Flappa Posted April 11, 2005 Share Posted April 11, 2005 1800 Zetec When started from cold I notice that the coolant level in the expansion tank rises. This I assume is because the thermostat is closed, and so the head from the water pump is effectively pressurising the system. There is flow through the heater which by-passes the thermostat. My concern is that as the level rises in the expansion tank (with revs), it must be pushing the air up the vent tube back into the system. Is this normal on Zetec's? Also takes ages before temperature gauge reads. Only seems to register once the thermostat has opened. Again is this normal? Quote Link to comment Share on other sites More sharing options...
geelhoed Posted April 11, 2005 Share Posted April 11, 2005 Temperature gauge will take about 5km to register anything, but before the thermostat opens I believe. The rise of the level is probably because of an *dare I say it* airlock *runs and hides* Quote Link to comment Share on other sites More sharing options...
neilwillis Posted April 11, 2005 Share Posted April 11, 2005 A quick search will give you lots of info on this. Quote Link to comment Share on other sites More sharing options...
MAT1800 Posted April 11, 2005 Share Posted April 11, 2005 Flappa, Mine is a 1800 zetec and the water level also went up, just as you described, although not sure about it rising with the revs. I'll try and check tonight. Also I ran mine this Sunday until the themostat had opened, and until the fan kicked in and the tempertaure gague hadn't moved? So it may be normal...although perhaps not right Quote Link to comment Share on other sites More sharing options...
Flappa Posted April 11, 2005 Author Share Posted April 11, 2005 I'm convinced with mine that the gauge doesn't read until the thermostat opens. All of the hoses get good and warm except the top hose feeding back to the thermostat housing. The heater hoses get nice & hot pretty quick and the heater produces lots of heat (no air lock there), but with nothing on the gauge. Coolant level in expension tank runs higher, and increases if I rev the engine. Then thermostat opens (I presume) and the top hose gets hot, the coolant level settles and gauge begins to read, jumping up to about 60 degrees from nothing. I can't see it being an air lock, because if it were then surely parts of the system wouldn't get hot as it wouldn't have flow Edited to add: Just spoken again to WF who advise that this is quite common and nothing to worry about Quote Link to comment Share on other sites More sharing options...
Cam Posted April 11, 2005 Share Posted April 11, 2005 Where is the sender unit for the temperature guage? If it is in the top hose after the thermostat there will be no reading unit the thermo opens. Quote Link to comment Share on other sites More sharing options...
chazpowerslide Posted April 12, 2005 Share Posted April 12, 2005 The Zetec effectivly runs a full bypass system before the stat opens. You have two circuits for the water to flow round. The first one circulates water around the block and head (and heater if fitted) only, when the stat is shut, this allows for fast warm up. The water circulates from the bottom hose, you'll find a smallish bore hose teed into the bottom hose, through this hose, round the side of the engine, up into the small inlet into the stat housing and back into the block/head, through the pump and back into the bottom hose and so on. When the stat opens (at about 94 degrees) the second circuit comes into play, the water exits the pump flows through the bottom hose on the rad, up the rad out of the top hose into the big fitting on the stat housing into the block/head and back through the pump. This is the cooled side of the system. When the stat is open both circuits opperate together. Any air in the system is bled out via the top hose to the header tank (you can see the water exiting the hose into the header tank if you look closely, this will cause a slight rise in level) The Zetec likes to be hot, around 94 degrees, at that temperature the water will have expanded a fair bit and you'll see a rise in the header tank level. HTH Chaz. Quote Link to comment Share on other sites More sharing options...
Flappa Posted April 12, 2005 Author Share Posted April 12, 2005 Thanks Chaz, that was quite helpfull. Now if the WF manual had a couple of paragraphs like that in it wouldn't life be wanderfull Quote Link to comment Share on other sites More sharing options...
deano.1 Posted April 12, 2005 Share Posted April 12, 2005 My 2.0 zetec does pretty much the same - seems as though its normal to me! Theres no air in mine Quote Link to comment Share on other sites More sharing options...
Ian Podmore Posted April 15, 2005 Share Posted April 15, 2005 Whilst we're on the subject of Zetec cooling, I did the undercooling mod last night. Shouldn't the bypass hose under the thermostat have a 19mm pipe on it instead of 16mm? Westfield and 'Hose Supplier' both use 16mm, but the outlet is 19mm on mine and the hose was a b.......d to get on. Is it just me, or is everyone using an undersized hose? If we are then I'll call the 'Hose Supplier' so that they can change the size of the outlet off the pump outlet elbow to 19mm in their kit for Zetec cooling mods. Quote Link to comment Share on other sites More sharing options...
steppenwolf Posted April 15, 2005 Share Posted April 15, 2005 I have the 'Zetec undercooling mod.' ( of course ) and my expansion tank also fills up. Shouldn't the bypass hose under the thermostat have a 19mm pipe on it instead of 16mm? Assuming that you are talking about the mod. that I made and not the one suggested by the factory, then 16mm pipe works fine and interfaces well with 15mm copper plumbing fittings as detailed on my website. Quote Link to comment Share on other sites More sharing options...
Ian Podmore Posted April 15, 2005 Share Posted April 15, 2005 Steve Yes, the very same. Highbury Hoses sell a plastic 16mm straight connector which saves one of the 15mm copper 'units' of your mod, and the other one is working well as a stopper. Their bottom hose from the pump with 16mm outlet is great. The hose I took off that is now blanked off at the large hose end was very tight to remove, and I couldn't get a new length of 16mm 'Samco' type hose on to the thermostat housing even after heating it, leaving it over a 19mm dia 'former'. I ended up buying some cheap 16mm hose which I again left over a former to put onto the thermostat housing. I measured the thermostat housing inlet afterwards and the diameter on mine is 19mm. Was just wondering if mine was the same as everyone elses as the hose should really be a 19mm otherwise it is under a lot of stress being stretched out to 19mm. Quote Link to comment Share on other sites More sharing options...
steppenwolf Posted April 15, 2005 Share Posted April 15, 2005 Ian, Interesting ... It was a while back that I did the mod. and haven't had to touch it since but I don't recall having any real problem fitting the hose to the bottom outlet of the thermostat but I was not using anything as 'fancy' as Samco coloured hose - just plain old Quinton Hazell black rubber ( I have this thing about everything on the car being either black or yellow! ) which I notice is actually 15.8mm and not 16mm. Maybe the pipe I used ( which came from Halfords ) was particularly malleable? Quote Link to comment Share on other sites More sharing options...
Ian Podmore Posted April 15, 2005 Share Posted April 15, 2005 Highbury do the silicon hoses in black as well, so that's what I got to 'match' the existing like you Only I couldn't use the 16mm silicon 3 ply hose. 15.8mm = 5/8" = 16mm nominally but is a bl**** tight stretch to 19mm Perhaps someone else can check the size of theirs? Quote Link to comment Share on other sites More sharing options...
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