I have a 1999 Acura CL I'm having a problem with coolant boiling in the reservoir.

Back story. I had the radiator cap come off and boiled all of the coolant out of the radiator. I don't think I tightened enough and it boiled out.

Refilled radiator and car would overheat after about 30min.

I took it in and had a coolant flush.

Does not overheat, but coolant boils in reservoir after about 45 mins of in-town driving.

Here is what I checked.

1. nothing blocking radiator no debris. Radiator about 2 years old.
2. fan is coming on, by visual inspection
3. both radiator hoses are getting hot indication the thermostat is working
4. No leaks, passed a pressure test.
5. new radiator cap
6. passed block test no hydrocarbons, not head gasket
7. coolant is circulating, not water pump
8. Temperature measured by service tech within operating range.
9. NTB said no air in system, flushed with vacuum machine

Brought it to NTB where I had the coolant flush, they could not duplicate the problem.

Any suggestions?

 

Your thermostat is bad

 

I took it to the dealer they tested it and apparently it was an intermittent problem with the fan motor. The motor would overheat and stop working. I replaced the fan motor and it solved the problem.

 

I got a 97 3.0 and I have the same problem but I already changed the thermostat and the radiator any suggestions ?