bldn10

987.1 w/ 3.8 L X-51 driven hard on R-compound tires for 4 years. L&N in-line PSF cooler. Last event, halfway through first lap of 2nd session the power assist went away. Checked the PSF and it was at the cold mark so I topped it off. Steering felt normal in paddock so I went back out. Same result. Checked PSF and it was full. Parked it. There was never the characteristic whine but there was a grumbling kind of noise when I turned the wheel lock to lock. But then I drove home about 250 miles and have driven another 250 since then w/ normal steering effort.

This certainly sounds heat related. Does PSF act like brake fluid? I.e. it boils and stops working when really hot? Why is this just now happening after 4 years?

Bill Lehman

You probably have a leak caused by hard driving and letting the fluid level drop. The LN solution is a band-aid. Much better coolers available which you should buy.

bldn10

Of that much I'm sure you are correct, Bill, but what about: "Steering felt normal in paddock so I went back out. Same result. Checked PSF and it was
full." I.e., it did it w/ a full reservoir.

Some background. At St.Louis last year I cranked up to go out and heard the characteristic PS howl. Checked the fluid and it was empty or close to it. But in the previous session I never lost power assist. I filled it up and started it up and realized fluid was leaking onto the header. Not good! I feared the Cayman curse but it turned out that I had a pinhole leak in the return line. Car was 3+ days at the St.Louis dealer and cost me $2000+. They said the pump was OK.

Bottom line is that I was not totally devoid of fluid and never heard it howl but still lost power assist.

When I got the car I bought an underdrive pulley but could not get it on because of the lack of clearance w/ the 3.8.

I already have a center radiator so where would a real cooler go?

bldn10

Update: I installed a small cooler in front of my center radiator. I discovered in the process that the high pressure line was leaking at the rack, and replaced it. I was at Sebring 2/17 and so far so good. Not very hot though.

bldn10

After doing Sebring, Memphis, and Barber, in the 4th session last weekend at Road Atlanta (on slicks) the return hose blew off the stem at the rack. I had 1 good clamp on it. The reservoir cap was missing too. I reclamped it and added another one, ran a session OK, and then it blew off again. Why would the low pressure hose blow off? What is the best clamp for this application?

Brian C in Az

If the cap blew off, then there must be some excessive pressure in the reservoir. Possible bad steering rack, possible that the return line somehow was restricted with debris then the pressure dislodged the debris and blew the cap off. The return line could have blown off after the cap during a second clogged line scenario where the debris didn't dislodge in time and the hose blew off.

bldn10

FWIW I bought some Swedish clamps and I tighten them every time I have the LF off. So far so good.

bldn10

Update. The clamps have held but the pump finally gave up the ghost. I had it replaced but I still have a serious leak because I have to refill it about every 2 track sessions. Where is the most probable leak source? This is getting old.

Deadeye

Have you looked inside the rack boots for leaking fluid? Check all lines for any damage, crushed etc.?

bldn10

I'm fairly certain that it is the vicinity of the pump. For quite awhile there was some kind of liquid on the top of the engine on the left side. The guy who replaced the pump said it was really nasty and he cleaned it off as best he could. Now it is the same again. Also, a few times after a session I've noticed smoke/vapor coming out of the LR wheel well and/or air intake vent. I think that is PSF. One of the lines was replaced 3 years ago so maybe the crappy plastic connector on the other one is leaking. I wish the mechanic had figured out where the leak was when he had it all exposed.

Brian C in Az

Having a PS fluid leak on the engine can start a fire. FYI

RobC4sX51