I have been running poly line, similar to hose found in ice maker kits, for over a year now without any issues. It appeared to be very strong and stable. Surprisingly I have also been running fine without a fully functioning thermostat in the car. It's been stuck in the open position since I bought the car and it takes quite a long time for it to reach normal operating temperature. While this has affected my switch over times, it hasn't really been that big of a deal.
Well I finally got around to replacing that thermostat a couple weekends ago and boy were things great. I had a heater! I could switch over quickly! I could also melt my hose!
I run two pex lines for coolant, and two poly lines for oil. These are wrapped in pipe insulation, then a 10 mil plastic plumbers tape surrounds the outside. I must say that I did a pretty good job, because most of the oil was stuck inside the wrapping. The bad thing is that it acted like a pitcher when I cut the tape open.
The PEX has been pretty good. It feels strong so I think I'm gonna stick with it. As for the oil, I am going to upgrade to aluminum. For those wondering, the original intent was to do this as cheap and easy as possible just to prove/disprove the vegetable oil for diesel concept. Now that I have seen it, I have no issue with using better materials and putting forth more effort.
Choose wisely for your material selection
-- Rodney
