I use the term vacuum in a different sense than most mechanics think. When you apply the hydraulic pressure youre moving the fluid in a sealed system, and the opposite end of the system (master cylinder reservoir, ultimately) loses fluid- but in the proper situation, the reservoir is airtight...the fluid moving downward from the master cylinder and through the lines creates a vacuum pressure to pull it back when you release the clutch =). Its all physics, and I am oh so close to my degree.....Cant wait to get out of school, but thats another topic =p.

 

Murphy at his best.
...actually Murphy at his best was me losing my 5th gear at 1AM in the middle of nowhere, Oklahoma, on a cross country drive......

 

Quite right. A negative pressure (or vacuum) is applied to the slave cylinder by the hydraulic fluid returning to the master cylinder when you release the clutch pedal. I only took issue with the original statement because it sounded as if you thought that the friction causing pressure applied to the clutch by the pressure plate was derived from the hydraulic system, rather than the springs in the pressure plate.

No harm -- no foul...

Best of luck with your studies!

You might like this website: http://www.physicsforums.com/

 

You're my new best friend

 

Drove the Mazda to my son's baseball game tonight and when we got home, it was overheating with the steam coming out from under the hood and all that. Opened the hood to find the steam rising from somewhere under the air filter housing and from the valley between the valve covers. Looked under the car to find the bottom of the engine wet with coolant as well as the driveway under the car, but no coolant in the reservoir. All this accompanied by the same smell as I get from the air vents.

What's my next move.

 

This is just a wild guess, but since it affects both stick shifts and automatics alike, and seems not to be linked to degraded performance, slipping in the drive train etc. and is at its worst when the car is stopped or slowed after a brisk run, how about this?
What if the hot exhaust pipe is cooking up some undercoating on the floor pan just above it?
I know that Mazdas have pretty small clearances between the exhaust plumbing and the floor, and have quite extensive heat deflectors. The hottest area is located directly under the front center console. Maybe just feeling the shift lever to check how hot it is at its lowest point after a good work out would give some clue to this mystery.

 

For Skawee:
With a cookup like that, everything smells hot. Your next move is to find out what caused it and why. Could be a defective thermostat, ruptured rad. hose, failed water pump, etc. Steam from under the air filter suggests the bottom hose let go.
You've got to repair the evident damage, refill the cooling system (don't waste antifreeze, use water) then do a gentle test run and see what goes on. Before the engine gets too warm, unscrew the filler cap and see if you have a good water flow.
Also check your exhaust; if it's blowing white smoke, i.e. steam, in all probability your head gasket's a gonner.

 

Thanks oldeng, I'll check it out and post my findings.

 

OK, I filled the coolant system with water and started it up. At first there was no visible signs of leakage and so I drove it around the block a few times keeping an eye on the temp gauge. Held a steady temp in its normal range. Pulled into the driveway and looked under the car to see a nice steady fast drip (or maybe a slow flow) from under the area of the air filter housing. Coolant level in the reservoir was zip. No white smoke from the exhaust (yippee!) and the temp was still normal when I shut it down, but would not have stayed that way I'm sure.

oldeng, I'm hoping this is the bottom coolant hose you mentioned. Is this accessible if I remove the air filter housing (assuming you are familiar with the 2000 626 V6)? I put the car on ramps before I shut it down and looked from underneath, but couldn't pinpoint the location of the leak.

 

That's a relief you've got no white smoke. Now let's hope you stay lucky and it's the bottom hose. I can't help you re the strip down, but you could go to a library and get a Haynes or Chiltons manual I'm sure.
I should have told you, but with the car running and while your rad. is still full, you should check for signs of water circulation which would confirm your water pump is OK, and also check for water coming from under the timing belt cover, which would indicate a shot water pump bearing or gasket.