Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: spiketheskinnydog on 23 December 2006, 17:29:40
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I've just changed my cam cover seals, cleaned out the breather system, changed the DIS pack and given the whole thing a good wash to clean off three weeks worth of bird crap - not something I'm wanting to do again in a hurry!
But my question is this - if the cam cover seals leak due to the build up of pressure resulting from a blocked breather system, is it permissible to just leave the dipstick poking out a little to avoid the problem occurring again in the future?? This was suggested by my brother: he's a fully trained Ford master mechanic, but I'm reluctant to trust him on this one! the dipstick looks as if it should be pushed fully home, given that its got some little seals on it, but everything seems to run nicely with it poking out. Any ideas???
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Well not being an expert on engine matters.....but i would have thought this wasnt a good idea.....as you could get oil coming out as well as other crap getting in......plus if the breathers are nice and clean you wouldnt need to do this :y
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PS think i read somewhere that if the dipstick pushes itself out a bit then this is a sign of pressure build up in the sump and could suggest blocked breathers :y
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Dont see how this would work. Pressure that is strong enough to pop a cam cover gasket would just blow the dipstick out of its tube anyway.....if it was related...which I dont think it is.
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Interesting theory and says a lot for "Ford master mechanic" :D
The dipstick leads to the engine sump...
The crank case seals are on the top of the engine.... ;)
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Hi,
This might explain it better.
Cleaning crankcase breather system on V6
11. Jul 2006 at 07:12 (c)2006 Ronald Mc Burger
This guide will save you the hassle of blown rocker gaskets. It is a preventative measure and I would suggest you do it when you first get the car and then every 12 months thereafter.
Sidestepping for a moment, the chain of events is basically this. If the oil is old and hasn't been changed regularly or for some time, it will be black coloured and this is where it all starts to go wrong. Of course, the car still runs beautifully, so you'll do that oil change next month won't you?
The problem is that oil serves many purposes and in this case it has soaked up lots of microscopic particles. During the normal running of the engine a 'mist' of oil is present in the crankcase, a bit like the water mist at Niagra falls. As the engine on the V6 is a sealed unit, crankcase ventilation is essential and thus the breather system. This mist is sucked up into the breather system and, over time, tiny deposits of crud start to build up until it reaches a critical point. You will not be aware of this because the car still runs and you can do that oil change the next month again!
At the point where the system becomes unable to cope with the demand for ventilation, the pressure in the crankcase builds up. It has to get out somewhere and always takes the weakest option, which on the V6 is the rocker gaskets. Once that escape occurs, you have gasket failure and thus the leak starts.
So, maybe now you see why this is so important. Oil changes are one of the cheapest preventative measures you can do, yet many people leave the oil for years as the car 'seems' fine.
Now that you understand the importance let me quickly run through the system that you will need to work on. Starting at the back of the engine, drivers side, is the crankcase breather box. Next to this is another small electrical box which is also part of the breather system. From the breather box are two tubes, one large and one small. From the electrical box is one small tube. The two small tubes connect to the plenum at the back. The bigger tube divides in to two and then both bigger tubes also join the plenum.
The black plastic box on top of the pleunum is actually in two parts. The cover, which has ECOTEC written on it, and the main body. Through a series of channels in the internal parts of this box means that the two bigger tubes are fed pre throttle and the two smaller tubes are fed post throttle. This means that you get higher negative pressure to vent the crankcase under throttle.
So to the cleaning. (at last).
FIRST OF ALL THE ENGINE MUST BE COLD!
This job will require the removal of the wipers & scuttle for better access to the plenum cables and breather box. While you are working there you will get a good view of the Heater Bypass Valve (HBV).
CLICK PHOTOS TO ENLARGE IN NEW WINDOW
Unclip and diconnect the 4 breather tubes on the back of the plenum. Remove the plenum and blank out the 6 intakes with paper towel in case of parts and dirt ingestion.
Remove the 4 TORX bolts and seperate the throttle chamber from the plenum.
Carefully prise off the ECOTEC cover, being careful not to prise the actual black breather box at the same time. This will reveal a hidden TORX bolt securing the black box to the plenum.
Remove the 3 breather tubes - 1 small one from the breather box, 1 large one that divides into two from the same breather box, and lastly the last small breather tube.
Starting with the Vent housing, the smaller pipe (brass) has a very small hole in the centre.
