Long story short during engine freshen took oil cooler to radiator shop for a good cleaning. They hooked it up to machine that applied 160 psi and now it leaks. I don't believe it was leaking before as I never had any indications of such.

In any case, I am looking for a replacement and need to know what size would support an HP500. I never had the stock oiling system and always used a 3x20 Eddie Marine combination cooler. Those have gone stupid expensive, now I wonder what else I may use and still keep oil temp in check.

Hardin Marine thought their 2x18 combo cooler would not be enough, http://www.hardin-marine.com/detail.aspx?ID=842

Any recommendation on a reasonable priced cooler for HP500 oil?

I run a Hardin 16x2 cooler and hp500 oil thermostat with -12 oil lines on my hp500 clone that i put together this winter. Have 20 hours on it now, idleing headway speed its 160-180 and wide open 212-220 on gauge so you will be fine with a 18x2. I was just out today runiing it hard...works great.

Cool Ballon78...Glad to see you have your problem fixed That's why I stated you need to get rid of all the stock lines and run -12 to everthing and run the oil thermostat.

Rockfish, may have one more HP500 Thermostat block left....I'd buy that, thats where i got mine, swap out the thermostat, and spring in the oil thermostat block just for insurance, plum it all to a hardin cooler, mine 16x2 was 109.00 cheap and be done with it. The AN -12 hose 10 feet and 8 fittings will run about 200-250 depending on where you have your cooler, but mine is in front mounted like a stock mpi set up, worked out good for me. So about 600 or so for whole job....Mercry racing get 1000 just for parts no hoses. Plus i love the clean install on the back of head, filter is easy to chang now to, after i ran mine once I changed oil and it was much easier than the old remote setup.

Found this at
http://www.mrcool.us/skin/frontend/d...ct-listing.pdf

They seem to think a 2x16 is good for up to 425 and the 3x18 up to 700 hp. Note actual cooler length is 12". What water temps have you been in with your setup? Are you measuring in pan or after cooler?

Look up seakamp engineering on the internet. They provide a lot of OEM coolers. I got 3" x18" coolers for my modified 500 hps for <$250 apiece. Same fittings as my old stock coolers or you can specify.

I ordered two 3"x18" coolers from Mr. Cool and could not beat the pricing.

Man you should have looked at CP performance There coolers are now cheaper than mrcool.

When I looked for a 3"x18" cooler over a month ago CP was $150 more than what I paid from Mr. Cool. CP did not lower prices until Mr. Cool came on this site and advertised. And then it was only if you asked CP if they price matched. If they have lowered their price now, then that is good for everyone. I like CP and they helped me out quite a bit when they carried Gaffrig.
And Mr. Cool still cut me a better deal than what he has on that price sheet when I bought multiple. I just called and asked what he could do for me.

the hardin coolers are seakamp...I asked cp when i called, nice quality, nice drains. 3/4 NPT in and out on the 16.. 109.00