Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: harpersimon on 20 June 2010, 16:16:36
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My coolant drops a bit.. do these cars 'use' any?
Would a new expansion tank cap be useful?
I noted it does get a bit hot, fans cut in and bring it back to 80 from near 100, but the other day I noted it chucked some out the overflow when cooling.. why would that be?
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define 'a bit'? No they should not use any, mines not used any in 8k since i changed it.
Most likey cause is HBV :y
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My coolant drops a bit.. do these cars 'use' any?
Would a new expansion tank cap be useful?
I noted it does get a bit hot, fans cut in and bring it back to 80 from near 100, but the other day I noted it chucked some out the overflow when cooling.. why would that be?
Overfow - it should be a sealed system!! Do you mean the vent in the cap? If so its probably been overfilled.
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Hello - yeah I wouldn't think coolant useage is normal :-) - and have read some bits and pieces about the Heater Bypass Valve..
There are no obvious leaks - nothing under the car after sitting or being used..
(By overflow I meant is there some pressure driven valve to let some out if there is too much pressure/coolant?)
what happens is:
the car has plenty of coolant - up the tank seam when cold.
Runs with apparent normal temps
Then when its cold, appears to 'expand' a hell of alot back into the tank - to the point the tank fills up. Its not over full if the fillmark when cold is accurate!?
not sure whats going on.
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The fill mark is the ridge to the expansion tank, it should be at this level when cold.
The only possible escape for coolant is via the cap on this tank, or the cap on the rad (bottom of rad passenger side) So not sure what this pressure driven valve is you refer to?
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The fill mark is the ridge to the expansion tank, it should be at this level when cold.
The only possible escape for coolant is via the cap on this tank, or the cap on the rad (bottom of rad passenger side) So not sure what this pressure driven valve is you refer to?
Hi - sorry maybe I am not clear - I didn't know if there WAS a valve for expelling pressure/coolant on these, I am not saying there is an issue WITH mine, just asking IF there is one - to try and work out where some of my coolant goes :-)
I have normal coolant level, filled to the seam / level mark when cold as you mention.
Run the car no issue (gets warm when stood in traffice but fans cut in ok)
Seems to expand too much back into the tank when switched off, and some then escapes.
So I guess the question is why does it expand loads of coolant back into the tank, when it has the correct level when cold?
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Sorry both getting confused there, no there is no release valve, as mentioned above its a sealed system.
Has anyone ever put rad weld in the cooling system? Also when its up to temp, does the big pipe from the top of the rad to engine get hot?
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can't answer those but will check . No Rad weld to my knowledge, but bought from dealer so no one is going to mention that if they had. Rad and hoses etc look in good condition on general inspection. I'll have to check the top hose temp when next running the car, as its near cold now. Assuming it ought to be hot?
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can't answer those but will check . No Rad weld to my knowledge, but bought from dealer so no one is going to mention that if they had. Rad and hoses etc look in good condition on general inspection. I'll have to check the top hose temp when next running the car, as its near cold now. Assuming it ought to be hot?
Yup, will tell if its hot going into the engine....
Rad weld signs are silt/crap in in the expansion tank /under the cap, if your coolant is nice and clear its never had it :y
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mm I feel a flush coming on then, as its pretty crappy in there.. browny sort of residue. Think I will pull the bottom hose, drain and refill at some point. Any special bleeding techniques, or literally drain it and refill it? (I'll also remove header tank and clean out)
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mm I feel a flush coming on then, as its pretty crappy in there.. browny sort of residue. Think I will pull the bottom hose, drain and refill at some point. Any special bleeding techniques, or literally drain it and refill it? (I'll also remove header tank and clean out)
Oh :-[
This sounds like oil cooler failure :'(
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really? mm not so sure. no oily smell, no oil in water.. no loss of oil.. I'd say more silty/crap than oily brown colouring. Hard to tell I guess when you aren't looking. How else would I check the oil cooler incase?
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really? mm not so sure. no oily smell, no oil in water.. no loss of oil.. I'd say more silty/crap than oily brown colouring. Hard to tell I guess when you aren't looking. How else would I check the oil cooler incase?
