i just recently finished my 355 with vortec heads. i bought the heads from a guy who had them re built at a local machine shop and they checked out ok. i know vortecs have a cracking problem. the problem im running into is im loosing coolant and i cant find out where. the whole engine is new as is heater core. i checked the oil and cant seem to see anti freeze in it. i did a pressure test and didnt see anything. im getting really pissed at this. thanks

 

When you pressure tested the cooling system was there any drop in pressure? How long did you leave it on for? How much are you losing? If no pressure drop and it appeared low after you filled it for the first time it may have just burped air out of the system after a cooling cycle.. if it is something that is occuring over and over again with no external leaks visable and it isnt leaving drips where u park it and there isnt any in the crank case and the heater core isnt leaking the only other place for it to go is out the tail pipe. Have you checked the plugs for signs of coolant making its way into any of cyls? If your coolant level is slowly dropping and your pressure tester holds steady over night it might only occur with the engine hot and running due to thermal expansion.. let us know a bit more info/what u find

 

i had it one for like 15 mins with no pressure drop. maybe im stilll working all the air out of the system? its literally a brand new motor and i haven't even drove it on the street. how much coolant should the system hold? i dont see any thing at the tail pipes. i think this weekend im gonna do a cylinder pressure test and check the plugs. thanks

 

If its litterly a new swap and you barley ran it since filliing the coolant system, see no external leaks, havnt driven it yet, and it havnt reached a high enough temp enough times to allow the thermostat to open, and then allowed it to cool at least 2 times and there isnt any noticeable signs while running or noticeable leaks, take the rad cap off, top it off, fill the overflow tank to the full cool line and let it run til it the cooling fan(s) turn on, allow it to cool, top off again and enjoy. If this is an engine that's just been installed, cooling sys filled, and ran for the first time(s) with no visable external loss and nothing mixed in the oil, and hastned been ran to opterating temp and topped off at least once or twice, you are probably just being paranoid about it If not let us know what you find