AlwaysBroken

Are there any tricks to getting cars not to leak oil/coolant/etc? I've had adventures and I wonder if I could have solved my problems better. Are there advantages to using AN lines vs NPT/barb or does it just give better looks?

Regarding oil, most of my problems arrived when I installed an oil filter relocation place, oil thermostat and oil cooler. At first it leaked like crazy, mostly where the NPT male threads for the tubing went into the female sockets for the oil filter/thermostat and cooler housings. I fixed about 95 percent of the problems by sealing the threads with permatex gray before I tightened them, but it still oozes a tiny amount of oil from the adapter plate. I strongly suspect that it's just a side effect of making the parts out of cheap aluminum casting and then cutting threads into them. Nothing fits perfect and I've pretty much accepted that my car will always be sort of greasy on the underside. I am kind of afraid of what will happen when I install a shimmed oil pump and suddenly have 70 psi trying to get out.

Regarding coolant, I pretty much had zero problems until my rubber coolant hoses just started wearing out (due to age) and causing overheating problems. This prompted me to overhaul everything, do the reroute and replace all my hoses with stronger stuff. I did the heater hoses with rubber w/ braided stainless and hose clamps (which has been rock solid). The main hoses to the radiator got replaced with those stainless flexible hot rodder radiator tubes which are incredibly sturdy but getting the ends to seal properly is challenging. The first half a dozen times you drive the car, stuff will leak once pressure builds. I just kept retightening and adjusting until it stuck. That being said, the car hasn't leaked coolant since early 2012.

codrus

The reason that the NPT threads leaked in the thermostat sandwich plate is that the threads in the sandwich plate aren't NPT, they're BSP. There's nothing wrong with cutting threads into cast aluminum, it works fine.

The main reasons for AN lines over barbs, rubber hose, and worm-gear clamps is that they are sturdier. They'll take more pressure, they'll survive impacts from stuff, and they can be taken apart and put back together without needing to replace parts. They don't leak if you do it right, but then the same is true of NPT.

--Ian

AlwaysBroken

http://www.summitracing.com/parts/prm-10695/overview/

This looks like what I got except mine has 4 fittings under the filter housing.

Why would something made in the US use BSP pipe fittings?

codrus

OK, most people use the Mocal thermostats, like the one included in this FM oil cooler kit:

https://www.flyinmiata.com/nb-fm-com...ooler-kit.html

Mocal is a UK company and uses BSP. BSP threads are very close to NPT threads, but not quite the same, so it's a common confusion.

(The kit you linked to doesn't include a thermostat, BTW.)

--Ian

AlwaysBroken

No, I pieced my setup together separately. Maybe a bad decision, but I was an ultra-poor at the time. I checked perma-cool's website and all their stuff is NPT btw.

But doing it myself vs buying from FM saved me a few hundred bucks. And besides the leak issues it's been fine.

codrus

I wasn't saying you should buy the FM kit, it was just the first convenient picture of the Mocal thermostat I could find. It's a standard off-the-shelf part, not something FM-specific.

Anyway, if you want advice on why your thermostat fittings leak, you'll probably need to post pictures of it, because lots of people thread AN fittings into cast aluminum and it works fine.

--Ian