replaced thermostat and...

this morning on my way to work there was coolant everywhere when i got to work, it looked like it came out of the overflow reservoir, it is a 1994 cherokee 4.0 do i need to burp this thing? i have searched around and conflicting information everywhere. I put in a stant 195* premium thermostat, there is no gasket and was no gasket on the one i took out either. I replaced the water outlet gasket. when i replaced that and connected all the hoses i filled the radiator, then when it heated up i also filled it up again my overflow reservoir is at about half full, i drove all the way home, temp seems to fluctuate around 190-210, what am i doing wrong here. i also have a stant radiator cap the one with the vent lever.

I've always used a gasket on my 90's thermostat housing I dunno about 94's though.

ya its weird i just went out now to see what would happen once the engine is cool and it has pulled almost all of the antifreeze from the overflow bottle out into the radiator, so this is a good sign i think

when i upgraded an repaired my coolant system i would let it run for a while and top it off every so often and check it on short trips, mine seemed to only overflow once i turned it off so i bought a new coolant bottle and cap to seal it up tight and that seemed to work well.

oh and btw i replaces almost my whole cooling system in the last 6 months and haven't had any issues since

Try to "burp" the system. Run for a while with the heat on and add coolant when necessary. My 95 had a gasket w/ the t-stat...so I would check that also.

How many pounds is your radiator cap? I had a similar problem on my '90 (converted to open system) in which the cap would release the fluid into the res then spill out. When it cooled back down it sucked what was left back into the radiator. I got a 16lb (non-lever) cap and problem solved. I think the Stant book calls out for a 13lb or something.

well the whole reason for this change was that my coolant was dissapearing in the first place so it kinda p'ed me off... so i am trying to figure it out, what is the proper way to burp this open system????

Run the vehicle for a while with the heat on, cap off. When the t-stat opens you will see bubbles come up the radiator. Let this happen 3-5 times, while topping it off and giving the upper and lower hoses a little squeeze every now and then to get the air out.

If your overflow bottle is filling up something is wrong with your radiator cap. Or, a heater hose is leaking coolant all over when hot. Check the pressure in the radiator. If, it is more than 15lbs your head gasket may be leaking. There should be some expansion from the heat and steam but, should'nt fill the overflow bottle up.

i have a brand new rad cap, and i thought the whole point of an overflow bottle was so extra fluid could come out of the radiator. i am going to check out the radiator hoses but i don't think theres anything wrong with them.