I have a question, I have a 1985 GSL-SE MAZDA rx7 and It has the front mount oil cooler and It keeps seeping oil around the big bolt on the bottom of the oil cooler. were you drain the oil at. I know it is tight. and it always seeps a little oil. Are they just knowing to do this or what can I do to keep it from leaking?

 

Weld it.... best insurance for it to not leak...ever.

Chances are you have a crack in your Oil cooler bung... its pretty common and not that difficult to fix if you know how to weld or can take it to someone who welds aluminum.

Try searching for "Oil Cooler Crack Repair" or along those lines.

Edit~ Doh, the big bolt on the bottom (Shoulda read the whole post ) is the oil pressure regulator in the oil cooler, I believe that has a washer to seal it, but you can overtighten it easily.

 

As far as I know there is no oil pressure regulator in the cooler. That large nut houses the thermostat which bypasses the cooler at lower temps.

 

Doh, that's what I meant... damned thing looks close to the oil pressure regulator in the front cover, or is that thing a thermostat too?

 

I final found out maybe why it was leaking I found a torque setting for that large nut on the bottom of the oil cooler. I loosened the nut and torqued it to 43 foot pounds of torque tonight and I took it out for a drive and no leaks. Also it is a thermostat that is in side the oil cooler which opens and allows the oil to go though the oil cooler. Thanks for some of the advice.

 

Mine is actually leaking from the oil line that runs to it. The one closest to the ground on my 84 gsl-se. Anyon know what size wrench it would take to get it off? I figure just a new washer will help.

 

When you take the line off clean the area of oil and have a really good look at it. Probably be hard with it in the engine bay but if you put it back together and it's still leaking your going to be frustrated having to do it twice. Good chance the bung cracked (as mentioned above). This happens easily and often.

 

23mm if I remember correctly.

 

Bung (the threaded part welded or maybe soldered to the oil cooler) is likely cracked. I have three oil coolers, all cracked. One just got welded and is not yet tested. I made up a tester but am wary about how much pressure to test with. Don't know why they crack as thread is not pipe - tapered. Maybe vibration?

rosa and now neurosa too.

 

The bung for the thermostat rarely cracks/leaks. Leaks at that spot are either improper torque settings, as you discovered, or the sealing washer is toast. This is also not a an oil drain, drain from the oil pan.