Picture shows housing off the car for clarity only. You do NOT remove this box!
Don't mistakenly think that the whole pipe should be clear, it shouldn't. It is just the little hole in the centre that needs clearing. Firstly, clean around that pipe with carb cleaner and a rag. Don't go mad with carb cleaner as it is highly flamable (hence cold engine). Clean the pipe to get rid of any crud and you will now see the hole. Using a stiff wire and a small squirt of carb cleaner, push the wire about 4" into the hole and give it a good wiggle around. A very quick squirt of carb cleaner to finish.
Next, the big pipe.
Scoop out as much crud as you can with a screwdriver or similar. Try not to push the crud back into the box if you can. When you have done this use a rag and carb cleaner to wipe the inside and outside of that pipe. DO NOT squirt tons of carb cleaner inside unless you are immediately doing an oil change. Car cleaner is not good inside the crankcase as it eats seals! Don't believe me? Squirt some on to your latex gloves and watch what happens.
Next, the electrical box pipe needs the quickest of squirts and a wipe, also a gentle poke with that wire, but DO NOT force the wire in, there is a seal inside and you may puncture it.
Now move onto the 3 tubes. Use as much carb cleaner as you like now, but away from the car. Clean and clean again. They need to be totally clear. The bigger 'Y' tube fits nicely onto a garden tap to get a final blast through. Don't cut corners, this is where most of the crud will be, in that bigger tube at the top.
Black breather box needs tons of carb cleaner and some gentle prodding with the stiff wire. You should be able to blow through all 4 pipes when cleaned and you should meet no resistance.
The plenum needs general cleaning inside with carb cleaner, but most importantly around the round recess near the front where the black breather box feeds its two smaller tubes to.
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The dipstick leads to the engine sump...
The crank case seals are on the top of the engine.... ;)
:-? And of course the rocker covers & sump are quite seperate or the oil from the top of the engine wouldn't drain back down to the bottom of the engine! :-? ;)
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The dipstick leads to the engine sump...
The crank case seals are on the top of the engine.... ;)
:-? And of course the rocker covers & sump are quite seperate or the oil from the top of the engine wouldn't drain back down to the bottom of the engine! :-? ;)
All dependant on whether the end of the dipstick tube (not just the stick) ends above or below the level of the oil??
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Despite one observation above the crankcase pressure most definately affects the pressure under the cam covers, simply because there are oilways allowing the oil lubricating the cams to find its way back into the sump, as a more clued-up writer has already stated. There is no doubt about that.
It is also clear that no oil comes out of the dipstick pipe whatsoever, so oil loss isn't an issue.
I'm going to leave the dipstick poking out, thereby allowing any pressure to vent to the atmosphere.
As an aside it is commonplace for tuned ford pintos to vent directly to the atmosphere, although via a small breather filter, simply because it is not possible to do so by any other reasonable means. I am aware of several engines running this system with no ill effects, including one of my own!
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Interesting theory and says a lot for "Ford master mechanic" :D
The dipstick leads to the engine sump...
The crank case seals are on the top of the engine.... ;)
Ford Master Mechanic = Many many years of hard work, numerous examinations, on-job and formal training, regular testing and re-testing etc etc etc!
Also, please see my previous statement as to why the crankcase and cam covers share the same air pressure - its not that difficult to to understand really!
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Well, if you already you know the answer, not much point in asking the question :P
Perhaps you should have taken the master mechanics word for it.
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Well, if you already you know the answer, not much point in asking the question :P
Leave him alone STMO he was only asking for confirmation and now has Laidback scratching his head - that doesn't happen often :o
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Well, if you already you know the answer, not much point in asking the question :P
Leave him alone STMO he was only asking for confirmation and now has Laidback scratching his head - that doesn't happen often :o
I have no problems at all with the content, just way it is written
:P again
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Well, if you already you know the answer, not much point in asking the question :P
Leave him alone STMO he was only asking for confirmation and now has Laidback scratching his head - that doesn't happen often :o
I have no problems at all with the content, just way it is written
:P again
:P Q. Has BoBo nicked your smiley? ;D
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Well, if you already you know the answer, not much point in asking the question :P
Leave him alone STMO he was only asking for confirmation and now has Laidback scratching his head - that doesn't happen often :o
I have no problems at all with the content, just way it is written
:P again
:P Q. Has BoBo nicked your smiley? ;D
He will return, bigger and smilier, after the "festive" season :y
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Firstly I would like to say that I understand the question and I don’t know the answer.
