So my 1994 Z28 with 139,075 miles on it had a leak in the radiator and the heater did not work. I had the thermostat changed and ran some flush through the system to unclog the heater core. The radiator started leaking a couple weeks afterwards, I took it to the shop today to have the heater core and radiator replaced to get some heat going..the mechanic said that the coolant is not flowing because there is air in the coolant. He suggested that it could be a blown head gasget or a cracked head...and that if I did replace the radiator and the heater core, it would help the heat but the air would find somewhere else to be released and the bigger problem is this air in the coolant.
He also said that you cannot tell if it's a cracked head or a head gasget until you take it apart and take the heads to a machine shop, if it's the gasget the heads would be resurfaced and a new gasget put on and we're on the road. If it's a cracked head, that's another story, probably a new engine would be the case.
Does this sound right? This is the first time I've taken this car to this mechanic, they were recommended to me and said they did some diagnostics to the radiator to determine the air in the coolant issue.
Is this a lemon or what? Need some advice now that I've picked myself up off the floor..

 

so he is not thinking that air can get in through a hole in the radiator? fix the current problems and see what happens. could also be a very small hole in one of the hoses. in any case i would not tear the motor down just yet. once you get the radiator fixed do a pressure test on the cooling system to see if it will hold pressure.

 

He said it was tested by putting a tank on the radiator and then the system was overfilled, then they saw air bubbles coming through in the water, exhaust gases apparentely....

 

ok well then it sounds like you have a blown head gasket or cracked head or block. have you had the coolant tested? you can get a kit at a parts store that tells you if theres exhaust gas in the coolant. that would confirm.

 

A compression test can determine if the heads need to come off the engine or not. If you get a hole or 2 with low compression remove the heads and see what is going on. The Mech is right you cant really tell cracked heads or blown gaskets untill you get the heads off. As for that being the "only" thing that will put air into the coolant... um... no there are afew things that will do that, holes in hoses, radiator, heater core, intake gaskets, thermostat housing gasket and stuff like that. Fix what you know is bad first and if something else is wrong then adress that when you get there. If you need to fix head gaskets because the car overheaded because of the leaky radiator and you fix the head gaskets but not the Rad and you over heat again then you are fixing heads again... not fun...


Massey

 

Put Bar's Leak in your coolant and run your car up to temp them shut it off. Repeat getting it up to temp and shutting it off and letting it cool down like 7-8 times. It will fix the issue. I promise It sealed both of my blown head gaskets and my timing cover gasket. This was 5 months ago and I haven't had any issues with it since!

 

I hope you didn't use that brown sludgey goop with the pellets in it?

 

No what I used looked like liquid gold. Really shiny and metallic colored. It was kind of thick like chocolate syrup lol

 

pressure in the cooling system i believe is normal, run your car to normal temp and open the rad cap (not recommended lol), trust me pressure builds up with or without a blown head, however a blown head will increase pressure to a point were it starts blowing holes in the system causing leaks in the rad, heater core, and or water pump. Ive have to many cars with blown heads to even think my car has a blown head. Im lucky I bought a car that runs good with 145k on the motor and i still have awesome MPG and power.
Some of the stories i read on this site are a little scary however ive had good luck with chevy's so long as i take good care of them.

 

any kind of "mechanic in a can" type stuff like that frightens me. if it were that easy to just pour it in and it magically fixes everything then shops would go out of business...