Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: MV6Danny on 12 July 2012, 23:32:42
-
Hi guys i have a bit of a problem with my 3.0 MV6. About a month ago my car started to mis-fire or is running rough when i start it up, after about 30 secs to 1 min it stops and the car runs fine. well on the way to work today the temp gauge went right to the top :'( then back down to normal and did this a few times. I got to work and decided to have a look to see if it had enough coolant in it, upon inspection i discovered that there was no coolant in the tank. after 2 hours when the engine had cooled down i topped up with water. It took about 3.5 liters to fill it up. I warmed the car up with the expansion tank cap off to make sure all the air was out of the system. It looked like there was some sort of scum on top of the water. I decided to have a smell and i think i could smell fuel or exhaust gas coming from the tank. :'( I dont know if it was coming from the tank but pretty sure it was. Does anybody have any ideas on this or any advise on what to check as the car shouldnt have used that much coolant. Could this mean the head gasket is gone or maybe the heads are cracked. there is no water in with the oil. Thanks guys hope someone can help. :y
-
Test compression.
Very rare for V6 HG to fail (firerings, anyway). 1998 3.0l have a failure mode where coolant leaks to outside of block.
-
Update. Went out this morning to check the water after the car been sat overnight. Completely cold and the cooling system was pressurized. when i opened the cap it released pressure and i smelt the tank and it smelt of fuel. Is this a sign of a cracked head?
Test compression.
Very rare for V6 HG to fail (firerings, anyway). 1998 3.0l have a failure mode where coolant leaks to outside of block.
Do you mean test the compression of the cylinders?
-
Update. Went out this morning to check the water after the car been sat overnight. Completely cold and the cooling system was pressurized. when i opened the cap it released pressure and i smelt the tank and it smelt of fuel. Is this a sign of a cracked head?
Test compression.
Very rare for V6 HG to fail (firerings, anyway). 1998 3.0l have a failure mode where coolant leaks to outside of block.
Do you mean test the compression of the cylinders?
IMHO if it held pressure that long then it is a "sealed" system .. and there are no leaks ..so the chances of it being a head gasket are very slim .. and there is no other way of fuel getting into coolant that I can think of.
-
Well that is what i would have thought to. But when cold the system should not be pressurized. And there is definatley a strong smell of fuel or exhaust gas coming from the expansion tank. Could the head be cracked?
-
Might be worth popping to a mot station and ask them if they can do a "sniff test" on the bottle.
If the water is leaking onto the exhaust manifold from a pipe or the hbv, the antifreeze can can smell a little ;)
When it was coughing and farting, did you pull a plug lead off to see if there was any water in there ?
-
Might be worth popping to a mot station and ask them if they can do a "sniff test" on the bottle.
If the water is leaking onto the exhaust manifold from a pipe or the hbv, the antifreeze can can smell a little ;)
When it was coughing and farting, did you pull a plug lead off to see if there was any water in there ?
Personally find the Sniff Test a load of rubbish.
If your head gasket had gone on the firing ring the compression could push water out of the reservoir at every upward stroke of the piston if that makes sense. Water would come out of the exhaust...seen it that bad water was coming out of the exhaust like it was a firehose.
You say you do have a water leak but dont know from where? If you system is still holding pressure over night I would think it seemed to be water tight... Try turning the heating to hi for the day see if the water leaks. The following day turn heating to Lo, then see if it leaks then too.
-
3.5 litres is a lot to loose, there'd be steam out the exhaust like the orient express.
I'd say the hbv is leaking in either hot or cold position. Depending on the CC setting used when the water was lost....?
Some light scum on the surface of the coolent is not unusual, ESP if the coolent is old.
Might be worth getting the coolant level warning fixed too. :)
-
And yes, sniff test is suspiciously unreliable. In favour of the mechanic with the large bill.
-
i understand what is being said but the cooling system was flushed about 4 months ago with fresh new anti-freeze being put in. TBH i havent checked it since i changed it, it shouldnt loose water. If the HBV is leaking that would not explain why the system is pressurized when cold and the coolant smelling of fuel or exhaust gas, where as if the head is cracked the compression in the cylinder would keep the system pressurized and appear to be water tight. Is there any know case of the head cracking.This is the only thing that i can think of to explain this. also its strange that it runs lumpy for upto a minute when first started until warmed up slightly.
-
3.5 litres is a lot to loose, there'd be steam out the exhaust like the orient express.
I'd say the hbv is leaking in either hot or cold position. Depending on the CC setting used when the water was lost....?
Some light scum on the surface of the coolent is not unusual, ESP if the coolent is old.
