Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: arronsweeney on 27 May 2007, 08:07:54
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hi
i am new to this site , i have a prob with my cooling system i had a water hose burst on me last week the one from the engine to the radiator at the top of the engine, i have now replaced it and the temp still keeps rising to max, any one out there got any ideas before she is garaged,also i have ben told omega 3lite elite has 2 thermostats can anyone tell me where they are located
thanks
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Welcome to the forum :y
Someone should be along shortly to answer your questions.
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What year is it?
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It has only one thermostat.
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it is a m reg automatic please can you tell me where the thermosat is
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I can't sorry, I'm no V6 expert.
MJ - have you got a picture?
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Ok, the 1 thermostat the omega has (it has 2 temp sensors) is in the valley between the the 2 banks of cylinders. You need to remove the plenum (silver slab thing on tope of engine) to see it, let alone access it.
However, this is not going to be your problem.
The hoses don't usually fail unless something else is wrong...
When the coolant was replaced, was the cap left off with the heater controls turned to max for a good 30 mins? This will bleed the system out.
Tell me it is using the correct 50/50 antifreeze mix and not just water?
Are the pipes goiing rock hard, as if the system is overpressurising?
Any signs of "mayo" (does it look a nasty brown colur) in the header tank?
Is the radiator getting hot and are the cooling fans kicking in?
Any noticeable water loss?
Tak a look at the back of the engine, any signs of water back there?
Lots of questions I know, but it helps give us a better idea.
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I can't sorry, I'm no V6 expert.
MJ - have you got a picture?
Yes - see links below:
http://www.omegaowners.com/forum/YaBB.pl?num=1176231166/2#2
http://www.omegaowners.com/forum/YaBB.pl?num=1176463939/18#18
http://www.omegaowners.com/forum/YaBB.pl?num=1178095004/14#14
As LB said, only one thermostat....
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is 50/50 antifreeze mix imperetive or is clear water not sufficient in summertime,
initially coolant was not replaced after replacement of hose just water was added and heater controls had not been turned to max untill possibly 10 mins after running engine, i know it should have been done initially . signs of mayo are present in the header tank radiater is getting hot and cooling fans kicking in , no noticible water loss , when the engine is switched off the replacement hose seem to suck in flat and out again several times
the temp in the car rises untill i reduce pressure on header tank
thanks
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You say you have signs of cross contamination in the header tank. How is the oil looking (ignore a slight amount of mayo round the oil filler cap)
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Clear water as coolant is nver sufficient... :(
The "antifreeze" also acts as a corrosion inhibitor, which is where I think the problem is...
Signs of mayo? How much?
Hose sounds like it is no good at all and collapsing in on itself.
Are the other hoses quite "soft" feeling when cold?
Ok, it sounds like there are a couple of potential problems.
1. Run the car with the heaters on and the header tank cap off for 30 mins.
The car should blow really hot air into the cabin.
While it is doing this, have a look closely round the back of the engine on the drivers side for signs of leakage. Maybe put your hand in there to check..
2. This mayo... is it becoming quite thick and brown in the header tank?
If yes, then oil cooler has failed, which is my initial suspicion.
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The 50/50 mix is important to stop internal corrosion. You'll probably get away with it in the short term. Long term it may cause head gasket failure, which is otherwise very rare on the Omega V6's.
I think LB66 suspects an oil cooler failure which rapidly sludges up the coolant system and causes blockages.
Thermostats are hard to change on the V6's but fortunately don't fail very often.
Brown sludge in the expansion tank is the sign of oil cooler failure which very soon turns into vast amounts of brown sludge. Once this is fixed it is essential to flush the whole coolant system thoroughly or the blockages will remain. Flushing can either be done by numberous (like 10+) coolant changes with a small amount of usage between flushes, or by a more brutal method of adding a healthy dose of degreaser to the coolant system running for a while then flushing out.
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Clear water as coolant is nver sufficient... :(
The "antifreeze" also acts as a corrosion inhibitor, which is where I think the problem is...
Signs of mayo? How much?
Hose sounds like it is no good at all and collapsing in on itself.
Are the other hoses quite "soft" feeling when cold?
Ok, it sounds like there are a couple of potential problems.
1. Run the car with the heaters on and the header tank cap off for 30 mins.
The car should blow really hot air into the cabin.
While it is doing this, have a look closely round the back of the engine on the drivers side for signs of leakage. Maybe put your hand in there to check..
2. This mayo... is it becoming quite thick and brown in the header tank?
If yes, then oil cooler has failed, which is my initial suspicion.
That will be very hot, be careful
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car has slight oil leak oiles on min but looks ok nice dark colour not grey
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the mayo is not sludgy it just seems to be dirty water
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does anybody know where the valve is to empty water system on 3 litre elite
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Looking at the car from the front, it's at the back of the radiator, bottom right.
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Red thumbscrew.
Only will drain half the system (5 litres). To get the rest out is more involved.
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It just occurred to me, perhaps they were referring to 'thermoswitch' rather than 'thermostat'? A thermoswicth is a temperature sensor that activates the fans when the engine temp goes up. If it isn't working properly, what you will see is that the car behaves perfectly normal when driven mildly on motorways, but as soon as it is left to idle it will boil over.
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it may possibly as Dave is thinking, be oil cooler failure. Time consuming but do able at home if time allows.
Thermostat is not hard to do but involves a fair amount of stripping to the valley, where oil cooler also is.
incidentally - for my own knowledge - what sort of thing causes over pressurising?
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Overpressurising is caused by air getting into the system.
As you know the coolant system is pressurised under normal operation.
However if there is a small leak in the system, then the following can happen...
A small leak can allow water to be pushed out under pressure...eg engine under load.
However, when that pressure is reduced, ie. when the load is reduced then a vacuum is formed at the leak.
This then sucks in air...
When air is heated it expands and takes up more "space" than water.
Get enough air in the system (and it doesn't require much) and the system becomes overpressurised causing overheating problems.
Dead giveaways are rock hard coolant pipes pipes and a "hissing" from the coolant cap as it tries to vent off the excess pressure.
If you suspect this, BE VERY CAREFUL when loosening the cap as the water will be above boiling point and under tremendous pressure.
Use a towel and VERY gently turn the cap so it just starts to release pressure. Turn it too quickly and the cap will blow straight off and soak you in boiling water!!
This has happened to me and it is very very unpleasant!
Now move away and leave it for a few minutes to allow the pressure to vent off safely.
The most common cause of air getting into the system is a a split in the heater bypass valve. As many of you know, that is situated at the back of the engine, towards the drivers side.
Don't try and drive the car unitl the problem is resolved. The pressure and heat can cause failure of other components very quickly.
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So Dave - sorry for the thread Hijack :-[
I can clearly see my vectra is over preassurised - it blew top hose off even when it was tightley jubileed.
Running car for 5 minutes has coolant shoot back out expansion tank ...
Car as you know had oil cooler failure. But when i got the car in its post cooler failure stat the bottom hose was blown straight off. Again sounds like overpressurising.
So can over pressurinsing cause oil cooler failure and perhaps i have fixed the effect but not the cause.... :-/
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Markie, yours is almost certainly overpressurising due to the coolant being unable to circulate.
If you block the system, you very quickly develop a heck of a lot of back pressure that has to go somewhere...
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Markie, yours is almost certainly overpressurising due to the coolant being unable to circulate.
If you block the system, you very quickly develop a heck of a lot of back pressure that has to go somewhere...
dam ...i was looking for an easy fix ;)