Yes, I did search, and I've found lots of suggestions on which thermostat to use for a hot or cold running zetec. My question is, what is the OE spec thermostat's temperature? My service manual says 195 and I'm just trying to confirm this so I can get the proper replacement. Engine temps are fine, just want to replace it to be safe.

195 degree.

Thanks, I thought so. Is it even possible to buy thermostats hotter than that?

i don't think so, You can buy a 180 degree though.

When opening the radiator petcock, does all of the coolant in the system really drain? Or does a lot remain trapped in the head, block, and heater circuit?

When you drain it from the bottom it almost all comes out.
You can raise the rear end to help aid it as well.

I'm just wondering because in the coolant flush how-to it claims that some remains trapped in the block and has to be drained by loosening the temp sender.

I guess this isn't the case?

Some could stay in the water jackets in the head.
Pull the thermostat housing apart at the same time and find out.

of course some is going to get stuck in the engine, nature of the beast ... there should be drain plugs on the block for this reason. If you want to make sure you have it all out run some water from a hose through the system until it comes out clear ... then you are going to mix the coolant with water anyway so go from there ...

I wouldn't use tap water from a hose in the cooloing system. Too many minerals in there. I only pure boiled off water to cut down on hard water deposits and scaling in the system. That is a great way to plug the rad and heater core.

Originally posted by SquareHead:

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I wouldn't use tap water from a hose in the cooloing system. Too many minerals in there. I only pure boiled off water to cut down on hard water deposits and scaling in the system. That is a great way to plug the rad and heater core.

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i use distilled water when mixing coolant to 50/50

but I can see your point with flushing it ...