Might be worth getting the coolant level warning fixed too. :)
does mine have a coolant level warning and how would i fix it?
-
i understand what is being said but the cooling system was flushed about 4 months ago with fresh new anti-freeze being put in. TBH i havent checked it since i changed it, it shouldnt loose water. If the HBV is leaking that would not explain why the system is pressurized when cold and the coolant smelling of fuel or exhaust gas, where as if the head is cracked the compression in the cylinder would keep the system pressurized and appear to be water tight. Is there any know case of the head cracking.This is the only thing that i can think of to explain this. also its strange that it runs lumpy for upto a minute when first started until warmed up slightly.
Just how does that happen on a stationary engine overnight ??? It would overpressurise like a bandit whilst running I agree .. but not overnight ....
Given you haven't checked the water level for 4 months, and there are no leaks on the floor .. my bet is still the header tank lid, however .. what you haven't said is if it STILL leaks ... one loss of water over 4 months means absolutely diddley-squat .. other than you don't do maintenance on your car properly .. :(
So, fill it properly, run the car and monitor it DAILY for at least a week ... if it is still losing water then I'll believe you have a problem .... if it does not .. problem does not exist.
-
cooent level warning is underneath the exp tank little plug.
the fact that you may have cooked it a bit may not be good the other thing is get a pressure test done on the system.
-
3.5 litres is a lot to loose, there'd be steam out the exhaust like the orient express.
I'd say the hbv is leaking in either hot or cold position. Depending on the CC setting used when the water was lost....?
Some light scum on the surface of the coolent is not unusual, ESP if the coolent is old.
Might be worth getting the coolant level warning fixed too. :)
does mine have a coolant level warning and how would i fix it?
Would have thought so. My 99 cdx had coolant level warning. Hbv and oil coller cover plate tested it regular as well.
Head cracks are not even remotely common on the v engine. It's not that.
Coolant will leak and then not leak from the hbv depending on settings.
Grumpy running could be a number of things unrelated. Ht issues. Air lake. Sticky icv. Did the coolant loss start at the same time as the rough running?
Was the coolant level monitored after the service?
-
i understand what is being said but the cooling system was flushed about 4 months ago with fresh new anti-freeze being put in. TBH i havent checked it since i changed it, it shouldnt loose water. If the HBV is leaking that would not explain why the system is pressurized when cold and the coolant smelling of fuel or exhaust gas, where as if the head is cracked the compression in the cylinder would keep the system pressurized and appear to be water tight. Is there any know case of the head cracking.This is the only thing that i can think of to explain this. also its strange that it runs lumpy for upto a minute when first started until warmed up slightly.
Just how does that happen on a stationary engine overnight ??? It would overpressurise like a bandit whilst running I agree .. but not overnight ....
Given you haven't checked the water level for 4 months, and there are no leaks on the floor .. my bet is still the header tank lid, however .. what you haven't said is if it STILL leaks ... one loss of water over 4 months means absolutely diddley-squat .. other than you don't do maintenance on your car properly .. :(
So, fill it properly, run the car and monitor it DAILY for at least a week ... if it is still losing water then I'll believe you have a problem .... if it does not .. problem does not exist.
That doesnt explain the smell of exhaust gasses or petrol in the water though does it? I will be monitoring it daily to see if the water level does drop. when i changed the coolant (when you met me at skurrays to get the antifreeze with your trade club card) The coolant level was fine and hadn't checked it for months be for i changed it.
-
3.5 litres is a lot to loose, there'd be steam out the exhaust like the orient express.
I'd say the hbv is leaking in either hot or cold position. Depending on the CC setting used when the water was lost....?
Some light scum on the surface of the coolent is not unusual, ESP if the coolent is old.
Might be worth getting the coolant level warning fixed too. :)
does mine have a coolant level warning and how would i fix it?
Would have thought so. My 99 cdx had coolant level warning. Hbv and oil coller cover plate tested it regular as well.
Head cracks are not even remotely common on the v engine. It's not that.
Coolant will leak and then not leak from the hbv depending on settings.
Grumpy running could be a number of things unrelated. Ht issues. Air lake. Sticky icv. Did the coolant loss start at the same time as the rough running?
Was the coolant level monitored after the service?
I dont know as i didnt check the coolant level when it started running rough on start up just assumed it needed new plugs and leads. and no didnt monitor the level after the service. After the initial start up the car runs and ticks over fine.
-
Pressure test is a good idea too. But may still give false results if the hbv is leaking in its cold/ac on position, but the test is done when hbv is in the hot position, for instance.
