Guest Posted February 16, 2003 Posted February 16, 2003 Been testing my engine again today (2.0l Zetec, carbs) and noticed that the header tank looks about ready to explode! Before starting, I filled the system to the minimum mark and then started up. Very quickly the header tank completely fills with water (not sure quite how high the pressure is...), even at 600 rpm idle; on hitting throttle is seems to get even more violent. When this first happened I put it down to the thermostat bypass being blocked off (as recommended by the factory) but now I have a new bottom hose, with the bypass connected properly and it still happens. The bypass is connected using a fairly narrow pipe but I would think it would be enough. Is this normal behaviour? Thanks, - Dan Quote
sedsy Posted February 16, 2003 Posted February 16, 2003 Sounds like you may possibly have an airlock in the system! have you tried putting a little bleed valve in the top hose inlet on the rad (good place to bleed from) Also check for any cold spots around the water system. Quote
steppenwolf Posted February 16, 2003 Posted February 16, 2003 This does happen with both the 'kludge' overcooling 'fix' of closing off the bypass pipe and when using a properly modified bottom hose with the bypass connected to it. Assuming that you have checked for air locks, it isn't a problem - it just looks alarming but it is only water circulating, it does not seem to be at a particularly high pressure and at least the engine will be running at the correct temperature! Quote
Guest Posted February 17, 2003 Posted February 17, 2003 Thanks for the suggestions. I considered an airlock although I did attach an extension to the header tank and then fill it, holding the header tank a good few inches above the heater. In spite of this, I did not check too thoroughly since I ran out of fuel and then had to empty the water (no anti freeze since I'm still (dis)connecting pipes regularly ). I'll try again later.... Quote
Matt Seabrook Posted February 20, 2003 Posted February 20, 2003 If you get pressure as soon as you start the engine then I hate to say this you may have a blown head gasket. But check for air first. Quote
DavidR Posted February 20, 2003 Posted February 20, 2003 Are you using water or water/antifreeze mix? My car would blow all the coolant out within 10 mins of starting when I foolishly used neat water to save money whilst getting it set up. When I put the correct mix of antifreeze in (and ensured no air locks) the prob stopped. So this tight fisted person learns a lesson David Quote
Guest Posted February 20, 2003 Posted February 20, 2003 Water doesn't look oily, just rusty so it hopefully isn't the head gasket. Yes, I am just using water at the moment so perhaps the problem will go away... Quote
Blatman Posted February 20, 2003 Posted February 20, 2003 If you are using just water, you are slowly knackering your head, and probably your water pump. Anti freeze does more than just stop the coolant from freezing. Get some Comma Xstreme RED, either pre-mixed, or if you buy concentrate, mix it 50/50 with distilled water. Do it at your earliest convenience............. To see why, pick the bones out of this................ Quote
stu999 Posted February 20, 2003 Posted February 20, 2003 Blatters is dead right. And to add my two penneth, flush the system out as well. Using just water in an alloy head causes the water gallerys in the head to start oxidizing. And it just so happens that sandpaper is often made from aluminium oxide particles. So unless its flushed out, when you refill the system with antifreeze, the residue from your prevoiusly eroding head floats around the system slowly 'sanding' the water gallerys away. Also the very reason why antifreeze should be changed every couple of years. Yes, the hydrometer may say there is plenty of antifreeze in the system, but unfortunately it cannot detect the amount of anti-corrosion inhibitors that may or may not be still in the system. I reckon that there would be a #### of a lot less porous VX heads (and others) in existence if the antifreeze was changed when it was scheduled in the service book.... Cheers, Stu. Quote
Guest Posted February 21, 2003 Posted February 21, 2003 I know that water alone is bad but is it actually gonna do harm using it for only 20 mins or so, then emptying the system (including blowing down the thermostat housing to get as much out as possible )? Bit worrying but I don't want to fill the system yet because I might still redo the plumming as it's a bit messy...... Quote
Blatman Posted February 21, 2003 Posted February 21, 2003 Difficult to tell without knowing how much harm was caused the water ways before you got your hands on it. If it was owned by some-one with no mechanical sympathy, who only ever topped it up with water, then it could be well on the way already, and you aren't helping it........plus, the additives in Ethelyne Glycol anti freeze break down quite quickly, so some damage will undoubtedly have already occurred. Why make it any worse, even if it is only negligible use/running? Limescale is the last thing you want to be depositing in your water jacket.......... Quote
brianm Posted February 21, 2003 Posted February 21, 2003 The best way to screw an engine, in a subtle sort of way, over a 3 or 4 year period is to run it on pure water. A few (summer) days/weeks inbetween mods on the car wont make any difference, but after this time the succession of rotted core plugs, head galleries, cooling pipe spigots etc etc becomes a bit monotonous. We may lable it anti freeze but in my view its primary function, apart from 1 or 2 nights per year is as an anti corrosion additive Brian. Quote
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