Time to fix an oil leak on a 85 12a that is coming from the bottom of the Oil cooler/filter (this is the setup where the oil filter sets on top of the oil cooler and not the version where the oil cooler is located under the radiator). Assume I need 4 "O" rings? What do I need for the “hard oil line”? Other than the 4 “O” rings and assume some type of gasket for the “hard oil line”, what else do I need before I start removing things? Other than the dealer, where else can I find the necessary parts? Does anyone have any hints for getting the oil cooler and tower off, including the “hard oil line”?

 

You will need the 2 crush washers for the banjo bolt. Mazdatrix has them. You may be able to find them at Auto parts or an implement dealer. You will have to drain your fluids, disconnect hoses, then remove banjo bolt , it's a bugger. Then you can unbolt the cooler. Have fun.
Todd

 

I got away with just replacing the two o-rings, keeping the same copper crush washers. I just kills me that Mazda charged me $4 an o-ring. I have learned better and now mail order all my o-rings from a large supplier. I did have to learn how to measure old o-rings to get the correct deminsions before they were pancaked. I also order all of them in the Viton compound, being it handles heat and deformation better then the standard Nitrile/Buna-N material.

 

If the oil leak is simply at the point where the cooler connects to the engine you only need 2 o-rings that cost 75 cents a pc at VB. You can get away with removing the 2 nuts and one bolt that secure the cooler. I removed the solid line that goes from the cooler to the front of the engine where it connects to the engine just to give me any play possible. You should be able to pull up on the cooler enough to replace the o-rings. Good Luck

Tim

 

Can you give us a P/N, PT Ray?

 

For the Mazda factory o-rings? I just told Mazda what I needed and they had it. The after market o-rings I get from air-oil.com. You just have to figure what size you need. I start by taking the mic and measuring the thickness. If a flattened ring measures 2mm thick, I figure it started as 2.5mm. A 1/2mm of compression seems to be the ticket. Getting the o.d. or i.d. is a little tricky. I know there is a tool to measure the i.d. of a ring but they have to be round. When you take an old ring from something like the ends of an om pump which are oval and slide them over something thats round they just break. I just take a piece of paper and wrap it around the o-ring (which follows around the oval shape) and use this to measure the oustside circumference. Take this and divide by pie (3.14) to get the o.d. And do the same for the inside. The grooves the o-rings go in are usually a couple mm bigger so there is a little room to play with. Not sure if all that made since, but it would not suprise me if someone knew of a more precise/easy way to measure.

 

Lol. I was hoping you'd remember the part number you ordered from air-oil.com after you did your measuring and material comparison.

 

ya, I had the same problems, my local dealer had a set of o-rings and I was back on the road 1 hour later leak free.. If your going to attempt to take the banjo bolt off good luck, that damn thing almost killed me, a massive 23mm box end wrench is a must...

 

man, thats one hell of a complex way to measure the o-rings.

If you go to an industrial supply place, they can measure them for you no problems.

For work we have two different ways to measure them, one is a large cone, but will break the rings if they are old and hard, the other is a cloth tape, like a seamstress tape, only it has all the O-ring sizes on it relating to how many durometers it is (N-90, N-70, etc) and you just put the O-ring over top of the tape and expand it out until you hit the right number.


Its awesome working somewhere that stocks hundreds of O-rings, usually just go dig through our bins of instock stuff and borrow one or two until the ones I ordered come in.