'brown residue' said oil cooler to me, but either way its going to be cause of over-pressurising.
The oil, or rad weld, has blocked up the rad most likely causing too much pressure.
Post up a picture of the inside of your expansion tank :y
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good call.. Ill have a pop at doing that..when I am able to get near the car again in a maintenance capacity (new baby :-) )
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good call.. Ill have a pop at doing that..when I am able to get near the car again in a maintenance capacity (new baby :-) )
Women can sort that out ::) (waits for sexist replies ;D)
If it is silted up your right in your previous post, lots of flushing is going to be needed! Not sure how handy with spanners you are but if rad is nackered need to pop the rad out, fill it with hot water and feel for cool spots.
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Still trying to establish whats causing my symptoms here - but have a theory..
I have carried out one system flush, run it abit, flushed again and to be fair the coolant looked pretty tired and crappy, but I am still getting it forced out of the pressure cap
Since the car temp fluctuates alot up and down (goes up.. fans kick in.. comes down.. goes up.. etc) more than I think is 'normal' - and when I turn the car off the coolant fills the header tank, and forces its way out of the cap - would I be right in thinking that system pressure is not being maintained, and therefore the coolant is boiling over/causing excess pressure which then escapes through the cap? (have had this on other car makes but wanted to check if this could be the cause of my issue)
My theory is that system pressure is never maintained totally 'sealed' and the coolant is running too hot.
The only escape I can see (having peered into where the HBV is, and examined the patches of coolant on the floor!) is from the header cap - which I am about to replace as its not that expensive, but the question is are there other potential system leak points/weak points?
Thing is I am assuming if there was a pressure leak elsewhere then I would also see a coolant leak from that point, so have pretty well ruled out other leaks.
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If you have coolant on the floor that might help diagnosis. If it's the cap the leaking, fluid should be close to the cap position. My car still has an intermittent leak under the gearbox, I thought HBV but now i'm almost certain it's the pipe going into the coolant bridge which is completely hidden from view behind the inlet manifold. I suspect in my case I will have a replacement car before I fix it ;)
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sorry if I wasn't quite clear, but I defo get fluid out the cap. Can watch it when I pop the bonnet! - just wondered if thats a cap failure, or it doing its job to let out excess pressure .. or something. I am running out of ideas.
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If it's overheating and pushing coolant out of the cap it could be overpressurising due to a headgasket leak between cylinder and coolant (you don't always get oil/water contamination with a HG failure) - you can test that if you do a dye test with a kit from a motor factors..
Alternatively it could be a faulty seal/pressure relief on the cap - a dye test is possibly easier than a new cap unless you can swap with someone..
good call.. Ill have a pop at doing that..when I am able to get near the car again in a maintenance capacity (new baby :-) )
Women can sort that out ::) (waits for sexist replies ;D)
You can tell I don't have kids.. I read that as the car being the new 'baby'! ;D
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LOL!
Its not overheating at all.. on the guage. Just seems like a pressure leak causing the fluid to boil up and overflow when the car stops. when Running its fine.. The net result is similar to what happens when you remove a coolant cap when the system is hot, only a lot slower. I can see the coolant trying to boil when I pop the hood after a run.
I may have a breakthrough though. While examing the cap, I noticed that there appears to be a crack around about a third of the tank filler neck.. so am going to get a replacement header tank. Can't do any harm.
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Little update to help those with similar issues. WORTH TRYING!
I replaced the cap, and still had the issue - but then got another Tank and replaced that and presto, issue seems resolved. There were obvious cracks around the neck of the expansion bottle that let in air and hence return the system to atomospheric well too soon when it s hot. Thanks for assistance.
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Sorry both getting confused there, no there is no release valve, as mentioned above its a sealed system.
Has anyone ever put rad weld in the cooling system? Also when its up to temp, does the big pipe from the top of the rad to engine get hot?
The cooling system isn't totally sealed. There is a pressure relief valve and an air admittance valve built into the cap.
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Its more pressure relief than air admittance though surely - as air in the system will make the coolant boil at normal temps (as was my issue) i.e. shouldn't be letting air in!