2000 Ford Focus Temperature gage pops to red at high speed

Tiny
DINISHA
  • MEMBER
  • 2000 FORD FOCUS
Engine Cooling problem
2000 Ford Focus Four Wheel Drive Manual 80,000 miles

When driving at higher speeds, usually over 60mph, the temperature gage pops to red. It doesn't gradually get to red, its very sudden. If I slow down, it will go back to the middle, suddenly.

We have changed the thermostat and radiator. We have checked the water pump, sensor on the engine and have pressure tested it also.

Although pressure tests show everything is fine, the water in the car is not circulating properly, because from the radiator, one pipe (lower) is cold and the other pipe (higher) is hot after a drive. The cold pipe does warm a little, but there is a clear difference between the pipes, which suggest that the water is not circulating. However when diagnosed by two mechanics, the reason for water not circulating is hard to figure out.

I've come to 2 next steps:
1. Change the thermostat to one that opens at lower temp (approximately 70 degrees) - open at a lower temp might make the engine not overheat a high speeds?

2. There must be a block in the cooling system somewhere? Even though the radiator has been changed, it could be somewhere else?

PLease help.
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Monday, March 29th, 2010 AT 12:04 PM

3 Replies

Tiny
RENAUDTN
  • MEMBER
Hello there,

The fact that your lower hose is cooler than the upper one is perfectly normal. It's cooler at the bottom because the coolant has been cooled down by all the air coming thru the radiator while you're driving. It's hot at the top because the coolant just got out of the engine and hasn't traveled down the radiator yet. I wouldn't change the thermostat for a cooler one; this won't fix the problem, plus your car may not run as well and you may see a drop in gas mileage. What I would do however is flushing the cooling system. Your water jackets may be a bit restricted.
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Friday, April 9th, 2010 AT 4:08 PM
Tiny
DINISHA
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I ended up changing the thermostat, and it seems to be working fine now?

I know a low temp thermostat results in more petrol consumption but I was reaching my limit with this problem.

Thanks for your advice.
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Saturday, April 10th, 2010 AT 11:20 AM
Tiny
RENAUDTN
  • MEMBER
Ok
If you can get by with it for now that's fine, but keep in mind that you haven't actually fixed the problem; your car is designed to run with a 192-195 F thermostat and a low temp thermostat may not only result in fuel consumption, but also in oil consumption, ring wear and increase emissions. Here in the US you'd fail an emission test. I don't know if y'all have such tests where you live.
Hope your car doesn't give you anymore trouble.
Good luck
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Monday, April 12th, 2010 AT 8:51 AM

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