Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Abiton on 30 November 2007, 16:16:50
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Help please :).
Last Sunday evening we noticed a subtle ticking noise coming from the engine bay, only present when putting one's foot down from low revs, silent at cruise. (Engine at full operating temp)
Took it out midweek to assess, and it was still there, but seemed quieter, you had to listen quite hard to hear it, under the same circumstances.
G/f said yesterday that it's getting worse again, so I just popped out and started it (was still quite warm), bonnet up. Nasty metallic clicking, quite loud, coming from front end of rocker cover, goes away with a little rev, but comes back at idle.
Oil/filter changed not more than a month ago, genuine materials. No EML.
What's that all about then folks?? ::) :'( TIA.
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Noisy tappet?
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Sounds like a noisy cam follower it. Not to much to worry about as long as it doesn't get too noisy.
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Is a cam follower a posh tappet?
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Sounds like a noisy cam follower it. Not to much to worry about as long as it doesn't get too noisy.
Thanks guys, had a feeling it might be sth like that, but I think it's too noisy right now. Fixable by a mechanical numptie? Or not too pricey at Vx/other garage?
Doesn't sound like it's going to sort itself out unfortunately.
Edit: Just thought, a relevant detail may be that the odometer says 141000 approx.
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Fixable by a mechanical numptie? Or not too pricey at Vx/other garage?
This job requires removal of the Camshafts, which requires removal of the Camshaft
Sprockets, which requires removal of the Camshaft Belt.
So unless you are confident of tackling these jobs, you're looking to paying
to have it done or living with it. (And it won't be cheap)
If you do get it done, get it done by someone you know and trust. The Camshaft Bearing
Caps are matched to the Cylinder Head and to their position on the Cylinder Head.
They must be removed and refitted in a set sequence and manner. If whoever does
it screws it up and damages/ breaks a cap, or puts them back in the wrong position,
then you're talking a new Cylinder Head.
Seeing as you say the tapping stops when you rev away from idle, this would indicate
that the increasing oil pressure is filling the cam follower, expanding it, and closing the
gap. So it may be worth looking to increase your oil pressure at idle.
Another oil and filter change may do this. If not, then maybe an oil pressure relief valve
replacement.
I've never replaced this, but I believe it can be done without dismantling the engine.
The experts on here should be able to give you pointers on this.
Hope this gives some help in deciding which course of action you may wish to take.
Even if it's only turning up the radio volume at idle. :)
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Before you go down that route try the stuff from halfords that frees sticky followers. then change engine oil and filter.
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_203145_langId_-1_CarSelectorCatalogId__CarSelectorGroupId__varient__categoryId_58757_crumb_33958-31345-58755_parentcategoryrn_58757
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Does the oil light ever come on at idle? Just wondering if low oil pressure is the problem?
Then again, all of them would be complaining in that instance.
Might also be worth checking the cam belt and tensioners just in case a tensioner is breaking up or the belt has jumped and is causing light valve to piston contact. When was the belt last changed?
Likelihood is it's just a noisy tappet but you can't be too careful.
Kevin
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Never seen an oil light, cam belt/water pump were done by Vx in August approx.
The noise was sufficiently alarming earlier to wonder if there was something drastic going on, but I don't know that it would come and go if it was valve timing related, would it? :-/
Might give mahony's recommendation a go, unless anyone's got anything bad to say about that stuff?
May drive it round to Vx in the morning and slip a chimp a fiver to have a listen. Unless there's anyone on OOF near me with 'practiced ears'. The tappets on my 150K mk2 Golf make a similar noise on the occasional cold-start, but only for 2 seconds, so I guess that's just oil lack, rather than 'stickage'. Don't know what a sticking one sounds like, or perhaps now I do? :'(
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The other possibility is an exhaust manifold blow but if it goes away above idle I'd say it's a tappet that quietens as oil pressure picks up.
Kevin
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This sounds like the same noise that's started coming from the top of my engine in the last couple of weeks or so (sounds like it's coming from the driver's side bank), but the rate of ticking increases with the RPM? If I didn't know better (and if it was a F*0rd), I'd say it was camshaft bearings?? Anyone any suggestions?? :-/
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Gold star for Kevin Wood and the exhaust theory. Just took it round to Vx and the nice Parts Man came out to have a listen. Without any hesitation (barring a quick 'squirt' on the throttle cable) he pronounced "Exhaust manifold gasket, or cracked manifold".
Realising now that my observation about it going away with a little rev was severely flawed, as I moved into the driver's seat for this, which meant I couldn't hear what was happening locally.
Anyway, had a little look at whether I had the tools and skills to get the heatshield off (probably not!) when I observed...
