Why would a 1998 corvette expell gas vapors through gas cap in temp of a 100 degrees plus

You may need a scanner to proceed - - is the cooling fan coming on at 230 degrees and does it cool down the engine to normal (200 degrees) ?

Vapor lock, from my experience, is a pretty rare problem. Unless you have put too much starting fluid in through the air intake. If you have not tried to use starting fluid, you should try to spray some through the airfilter, or the air intake for the motor, while someone is trying to crank it. Do not over-saturate it, or it will cause vapor lock. (vapor lock is all fuel vapors and no air). I have a suspicion that a few squirts of this will get it to fire up. If it starts but then goes out after the starting fluid is burned up, then you may have a problem with the fuel not getting to the engine.

are you loosing antifreez? or bad smell in tank for antifreez if its whitish or a creamy color possible head gasket ,after car warms up do you get any water vapor or excessive moisture out tail pipe. let me know what you find ,good luck ,hope this helped

98 and 99 intrepid was manufactured with weak fuel pumps causing them to vapor lock try pouring cool water on the fuel rails on the intake to calm vapored gas then try to start it. Even the temp gauge at half way mark is probably still low on coolant causing engine to be warmer than normal causing the vapor lock to fix this problem replace the fuel pump with a 2000 or newer intrepid fuel pump that carries a little higher psi to prevent vapor lock from reoccurring this pump is compatible with your 98 it will plug right in

Hi John,
Your right with your diagnostics, you have a blend door problem. If your switching to cool air and it is still hot then you also have a heat exchange unit fault, this is the component that changes the water flow from hot to cool by shutting off. If it is not operating correctly this will give you constant hot air no matter where you temperature switch is positioned.
As for the warm air while the engine is cold, sounds like the blend door is still open to atmosphere tempreture and if it is hot outside will pull that hot air into the inside of the vehicle.
Have the heat exchange valve checked, and the only way the check blend door operation is to remove the wiring from the blend doors and have the circuit tested. If the circuit is ok then the blend doors will need to be replaced.
Hope this helps

200 degrees is not hot; the radiator cooling fan shouldn't even come on until 210 degrees.

I believe you are referring to the coolant overflow bottle. If this is the case then yes it is NOT connected to anything. It is to expel excess coolant in the event that the pressure in the cooling system reaches a predetermined pressure, the cap will release the coolant in a controlled manner thereby filling up the overflow bottle and expelling the pressure along with coolant. This is to prevent coolant from spraying on the engine and starting a fire due to the high temp of the engine.

Sounds like your gas cap may not be on right or is faulty ...and is now heat is forcing the fuel out of your gas tank. If removing and reinstalling the gas cap or even replacing it doesnt work, this is just an idea as to what the problem is. This is a very hazardous driving situation. I would NOT let anyone drive this car at the moment. Call a repair shop that has the ability to tow the vehicle. and expect a price tag somehwere in the range of 600-800 dollars to replace a fuel pump plus towing. Leaking fuel at that rate is not to be taken lightly. In anycase,it could be a fault in the fuel vapor canister, fuel lines clogged or damaged or even a faulty gas cap. I just want you to be safe at all costs...and if towing it ensures it...then do it.

Cooling fan relay would be a good starting place.

Hi,try replacing the gas cap, thi can cause vapor lock.....