jet911

Looking for some advice/opinions: '86 Carrera

I know the correct way to measure the oil level is not by using the oil level indicator gauge, but to check the oil via the dip stick with car on level ground when the engine has warmed up to running temp and the car is running.

My question is that when the car is cold and I turn on the ignition but do not start the car, the level gauge moves a bit (to the low red line). I then checked the oil level and there is no oil registaring on the the dip stick. Where did all the oil go? After the car hits running temp. The level gauge will move up to the middle mark only when I come to a stop. When I check on level ground, the oil is at mid point on the dip stick. As long as the car is warm, the level indicator gauge is at mid point on level ground and the car shows oil on the dip stick even after I turn the car off. When I turn the key on, but do not start the car, the level indicator moves to half way. Also, after the car is at running temp., the gauge will never registar except when I come to a stop, however as I take off, the level indicator drops to the low red mark and stays there until I come to a stop again. It has never done this before. It is also making gurgling sounds when car is both cold and warm. It has not done that before. Also the other day, the car being cold, I started it and the oil light stayed on for about 10 seconds then went off. It has never done that before either. Any ideas of what is going on? Should I continue to drive? I'm starting to get a bit paranoid. With no oil in the sump (or only a little), I'm guessing the rest must be in the lines and engine. I just do not want to cause any damage.

Sorry for the lengthy post. It is a bit difficult to explain. Also, today I checked and cleaned the connections to the oil sending unit on the oil tank behind the right rear wheel. Did not change the reading.

Thanks for your input and help!

Noel

The oil should be checked with the engine RUNNING at operating temperature. The 911s (Pre-996) used a dry-sump lubrication system and you just can't get accurate measurments with the engine off. For example, some of the oil from your tank will drain into the sump. It just depends on how long since you last started your car. I sometimes go for weeks without starting my car and bet that there is a lot of oil that drains into the sump.
Noel

jet911

Thanks Noel,
I've owned my car for three years and drive it three to four times a week. I do want not to come across as being a jerk or arrogant, but I do know that to accurately check the oil level is to check the oil level on the dip stick after the engine is warmed to running temp with the engine running. That was not my question.

Only until recently, when I turn on the ignition key, the oil level gauge has registared at a "fairly" accurate level since the car is parked on level ground. In other words, the indicator on the oil level gauge has moved up to the half way point. In my mind, this indicates that the oil tank is half full of oil or at least there is oil in the tank. Only recently has this changed. I don't like it when things change, this is why I pose the question.

Why would the dip stick show half full and the level indicator at the half way mark when I turn off the car after it is fully warmed up. Let it cool overnight and when I check in the morning, the gauge only shows at the bottom red indicator and the dip stick not showing any oil? With the car off, how does the oil leave the tank? If it leaves the tank, where does it go? Are the thank and the sump two different things? If so, can oil move through the engine, oil lines, cooler and sump (?) without the engine running to pump the oil?

Thanks!

bones

It's absolutely normal for the oil level gauge to register zero when moving and show about 1/2 full on a hot engine when idling / stationery (that's how it was designed). I think you just haven't noticed before or the engine was chronically overfilled which is unlikely without other symptoms and like Noel mentions, 'the oil should be checked with the engine RUNNING at operating temperature'.

jet911

Thanks bones,

I regularly check the oil level with the engine at operating temp and with the engine "RUNNING." I like to keep the oil level on the dip stick at the mid point with the engine warmed up and "RUNNING." In fact after it was returned to me from my wrech after a tranny rebuild, they over filled it. I had to drain out oil to get it to my "preferred" level.

I pose this question - for two years I drove the car at the correct oil level as described several times. During those two years, I have taken the car on several road trips. During all those road trips and driving around town, after the car reached operating temp, and I was traveling on level ground, not cornering, but going straight at 80 mph on level ground, the oil level indicator would come up to level. In my mind, that means that oil is moving through the car as it is designed to do. Now however, the level indicator does not come to level after the car is warmed, running at 80 mph on level ground.

Sorry - I'm a very **** person I guess and don't like it when mechanical operationing things suddenly change from the way they have been performing. In my mind something caused this change and history has shown that after a change like this in mechanical operations, something "may" be indicating wear or fatigue. I'm simply trying to figure out why this change in the oil level indicator happened as nothing else has changed.

Thanks again!

purrybonker

I don't know what caused your previous condition, oh **** one (lol), but the way your car behaves now is exactly the way my car has always behaved. FWIW.

purrybonker

BTW, my car is an '87 3.2

jet911

purrybonker,
Thanks!

I just get "nervous" when things change and I don't know why...

MRFLATSIX

Hi Jim:
It sounds to me like your lubrication system is working normally. I wouldn't rely too heavily on the gauge as those things are not too accurate and they do get out of whack. It's the dipstick that counts. You say you're hearing gurgling noises. When did you last change the oil filter? what kind is it? You should only use German filters such as Manne, Mahle, Knecht. American filters make that gurgling sound. I think it's got something to do with the valves in the filter. I know this from personal experience.

TMH

Jim,

You state that you have noticed a difference in the reading of the oil gauge. I agree with the others who have said that the engine's lubrication system sounds like it is operating properly. But there has been a change you noticed. Sounds like the change is in the gauge itself. Might something like what you reference be caused by a change in electrical system ground status, like one or more ground wires are beginning to corrode? This might explain the change you have seen occur over a time period. It is pretty well known that flaky behviour in any/all instruments can many times be traced to ground issues. Maybe check/clean up the terminals of your ground wires and see if things get back to what you had been used to regarding the oil gauge indications.

Just a thought,
Tom

jet911

Thanks all for the replies!

I use Mahle filters and last changed the oil about 2,000 miles ago (last spring) from the straight 30 weight castroil the wrench put in to 20-50 Castroil that I had always run.

Yesterday I checked the ground wire to the sending unit. I cleaned off all the gunk that had built up, sprayed the area with a cleaning agent, took off the ground and cleaned and reattached. No change. I does seem to be working.

The next step may be checking the grounding strap on the tranny. The yo-yo's that rebuilt the tranny (of which I'm very diappointed), had to drop the engine/tranny 5 times to get it completed (notice I didn't say right). I guess this is part of why I'm so nervous (the rebuild was complete just before the first of the year and I did't drive the car much until early summer). The guggling, oil level gauge change issue, etc., have all happened since I trusted my P-car to this wrench who claims to be a P-factory trained mechanic.

I guess my major concern was when I checked the engine oil when cold and there was none registaring on the dip stick. I just thought that was odd. I thought there should always be ample oil in the tank to at least registar on the dip stick whether the car was hot or cold, running or not running.

I do appreciate everyone's input and suggestions - Thanks!

bones

Hi Jim I've often had trouble with 'little' items like gauges not working when I've had to take my 911 into my trusted favourite workshop, they do the big stuff well but miss out on the details like making sure everything that worked when it went to them still is!
But the good news is everybody thinks you car is healthy.

CDiercks

The reason you do not see oil registering when the car is cold is because the car is cold! When the engine warms up, the oil warms up and expands. With 12-14 quarts of oil in there, there is a lot of oil to expand and take up the extra space in the tank. That is why it is so important to check it when warm. Also, when you accelerate, the oil in the tank is sloshing around along with the float for the oili level sender. When you slam on the brakes, the oil rushes to the front of the tank, where the float is, and causes the gague to go all the way up. I use the oil level gague as more of a "idiot gague" (like idiot light) to just let me know that there is oil in there. If I don't see it bouncing around, I know I got problems. Hope that made sence!

ps: like others said, when it is cold some of that oil probably also drains into the sump which would lower the tank level further.