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[JoeRadosavljevich]

Well since this is not an urgent matter rather thoughts exchange I think this is the right place.

Well my '94 saloon has developed an engine knock But there are some funny facts about it.
-it lasts for the past 3 and a half years since I bought it and it was present while I was considering buying it
- or 4000 miles (more than 5 000 km)
-it does not happen when the engine is below operating temp
- it does happen ONLY in between 2.500 and 3.000 revolutions
-I can rev it in red line and not a sound but when the revs rise past 2.500 rpm there is sort of very distant, very muffled metal to metal sound, like hammer to nail sound it sounds like it is not up here but down there, if you know what I mean
-other than that there is nothing wrong with it
-when I give it some quick slam on the gas pedal there is no knock. Only when I rev it slowly

So, what do you think?

[simON73]

it can be due to:

-   an increased gap between the rocker and the valve stem or the wear of these parts, inaccurate adjustment of the gap during engine assembly.
-   perhaps there is a large main bearings wear. Another symptom is the reduction of oil pressure in the engine lubrication system. How to fix? It is necessary to replace the main bearing shells.
-   connecting rod bearings worn. So they should be replaced.
-   the increased gap between the pistons and cylinders. You need to replace worn parts with the new standard size
-   early ignition or the increase of the gap between the piston pins and con rod bushings in the piston boss

[Kevin Wood]

It could just be a lifter getting tired, or nothing to worry about at all. It's just so difficult to diagnose odd sounds over the internet.

How many miles has the engine done, and has it had a decent service history?

All Omega engines are pretty robust and go for high mileages before you get any problems other than the odd hydraulic lifter that's sticky. You can get an oil additive that sometimes helps fee up sticking lifters.

[baggers]

From description, would guess at lifter.

[JoeRadosavljevich]

The world needs you, people. You are the best-est- .

[JoeRadosavljevich]

Now that the glorification part is over and some great people were curios I feel like I should respond.

There are a few miles below 222k kilometers on the clock. I believe it to be correct based on this car's temp gauge problem described here when I bought it. When I removed the instrument clusters it all seemed factory labeled, dusty & intact. You know, no finger prints and such. If that's any indication....

Back to car's engine. Well since the service history is absolutely non existent and oil was missing from the dipstick when I bought it I suppose it suffered bad treatment. Mr. Wood (pardon me if you are younger) is right, these engines are solid. It doesn't burn oil other than a typical puff of blueish smoke on first start up, oil is black as sin, consumes no water and it starts on every turn of the key. Always dependable.

Lifters can be heard only after it has been sitting for more than a week and only for a second or two.   When it runs on LPG I can do a coin test on it. It does misfire on petrol.

What irks me is that I am unable to find a knowledgeable mechanic for this car. They all claim they know these engines but when I asked for a price for the thing that seals crankshaft/camshaft from oil leakage they stated that it's a one day job since the rad should be removed for such procedure. I shut the door. All I am left with is the courtesy of you people.   

[05omegav6]

It's probably a good days work to do, but removing the radiator is an hour of that day wasted...

Basically it's a cambelt change and cam cover change rolled into one with a couple of extra steps halfway through

Rear crankshaft seal is another day to itself as it's a gearbox out job...

[ted_one]

Possible idea......road trip over to the UK in May....come to the High Wycombe meet, and pick the brains of some of the best Omega enthusiasts/mechanics available,and depending on the outcome you could possibly get the car into Serek's place for some TLC if needed,or if it's a DIY job you will be able go home with the knowledge from the guys that you have met, AND you will also be the first non UK member/car to attend the High Wycombe meet....go on you know it makes sense

[JoeRadosavljevich]

It's probably a good days work to do, but removing the radiator is an hour of that day wasted...

Basically it's a cambelt change and cam cover change rolled into one with a couple of extra steps halfway through

Rear crankshaft seal is another day to itself as it's a gearbox out job...

That's what I said but didn't know that there was a rear crankshaft seal. Oh, another day another lesson.

[JoeRadosavljevich]

Possible idea......road trip over to the UK in May....come to the High Wycombe meet, and pick the brains of some of the best Omega enthusiasts/mechanics available,and depending on the outcome you could possibly get the car into Serek's place for some TLC if needed,or if it's a DIY job you will be able go home with the knowledge from the guys that you have met, AND you will also be the first non UK member/car to attend the High Wycombe meet....go on you know it makes sense

Roadtrip to UK is definitely on my mind and money is in the way. Don't know if I will make it to the High Wycombe meet

[Andy H]

V6 Omegas that have suffered long intervals between oil changes are prone to the oil pick up becoming blocked.

The symptoms can be difficult to identify because at low rpm the oil pump can pull enough oil through the strainer to lubricate the bearings (and operate the oil pressure switch )

At higher RPM the oil pump struggles to pull enough oil through the strainer. There might be enough oil pressure to operate the oil pressure switch but the bearings need more oil flow than they do at idle and the pump is unable to provide it.

If you haven't done so before I would recommend that you drop the oil pan and clean all the gunge out of the sump and oil pick up.