Well I've totally run out of options on this plane. Oil coolers are routed correctly and are the proper part numbers. The oil sump screen was clear and clean. Yes, we tested the vernatherm in a water bath.

Have you checked the "inside" of the oil hose?.....they can collapse and that would restrict flow. Ya can't tell from the outside of the hose.

We have not checked the insides of the oil hoses, I suppose that is the last thing we can check. How would a hose, under 60-70psi of oil pressure, collapse?

Too much oil, too little oil? Checking when cool on level ground?

Don't know....I know it happens to fuel lines.

We're running the oil level at the maximum of 12qts checked on level ground.

I pulled this from a rather long blog. May be of help.

http://www.skymachines.com/N3068T/Lance-Review.pdf

Among recurrent ADs are: 77-12-06, which requires the shanks of Hartzell Y-blade propellers
to be inspected and cold-rolled every 2,000 hours or five years (90-2-23 also calls for a
one-time inspection and possible replacement of the hub, and 94-17-13 requires recurrent
inspection of hub grease fittings); 78-23-01, which requires the fuel drain lever doors in
naturally aspirated Lances to be checked every 100 hours until they’re replaced; 93-5-22,
which addresses the fuel injector lines on the TIO-540-S1AD engine; 95-26-13, which requires
recurrent inspection of oil cooler hoses.

Hi Steve, thanks. We have the 'D' style oil cooler hoses on the aircraft which eliminates that AD.

I'm a little late to the party with pictures but i discovered it's next to impossible to get a decent shot of anything in that tight area between then engine and firewall! At any rate if your hoses are routed per the book they are likely the same as ours. The LH cooler outboard hose goes to a fitting on the accessory case near the LH mag. (we swapped the IO540K1G5D engine for a non D) The LH cooler inboard hose is routed to the bottom of the RH cooler. The RH cooler top hose goes to a fitting close to the oil filter adapter.

Random thoughts of what I might try in your situation:

The dipstick is correct and 12 qts isn't actually 14? I once srewed up the oil change on a warrior and ended up with 10 qts instead of 8. Oil got very hot on the next flight! Being overful caused the oil to become aerated and all that air in the oil made the cooler ineffective.

Pull the vernatherm again and see if it marked indicating seating all the way around, I know you've surfaced the seat and installed a good fitting vernatherm but maybe for whatever reason it isn't seating yet?

Is oil actually circulating through the coolers? Are they too hot to touch after flight?

What oil is in the engine? I've found Aeroshell w100 will run slightly cooler than mineral 100 or 15w-50. (8-10 degrees)

I assume the oil pressure is somewhere in the green? Is the pressure dropping substantially as the temp goes up to 239?

I have a customer with an 81 PA32R-301T who suffered high oil temps, he pointed it out to the PO when he purchased the aircraft, PO said it was always like that - often 210-220 in cruise. I traced the oil lines and found that the cooler was being filled from the top fitting, reversed the lines and now he sees 180 all day long - cruise or climb.

We checked the coolers and they are warm, however the top of the rt cooler is 50 degrees cooler than the bottom whic suggests that there may be an air pocket. Looking at the plumbing it looks like it feeds the cooler from the top. Every system we plumb in the race cars we plumb the inlet from the bottom and outlet from the top to push any air out. The mechanic says this is plumbed correctly, but I'm not so sure.

If oil enters from the top, wouldn't any air bubbles automatically form an air pocket at the top of the cooler?

Ok, the problem has been solved. I switched the oil lines on the copilot cooler so it would fill from the bottom and now the overheating issue has been resolved. You have to love a&ps who don't do their jobs correctly.

Ain't BT a wonderful thing even for the Piper guys!

I'm not a piper guy, in fact out of the three, I like pipers the least.