
Has anyone done this?
Will it struggle to keep temps up?
Many Zetec installation suffer from "over cooling". This was identified by Westfield owners with varying solutions to stop the problems. Why
would you want to remove the thermostat? Would you remove one of the pistons and try to use the engine?
JC
just thinking about keeping the engine cool during the sva test, where its stood and revving, and my rad (from micra) seems to be struggling.
I would put the thermostat back after SVA as I have no problem in normal use.
I started a thread last night about using two fans to increase air flow during stand still. However I am unsure whether this will be enough, so I am
thinking of alternatives.
Removing the stat may actually cause more overheating problems. Many engines use the stat as a restrictor to help pressurise the coolant, to avoid localised boiling at hotspots (e.g. around the exhaust valves). Removing the stat will reduce the coolant presure and allow it to boil at a lower temp.
You don't have to remove it, just increase the flow. Start by drilling a 3mm hole in the thermostat opposite the ball bearing (if it has one). If still hot, increase to 5mm. Finally you could do what I do - remove the centre of the thermostat completely. I've done this because the Raceline water rail has no TS by-pass, but the principal is the same.
I have a Raceline water rail on mine and had terrible overheating problems, steaming up and blowing hoses off!. Traced it to the thermostat being too
far away from the engine and not getting hot enough to open.
Solved it by removing the 'stat and it runs around the 75 degree mark which I think is a little low but no problems so far.
coozer is exactly the same as me, mine runs about 75 upwards without a stat. on a raceline water rail
Keep the stat and if needed drill a small bypass hole in it to allow enough flow of hot water to activate the stat. Removing it is a bad idea and can cause a number of problems which have been discussed before.
Thanks guys.
I had another look at the thermostat and its just seems to open very late (96C), I now have one that opens at 92C and is fully open at 96C.
I have had the hose leading out the thermostat (a flexi) housing split presumably it just could not cope with the heat that the zetec runs at.
I'll try and replace that as well with some metal tubing.
Shame really, car works well only trouble is when Mr SVA wants to rev it when its stood still.
Are you sure you have it plumbed correct or poss an air lock? Mine runs with a thrmostat and polo rad and single small fan cuts in and out every few mins when on tick over even on a hot day after a run.
Not a great idea to remove the stat, 75 is too low a temperature to run at, and more to the point it will follow ambient temperature, i.e. cold in winter, hotter in summer. The thermostat is there for a good reason, just a shame some of the aftermarket water rails were so badly engineered.
Modern engine need to run hot for emmissions purposes --- even changing to a lower temp thermostat such as a an 84c can reaally cause problems
getting cars through MOT.
Drill a hole in the thermostat plate but you should also have a by-pass hose fitted to keep the coolant circulating and keep the bottom of the
cylinders warm.
Yup have bypass hose fitted.
And I am fairly sure that there are no air locks.
Maybe the hose was just not up to the job. It was some flexible black tubing.
The engine was only running at about 99-100C max when the hose ripped, which must still be well within the operating temperature of the zetec, as I
now read somewhere that the original thermostat does not openfully until 106C.
So was the engine actually not getting too hot?
Lars sorry to hear about the burst hose, my thermostat opens about the 85/88 Deg C area according to the Megasquirt. You may have a sticky
thermostat!
Yes chris.russell is the fellow builder in Didcot.
ATB Dan.
Mine overheated earlier, thermostat was stuck open so no water flow. Fine with it out - Tiger say they don't fit a thermostat to any of theirs.
But only getting about 75 to 80 degrees on a short run this evening.
So will probably go back to a thermostat, unless anyone else runs one without with no trouble?
Thanks
Ed
As an update I'm going back to the Ford thermostat housing so it runs as henry intended

