whenever I park with the car while it's running or I'm in bad traffic for a while my clutch pedal loses pressure which I'm guessing is from under hood temps. it comes back a few minutes after pulling over and opening the hood or on the highway cruising at a steady speed. now that it's getting really hot outside it's becoming a problem again. I live in central Florida.

Does anyone have any suggestions?

does the slave cylinder suppose to have a heat shield?

 

Have you tried bleeding the clutch fluid? The brake fluid it uses is very hydroscopic so, especially in humid environments like Florida, it will absorb water from the air and should be changed about every 2 years. You could also have some air in the line. If not, the slave cylinder is a cheap/easy part to replace. It does not have a heat shield; just a rubber boot that protects the piston.

 

I'm also leaning towards air in the system. Look into bleeding the system. I never had to do it on my 99 5spd so not sure where the bleeder valve is, but if you can get a hold of a vacuum bleeder that would be best. Might as well change the fluid while you're there.
I think this would be the cheapest thing to try of the other possible causes.

 

fluid was completely flushed and bled when I put the new throwout bearing last October (2020).

whenever it loses pressure I just pull over, open the hood and within 5 minutes the pressure comes right back.

I have a new slave cylinder on the way.

 

Assuming you have no air in the system, a bad slave cylinder would mean you are loosing fluid, fluid loss near the top of your tranny, by the clutch fork, and need to be constantly topping off your clutch master.

You could have a bad clutch master cylinder. A bad clutch master with an internal leak, will not show any fluid level loss. A bad master can leak in two ways.....1. internally, seals are worn and can't hold pressure, there will be not visual signs of leak.........2. leak at the rear, input shaft going through the firewall to your clutch pedal, you will see level drop and need to top off fluid.

in an extremely rare situation most likely not your issue, you could have a bad throwout bearing. the throwout bearing is seizing up and not sliding on the tranny input properly, not allowing the pressure plate to engage or disengage the clutch disc. Your pedal will be down to the floor and not pop back up because the throwout bearing is not sliding correctly, but you will be experiencing alot more issues, such as squealing, not being able to shift properly, stuck in gear, stalling, etc.

 

with my situation I'm not experiencing any loss off fluid. pressure just drops as under hood temperature goes up from neing parked while running or in traffic on a hot day. once the car is on the highway or I stop and open the hood pressire returns withing 5 minutes..