Need help from 74 911 owners - oil line question

[cfries]

I am trying to chase down an oil leak and started replacing some worn hoses. Its a 75 Carrera but with a 74 engine (serial 6145146). I didnt even think twice before ordering a 75 hose (911-107-743-10-M20). That part is wrong. Can someone with a 74 911 shed some light on what part I need. I found part 911-107-729-10-M20 but it doesnt look the same even though it goes where I need it to go (thermostat to engine hard oil line). My part looks like 911-107-742-10-m20 but this is for cars without external oil cooler. what I do have is 911-107-739-10-m20. Sorry if this is confusing but thanks for any help in advanced.

[klaucke]

I believe what you need is 911-107-729-10, if you have 74 style exhaust; that is, early style heat exchangers (i.e. SSI style). This is for the hard line that goes from the (oil pump in the) case, looping around and down under the flywheel, like cars up to '74 had (excluding California markets). We can call this the "sump outlet line" for clarity in the rest of this post. In 75, w/ the addition of thermal reactors, this sump outlet line changed, and consequently, so did the pipe that goes from the sump outlet line to the the T-stat (or oil tank for cars w/o front coolers). '75 and newer require 911-107-743-10 to go from the t-stat and mate up to the later style sump outlet line on the engine. This line does not apply if you have a '74 engine w/ the stock exhaust and sump outlet line.

[cfries]

Klaucke, this is perfect. this forum is so great, thanks to guys like yourself. this picture also tells me how the line is suppose to run. the existing hose I took off is nothing like 729, but never looked right when mounted. it also was very close to the inside of the tire. Thanks for the help.