Omega 2.2 petrol 2003 excessive pressure when oil filler cap removed at idle

[Andy A]

Omega 2.2 petrol manual 2003.

When the engine was at idle I had problems taking the oil filler cap off took and when I did get it off I found an excessive amount of air pressure coming out of the rocker cover. So much pressure that when I went to put the cap back on, it would rattle against the opening because of the excessive amount of air pressure pushing past from the cam cover.

I have already replaced all crankcase breather pipes with new and cleaned out throttle body etc, months ago. I did  not have this problem back then.

The engine runs the same as it always has with the exception of only doing 17 mpg around town with the air con off. Way below where it should be for a manual 2,2 petrol.

It does not use any oil or lose any coolant.

Anyone know what might be the problem and what I need to do to fix it?

Thanks

[Andy A]

Omega 2.2 petrol manual 2003.

When the engine was at idle I had problems taking the oil filler cap off took and when I did get it off I found an excessive amount of air pressure coming out of the rocker cover. So much pressure that when I went to put the cap back on, it would rattle against the opening because of the excessive amount of air pressure pushing past from the cam cover.

I have already replaced all crankcase breather pipes with new and cleaned out throttle body etc, months ago. I did  not have this problem back then.

The engine runs the same as it always has with the exception of only doing 17 mpg around town with the air con off. Way below where it should be for a manual 2,2 petrol.

It does not use any oil or lose any coolant.

Anyone know what might be the problem and what I need to do to fix it?

Thanks

Also forgot to mention that if I put my hand over the oil filler hole it makes a similar sound to putting my hand over the exhaust tail pipe. A puff, puff, puff sound with the amount of pressure pushing past the palm of my hand. If that makes any sense.

Thanks

[TheBoy]

I'd be checking the breathers again.

[Andy A]

I'd be checking the breathers again.

Thanks for replying.

I took the three breather pipes off the cam cover and they are clean.

With the engine running I put my thumb over the small pipe from the cam cover that goes to the throttle body and that is sucking air nicely. So the hole in the throttle body is clear.

With the engine running I stuck a thumb over the large hole on the can cover where the breather pipe came off and there was plenty of air coming out of the small hole. I then blocked the small hole and there was plenty of air coming out from the large hole. So no blockage in the cam cover itself.

Is there any other pipes or valves that I need to check?

How much positive pressure should I have coming from the crankcase?

Thanks

[TheBoy]

Is the oil level correct? Not over filled?

[Andy A]

Is the oil level correct? Not over filled?

Yes the oil level is correct, just below the max mark when cold.

[RobG]

Metal pipe entering crankcase clear?

[Andy A]

Metal pipe entering crankcase clear?

If you mean the one at the back on the pass side that connects to the rubber hose from the cam cover and connects to the bottom crankcase then yes it is clear. 

[Steve B]

Omega 2.2 petrol manual 2003.

When the engine was at idle I had problems taking the oil filler cap off took and when I did get it off I found an excessive amount of air pressure coming out of the rocker cover. So much pressure that when I went to put the cap back on, it would rattle against the opening because of the excessive amount of air pressure pushing past from the cam cover.

I have already replaced all crankcase breather pipes with new and cleaned out throttle body etc, months ago. I did  not have this problem back then.

The engine runs the same as it always has with the exception of only doing 17 mpg around town with the air con off. Way below where it should be for a manual 2,2 petrol.

It does not use any oil or lose any coolant.

Anyone know what might be the problem and what I need to do to fix it?

Thanks

That is about normal    And is the flexi pipe on the end of the metal crankcase breather pipe clear

[Andy A]

Omega 2.2 petrol manual 2003.

When the engine was at idle I had problems taking the oil filler cap off took and when I did get it off I found an excessive amount of air pressure coming out of the rocker cover. So much pressure that when I went to put the cap back on, it would rattle against the opening because of the excessive amount of air pressure pushing past from the cam cover.

I have already replaced all crankcase breather pipes with new and cleaned out throttle body etc, months ago. I did  not have this problem back then.

The engine runs the same as it always has with the exception of only doing 17 mpg around town with the air con off. Way below where it should be for a manual 2,2 petrol.

It does not use any oil or lose any coolant.

Anyone know what might be the problem and what I need to do to fix it?

Thanks

That is about normal    And is the flexi pipe on the end of the metal crankcase breather pipe clear

Yes all clear.

Could a blown head gasket cause this?

[4x4]

Oil cap shouldnt rattle when engine is running,check black rubber seal is intact,or replace cap.

[Andy A]

Oil cap shouldnt rattle when engine is running,check black rubber seal is intact,or replace cap.

I was tying to point out that there was so much pressure that it rattled the cap as I was putting it back on. It was fine once fitted. Sorry for any confusion.

[05omegav6]

Once warmed up, what is the temp gauge showing?

[Andy A]

Once warmed up, what is the temp gauge showing?

Just run the engine up to temperature and its around 92 deg max.

[05omegav6]

Once warmed up, what is the temp gauge showing?

Just run the engine up to temperature and its around 92 deg max.

Ok, that sounds pretty normal... lazy thermostat and consequent cool running kills the fuel economy, but, that said with the lower temps lately... does the 2.2 have a separate ECU temp sensor?