cowtown

This is slightly complicated, so please bear with all the details:

I don't know what's going on with my '95. I am using the dipstick (not the gauge) to check level, and I have notched the dipstick to make it easier to read. I'm fairly confident that I'm reading its level correcly.

What started all this: Two weeks ago, my normally working oil level dash gauge started sitting on the bottom at all times so I figured the sender was bad. I pulled the sender and tested - all fine. Gauge registers properly when sender arm is moved. So I start disregarding the gauge completely and using only the dipstick, thinking that I'll figure out the gauge issue later.

Oil level was a bit low per the dipstick (1/4 up from bottom of spiral) so I went to add some Mobil1 20/50. Engine running, warm @ 190 or so and on level ground, just like the last 10 years I've been adding oil to 911s. The oil came spilling out of the TOP of the oil filler neck (no extension installed). It was that full.

But the dipstick still showed low. I shut it down, let it sit overnight, then checked the dipstick again (running, warm, level). Same level-too low. I looked down into the oil filler neck and could see the oil just below the level where the filler clamps at the bulkhead in the engine bay(!).

So oil is low per the dipstick, but I can't add any. My only thought is that there might be a blockage in the hose between the filler and tank, but that seems nearly impossible. I'm not getting any oil into the intake, so I don't think it's overfull.

Before I pull it apart, can anyone shed light on this weird behavior?

jnx

I know if you pour it in too fast, it will back up and overflow and appear to be full. This happens upon refill at about the 9 qt. range. Did you try to pour in in slowly?

dhicks

This sounds very odd.....I have had the odd "burp" when I have filled too fast but if you can actually see oil in the pipe that seems to me that you MUST be over full or you have some sort of air lock (not heard of this before).......maybe you could drain and just see how much you get out...if its about 10 quarts then all would seem ok and you just had some sort of lock....it might even help to drain everythiung....Thats where I would start but others may have a better suggestion

chris walrod

I'm with David, drain just the oil tank and try to measure what you get out of it. Refill and see where your level is.

Garth S

The oil fill line is nearly a meter long and ~20mm diameter, made of the same corrugated plastic as the short 'extension tube'.
If blockage is suspect, it should be easy to snake a length of something like fuel line hose down to verify that all is clear.
While my extension tube has no bottom screen ( nor does a spare sitting here), apparently, some are: i noted this image in an ebay auction - perhaps something like that became lodged in the tube.

TMc993

A wild guess....

Be certain that you have run the engine until it is HOT, not just warm. I have noticed that if I run mine on a cool day and the oil temp gauge never gets above 8:00 o'clock, that it is difficult to add oil.

On the other hand, if I run it so that the gauge runs up to 8:30 then drops back to 8:00, then it is quite easy to read and fill. I read here that there is a point to which the oil must be heated before a valve opens and lets the oil in the tank fully circulate.

Bottom line...This may not apply anywhere else, but with my car, the hotter the oil, the easier it is to read the oil level and fill the oil tank.

xrix

I had a lot of trouble getting the final 1/3 of the oil in last time I changed - it did keep backing up and wanting to overflow from the filler.

We put a vacuum pump on the dipstick tube which seemed to help. This may be worth a try.

cowtown

Just to close out this thread, before resorting to draining the oil out, I did as Garth suggested and sure enough, there was some resistance. So it seems that there is a kink or dent of some kind in the fill tube between the bulkhead and tank. I did get enough oil in to get to the middle level on the dipstick, and have a new tube on order so I can replace it at my next oil change in a few days. I don't know how in the world that line could have gotten damaged.

Thanks everyone,
Colin

RallyJon

Is this hard to do? Is there a DIY anywhere? Thanks -Jon

ZombiePorsche44

The extension neck (pull out tube) in the oil fill tube disnigrates over time and can leave a pieces of the plastic extension in the filler neck.

I pulled mine out and threw it away and removed the broken off pieces so I just have a fill tube with no extension and have to use a funnel to add oil, but my car will fill with oil, warm, hot or even cold if I choose.

ZP44

96C4S

From the picture above wouldnt the screen cause blockage for a metal pipe to pass through

jnx

Jon, The oil sending unit is on the oil tank. It's visible when you take the liner out to change the oil filter.

99firehawk

FILL IT WITH IT RUNNING AND POUR SLOW

RallyJon

Doh! Betrayed as not having done my first oil change yet. This weekend for sure...

cowtown

I guess I have one of the cars without the screen. I have an early-build '95.


RallyJon, just 4 8mm nuts hold the sender on. You can use a new rubber gasket but I just cleaned my old one up and reused.