Question: Fog inside passenger compartment

[rlvincent]

I just purchased a 93' Vette, and when I turn on the air conditioner fog comes out of the air ducts????

 

[road agent]

Heater core is leaking.

 

[John Robinson]

Heater core is leaking.

I agree.

 

[muddywaters]

I agree also, Your in sunny Fla., just by-pass the heater core til your ready to make the repair. I've done heater cores in Vette's before, there no fun.........

 

[rlvincent]

Thank you.

 

[jmccloud]

Perhaps not so bad

If you do NOT smell antifreeze (you do have antifreeze in the coolant?) when the A/C is turned on, the heater core is likely not leaking. Especially in the humid south, the A/C evaporator can retain condensate water and fog the windshield upon starting. This is especially true if the car was parked in hot surroundings (with A/C running) then started later in the cooler part of the evening. A plugged A/C condensate drain or low refrigerant charge induced frosting of the evaporator coil will exaggerate this phenomenon.
Your symptoms frequently indicate a leaking heater core. But that's such a PITA to fix, check out all the other possibilities and hope for the best.
Good luck.
BTW Welcome to a great site and come back often, especially to post the outcome of your situation.

 

[Dustoff529]

Agree

If you do NOT smell antifreeze (you do have antifreeze in the coolant?) when the A/C is turned on, the heater core is likely not leaking. Especially in the humid south, the A/C evaporator can retain condensate water and fog the windshield upon starting. This is especially true if the car was parked in hot surroundings (with A/C running) then started later in the cooler part of the evening. A plugged A/C condensate drain or low refrigerant charge induced frosting of the evaporator coil will exaggerate this phenomenon.
Your symptoms frequently indicate a leaking heater core. But that's such a PITA to fix, check out all the other possibilities and hope for the best.
Good luck.
BTW Welcome to a great site and come back often, especially to post the outcome of your situation.

I would agree that it is likely humidity, happens when the cool air is blowing at "dew point" causes the air in the cockpit to be "foggy" . If the fog goes away after the A/C runs for a bit, then that would be my answer
When I have your wounded

 

[rlvincent]

Testing.
I see you are on line, one more question if you get this message.

 

[jmccloud]

Testing

Go ahead and ask.

 

[rlvincent]

BRAKE WARNING LIGHT - AND SOME TIMES REAR HATCH WARNING. I recently replaced the Power Brake Booster, and everything was fine. Now the brake pedal has more travel, and Brake Warning light comes on when brakes are applied?

 

[jmccloud]

Brake warning light

It's usually necessary to 'bench bleed' a new master cylinder in order to get full depth travel of the piston and push out all of the air. Did you 'bench bleed' the master cylinder? If not, there may remain air in the cylinder and cause a soft pedal and perhaps a warning light. If pumping the brakes stiffens them up, that's a sure sign of trapped air.
There's a sensor on the rear hatch that may need adjusted, or make sure that the latch is positioned to hold the glass down tightly.
Good luck.
PS sorry for the delay, the wife called for dinner.

 

[rlvincent]

Thank You

It's usually necessary to 'bench bleed' a new master cylinder in order to get full depth travel of the piston and push out all of the air. Did you 'bench bleed' the master cylinder? If not, there may remain air in the cylinder and cause a soft pedal and perhaps a warning light. If pumping the brakes stiffens them up, that's a sure sign of trapped air.
There's a sensor on the rear hatch that may need adjusted, or make sure that the latch is positioned to hold the glass down tightly.
Good luck.
PS sorry for the delay, the wife called for dinner.

I replaced the Power Brake Booster, not the Master Cylinder. Do the brakes still require bleeding?

 

[jmccloud]

Brake bleeding

Brakes would need to be bled if any hydraulic lines were disconnected. If the brakes are 'soft' and stiffen with pumping, they likely have air in the system and need to be bled. It is possibly not related to the booster replacement if no hydraulic lines were disconnected.
Do they 'pump up'?
Also, the brake warning light indicates low fluid, leaking master cylinder or poor pressure balance in the two hydraulic systems (a leak).

 

[G Winter]

One other thing, if you can pump the brakes up then hold pressure on them. If the pedal slowly goes down then you may have the pistons in the master cyl leaking past and needs to be rebuilt or replaced.

Glenn

 

[rlvincent]

It was the HEATER CORE.

 

[TWISTERUP]

It was the HEATER CORE.

OUCH !! They're a pain:eek

 

[TWISTERUP]

BRAKE WARNING LIGHT - AND SOME TIMES REAR HATCH WARNING. I recently replaced the Power Brake Booster, and everything was fine. Now the brake pedal has more travel, and Brake Warning light comes on when brakes are applied?

Could be a line,hose or caliper ..but if you're not leaking/loosing brake fluid....then it sounds like a internal leak in the master cylinder.