Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: PAULCDX on 23 March 2012, 17:21:21
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Hi Guys,
Driving home from work just now and noticed whilst sitting at the lights my temp gauge was creeping up towards 100c, went down slightly when I started moving but then noticed steam / smoke coming from under the bonnet in the area where the header tank is.......
As soon as I got home and turned the engine off, I could see lots of coolant coming from that area running along side the kerb down the road. On checking the header tank it was wet on the top and it looks like I've lost a lot of coolant / water?, as that happened the coolant level warning came on the display.
I'm just waiting for the engine to cool down then I'm going to top the bottle back up and have a look for any drips under the car.
Any ideas?
Thanks in advance :y
Paul
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several possibilities come to mind ...
Have you recently removed the header tank cap ?? if so it might not have been put back on correctly
Header tank "Neck" that the cap fits on .. prone to cracking .. check for tiny cracks around the neck .. if present it will leak when the system pressuirises
Header tank cap seal .. if perished this will leak
Header tank cap .. has two "internal" valves for inward/outward pressure refief .. if these fail then the system does not pressurise and the boiling point is lower .. if it boils it will leak through those relief valves
Header tank has several hose connections, check these if it not just the tank cap that leaks ...
HTH :)
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Cheers Entwood, I will take a look shortly and see if I can see any leaks etc........ Cap was last removed when I had the stat changed but that was over four weeks ago....... Been using the car daily with no problems until today
Cheers :y
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Well, just been out to the car only to find the header tank completely empty......... So I've topped up and started the engine to see what I could see. The temp gauge rose to 100c again and then I heard the fans kick in.......... I had another look under the car and could see I'm still losing water / coolant and the header tank is now half empty again?
Have I got a faulty tank / cap or could it be HBV? or perhaps something else? Car has been running fine for weeks until today :(
Thanks in advance
Paul
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My answer was due to your comment about the header tank being wet .... If the leak is from somewhere else then those ideas don't apply !!!
HBV is at the back under the scuttle ... you need to accurately pinpoint where the leak is coming from ...
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From what I can see it seems that when the car is running hot and at max pressure, water is seeping out from tubes and running down onto the floor causing a puddle and trail down the kerb. Guess it could be coming out from the header cap also?
As I say I topped up the water, and then saw the car temp gauge rise and then more water loss?? Bottle is now half empty again.......
Cheers :y
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Is this the first time you've had cooling problems Paul?
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Yes Pete, all been fine since the stat was replaced mate, is it worth changing the header tank and cap?
Not sure what the problem is. Don't really want to use the car at the moment if I keep losing water and overheating
Cheers Pete :y
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It might be worth flushing out the system just to see what comes out.....is your rad in good condition?
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Ummm I think so? I will have to ask someone to help me as I'm not a mechanic I'm afraid.
From the symptoms I've mentioned, what is the likely problem? I will buy a new header tank if that's worth a try?
Thanks for all the advice :y
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Have a good nose under the car mate to try and pinpoint leak - if its HBV you will see coolant dripping around join between back of engine and gearbox driversv side. Feel under and around header tank for wetness.
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Ummm I think so? I will have to ask someone to help me as I'm not a mechanic I'm afraid.
From the symptoms I've mentioned, what is the likely problem? I will buy a new header tank if that's worth a try?
Thanks for all the advice :y
Paul .. attack this with some logic ....
Remove header cap, top up with water, run engine without cap on - this will prevent any large pressures building up - look for any obvious leak over quite a few minutes. Given the amount you are losing you should be able to spot it !!
Places to look, HBV at the back of the engine, Radiator .. along the top and sides - where the pipes join the rad are plastic connections these can break, header tank already discussed
As the engine warms up, do you get bubbles/boiling inside the header tank ??
If the answer to all the above is "no leak" .. the water level does not change .. then on to the next step .. if the level HAS changed .. you have a leak but have not yet found it !!!
Place the cap back on the header tank and as the pressure starts to build look carefully for leaks, same places as before..... but this time you are looking for a pressure leak ... might be a spray/jet/ooze ... probably more than a drip.
Just "guessing" its the header tank is pointless.. diagnose BEFORE rectification
HTH
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Hi Entwood,
Thanks for that explanation, I will have a go at this tomw mate and update :y
Anybody passing through west mids / Wolverhampton over the weekend please feel free to drop by :y
Thanks
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Several pipes around the back of the engine all with the potential to leak under pressure especially if work has been done around that area which causes stress and movement on the joints.
Would think loosing that amount will show up pretty quickly though.
Best of luck and lets hope it is just something simple to fix.
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hi paul, got your PM in my email, am away at mo, using phone, best to text me as my phone won't let me reply to PM's. I can have a look next weekend. Maybe a blockage, or unwanted introduction of air. Unlikely, but the stat we fitted was an unknown, may have stuck shut, is the top hose hot? Catch up on phone sunday night if you like, don't run her while she is overheating :y
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Cheers James, :y
Car is now off the road and I hope to catch up with you by next weekend.
