Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: UrbanFox on 26 January 2011, 21:51:48
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well, I'm stumped now.
replaced the waterpump, thermostat, new radiator.
flushed the system through, radiator gets hot all over, top and bottom hoses get hot, but the car still boils over.
if I rev the car the temp goes down.
any ideas before I go crazy?
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Is your fan working if not check the fuse i had same problem
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I can't see how that would make any difference though? the temp goes down when the engine is revved?
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i've had a similar problem with a mazda and i've gotta say i never found the problem but the suggestions were head gasket, so i changed that to no avail and then cracked block :( although rare it can happen if the cooling system is 100% then why does it overheat fingers crossed it's not so serious, as an afterthought check all the hoses are in good condition as when they get hot they can shrink and not flow properly, just my view though :-/
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when you say boils over does it force coolant out of the expansion tank,it could be that the pressure cap is knackered as the system needs the pressure to raise the boiling point
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hoses are all ok, not using or losing water. it really is a mystery! :-? :-/
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when you say boils over does it force coolant out of the expansion tank,it could be that the pressure cap is knackered as the system needs the pressure to raise the boiling point
it only does it if you release the pressure, but you can see the water rising and bubbling upto the top of the expansion tank.
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exactly what my mazda used to do, would love to know why!! but too much pressure in the system points to one thing in my opinon and that's head gasket sorry :(
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have you tried running without the stat in?
but saying all that are your fans kicking in? because if they're not obviously the water coming in is still hot and then it releases and then gets hotter and hotter and if it sits for a bit then you rev the car cooler water comes in via the pump e.t.c could be a course of thought
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Had a similar problem like this a few years ago with a mates V6 Granada. He had taken it to a garage first to get it sorted and they did as any of us would have, head gaskets, thermostat, water pump etc, all genuine Ford parts. Still overheating though, lol! But not when revved, it did cool down some but then overheated again. He asked me to have a look as he couldnt afford to keep going back to the garage
I stripped it down and sure enough all parts replaced were genuine Ford so they shouldnt be causing any problems and werent showing any problems. Put it all back together as gaskets had only had about ten miles on them, still overheating. After much head scrathing, pulling bits off and on, I did eventually find the problem. The brand new Ford water pump! The impeller was spinning on its shaft,thats probably why it cooled down a liittle when revved, the impeller was getting some drive. Worth a look? Lol
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If it was head gaskit the temp would go up when you revved it
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It does sound like a water pump problem to me, but if irs a new pump........ :-/
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was the new pump genuine vx or pattern part?
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Clutching at straws a bit I know .. but aux belt condition/tension/routing might be worth a check ??
I "know" the tensioner is "supposed" to be automatic .. but if it's failed/failing the belt "might" just be loose and not spinning the waterpump sufficiently at low RPM ??? High(er) RPM gives enough "oomph" to drive the pump better ??
:(
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Belts all spin ok.
Old water pump was fine but was replaced any way.
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when you say boils over does it force coolant out of the expansion tank,it could be that the pressure cap is knackered as the system needs the pressure to raise the boiling point
it only does it if you release the pressure, but you can see the water rising and bubbling upto the top of the expansion tank.
Lol, so it does it as you crack the header tank cap and not any other time?
If so its fine, by cracking the cap you lower the system pressure, this lowers the boiling point of the coolant causing flash boiling around the head etc.
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Yes, but the temp raises to 100+ degrees C on the temp gauge, rev the engine the temp drops to below 92.
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Yes, but the temp raises to 100+ degrees C on the temp gauge, rev the engine the temp drops to below 92.
I'd say that was a fan/switch problem :-/
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Yes, but the temp raises to 100+ degrees C on the temp gauge, rev the engine the temp drops to below 92.
I'd say that was a fan/switch problem :-/
Ive never known a car to do this though? the temp will even drop from 92 to below 90 when revved as well, and then heater cools off.
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Have you given the matrix (on its own) a good flush out?
Reason I ask is that on the 4-pots at least, maybe also the V6s, the coolant going past the gauge sensor is on its way toward the heater matrix. If the matrix were blocked somewhat (as you allude to in the last post) then the gauge sender may be sampling in a reduced flow, which is alleviated by revving the engine which produces more overall flow.
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Have you given the matrix (on its own) a good flush out?
Reason I ask is that on the 4-pots at least, maybe also the V6s, the coolant going past the gauge sensor is on its way toward the heater matrix. If the matrix were blocked somewhat (as you allude to in the last post) then the gauge sender may be sampling in a reduced flow, which is alleviated by revving the engine which produces more overall flow.
Yes I have mate - gave it a right good old flush with the hose pipe! :)
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Yes, but the temp raises to 100+ degrees C on the temp gauge, rev the engine the temp drops to below 92.
I'd say that was a fan/switch problem :-/
Ive never known a car to do this though? the temp will even drop from 92 to below 90 when revved as well, and then heater cools off.
Even at around 90 the heater should be nice and hot, mine blows warm air from when the needle sarts to move off the stop. Are you sure the matrix is clean?
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100% clean. spent ages flushing it. heater does get warm, but cools off when the engine is revved.
infact it cooled off while I was driving it
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100% clean. spent ages flushing it. heater does get warm, but cools off when the engine is revved.
infact it cooled off while I was driving it
whatever you replaced is the same as you already had.. with a good thermostat the engine isn't suposed to drop below 88-89degrees if you rev it, and your water pump isn't doing its job.remove the upper hose from the cooler tank and see if water comes out
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Is this the one from the throttle body or the one from the top of the radiator?
The throttle body one returns water all the time - the other one returns when the engine is revved.
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I'm going to replace the fan switch tomorrow anyway