However – on my previous Omega, I had the breathers cleaned at 40k as pre-emptive measure, and my current Omega has done 50k and the cam covers are not leaking yet in spite of the fact that the breathers haven’t been cleaned so far.
I guess that this shows that if you do clean the breathers properly and change the oil regularly then the gaskets should be good for the next 40k-50k easily…
So as a theoretical issue this may be interesting, but from the practical point of view I find the disptick trick – even if it does work, which may very well be the case – pointless…
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Now ..... play nicely!! ;)
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Well, if you already you know the answer, not much point in asking the question :P
Leave him alone STMO he was only asking for confirmation and now has Laidback scratching his head - that doesn't happen often :o
I have no problems at all with the content, just way it is written
:P again
:P Q. Has BoBo nicked your smiley? ;D
He will return, bigger and smilier, after the "festive" season :y
Thanks for that most valuable help STMO. Your comments fully answered the query!
Actually, I took exception to your comments regarding your opinions as to the value of highly trained mechanics. I feel that I am reasonably proficient with most mechanical issues, but there is no doubt that someone with years of training would be on a totally different level. In fact, my brother's training took longer than my GP's, and I really wouldn't like to argue with him either. The point of my enquiry was to find whether anybody had any experience of this simple measure, not to get into some daft arguement. I am aware that there is quite a complex breather system on the Omega, including some sort of purge/pressurisation system on startup. I believed that leaving the dipstick poking out a little, so as to vent the crank to the atmosphere, may have some consequences on this, although I couldn't be sure what. Aren't questions such as these the reason why forums exist??
Anyway, I accept the reasoning from other users (that there should be no problems with cam cover seals blowing if the breather system is kept clear), which seems entirely sensible. My Omega's breather system has been fully cleaned when the seals were changed, but as its always had regular oil changes (as evidenced by the service history) I was suprised to see that they bunged up in the first place.
Perhaps use of a synthetic oil would improve matters, although I've heard that its not really good practice to use synthetic oil in a high milage vehicle that has always used mineral oils (My Omega's done 104,000, which seems bugger all to some of the Omegas I've seen though!). Any thoughts??
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Absolutely :y
Not convinced myself about the dipstick thing, but good to see a debate over it :)
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Nuff said :y
PS. I didn't say ANYTHING about mechanics.
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... Anyway, I accept the reasoning from other users (that there should be no problems with cam cover seals blowing if the breather system is kept clear), which seems entirely sensible. My Omega's breather system has been fully cleaned when the seals were changed, but as its always had regular oil changes (as evidenced by the service history) I was suprised to see that they bunged up in the first place.
Perhaps use of a synthetic oil would improve matters, although I've heard that its not really good practice to use synthetic oil in a high milage vehicle that has always used mineral oils (My Omega's done 104,000, which seems bugger all to some of the Omegas I've seen though!). Any thoughts??
Just a couple of points about the oil issue…
There are two reasons why you could have problems if using synthetic oil after using mineral for a long period.
The first is that on older vehicles the seals rubber compound used to be chemically react with the mineral oil in such a way that if it was coming in touch with synthetic oil the rubber would start leaking – this should not be a problem with newer vehicles however where modern rubber compounds are used, but I don’t know for fact if this affects the Omega and if so up to what model year… At any rate the reason older engine start leaking when synthetic oils are first used ahs nothing to do with synthetic oils being ‘thinner’ and some people believe, because a 10W-40 synthetic oil will be just as thin as a 10W-40 semy-synth…
The second is that high-end synthetic oils have detergent additives and such can shift deposits previously untouched by lower-quality mineral oils. In this case, when changing from mineral to synthetic oil a second oil change after around 1,000 miles is recommended.
As for the fact that the breather on your car needed cleaning in spite of the fact that oil has been changed ‘regularly’, keep in mind that most owners will service the car at best according to the manufactures recommended schedule – which are specified with fleets in mind where buyers want to be re-assured by low running costs. In the Omega’s case, changing the oil every 10k or 1 year on the earlier models or 20k 1 year on the later models as per Vauxhalls’ specifications, is no where near enough to keep the breather clean – the oil need to be changed every 3k-5k, but few owners actually do that hence the breather problem. The actual service interval depends on your driving style - city driving with short trips as opposed to long motorway drives etc.
