Sebring thermostat I rebuilt the engine (2.7) new water pump,head gaskets,crank,1 rod, thermostat,radiator. It runs great but is overheating. It has heat but the lower rad hose going to the thermostat stays cold and the upper hose gets hot. The fans come on. I replaced the thermostat again. I'm thinking that I have a headgasket on wrong. Is that possible? and still have heat?

Hi
Did you have the radiator rebuilt/rodded out? Is the cooling fan working as designed? Is the radiator cap new, is the thermostat new, did you bleed the air from the cooling system completely? Are you using 50/50 mix of coolant and purified water. Another problem is the head gasket or cylinder head may be leaking regardless that you just rebuilt the engine. Did you have the head test for leaks or cracks? All these things can cause overheating

There is a blockage in the engine coolant path causing insufficient cooling. When the coolant flows, it removes the heat produced from engine combustion to radiator to cool. If there is no flow then the coolant becomes stagnant, therefore the heat is built up without being dissipated to nowhere hence the engine gets overheated. If this is not fixed then the heat will cause the head-gasket blown due the the metal expansion.
Repair at this stage becomes very expensive.
1- Take off the thermostat.
2- Put back the hose connection.
2- Run the engine and feel the upper hose to see if cooling flowing through it.
4- IF Yes. Run engine like this for few days, if no over heat , buy a new thermostat and put it back. Your problem is resolved.
5 IF No. You have a bad radiator. It clogs up so you don't feel the cooling flowing. Buy a new radiator, don't ever use a rebuilt one.
Good luck.

Try replacing the thermostat first. If it's new with the head job then try removing it altogether and see if that helps. New ones can go bad. Make sure it is installed with the coil down in the engine.
Is there any chance that silicone or form-a-gasket was used in the rebuild especially around a water jacket? Silicone can break off after the part is tightened and could be plugging a water passage.
When you redid the head was there a choice of more than one head gasket and did you compare the new with the old to be sure it was an exact duplicate? I would be extremely suspicious of either the wro ng head gasket or it being up side down.Either of these could block water passages and create your problem. Hope this helps.

Usually when an engine overheats it is caused by:

1. In town driving and the fan switch on the radiator has failed and the cooling fan will NOT turn on. Check the fan by disconnecting the plug and applying power from the battery + and - to the 2 terminals/ The fan should run. If the fan runs only when you apply power from the battery and not while the car is running then the radiator fan switch is the prime suspect. It can be a fuse... or a relay but usually the problem is the switch itself. It screws directly into the radiator on the back side and will have 2 terminals on it.

2. The engine coolant thermostat located at the end of the top radiator hose is stuck closed. (Actually it is under the fitting the top hose attaches to on the manifold)

3. The impeller has falied inside the water pump housing. You can check to see if the impeller is working AFTER you have checked the thermostat. Fill the radiator with water all the way to within about 1/8 inch of the top of the radiator. On a WARM engine start the car and then rev the engine. You should see water flow inside the radiator.
No flow = bad water pump.

4. Engine Head gasket is leaking.
Pull the engine oil dip stick and see if the oil appears milky in color. If it does not look like oil and is milky then the engine head gasket has failed.
Also with the radiator cap off if you rev the engine and see quite a bit of water pushed out of the radiator then the engine head gasket has failed.

Those are all standard.. overheating problem checks. Hopefully the overheating incident has not caused other engine damage to your vehicle.

Thanks for using FixYa!

Kelly

First, anytime a thermostat is overheated, it's ruined.

Second, if this car has electric fans, are they running when they are supposed to? If not, replace the fan control module, and/or test/replace the fan motors.

When the radiator was replaced, were you certain to purge the radiator and engine of all air before replacing the radiator cap? When you refill an emptied system, you always start the engine and watch the fill level in the radiator, refilling as necessary until you know the thermostat has opened. You need to have the heatrer controls set to full hot as well. Once the radiator is filled, put the cap in place, and fill the reservoir to the level indicated for a hot engine.

Finally, check to make sure the lower radiator hose is not collapsing while driving. While this is difficult to check (because your going down the road), just replace it when you replace the thermostat.

All of this assumes you do not have a cracked head or blown head gasket.

YOU COULD HAVE A DEFECTIVE WATER PUMP OR THERMOSTAT ALSO RADIATOR PRESSURE CAP.MAKE SURE YOUR WATER PUMP IS BEING TURNED BY DRIVE BELT.NOT SLIPPING.MAKE SURE COOLANT SYSTEM HAS BEEN BLED AND YOU HAVE HALF ANTIFREEZE HALF WATER.CHECK YOUR CRANKCASE WHEN CAR COOLS DOWN.IF OIL STILL LOOK LIKE MILK SHAKE.YOUR NEW HEAD GASKETS LEAKING.THE MECHANIC WHO REPLACED HEAD GASKET DIDNT DECK THE HEADS.THEY PROBABLY NEED SHAVED A LITTLE SO HEAD GASKET WILL SEAL.

the engine is overheating or u have a defective radiator cap

reffer to owners manual

Several things can cause this overheating. Have you recently done a:
1. Check Hoses for Leaks
2. Check Radiator for Leaks --- Also, Change Radiator Cap ( can loose pressure there if
cap is bad)
3. Check Water Pump for Leaks. If Water Pump is bad, you will hear a loud noise from it
4 Complete Tune Up? Should be done at least 1x a Yr. Depending on how much you drive the Vehicle. Includes: Plugs, Plug Wires, Gas Filter, Air Breather Filter, PCV Valve, Adjust Timing,
Check Belts -- see if worn
5. Changed your Thermostat & Gasket and have the correct degree Thermostat in the Vehicle?
6.. Had your Radiator Rod and Cleaned out?
7. Temperture Sending Unit (located near Thermostat) could be bad
8. 02-Sensor (Generally located in the Exhaust Manifold - needs a socket with a space in it
to allow the Socket to fit over this top wire of the 0-2 Sensor )
9. Change oil and oil Filter.
10. Change Gas Tank Cap ---

Do all this yearly ( except the Radiator Rod & Clean ( do every 2-3 yrs), and you should not have
any over-heating nor stalling out, etc. and should pass emissions as well.