Got the engine running, for about 30 seconds. And the scavenge oil pressure blew out the remote cooler.
Good news is engine runs and 123 ignition works fine.

Bad news... now have to track down why the cooler blew. Thermostat is the Improved Racing type. Oil lines alignment is all correct. Will check next for restrictions in the -12 hoses. If no restrictions in oil hoses, I may skip the thermostat altogether.

How high did oil pressure go? Usually tube fin coolers like that are rated to ~200 psig, with 300 psig burst pressure. Seems like a defect...

No idea of the scavenge oil pressure. Pressure side read about 85 cold.

My take is that not much oil should have gone to the remote cooler given the low oil temp at the thermostat.

85 cold sound about right for idle/low rpm. Mine goes to 100+ when reved up cold.

Paul/prs9146 did his cooler in when he mis aligned the oil filter console onto the oil tank. Not saying that’s what you did but it’s probably worth checking.

Thanks Mark. That's the first thing I checked after the fried cooler.

At the two connections to the cooler, I lifted one up and oil came out the other... same thing when lifting the opposite one... oil out the other. Leads me to believe that the thermostat ports to and from the cooler are connected. Something smells Denmark wrong with this thermostat.

After that, I was easily able to blow out both hoses with compressed air, so I don't suspect a hose kink.

Oh that sucks

I was going to say stuck relief valve in the case but that's not it,must be the thermostat, funny how is was passing cold oil to the cooler ?,that cooler has hydrauliced @ huge pressure almost like the return oil had nowhere to go...just saying.
Is this a stand alone or still using the stock engine cooler also ?.
Strange one to sort,got me thinking .

Oil filter console rotation could be off.. I double and triple check that on my installs?

Crap, that sucks. This is a dry sumped engine? Any chance of a blockage after the oil cooler in the scavenge circuit (which would cause pressure to build "upstream" including the cooler)?

Roger that on the oil filter console. That may be what Mark mentioned. I'll check in the morning. With no blockage in any lines, it's either that or a bad thermostat.

Maybe I got sloppy with that console. Right now, I hope so.
Thanks for mentioning.

The base 123 ignition without an MSD seemed to work fine. 2.2S switched curve. I'm off 1 tooth on the distributor drive but had enough to get it running.

Yes, dry sump in a warmed over Carrera 3.0.

GTS seats arrive tomorrow, windshield Wednesday. Still need sun visors and rear license plate lights, then about good to go.

My understanding is that when cold the thermostat ports are connected wide open so the oil does pressurize the cooler but doesn't really flow through since it short circuits to the t'stat exit port. When hot the plug moves to isolate the t'stat inlet port from the outlet port forcing the flow to go through the cooler.
Methinks that your return is deadheaded, like nowhere for the scavenge oil to go to so huge pressure spike on the whole cooler system....

Thanks John. Agree ports should be connected. Alternative tstat setup is to reverse it, per their diagram. Deadhead is highly likely located at the oil filter console. Fingers crossed that it is.

oil return has a restriction and pressure side just builds up pressure until something go's pop,in good condition the 911 pump can make big pressure when faced with a restriction.
Just my 2 cents ok.

Yup, oil filter console installed wrong. The black blocked off port was facing the tank orifice. An expensive and time consuming mistake. So enter the cooler into the wall of shame. Thanks guys for all the suggestions and comments.

Well just a cooler not an engine so thats positive.

That's right Ben. Also on the positive side, I inadvertently pressure tested all my made up hoses!

Last time I saw that happen, cost an intermediate shaft
and massive damage to a turbo oil pump..
Had to split the case to replace the oil pump and shaft...
Wasn’t pretty or fun...

With the cooler popping so quickly I doubt any damage took place. There wasnt extended pressure.

BTDT... cleaned up the mess from it.


Mine wasn't from a misaligned filter console.

50wt Valvoline VR1 + 35 degree day + no thermostat + 3K rpm at startup = blown $500.00 factory 964 oil cooler.

I replaced the oil cooler and changed to 20W50 Valvoline VR1 to fix it.

I believe Paul’s story was when the cooler blew, the front lid was open and blew oil all over the shop.

I'm in the club. pretty new mocal 25 row. Started car on cold day, maybe 25 F. No therostat or pressure relief. Oh well, knew it might happen. It was cold, I was at the shop, had ran it two hours before and that was my ride home. rolled the dice.

Think I Ubered.

I got lucky... the system was all air at first. When I heard bubbling air escaping at the cooler I shut her down. Lost at most a quart of oil.

I lost 16 quarts on the driveway and garage floor. I put down kitty litter in the garage, and let it sit for about 3 weeks before cleaning it up. It soaked up all the spilled oil and left the floor clean. The driveway still has a stain on it.

Ok, new oil cooler installed, fixed the oil filter console, and added oil. Engine up and running now. Charging properly, oil temp and pressure gauges work, no operable tach. Now to time it and set the carbs up.
Ben's 3 outlet muffler is quieter than anticipated, at least with the GT outlets closed.

Clutch,transaxle, shifter all work. Tightest shift mechanism I ever felt on a 914 or 911. Boxster brakes work, handbrake works, doors and window mechanisms working. I swapped the left and right inner door latches. Left side on right and vv... prefer to use inside hand to open the door from inside.

Need windshield, trim, sun visors, and license plate lights. End is in sight.