Hi everybody, my 2004 Ford Focus SE 2.3L engine is getting pretty hot. On the freeway it's fine but on the street the temp gauge goes into the red zone. Couple months ago I put a new radiator in and flushed the system everything was fine. I didn't change the thermostat (I was lazy) but those usually fail open right? Checked the dipstick and the oil is not milky and there don't seem to be any leaks. Where should I start?
Any codes showing or stored?
None
I didn't change the thermostat (I was lazy) but those usually fail open right?
Thermostats can and do fail in the closed position. Aside from that you might want to do a head gasket test to see if there are combustion gases getting into the coolant.
https://www.youtube.com/watch?v=v0U8Iyf0kk4
Regular thermostats fail closed and blow up your engine, but you can buy what's called Fail Safe thermostats. When you put in the new radiator, did you properly burp the air out of the system? Since the radiator is new it could be -
radiator cap
thermostat
temperature sensor
water pump
fans
fan control module
Also check the fuses and relay for the fans.
I've run into this before. Car overheated at idle and low speeds but didn't overheat at higher rpms and high speeds. Something to keep in the back of your mind if the thermostat isn't the problem
Did you make sure to burp all of the air out of the system?
The wife was driving when this happened so I have some new info. After she got off the freeway the temperature started to go up so she hit the gas to get home faster and the temperature started to go down. More air flow or bad water pump?
Start simple, does the fan turn on? is the radiator hot in all places? maybe just replace the thermostat to be sure it's not that?
Anyhow, before chaining water pumps, I think it's a good idea to test the head gasket just to be sure...
You are only supposed to fill the reservoir to the max line when the engine is hot, not cold. If you fill it cold, it'll expand and go above the max line.
Aye caramba!
And it overheated again! 😡 I'll go buy a thermostat.
The wife was driving when this happened so I have some new info. After she got off the freeway the temperature started to go up so she hit the gas to get home faster and the temperature started to go down. More air flow or bad water pump?
Possible problem with the radiator cooling fan.
I ran it for about 30 minutes and the coolant level stayed exactly where it should, the fans came on and off as they should. I'm gonna let it go and see if it heats up again, but the only thing out of the ordinary was the coolant level was above the Max line. I'm not sure how that happened because it was perfect after I put the new radiator in.