(http://i219.photobucket.com/albums/cc138/EZ_Pete/100_0568.jpg)
Errrm, there should be a stud/nut in that hole, right? It's looking like my top-hose replacement may have been "closing the stable door after the horse has bolted", as it looks like it may have been spraying coolant at that stud... :'(. In my defence, we haven't had the car all that long.
Could be almost accesible enough to drill/tap/replace in situ, I suppose, but presumably the gasket will be be U/S now. Oh dear.
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Ah, you're not the first to go down this route on a 4 pot Omega. A common problem, along with cracking of the manifold itself. :(
I believe they have been repaired in-situ. I'm not very familiar with them myself but I know there are a few guys on here who are so I'm sure someone'll be along with some advice.
Kevin
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Ah, you're not the first to go down this route on a 4 pot Omega. A common problem, along with cracking of the manifold itself. :(
I believe they have been repaired in-situ. I'm not very familiar with them myself but I know there are a few guys on here who are so I'm sure someone'll be along with some advice.
Kevin
I'd really appreciate any suggestions on dealing with this please. Sorry to bump, but I'm scared about what this is going to cost :(.
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Saw your picture of the broken stud......from the angle, I'm assuming its on a 4 cylinder unit ?
I've got exactly the same problem but on a V6 and I can only just get my hand in to feel the stud had sheared.....it was still in place. I get the fut fut noise but it reduces a lot as the engine warms up. Do you know if anyone has a solution other than taking the engine out and drilling the stud to replace it ?
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I'm not sure what access there is on a 4 cylinder. I remember Taxi Driver had / has the same issue on a 4 pot. Not sure if it's been tackled yet.
I guess the first step would be to remove the manifold (these are prone to cracking, by the way, so give it a once-over) and see how much stud there is protruding. Then regularly drown it in plus gas for a few days before tying to remove it, if there's enough protruding. Maybe there'll be enough length to weld a nut on the end and get it out that way?
Failing that, try a reverse drill bit style extractor? If that didn't work I think I'd be off to an expert with the head to drill it, bearing in mind the alloy head is a lot softer than the stud. :o
Kevin
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I always opt to pop the head off - I'm not confident space wise to tap in situ - especially on V6.
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Taylorc, yep, 4-pot.
I'm going to have a try at sorting this in-situ with assistance from a workmate with a workshop and lots of experience. Thinking about making up a drill guide that fits into the hole in the manifold, if I can get a better photo that suggests the stud is actually central w.r.t. that hole. Prodding a toothpick in there suggests that it's broken close to flush with the head... :'(. Some sort of right-angle drill gadget looks to be needed tbh, no room for even the smallest of pistol-drills as far as I can see.
Just had the heatshield off to have a look at some of the other studs/nuts, and to look for cracks, studs nuts on topside don't look too badly corroded, one possible tiny crack, need to clean it up a bit and look in daylight.
So James, you make this "popping the head off" sound like a breeze, care to PM me your phone number? ;)
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Well I finally got there...
Got the manifold off without significant dramas, the stud had broken about 2mm sub-flush at an angle of about 20°. Tried drilling and 'easy-out' type thing, without any luck, really didn't want to give it heaps as I didn't want a snapped off easy-out in there.
Ended up making a drill guide out of a thick steel plate that fitted over the nearest two good (new) studs and had a 6.8mm hole through a hardened bush in the position required to drill. Worked unbelievably well :o. Bit of careful work with a tap and I had a new stud in the original thread.
Couldn't have done it without a very diddy mains drill loaned by Stan, our lovely old neighbour.
New studs and gaskets all round, obviously. Total for parts and one or two tools bought <£50, I'm very chuffed, as is my girlfriend ;D.
Changed my theory about the cause of the stud failure, though still coolant related. Rather than the top-hose connection leaking/squirting, I'm fairly sure it was actually the thermostat housing-to-head where the leak was, new seal in there now.
Merry Christmas one and all, and thanks for the advice. :y
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Well done!!! Before reading all the threads, I thought you were heading up a blind alley and were going to have to get the head off to do the job.
Mine had done the same, which has now been sorted properly. Previously, though, someone had re-drilled in situ, but not straight!!! AND had drilled too far so that the hole was visible on the face of the head (when it was removed due to head gasket failure).
This is obviously a weak point on these engines (along with a few othe weak points?????).
Just as a point of intreset, my head just been welded to repair corroded waterways and skimmed at a local workshop. They did a great job, included reseating the valves, and replacing valve rubbers and replacing two broken studs. All for £220 inc. VAT.
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I believe Taxi Driver here had similar problem....
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Of course the drilling jig will be made available to any members with a problem with the same stud. It may well fit in other positions too, as I think there are some symmetries in the layout of the studs.