i dont have a fan shroud, the fan is a aftermarket 5 or 6 blade flex fan .i still have the factory 6 blade fan if it will make a difference i will change fans
pipman, take it one step at a time. 1st. forget about heater core for now, just take it out of the equation at this time. As the others have said it is either a hose/clamp or leaking problem. 2nd. check coolant level, make sure it is full. 3rd. if you have a coolant pressure tester. pressurize the system and see if there is any leak down. Some parts houses rent them out. 4th. If there is no leakdown or if you can't test system, leave cap off and start car. watch coolant level and when t-stat opens it should drop. continue to add coolant untill it is full. It will start steaming as the coolant enters motor and hot air enters radiator. 5th. Do not worry about temp gauge right off. More often than not it will show as it is overheating, which it is before the t-stat will open. If the block and head is empty. Air does not heat the t-stat like coolant does, don't ask. If you had a cracked head or a blown gasket you would see coolant seeping out between head and block or you would smell a sweet oder plus a white smoke when car is running. Sometimes air gets locked in the system and it can be a pain getting it out. Take your time, keep your "COOL" Above all, think simple, don't let immagination exagerate the problem. Most of the time it is simple. Good Luck P.S. When t-stat opens you should see coolant circulating in tank. It should be flowing pretty good but if it isn't and as others here have said about raditor being clean ETC ETC possibility is you might have a bad water pump even if it is new or rebuilt. I have had a couple of new ones that the propeller just spins on the shaft. Don't get excited about this until all else fails. Not a common thing.
I learned a trick to the air pocket problem many years ago from my grandfather. I always drill a 1/8th inch hole close to the edge of the Thermostat and when I install it I put the hole at the top of the opening. This allows air to be forced out by the fluid and does not allow enough fluid to pass to effect the heater operation.
your going to want to fix this, at idle there is no air being forced through radiator. When idleing with no shroud your really just blowing air around in engine bay not really pulling heat through radiator. My rule of thumb with fan on you should be able to put a dollar bill on front side of radiator and it should stick. If not your not pulling enough air through the radiator.
