Strange gurgling sound from Oil tank 70T Barnfind

[ARCSinAK]

Hi Gentleman-

Well after 8 months I was able to get my 70T barn find on the road for the first time in 17 years. I was amazed how peppy the base 2.2 felt compared to my US spec 80SC. I rebuilt the Zeniths and cleaned sealed the tank replaced all fuel lines ect. Sure feeling good to take her for a drive after all the hours of work. My question is in regard to a strange, moderately loud grumbling gurgling sound coming from the oil tank. I placed a 24" hardwood stick on the tank and noise is definitely coming from this area. The motor sounds smooth accept for a bit of tuning left to be done on the Carbs. Your thoughts are welcome.

Jed

[Fixer]

Sounds like bubbling, Did you replace the oil tank cap seal?
I would worry about anything that could lead to oil starvation.
Congrats also!, Beautiful car

[ARCSinAK]

Thanks for that info, no I did not but is sounds much more dramtic than just bubbling. It's quite loud, I can hear it while sitting in the car at idle. I do not have the hose from the back of the air cleaner hood to the neck of the tank fill hooked up at the moment, could that be a factor? . The sound is accompanied with vibrations too.

[ARCSinAK]

I just took the oil cap off the SC it has a seal, no change. Then I placed my ear to the open oil fill tube and the sounds are very loud. Like warbling and almost metalic grinding sound, very strange, I thought it was just a resevouir. I placed a hardwood dowel on the valve covers and various other spot on the case and the motor sounds smooth. I need to firgue this out as I am leary of driving it now.

[quattrorunner]

Oil pressure shows good? And the level changes with different situations like driving or idling?
I had a 72t and I remember sounds from the tank too. Maybe not the same but mine sounded like bubbles and gurgling.
If the oil pressure is good and level ok, I wouldn't worry too much.

[Daves911L]

I think what you are hearing is the oil pressure relief valve in the filter mount opening. I've heard this before, and it is a strange gurgling/singing sort of a sound. Very distinctive. It is not normal for this valve to be opening, except maybe on startup with very cold oil. Not likely to be a problem in your locale. Some physical obstruction in the filter or filter mount. Or perhaps the wrong filter. You don't by chance have some sort of aftermarket oil cooler plumbed in at the filter mount? This is certainly something that should not be ignored.

[ARCSinAK]

My oil presure and level switch are out the moment, well the level switch is bouncing around. I changed the oil, got her to 190 and checked the level on the stick prior to driving. I know I have to get the oil pressure switch handled, I just wanted to go for a drive so badly after 8 months. How does one check to see if it the sending unit or the gauge? I have inspected the wire from the sending unit by on the right side of the fan all wires seem to be in order. No I do not have a after maket oil cooler, the sound is quite dramitic, justed hooked up the breather hose to the back of the air intake to the filler neck no change. I guess I could remove the oil filter and do a visual inspection of the neck.

[ARCSinAK]

[Daves911L]

Since you mention you just changed the oil, is the oil filter correct? Just because it will physically screw onto the mount does not mean it will work right. 911s flow much more oil than most other cars, and require a filter capable of passing a large volume. A too restrictive filter would cause the relief valve to open.

[ARCSinAK]

It's a Mahle

[DRACO A5OG]

Maybe po dropped dip stick?

[ARCSinAK]

I had a recollection that when I changed he oil 8 or 9 months ago, before I rebuild the Carbs and tried to start the old T, I did have a smaller hole oil filter just the SC style, so I left the original on. I just changed the old filter out and put a new Bosch filter on, magically the noise went away. Must have been clogged with gelled oil after 17 years. Now on to the Oil pressure switch. It is pinned at full pressure on the guage and does not waver, when I remove the wire to the sensor on the case the neddle doesnt move. I pulled the gauge and it looks like one of the wires insulation is compromised and nicked but still intact.

[DRACO A5OG]

Oh good, that was easy.

Once you pull the ground, it will peg up.

Take a close look at the solder joints and re-flow if needed. also the connector, if loose re-flow it as well.

[ARCSinAK]

Almost forgot thanks for all of the help love this place.

[ARCSinAK]

It pegged always regardless of what I do. Can u define re-flow?

[DRACO A5OG]

Re-flow, re-flowing the solder on the terminal to insure full continuity of electrical flow, if a crack is present you will have a short in the system.

Pegged always, means the ground is shorted somewhere, back of the gauge or solder joint or the connected at the sending unit

[ARCSinAK]

10/4 thanks

[tazzieman]

Nice colour!
Thought gurgling might be the creature from the black lagoon but as oil recently changed , it seems not

[ARCSinAK]

Ha, Thanks I'm sure I'll find a few of those in the future.

[Fixer]

Originally Posted by Daves911L

Since you mention you just changed the oil, is the oil filter correct? Just because it will physically screw onto the mount does not mean it will work right. 911s flow much more oil than most other cars, and require a filter capable of passing a large volume. A too restrictive filter would cause the relief valve to open.

+1 on proper filter

Also, forget the Oil Pressure Instrument for now, check the pressure at the motor with a good quality hand held pressure guage so you are sure.