R400 Duratec: thermostatic sandwich plate for oil cooler

[John Vine]

I fear I've inadvertently confused you, for which I apologise.

In post #21, I reported that my water temp was lower than my oil temp, and as a result I was wondering what (water) thermostat was fitted to my engine.  My thoughts were that, if the stat were to open at a lowish temp (say mid 70s), that might account for the water temp being lower than the oil temp.

To be clear, I'm not asking about the fan switch, but I think I introduced further confusion when I mentioned senders!  (I did that so that it was clear that both my temp senders are the same so should produce a similar range of signals.)

So, to summarize, what I'd like to know is whether I have this thermostat (unspecified deg) or this one (82deg) or something else?

JV

[7 wonders of the world]

With those temps I'd say you have the 82 degree stat, oil temp is fine and should normally be higher than the water - assuming the oil temp is measured in the correct place, ie as near to the point where the temp is highest.

[Pendennis]

Yep, I also have the race stat as shown in your second link. Opens at 82c not convinced it closes much after opened though.

Not really related but maybe of interest, I suffered over pressurising of coolant circuit during long periods of high rpm (8500) which initially I put down to this wax valve closing causing an increase in pressure that my circuit couldn't cope with, (bypass smaller than flow pipe) so I removed the stat but it made no difference. Now I'm in process of putting it back in circuit and employing an expansion tank. What's this got to do with me I hear you say, nothing really but what it does imply is I am not convinced this stat closes accurately to control the circuit. Could have faulty stat though..

[John Vine]

Thanks chaps.

...assuming the oil temp is measured in the correct place, ie as near to the point where the temp is highest.

I measure the oil temp at the blue plug in the sump:

JV