Thermostat not opening

[whitey]

Hey ive brought two new thermostats for 1600 ford crossflow. the previsous one was new but when i took it out it was slightly bent. ive recently put another one in and when driving home today the temp gague kept on going up and up . it looked like the thermostat didnt open . i pulled over when it got near the dangerzone. after 5 minutes i started the engine and took it down the road the engine temp seemed fine. anyone know what is going on . broken thermostat maybe an airbubble?
tanks in advance : )

[dude]

Did you bleed the system properly?
New thermostats can be faulty, try boiling it.
Drilling a small hole can help the thermostat open a bit earlier. I don't know if you can put the thermostat in the wrong way round in a crossflow, but it's worth looking up

[rodney]

is the water pump pumping water properly?,.

[bl1300]

You can test the thermostat off the car to see if its working just heat a saucepan full of water to boiling, with the thermostat in, on the hob, and it should visibly open, it would be worth looking up the recommended bleeding procedure for application as well so as to be sure its been effectively bled.

[Kev]

I bought a new one that was faulty once. I sent it back and they sent a replacement. One could have easily slipped the net at the factory.

[ejenner]

Another easy way to check is to remove the thermostat and drive it with no thermostat.

The thermostat is there to help the engine warm up quicker. Only consequence of running without it installed is that the engine will take longer to warm up so no danger of breaking anything.

If the car still gets to overheating then you know the thermostat had nothing to do with it.

[ChasR]

And drink a little more fuel. In an old Mondeo V6 it was the difference between the car doing 17-18MPG to never falling below 24MPG.... Quite handy in a daily driver .

[ejenner]

yes, of course. There is a reason why manufactures go to the trouble of fitting them. Also nice to be able to use the heater in winter!

[RobinJI]

May 3, 2013 19:41:13 GMT ejenner said:

Another easy way to check is to remove the thermostat and drive it with no thermostat.

The thermostat is there to help the engine warm up quicker. Only consequence of running without it installed is that the engine will take longer to warm up so no danger of breaking anything.

If the car still gets to overheating then you know the thermostat had nothing to do with it.

I can't say for the crossflows, and usually it's a good plan, but in some engines they do NEED to be present for the cooling system to work. Certain engines use the stat to divert flow rather than just stop it. With it fitted and closed coolant takes one route, avoiding the rad but still circulating to keep an evenly spread temperature in the coolant and avoid hot-spots, with the stat open the coolant's re-routed through the rad. With no stat half goes each way, so you'll never get full coolant flow through the rad. I know this is the case on some VW engines, but my point's just to be careful to understand how the system works before trying this out.

[ChasR]

Removing the thermostat in Triumph Stags (and a number of other cars (Mondeo V6s and possibly some Porsches) can actually aid hot sports and overheating due to the thermostats preventing the flow of uncooled coolant back into the engine via the bypass hose.