Going to do a few checks now and will update shortly
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Update -
As per the advice given I have run the car a good half hour with the cap removed off the header tank and watched the temp gauge sit nicely at 85c, looked underneath and couldn't see any water dripping onto the floor.
Once I put the cap back on I watched the water level rise in the header tank until it got to a point where it forced it's way out the cap and the top and bottom hose connections? At this point the temp gauge was around 95c........
Any ideas as to what this all means?
Thanks in advance as always :y
Paul
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If your getting enough pressure in the water system to lift the cap and hose clips then you may well have to consider a head gasket issue. As rare as it is on these engines I can't think anything else which will cause this. When you had it running with the cap off did you have a good sniff of the steam coming out the bottle. Combustion fumes stink pretty bad when they make their way through the water system. You may have to get a "sniffer" kit to get a positive result
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Just a thought, I decided to have a look at the oil filler neck and the mayo is a dark brown colour and does smell quite a bit...... Not sure if this is related or normal? Couldn't see any oil in header tank or water on the oil dipstick.
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Mayo in the filler doesn't really prove anything with these engines. Short journeys can cause it
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Oh Sorry,my mistake, just never seen it that colour before or smelling that bad that's all......... Wasn't sure if it was related to my overheating problem
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Given what James said in his previous post about the stat being an unknown one .... I'm inclined to agree with his conjecture that the stat may be stuck shut, and once the pressure starts to rise within the system (cap on) you are getting a localised "boiling" that is causing rapid expansion and temperature rise.
If you can leave it until James can look at it, all well and good.....
If you want to do more diagnostics .. try this .... and if you do it with the cap off it will be safer .....
Start engine from cold .. preferably overnight cold ... allow to idle and stand with one hand on the top hose where it comes from the thermostat. That pipe should remain cold until the temp gauge gets to mid 80's at which point you should feel a sudden "surge" of hot water as the thermostat opens.
If the water warms up slowly throughout, the stat is stuck shut
If the water does not "surge" but seems to heat up from the radiator end "backwards" so to speak, the stat is stuck shut and you are feeling the thermal siphon effect
HTH
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Cheers Entwood, I will give that a try, failing that I will hold off until I can get it looked at by somebody who knows what they are doing :y
Thanks everybody for all the advice
Paul
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If the water warms up slowly throughout, the stat is stuck shut
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A stat that's stuck OPEN will result in the rad hose warming up slowly ................ ;) ;) ;)
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If the water warms up slowly throughout, the stat is stuck shut
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A stat that's stuck OPEN will result in the rad hose warming up slowly ................ ;) ;) ;)
You are correct .. thats a typo ..!!!!!!! Should read OPEN on that paragraph .. next one is the stuck shut version !!
and now the edit option has passed .. :(
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I just can't see this being the thermostat. I hope it is after all even with the B'stard bolt it's still a sight easier than doing the head gaskets. I fear that the fact it didn't boil over without the cap on is because the gases are free to escape. The car isn't actually over heating. It's only getting to around 95C it's purely a over pressure issue. If it was due to lack of flow caused by the thermostat being shut then it would of spit the water out the bottle without the cap on as well. Also I feel the temp read out would still go off the gauge. At no point has this happened from what has been written. If it's not due to a physical leak (ie cracked header bottle or HBV) then I'm afraid it's got to be caused by over pressure. I hope I'm wrong but I fear the worst.
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Oh that doesn't sound good to me :'(
Highest I saw the temp gauge reach was 100c yesterday whilst idling, at that point water level was at it's highest in the tank and started to spill out through the cap and top and bottom hose connections, same thing has happened today also........
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Under 2 bar pressure water doesn't boil until 120C. So either it's not under pressure so boiled at 100C which leads us to a leak or it was under pressure but the pressure was to great it caused the relief valve and pipe clips to let by. Only way you can over pressure the system is by extreme temperatures (dis proven by the gauge) or by the head gasket letting compressed gases escape from the chamber into the water system. Another thing you can try. Run the car until just before it starts to spew the water. Switch it off. Now leave it for 10-20 minutes then restart it. Look at the exhaust when you start it (arm extensions needed or somebody to turn the key) If it blows out a lot of condensation for a minute or so then you now have water back in the cylinder. These happens as the pressure in the water is now greater than the pressure in the chamber while the ended was stopped. You have to be sensible doing this test. If you leave the engine to long to cool then your end up mistaking the the "cold mist" for a head gasket issue. If the leak is bad enough you may get some hydraulic lock which can be mistaken for a flat or low battery.
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im sorta with doz on this one it sounds like a pressure problem is it a V6 engine if it is it is really rare on them but it does sound like pressure. :-[
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Seems simlar to the symptoms on my 3.0 when I bought it.
Turned out to be the water pump - the impeller had become detached from its shaft and wasn't turning !
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I would agree with everything doz says... if the header tank had bubbles coming from it when running with the cap off....
The pressure from a cylinder is way above the pressure of an uncapped coolant system, even when not firing it is way above 2 bar ... think compression test.... so I would expect gas transfer to be even easier .. that gas would have to escape somehow, so would bubble through the header tank.
