Engine idle and sound changes with oil cap off !!?!

[AttaBoy]

Hi guys,

Just today after a hot day I decided to check the engine for usuals like oil coolant etc..

Everything is ok, so while the engine idling I took off the oil cap to have a peek through I noticed that the idle changes and the engine sounds funny. Once I put the oil cap back on it went back to normal!!

Is this normal for this to happen?? Reason I ask is because I thought this could mean somethings not right??
Anyway if this something to worry about, then let me know.

By the way it is a VSAcclaim V6 Ecotec.


Thanks in advance..

[Boonz]

your PCV valve might be stuck open.... does it idle higher or lower?? if its higher its sucking in air thru the PCV valve into the T/B

[AttaBoy]

It rev a little higher I think.. not sure, hard to say because the rev needle did not respond or move.

[muttley383]

Since the engine breathing is virtually a closed loop system when you take the oil cap off you are allowing another air feed that will probably alter the idle.

[hsv1987]

nothing to worry about tho ..

[GOTMYN]

I was intrigued in this thread, so I took mine off today to see......

The engine sound/idle, did not change one bit.......
Not even any type of sound came from the filler hole.........

[PaRaDoX]

called a vaccume leak its normal :P

[Garth]

Hi guys,

Just today after a hot day I decided to check the engine for usuals like oil coolant etc..

Everything is ok, so while the engine idling I took off the oil cap to have a peek through I noticed that the idle changes and the engine sounds funny. Once I put the oil cap back on it went back to normal!!

Is this normal for this to happen?? Reason I ask is because I thought this could mean somethings not right??
Anyway if this something to worry about, then let me know.

By the way it is a VSAcclaim V6 Ecotec.


Thanks in advance..

these things run in whats called a closed loop system. when you take of the oil cap it alters the vacume, this alters the way the cars idle and prefrom at speed. there is nothign to worry about, if you take of hte oil cap and it doesnt alterslightly and make a funny sound then there is something wrong.