mhs26

I have a 1980 911 sc, engin was just rebuilt (top and bottom). For the first few months the car ran great, but just in the last few months a bubbling noise happens every time I start the car. This noise stops after 5 min of driving. When it's a very cold day the noise is louder. On really hot days almost no noise is heard. I think the noise is coming from the reserve oil tank. any ideas?

jlkline

Its likely to be oil passing thru your fender well thermostat which may no longer close completely. This occurs after starting while the oil is still relatively thick. I can hear mine on cold mornings, but usually in front of the thermostat at the lines going up to the cooler. When the oil thins out a bit when warmed up, the sound goes away.

jet911

Yep, I have the same noise on my '86. I believe it is the oil thermostat staying open for some reason allowing the thicker oil to gurgle/bubble through. It also goes away after warm. No issue.