ICE-MAN1

Hopefully yall can help me out, I have a 99 trans am when at a red light the car surges and has steam coming from under the rear of the hood on drivers side, and the surging gets worse in the rain while stopped. when I pop the hood there is a hissing sound and steam coming from the back of the engine compartment. Could it be the steam crossover pipe or something with the pcv? Need help thanks in advance.

G Atsma

If it's steam, you have a leak. Pressure test your system.

ICE-MAN1

How would I do a pressure test and locate the leak?

ICE-MAN1

bump!

nine8ss

iTrader: (5)

Borrow a cooling system tester from your local auto parts store. Make sure the coolant is full and screw the tester on. Pump some pressure into the system and watch for the leak to occur.

ICE-MAN1

Ok thanks would a leak be the cause of the surging also?

nine8ss

iTrader: (5)

First step would be to identify where the leak is coming from. We can then figure out if it is tune related or something else.

01CamaroSSTx

iTrader: (3)

Do you smell coolant?

01CamaroSSTx

iTrader: (3)

I venture to say it's the driver side coolant plug or the freeze plug on the cylinder head.

youguessit

Ever figure it out?

ICE-MAN1

Ok and to check to see if that's what it is I just try to reach back behind the head and feel for moisture?

01CamaroSSTx

iTrader: (3)

If your leaking coolant then you should be having overheating issues and have to add coolant from time to time. You could pressurize the system until you hear the hissing and try and put your hands on the freeze plug or the coolant plug and see if the hissing sound changes indicating the source of the leak. Also get a mirror back there and see if you can see where the leak is coming from usually there is a visual indication of the source as well and if the engine has antifreeze in it then you should be smelling that stuff also if its leaking. The surging may or may not be related. Do you have a check engine light on or have you seen your check engine light flashing at you while driving? Even if your check engine light is not on there may still be codes the ECM has registered so get an OBDII scanner and scan for codes as well. Good luck!

ICE-MAN1

No I haven't been having any overheating problems, and as far as I can tell I don't smell any antifreeze. I'll hook my scan tool up and see what it says. Thank you for the info

rednari2

iTrader: (1)

If you see steam from the back of the motor, and assuming there is no other known reason for the surging, you probably have a leaking head gasket. Do a compression test on the suspected cylinders. Also, keep in mind that a head gasket can leak to the outside but not into the cylinder. But since you stated the motor was surging, that's why I suggested a compression check.

RB04Av

AC condensate dripping on exhaust?

01CamaroSSTx

iTrader: (3)

I could see that if it was coming from the passenger side of the engine and if the head gasket is really done wouldn't it be overheating and loosing coolant?

RB04Av

AC condensate = what condenses out of the air, onto the (cold) evaporator, just like on the outside of your (cold) beer; and drips out of the housing

Completely normal; in fact the more the better

Symptoms of a bad head gasket depend entirely on where EXACTLY it's bad. That is to say, what it allows to leak into what else. Needless to say, the VAST majority of them fail where the pressure is HIGHEST, which is, between cylinders. They don't all that often involve coolant or oil or overheating. About 99% of all car problems that people automatically blame on head gaskets are something else, and in case they get fixed during a head gasket replacement, are basically just collateral damage.

Forget about head gaskets. Most likely, not your problem.

Look and see if your AC condensate is dripping on the exhaust.

cookseyb

Steam vent gasket or steam vent line..