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Nuff said :y
PS. I didn't say ANYTHING about mechanics.
Haha! You're right! It was that "Laidback" person!! My mistake, sorry! ::)
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So.....my training here has not fully rubbed off on anybody yet then as nobody (including a ford master Mechanic ;)) has spotted the bleeding obvious.....
The crankcase is vented into the breather system and the fumes are carried to the inlet where they are burnt by the engine. In reality, most of these fumes are blow by gases i.e. exhaust fumes and as such are inert (no oxygen or fuel in them in theory....if all is working correctly).
Now, if you let air in (as well as fumes out) of the crank case system then you effectively create an airleak as air will enter the dipstick, pass through the crankcase, into the breathers (if they are clear) and into the inlet.....and this is unmetered air i.e. it has not passed throough the MAF.
This is likely to result in poor idle and the idel valve working at one end of its travel (more likely to stick).
So, in short....no.....fix the cause, dont just botch round it....
And yes, I am aware that tuned engines often vent to atmosphere (I used to vent the naff old Fiesta pushrod engines the same way because bore wear was so dam huge on them it resulted in the carbs getting clogged up in no time) but, this is much easier to do on a tuned carb engine or one running MAP control EFi....although I do seem to recall this being an MOT failure on post 90's built cars (could be wrong)
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"The crankcase is vented into the breather system and the fumes are carried to the inlet where they are burnt by the engine. In reality, most of these fumes are blow by gases i.e. exhaust fumes and as such are inert (no oxygen or fuel in them in theory....if all is working correctly).
Now, if you let air in (as well as fumes out) of the crank case system then you effectively create an airleak as air will enter the dipstick, pass through the crankcase, into the breathers (if they are clear) and into the inlet.....and this is unmetered air i.e. it has not passed throough the MAF.
This is likely to result in poor idle and the idel valve working at one end of its travel (more likely to stick)."
Yeah, thats a good point! - One Carb conversion coming up!
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Actualy, this is a good post to learn from as many dont appreciate the air leak principle of air in the crankcase....
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Yeah, there's certainly a lot to think about. I'd better stick my dipstick back in I suppose! Who'd have thought dipsticks could be so confusing!
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Yeah, there's certainly a lot to think about. I'd better stick my dipstick back in I suppose! Who'd have thought dipsticks could be so confusing!
I work with a dipstick who is always confused..... :P
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I looked at an Escort a few years ago with a poor idle......the seal on the oil filler had gone and it was very loose, air was getting in and buggering the idle up.
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Just to show how engines are changing new supercharged Jaguar engines run negative not positve crankcase ventilation, if you dont push dipstick infully home the engine will run like a bag of s**t, right through the rev range. I think venting to atmosphere on old tuned engine like pinto's was due to to multi carb set up 1 choke per cylinder on manifold and carb and balancing them with crankcase ventilation would prove very hard also the provision was not put on the inlet manifolds so as not to disrupt fuel swirl through them possible causing fuel to drop off in the manifold reducing power.
But as has been said due to maf sensors now days, adding air into an engine by another source (dipstick hole)would cause running problems.
Also oil is supposed to get dirty this proves its doing its job of collecting dirt and carbon from the engine, which is why replacing it and the filter is so impotant. :y :y
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Just to show how engines are changing new supercharged Jaguar engines run negative not positve crankcase ventilation, if you dont push dipstick infully home the engine will run like a bag of s**t, right through the rev range. I think venting to atmosphere on old tuned engine like pinto's was due to to multi carb set up 1 choke per cylinder on manifold and carb and balancing them with crankcase ventilation would prove very hard also the provision was not put on the inlet manifolds so as not to disrupt fuel swirl through them possible causing fuel to drop off in the manifold reducing power.
But as has been said due to maf sensors now days, adding air into an engine by another source (dipstick hole)would cause running problems.
Also oil is supposed to get dirty this proves its doing its job of collecting dirt and carbon from the engine, which is why replacing it and the filter is so impotant. :y :y
Well, if your filter is impotent, try changing it! ;D ;D ;D
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Well they do say contaminated oil can affect you that way. ;D
I think the christmas Port is starting to work........................ [smiley=beer.gif] [smiley=beer.gif]
Cheers :y