240 Turbo oil cooler hardline-conversion to AN10

I have a fairly complete oil cooler setup from a Volvo 240 Turbo (B21ET) that I will replace the current B230FT water-cooled system with. One reason is that I can’t change the oil filter without removing the downpipe. Another reason is that a real oil cooler is a real oil cooler. Apart from the oil cooler itself and some hoses, I’m only missing the lower bracket (part 19) for the oil cooler, but that will be fabricated later on.

Most aftermarket oil cooling products today are AN-standard, just as fuel and Turbo plumbing. In contrast, the 240 has all metric fittings. Since my plan is to buy an oil cooler with AN10-fittings and fix steel braided PTFE hoses myself, I started to look for how I could AN-convert the 240 Turbo setup. I want to keep the hardlines instead of getting a block adapter. The reason for this is that there’s a lot of stuff in the way for the hoses, and the original hardlines look very nice. The problem is that the hose connectors on the hardline are metric L12 fittings.

Electrolysis and painting

This summer, before I’d done the proper oil cooler research, I derusted the hardline and brackets with electrolysis and spray painted them with 2k Temadur 20 silver metallic using a Preval sprayer with great results. It’s amazing how the electrolysis can remove scale rust. I then let the parts take a couple of hours bath in phosphoric acid to etch before painting.

Soldering AN10 fittings

So I went to Hydroscand, a chain available all over Sweden that presses hoses and has all kind of fittings and hoses in stock. They have helped me before when I replaced the rubber hose with PTFE on the hydraulic clutch line for the M90. The Hydroscand guy I talked to was very helpful and showed me the exact same fitting combination as was described in a reply on my thread in Turbobricks forum: ‘L12 to 3/8″ BSP and 3/8″ BSP to AN10’. He pointed out that the ferrule on the hardline probably had been overtightened and suggested that the best was probably to find someone who can remove the current fitting and solder new AN10 fittings. Unfortunately Hydroscand don’t do welding or soldering services. The cost for the adapters would probably be around $30 with some added weight as bonus.

So I found a local plumbing company, the kind that installs piping in bathrooms, fixes leaks and more. Showing up there with requests of installing American fittings was exotic, since they only work with metric stuff and normally don’t do work on cars… However he took on the challenge and asked me to go and get some steel weld-in bungs.

I went to a nearby Biltema and got a pair of AN10 steel weld-in bungs (79783) for around $10 that happen to have an inner diameter of about ~12.2 mm. The outer diameter on the oil cooler hardline is 12 mm. The plumber “simply” removed the ferrule from the hardline, inserted the hardline a couple of mm into the weld bung, and finally soldered it in place. The good thing about this conversion is that all measurements match the original setup very well, since no pipe was cut away. The L12 fitting nut was 22 mm and the AN10 nut is 1” (25.4 mm). Space shouldn’t be an issue, although I have not fitted the pipes to the engine yet.

Next step is to fix some paint on the new fittings and scuffs, and order a Setrab oil cooler with AN10 fittings and hoses.