:-\ :-\
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I think that will cause the car to boil. Which this one isn't or at least the gauge is telling us it isn't
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When I ran the car without the cap on I didn't notice or see and bubbles in the header tank........ I put my finger in the bottle and felt the water was warm but no bubbles....... Only when I put the cap back on did I see the water level rise and then escape I'm assuming under pressure.
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thinking about it does this engine have a pressure realease valve on them for cooling pipes to bleed air out of the system :o
like this
(http://www.donkennedy.co.uk/clit/BleedNipple.jpg)
i know they got them on veccy engines i cant see why not :y
run engine
release the bleed nipple with cap on and leave it open until no more air can be heard and pure coolant comes out be on hand with a BIG bottle of water to keep topping up :o ;D :y
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there could be and air lock somewear
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im watching this with intrest as mine has a problem where whilst moving all is well then min you stop it gets hot quite quickly, but min move cools right down again, and yes the fans do cut in
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im watching this with intrest as mine has a problem where whilst moving all is well then min you stop it gets hot quite quickly, but min move cools right down again, and yes the fans do cut in
sounds like your stat :y
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ummm don't know lol but lets hope there is and it's not a HG issue >:(
Car will stay off the road now until I can get it looked at ;)
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ummm don't know lol but lets hope there is and it's not a HG issue >:(
Car will stay off the road now until I can get it looked at ;)
prob good idea have a look tomoz maybe :y
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i may change it when do rocker gaskets now it warming up outside
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Let's hope it is the stat even though it was replaced only 6 weeks ago........ My car is fine when driving but once stood still temp gauge soon rises and water spills out after it reached 100c, temp gauge goes back down when moving.......
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If it's spilling out at 100 change the expansion bottle cap
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I did wonder if I should change the tank or the cap or both and see how that goes......... Are things still pointing towards stat fault?
Cheers for all the help :y
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Its hard to say Paul .... the cap will increase the pressure in the system and therefore raise the boiling point .... but under no pressure yours is not reaching boiling point, so, in theory, the cap should make little difference.
The "thermal siphon" within an engine works best at zero pressure, and yours seems to be doing just that .. controlling nicely with the cap off.
It is when you put the cap ON that problems start ....
So ... a small increase in pressure is leading to a large increase in pressure sufficient to cause changes in water level and pressure leakage ..
possibilities to my mind ....
Stat stuck shut, small pressure rise causes thermal siphon to cease, leading to localized "boiling" at the engine block, resulting in steam causing a large pressure rise and water displacement, as well as the block temperature rise you see.
perhaps all those could also be caused by the waterpump not moving water within the system ??
Not sure TBH
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Yes mate it would appear I see the problems when the cap is on..........
I am having a cambelt and water pump change done soon so hopefully that will sort out any water pump issues that may be there.
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Its hard to say Paul .... the cap will increase the pressure in the system and therefore raise the boiling point .... but under no pressure yours is not reaching boiling point, so, in theory, the cap should make little difference.
The "thermal siphon" within an engine works best at zero pressure, and yours seems to be doing just that .. controlling nicely with the cap off.
It is when you put the cap ON that problems start ....
So ... a small increase in pressure is leading to a large increase in pressure sufficient to cause changes in water level and pressure leakage ..
possibilities to my mind ....
Stat stuck shut, small pressure rise causes thermal siphon to cease, leading to localized "boiling" at the engine block, resulting in steam causing a large pressure rise and water displacement, as well as the block temperature rise you see.
perhaps all those could also be caused by the waterpump not moving water within the system ??
Not sure TBH
When was WP changed last cambelt change is any noises coming from belts knocks squeals etc
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To be honest yes there is, I have noticed some squeals what sound like they are coming from the belts / tensioners and after about ten mins it all goes quiet....... Then on tick over you here a slight squeak every now and then but I have no idea where it is coming from
Could this be something then?
previous owner had the water pump and belt last changed in 2008 at 45k, car now on 75k.......
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never go buy mileage or age,a part can fail at any time :y
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Agreed Martin, I've got all the parts here ready to be fitted along with other jobs lol,
So could the noise from the belts / tensioners area be related to the water pump failing? Maybe this is my fault?
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This one is now fixed. The new stat was fine and not to blame.
Repair cost total of £3 from Hellfrauds and took 30 seconds to fit if that helps narrow it down :) Now runs lovely up to temp, no leaks or over pressuring and good cabin temp. Top hose holding from cold test shows stat opens as designed.
Happy days :y
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Jubilee clip?
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This one is now fixed. The new stat was fine and not to blame.
Repair cost total of £3 from Hellfrauds and took 30 seconds to fit if that helps narrow it down :) Now runs lovely up to temp, no leaks or over pressuring and good cabin temp. Top hose holding from cold test shows stat opens as designed.
Happy days :y
What was the £3 fix that solved it :-\
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new header tank cap/seal.
The seal on the old cap was, er, non existant :y
Replaced, and now behaving perfectly :y
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Can't believe I failed to notice the cap seal was no good, just proves I'm useless and have no clue with cars ;D
Cheers James :y
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Just glad it was a straightforward fix for you mate to get you mobile :y