Firewall Forward - Cooling System

2005-02-06 - Oil Cooler arrives. (4.0 Hrs).

I got my first part for my 13B engine installation. I bought a used RX-7 oil cooler on Ebay for $56 + $18 shipping. You never know what you are going to get on Ebay, until it shows up. I have to say, that this part looks pretty good, once it was cleaned-up. I think $56 is a pretty good deal, considering that I have seen the stock Mazda oil cooler advertised for $600-$850.

The seller did a pretty good job of packaging the unit. This is what the oil cooler looked like after I removed it from the trash bag that it was wrapped in. Oil was still leaking out of the hoses, and there were a few bent fins, but it looked servicable.
This is what it looked like after a few hours of cleaning with Lacquer thinner. I know, I should have used gasoline, but I was too lazy to go out to the shed and get some.
Looks pretty good here, but I think we can do better. After this picture, I soaked the whole unit overnight in laundary detergent, which didn't help that much.
This morning, I spent two hours soaking and cleaning the unit in Metal Prep. I sloshed the unit around in used Metal Prep that was mixed 1:1. This got out a lot of the grease between the fins, and turned the Metal Prep solution black. However, the unit didn't really start to cleaned-up until I used a brush and some fresh, undiluted Metal Prep.

Normally, I don't use Metal Prep as a cleaner, I just use it as an etch. It's a lot cheaper to clean the parts in Dawn before dipping them in Metal Prep. However, after I saw what it did to the oil cooler, I just might splurge a little in the future. At $13 a gallon, Metal Prep is about twice as expensive as Lacquer thinner, which I don't even think about when I use it. Sometimes being cheap doesn't pay.

I had to use some safety wire to dig out some of the small pebbles from between the fins, and I still need to straighten some pins. You probably cannot tell from the pictures, but this unit really looks good. I'm pretty happy with my first engine part. This was a good buy.