. The guage was a bit below half. The issue with the guage is that it twitches. I understand it'll move with levels and draw from the engine but even when it sits idling it'll twitch alot, sometimes a quarter of the guage as if it has a bad connection. I can't imagine that to be normal.

It is normal :)

The best habit to get into is, before driving the car in the garage, do your oil check using the dip stick and look at the gauge to see if it can be trusted but never depend on it :D

The twitching can be from a loose connection, a change in car voltage, or an intermittent sensor. Since the twitching is irrelevant to the use of the guage, don't worry about it. The only thing you would like to have from the guage is a feel for how much oil is in the tank when the engine is warm at idle on level ground. It sounds like you have this from your guage.

-Andy