But anyway, I'd also go with the topping up and monitoring after or during every journey. Top it up, keep water bottle full in the boot. Drive it round the block, check the level. Top up of empty, change the climate setting, drive, check etc. see what the failure mode is. Any water under the car etc. feel under hbv for (hot) water. And son on.
If the hg is gone, which I doubt, Then it's too late to worry about anyway. Is the oil a normal oil colour?
-
Pressure test is a good idea too. But may still give false results if the hbv is leaking in its cold/ac on position, but the test is done when hbv is in the hot position, for instance.
But anyway, I'd also go with the topping up and monitoring after or during every journey. Top it up, keep water bottle full in the boot. Drive it round the block, check the level. Top up of empty, change the climate setting, drive, check etc. see what the failure mode is. Any water under the car etc. feel under hbv for (hot) water. And son on.
If the hg is gone, which I doubt, Then it's too late to worry about anyway. Is the oil a normal oil colour?
I will monitor it. the oil is fine no mayo in it on the dipstick. the hg failed on the firering on my mfl 2.5 and that ran really bad after it went sometimes failing to start or even turn over. but nothing like that yet. will have to try and pressure test it somehow. :y
-
what about the smell from the expansion tank then? is that normal?
-
what about the smell from the expansion tank then? is that normal?
Do you have any spare coolent left over from the service? If so does the stuff in the bottle smell the same? Are you aware of the original smell? What coolent is in it, is it vx red?
I'm not sure coolant tank smell is enough to condem hg tbh.
-
yes i do have some left and it is vx red. i will have a sniff tomorrow but tbh it is a very strong petrol smell in the expansion tank. cant remember what it smelt like when i changed the coolant. will check everything again tomorrow and post an update. Thanks Chris :y
-
When a cylinder fires the hot, partially combusted, petrol/air mixture reaches a pressure of several hundred psi momentarily. If you have very early stage failure of a fire ring it is possible for hot gases (containing unburnt petrol) to pass one way but not coolant in the other direction (or very little).
You are now aware that there is a potential problem. Fix the level sensor and make sure that the coolant bottle remains topped up. Odds are that it is a faulty HBV or small leak somewhere else. Even if you are looking at the worst case scenario it will probably several thousand miles before you need to do anything about it.
-
When a cylinder fires the hot, partially combusted, petrol/air mixture reaches a pressure of several hundred psi momentarily. If you have very early stage failure of a fire ring it is possible for hot gases (containing unburnt petrol) to pass one way but not coolant in the other direction (or very little).
You are now aware that there is a potential problem. Fix the level sensor and make sure that the coolant bottle remains topped up. Odds are that it is a faulty HBV or small leak somewhere else. Even if you are looking at the worst case scenario it will probably several thousand miles before you need to do anything about it.
Ive had the same problem with my 2001 2.2 and have been told that due to petrol smell and brown scum plus slight leak from the header tank area,it's the hg,but on reading this I'm now having 2nd thoughts.Also can someone tell me what a hbv is please. :y
-
When a cylinder fires the hot, partially combusted, petrol/air mixture reaches a pressure of several hundred psi momentarily. If you have very early stage failure of a fire ring it is possible for hot gases (containing unburnt petrol) to pass one way but not coolant in the other direction (or very little).
You are now aware that there is a potential problem. Fix the level sensor and make sure that the coolant bottle remains topped up. Odds are that it is a faulty HBV or small leak somewhere else. Even if you are looking at the worst case scenario it will probably several thousand miles before you need to do anything about it.
Ive had the same problem with my 2001 2.2 and have been told that due to petrol smell and brown scum plus slight leak from the header tank area,it's the hg,but on reading this I'm now having 2nd thoughts.Also can someone tell me what a hbv is please. :y
Heater Bypass Valve. Lives at rear of engine, controls flow of heated coolant to matrix for interior cabin heat.
http://www.omegaowners.com/forum/index.php?topic=90574.0
-
Given the proximity of the header tank to the engine,fuel inlet pipes and other bits and bobs; and as most engines are to some extent or other, dirty with old oil/fuel/gunge of various denominations ... "smell" tests are notoriously unreliable .... IMHO .. I certainly would not condemn a HG purely on the basis of smell .... :(
-
Given the proximity of the header tank to the engine,fuel inlet pipes and other bits and bobs; and as most engines are to some extent or other, dirty with old oil/fuel/gunge of various denominations ... "smell" tests are notoriously unreliable .... IMHO .. I certainly would not condemn a HG purely on the basis of smell .... :(
Unfortunately it's just been broken in the last 2 days so it's a tad to late,doh,but going to put bits on eBay, :'(