Just bought a 1989 Carrera Cabrio: oil level guage baffles...

[Navigueur]

The dream comes true...

Unusual car: no power steering, brake pedal hard, but effective, drives like a go-cart, hates pot-holes...






But the behavior of the oil level guage has me baffled...

Original engine, 78,000 miles, good compression, cat bypass and sport muffler...

At engine start after long rest: needle shows low level, near red line
Start engine: needle goes to 50%
On highway at 3000RPM: needle goes down to just above red line, pressure at 3,5
On stop at red light: needle goes to 99% full tank, pressure at 2
Manual measure warm engine shows normal level...

Are these variations normal?

[cashman]

That is normal during cold operation and warm up. Let the car fully warm up, park the car with the engine running, wait a minute. If your guage is anywhere near accurate it should read close to full (with full oil). Don't trust the guage and use the dipstick with the engine running. That is the best method for accuracy.

[ZOA NOM]

Definitely only trust the dipstick on level ground, engine warm at idle. The gauge will be close, sometimes.

P.S. Get some air in that right front.
P.P.S. Beautiful car!


edit: on second thought, the low air pressure in front is probably a good idea in the snow/ice. never mind

[hcoles]

level should be checked with engine "hot", this usually means the temp. gauge is to the first mark, I like to run about 1/2-1 quart low from full, check with the stick. In my experience until the engine is hot to at least the first mark, the indicators (stick or gauge) don't mean much. The reason for not running at the top, these motors have oil carry over at high rpm's in certain cases, i.e. oil comes up the vent tube and down the intake. You have approx. 14 total quarts of oil in there being a quart low is not an issue but you don't wan to go below having the gauge bounce when hot, otherwise you might forget about checking the oil. Checking very closely over time when you have a new-to-you car helps establish oil use, which is a good thing to know, so you can start a savings account.

[wildcat077]

Nice car Navigueur !

Maybe we'll run in to each other at one gathering or another this Summer !

Cheers !
Phil

[Porsche 911]

Sweet new 3.2 ride!
Replaced oil on mine recently. Like the posters have been saying, take measurement from dipstick with engine at idle for at least 5 mins on level ground.

From extremely low (almost empty) oil level, 5 quarts got my level about 65% full from the low mark and high mark.

[hcoles]

sorry to disagree - 5 mins may or may not bring the oil up to temp. it is up to temp. when it is not when it is likely - get it hot and it will get warm but may take 15/20 mins at idle - then add 1/3 or no more than 1/2 quart at a time and check gauge and stick.

[James Brown]

Check the oil after driving, get into that habit. I check it after I come home from driving twice a week. Do not rely on that gage under any circumstance other than idling warm. Oil is the life blood in these cars it cools and lubricates and needs extra attention for many years of trouble free motoring.

[vracer]

Navi.
I don't know what is unusual about your car. They are all like that. If your car did not come with an owner's manual, do a search. There is a PDF of an '87 floating around here somewhere. There are only a couple of minor differences, alarm, etc.

[Joe Bob]

Don't think 3.2s had power steering. 964s did......SCs and Carreras DID come with power assist brakes.

[JJ 911SC]

Originally Posted by James Brown

Check the oil after driving, get into that habit. I check it after I come home from driving twice a week. Do not rely on that gage under any circumstance other than idling warm. Oil is the life blood in these cars it cools and lubricates and needs extra attention for many years of trouble free motoring.

+1 on that.

I had the same worry when I got mine. Guage is only good when the car is idling for a minute after reaching Operating Temperature.

Got the habit of parking the car in front of the garage, walk around the car for a quick inspection and check the oil level using the dipstick.

Aussi simple que ca...

[JJ 911SC]

Originally Posted by Porsche 911

... with engine at idle for at least 5 mins on level ground...

A Porsche engine should never idle for 5 minutes

[Laneco]

AS others have said, the level guage is a bald faced liar. Yours sounds like it is reading "normal." Once you know where the guage reads when your car is up to temperature, it's just a comparison thing. Check the oil regularly and if you notice a change in the reading, check it immediately.

Just to make sure this is clear - engine oil to be checked after oil up to normal temperate - e.g. after a drive, on level ground and with the engine running.

angela

[Hugh R]

To be clear, the gauge indicates oil level in the car, it uses a level sensor. It will flucuate when driving but the key is hot, level surface idling compare the level to the dipstick (hot, running). you can learn from it what is normal when running, but the key is hot, idling, level surface. Make the gauge earn your trust as compared to the dipstick.

[Porsche 911]

Originally Posted by hcoles

sorry to disagree - 5 mins may or may not bring the oil up to temp. it is up to temp. when it is not when it is likely - get it hot and it will get warm but may take 15/20 mins at idle - then add 1/3 or no more than 1/2 quart at a time and check gauge and stick.

