Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: danzigfan on 01 April 2014, 11:57:56
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Hi guys, my omega had a severe radiator leak but that's fixed after replacing the radiator...almost :-[ I need to top the coolant up every let's say 1500 miles which is not so bad comparing to how it was. The point is there's no sign of coolant leak under the car and when I open coolant bottle cap there's a lot of hissing and the pressure's coming out of it when engine is cold, even after all night. Is that amount of pressure in cooling system normal or is there maybe head gasket on it'way...? And a bit of oil is leaking - seems from crank seal.
Thanks Stan
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Thats a good sign.
Its a presurised system so there should be pressure adn the fact its still there is good as it shows the pressure is not being lost.
If it was headgasket then there would be no pressure when cold/cool and you would get throguh much more coolant.
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Ok, so it's just me again ::) Thanks Marks DTM
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Is it hissing out, or hissing in? I'd be investigating further if I kept having to top up the water level.
If it's hissing out, i.e. the system is under pressure on a stone cold engine and when you open the cap air comes out, then where has that extra air come from?
If it's hissing in, i.e. the system is under vacuum on a stone cold engine and when you open the cap air is being sucked in, then where has the water that it's replacing gone?
I'd be doing a sniff test, if only for peace of mind.
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Sniff test will tell very little (not a conclusive test) and the coolant loss is more in line with a weaping seal and not a head gasket (e.g. top up every 1500 miles)
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The air comes out, can feel it on fingers
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Sniff test will tell very little (not a conclusive test)
I agree it won't rule a CHG problem out, but it will rule it in if the dye goes yellow.
and the coolant loss is more in line with a weaping seal and not a head gasket (e.g. top up every 1500 miles)
perhaps but how would a weaping seal cause an increase in pressure?
The air comes out, can feel it on fingers
That means there is more air in the system (and possibly less coolant) on day (n+1) than there was on day (n). Assuming the ambient conditions are similar (same temperature and pressure), and the engine was stone cold when you topped it up, and stone cold again when you remove the cap, then how has the extra air got in?
It could be a weaping seal, and when the engie is hot, the water pressure will force water out of the leak. However, it can't let air in whilst the pressure is higher than ambient. As the engine cools again the pressure will drop back to ambient. If the system is sealed, then this will cause a vacuum in the header tank. If the system isn't sealed (weeping seal still open) then air will get sucked in once the temperature drops enough to cause the internal pressure to be less than ambient. But this is unlikely to result in a system whose pressure is above ambiernt the next morning, unless there is a large difference in nighttime and daytime (measurement time) temps.
So next question - is the car garaged, or left out overnight? Next time you use the car, don't open the cap untill mid afternoon on the day AFTER you last drove it. Is it still under pressure then?
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It's always under pressure, it was the same with the old radiator
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Hi guys, my omega had a severe radiator leak but that's fixed after replacing the radiator...almost :-[ I need to top the coolant up every let's say 1500 miles which is not so bad comparing to how it was. The point is there's no sign of coolant leak under the car and when I open coolant bottle cap there's a lot of hissing and the pressure's coming out of it when engine is cold, even after all night. Is that amount of pressure in cooling system normal or is there maybe head gasket on it'way...? And a bit of oil is leaking - seems from crank seal.
Thanks Stan
Partially blocked radiator , same symptoms as my old elite .. check to see if the rad is getting hot all over :y
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I'll check that out tomorrow, I'm at work now, thanks Emd