2003 Lincoln LS overheating


Asked by Jan 16, 2016 at 10:03 AM

Question type: Maintenance & Repair

I have a 2003 Lincoln LS. I replaced the
radiator, radiator caps, reservoir just about
everything to do with the coolant system.
The problem I have is when they replaced
the thermostat. With the thermostat in the
car the car gets very very hot and the
mechanic says it will overheat. So  without
the thermostat the car runs fine. We just
put the thermostat back in because of the
cold temperatures in the mechanic tells me
if the heat is on high 90° fan blowing full
blast there's a good possibility the car will
not overheat. So when the thermostat is in  
The car runs very very hot unless I have
the heat on full blast. When the thermostat
is out the car runs fine but I don't have
enough heat. Is it a sensor ??? Please help
me with my next move.

5 Answers


This sounds like a plugged up radiator. Should have it flushed out or taken out and roded out, or replaced. Unless there is a electric fan system on there, the fans sound like they are not working.


I have a new radiator new reservoir new hoses everything has been replaced as far as the coolant system. The problem is with the thermostat in the car runs very very hot when the thermostat is out the car runs fine.

Tom Demyan

was the car overheating prior to all the work? Try more than one thermostat?


Yes. That's why I had the radiator replaced and I also have the reservoir replaced and both caps again thermostat in the car runs very very hot must leave Headerai 90°. Thermostat is out and the car runs fine but it's awful cold in the winter up here. I appreciate your help sounds like you're doing your best.

1 out of 1 people think this is helpful.

Well like Tom said, try another thermostat, very possible the one you got is defective. Do you see good circulation in the radiator? I'm thinking possible water pump. One other thing possible would be is a bad head gasket. You can verify if you do a compression test. You would have 1 or 2 low cylinders.

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