Hot Air

[300 z man]

I have an 88 300zx and when I put the vent on to have outside air coming in all I have is hot air. Then when I turn it off it continues to blow hot air. Gets worse when I speed up. What can be the problem?

[Perrenial Badass]

Does the air get hotter the harder you are on the throttle? If so, I'd put my money on a vaccuum leak. First thing I would do is pull the glove box and plastic trim panel off of the dash on the passenger's side and make sure that the vaccuum lines under there are hooked up and are all in good condition. If the leak isn't there, then check elsewhere under the dash and then check the engine bay. Find a vaccuum leak, fix it and see if it helps or eliminates the problem. If you can't find any leaks, try recharging the system.

[300 z man]

I havent recharged the system yet. Only got it running a few months back. I do think I have a vacuum leak some where and that would explain why it idles inconsistently.

Do you know where the vacuum lines go? One to the cruise control by any chance. Wish I had a schematic.

[evildky]

sounds liek the actuator dashpots, there are 2 vac lines that go into the cab, they enter the firewall near the battery, check them for any signs of cracking or splitting, then get your head in the drivers footwell, and look up at the hump behind the dash, you well see a series of dashpots, check each for it's abulity to hold vacume, chances are one or more are split and won't hold vacume

[AZ-ZBum]

Most common problem is bad vacuum lines. Start in the engine bay by replacing them one at a time.