continuing cooling issues

[MMAFIGHTER121]

ok, before i replaced my thermostat I was having an issue where heat would gradually climb until it was overheating, i'd turn on the heat full blast for a minute or two, then sometimes suddenly the temp would drop back to correct operating temp and sometimes it would more gradually fall back down, then i could turn the heat off and for the rest of the trip it'd run just dandy at the right temp. It also seemed like i was going through a lot of coolant having to refill the coolant tank a few times this month, but i could never find a single leak or puddle under the car! yesterday i finally got around to replacing the thermostat (my guess it was just sticking) and when i drove it to work this morning it looked like things were going to be fine, but sure enough after it was hanging out at the proper temp for a few minutes it began to climb up into the overheat range, now it began to overheat more slowly than before and when i turned the heat on it cooled off quicker than before; but i would like to avoid this altogether. Any ideas on what could be causing this??

 

[MMAFIGHTER121]

anyone? no ideas? just took it out for lunch break and sure enough that needle was climbing.

 

[NYC LS8]

Did you bleed the system correctly after the thermostat replacement?

I posted the AllData directions on how to do that in this thread:

http://www.lincolnvscadillac.com/showthread.php?t=45181

 

[JRiffe108]

Check very carefully for a leak. Inspect around the waterpump and the entire radiator. If no leaks are present, then you must be losing coolant into the engine. Blown head gasket or intake gasket. Have you noticed alot of steam on cold morning when first starting the car or even after driving for awhile? They have test kits to dip into the radiator to test for exhaust gases in the coolant.

Engine fan working properly? Dust or dirt caked between radiator and condenser? Blocked water jackets throughout engine?

What size (temp) thermostat did you replace the stock one with?

 

[lseguy]

If you are LOSING coolant, you have an issue.

If you are NOT losing coolant, then you more than likely have an air bubble. I am finding that you have to follow the bleeding procedure TO THE STEP in order to ensure that you get ALL the air out of the system. This includes filling the engine fill to the MAX..like the instructions say. I mean until you cant get ANYMORE in there.

 

[MMAFIGHTER121]

i'll try bleeding it tonight
no coolant steam from the engine on even the coldest mornings, not after long trips either, no smell of coolant burning, fan is kicking on, and i just replaces the thermostat with the stocker (NAPA part). side note: its interesting that there's a little screw type thing to make sure you put the thermostat in the right way...