... with engine at idle for at least 5 mins on level ground...
A Porsche engine should never idle for 5 minutes

.. idle at 15/20 mins, or never idle for 5 minutes. Which is it? Best is to do check oil level with dipstick at idle after the car's been driven. But if you don't feel like driving the car just to check the oil level, checking oil after 5 mins idling won't devastate the engine.

[Kidasters]

Originally Posted by Porsche 911

.. idle at 15/20 mins, or never idle for 5 minutes. Which is it? Best is to do check oil level with dipstick at idle after the car's been driven. But if you don't feel like driving the car just to check the oil level, checking oil after 5 mins idling won't devastate the engine.

It won't be accurate.

You can only check the oil under the following conditions:

You are at full operating temperature. That means all of the thermostats are open. That means all of the oil in the system is circulating.

You are on a level surface.

Your car is running. The oil pump in the Dry Sump engine needs to be circulating the oil

If your car gets up to full operating temp in 5 min, you have problems.

Idling for 5 minutes won't hurt the car. Idling for 30 minutes won't hurt the car. If it did, none of us would be able to drive in traffic. But - they were meant to be driven, so drive it.

And do like James does - check the oil when you get home.

Back to the original poster - the level gauge is only accurate at idle, engine warm, level surface. Pull the gauge out and send it to North Hollywood Speedo and have them install a much more useful voltmeter.

Oh - and power steering didn't come along until the 964 series. And the rack leaked. Ask me how I know. Also - you have vacuum assisted brakes on your car. The 964 also had ABS - which you don't have. The ABS pump on the 964 is notorious for getting fouled up from non-regular brake fluid changing. Again, ask me how I know.

If your brakes seem like they are too stiff - you may have a vac leak.

Drive your car and have fun.

Ken

[Porsche 911]

Originally Posted by Kidasters

It won't be accurate.

You can only check the oil under the following conditions:

You are at full operating temperature. That means all of the thermostats are open. That means all of the oil in the system is circulating.

You are on a level surface.

Your car is running. The oil pump in the Dry Sump engine needs to be circulating the oil

If your car gets up to full operating temp in 5 min, you have problems.

Idling for 5 minutes won't hurt the car. Idling for 30 minutes won't hurt the car. If it did, none of us would be able to drive in traffic. But - they were meant to be driven, so drive it.

And do like James does - check the oil when you get home.

Back to the original poster - the level gauge is only accurate at idle, engine warm, level surface. Pull the gauge out and send it to North Hollywood Speedo and have them install a much more useful voltmeter.

Oh - and power steering didn't come along until the 964 series. And the rack leaked. Ask me how I know. Also - you have vacuum assisted brakes on your car. The 964 also had ABS - which you don't have. The ABS pump on the 964 is notorious for getting fouled up from non-regular brake fluid changing. Again, ask me how I know.

If your brakes seem like they are too stiff - you may have a vac leak.

Drive your car and have fun.

Ken

That's why i said best to check oil level on dipstick at idle after it's been driven.. not hard to read

[nesslar]

Originally Posted by Navigueur

The dream comes true...

Unusual car: no power steering, brake pedal hard, but effective, drives like a go-cart, hates pot-holes...






But the behavior of the oil level guage has me baffled...

Original engine, 78,000 miles, good compression, cat bypass and sport muffler...

At engine start after long rest: needle shows low level, near red line
Start engine: needle goes to 50%
On highway at 3000RPM: needle goes down to just above red line, pressure at 3,5
On stop at red light: needle goes to 99% full tank, pressure at 2
Manual measure warm engine shows normal level...

Are these variations normal?

If your guage reads that high when your car is warmed up, you may have a bit too much oil in it. Maybe a quart too much.
I say that because you said, "Manual measure shows normal...". But by "normal" do you mean your oil level is at the high mark on the dipstick? If so, it's too much oil. You should strive to keep the oil level (warmed up) about in the middle of the dipstick marks. If your "manual normal" reading is there now, about in the middle, you are fine.
My guage reads only up to about 60-70% even when my engine is "hot" at a stop light; by hot I mean the temp gauge is about at 9:00.....your gauge could be a liitle "off", but I'm still gonna guess you have too much oil in there, if your needle is going clear to the top...

[Kidasters]

It was more your last statement:

"But if you don't feel like driving the car just to check the oil level, checking oil after 5 mins idling won't devastate the engine."

Sure it won't hurt the engine. Also won't tell you your oil level. Unless your car heats up to full temp after idling for 5 min.

[nesslar]

I also really like the idea of checking the oil after getting home, the car all warmed up. Then on the next drive you can be assured of a proper oil level and just go from cold! ...unless there is suddenly a huge pool of oil under there.....