Prolene

At Buttonwillow track yesterday, the clutch felt strange, as though it wasn't releasing enough and I had a hell of a time downshifting into 3rd at times. Two separate clutch bleeds later solved the problem.

I had put Valvoline Synthetic brake fluid into the clutch system a few months ago thinking the clutch system doesn't get much heat. WRONG!

heffergm

What's the problem with V. Synth fluid? If it's Dot 3 or 4, it shouldn't boil in the system. More than likely, you had air in the system that wasn't purged on the last bleed... which you subsequently removed after re-bleeding the system.

Prolene

The clutch had been fine for many months. Though heffergm makes a good point.

It is hard to imagine things getting hot enough to boil good brake fluid in the clutch system. Perhaps air in the MC worked its was down the line into the slave cylinder over the months and increased the effect of the volume of air.

Slows2k

Iv'e noticed that mine gets pretty contaminted after 8-10 months of driving. It's not just my car, All the ones I work on do the same. The exhaust manifold is pretty close to the bellhousing, unlike other hondas. I've definitely noticed the clutch doesn't want to fully release when the fluid is contaminated.

cdelena

I would think that the fluid you used was fine and that heat is not the problem (where would you get 300F in the clutch system?). The clutch components are not exactly precision parts (especially the slave cylinder) so air and contamination are the common problems. I think you have the answer.. your usage on the older parts is going to require a bleed more often.