Should the top go up and down smoothly when the car is a idle or is it normal to have to boost the revs to work? I thought my fluid might be low but it's right up to the top line.

 

Mine operates smoothly at idle, and has even since before the hoses started leaking and I replaced them all. I hope this helps, and would suggest that it could be a lot worse than having to add a few revs . . .

mws out

 

My top goes up and down smoothly with the engine off. Sounds like a weak battery with the lower charging voltage at idle.

 

And on this subject, I was advised (by the previous owner of my car) to avoid operating the convertible top with the engine running whenever possible. The reason given was that doing so with the engine running there was unduly high pressure from the pump. Is this so?

R

 

The roof operation is by a hydraulic pump the put out 1600+psi and the hoses, latch and rams have been known to fail because of the high pressure see the attached link about failures. Operating the roof with just the battery power to run the pump was suggested by many to prolong the life of the hydraulic components and that is why you were told to run it with the engine off. I am also attaching a chart that will explain the pressures delivered by the pump to operate the roof. Let us know if you have ant questions.

Link to failed hydraulic equipment JagRepair.com - Jaguar Repair Information Resource

Link to hydraulic pressure JagRepair.com - Jaguar Repair Information Resource

 

The notion that this can be thought of as a static problem ... dependent only on peak pressure ... was discredited long ago. Peak pressure matters, but the "shapes" (rates of change) of pressure pulses matter too. See the "voltage reducer" link in my sig. line below for relevant comparisons, including curves with the resistor operated as specified, i.e. with the engine off.

Ralphy's friend was right: all else being equal it is better to operate the pump with lower voltage, so engine-off is better than engine-on.

But the bad news is that the primary culprit in causing hose failures is temperature. So use of pressure-reducing relief valves and resistors with stock hoses has produced only limited reduction is hose failure rates.