Removing oil filler cap with engine running?

[wavinwayne]

Will anything bad happen if I do this? I just want to have a peek at how the oil looks in there after the engine has warmed up.
The car is a 2000 VW GTI 1.8L Turbo 4-cyl.

 

[TallPaul]

I don't see where there would be a problem, but I suppose it is possible that a certain PCV setup could have a bad reaction to this. I take the cap off my F150 all the time while running. In fact, Valvoline Synpower Oil Treatment and Maxlife Engine Protector both say to add to running hot engine. So I can't imagine it would hurt.

 

[Gary Allan]

Try it! The worse thing that's going to happen is that the engine will stall (if it has a crankcase vent system like my 78 320i had) or you'll get a little oil coming out of it (have rag in hand). The idle may also go up in some injection systems. Either way ..just lossen the cap and listen to what happens when you start to remove it.

Unless this engine has some "booby trap" element to it ..I can't see how you would do anything beyond making a mess.

 

[ron917]

I tried that once on an old lawnmower, and got a hot oil geyser. What a mess! Probably a lot of blowby on that engine.

 

[Razl]

Actually, you run the risk of losing your BITOG membership if you haven't done this on all of your internal combustible engines.

It's a right of passage

 

[wavinwayne]

I just did it & I must say, I was completely underwhelmed. Oh, well, I've gotta go think up my next question for the BITOGers........

 

[FowVay]

quote:

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Originally posted by Razl:
Actually, you run the risk of losing your BITOG membership if you haven't done this on all of your internal combustible engines.

It's a right of passage

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Exactly!! To be a motor oil freak there are some things that you just have to do once in your life.

Cutting filters open, sniffing oil containers, spraying oil all over garage when you remove the oil cap, etc... it's just part of the club.

 

[Ugly3]

quote:

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Originally posted by ron917:
I tried that once on an old lawnmower, and got a hot oil geyser. What a mess! Probably a lot of blowby on that engine.

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Old mowers had a "splash" oil system, real mess with the cap off.

 

[srivett]

If you can see the rocker arms through the hole you are in for some fun! VW has been known to put plastic covers over the rocker arms for several reasons...they also keep the oil in if you take a peak. They started doing this back around 84 for the gas and diesel engines.

Diesels don't have a throttle plate so they don't care if you open the valve cover.

Steve

 

[kevm14]

quote:

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Originally posted by Ugly3:

quote:

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Originally posted by ron917:
I tried that once on an old lawnmower, and got a hot oil geyser. What a mess! Probably a lot of blowby on that engine.

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Old mowers had a "splash" oil system, real mess with the cap off.

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Is splash lube kinda like controlled/intentional crank windage?

 

[ebaker]

Make sure the cap is not directly above a cam chain.

 

[kenw]

many cars have a splash baffle right under the oil fill cap. My camry in particular.

You can run it all day without splashing any oil out....or at least from the dealer to the house and back to get them to give you a new cap to replace the one they failed to replace after an oil change and which then fell somewhere along the route....

Many confuse it with sludge as it has a rough texture.....

 

[Blokey]

With the 3.5L V6 in my wife's Olds Intrigue, you can see the DOHC chain running when the oil cap is removed. The chain feels quite smooth as it's running too.

 

[srivett]

Yikes! Who is going to turn off the car when the chain drags your hand into the engine?

Steve

 

[TOMBUCK]

Some tight engines will stall out when oil cap is removed, most won't.

Don't forget to put the oil pan plug back in before adding oil during a oil change, it will cost some more $$$ for more oil after U see the mess under the vehicle.

 

[TallPaul]

quote:

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Originally posted by TOMBUCK:
Don't forget to put the oil pan plug back in before adding oil during a oil change, it will cost some more $$$ for more oil after U see the mess under the vehicle.

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And if you only have one vehicle you get to walk to nearest gas station for their oil, which may be twice over priced, twice outdated, and in old dusty/leaky bottles.

 

[Blokey]

quote:

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No, I've never reached in to see how smooth the cam is while in operation. . .

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Ohhh. Go ahead! It won't hurt!!

and I can still play guitar like Yngwie.

 

[moribundman]

The elves might escape.

 

[ekpolk]

quote:

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Originally posted by srivett:
Yikes! Who is going to turn off the car when the chain drags your hand into the engine?

Steve

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Not to worry -- he'll be able to turn it off himself -- after the engine has ripped his finger off and swallowed it into the depths of the chain race.

I've opened the filler on my Nissan/Infiniti 3.5L DOHC V-6, and you can see the intake cam on the driver's side spinning away. You can even see the forward-most lobe doing its thing, making a little splash of oil each time it comes around and "actuates" the valve. Engine continues to idle smoothly when opened without even a hint of an rpm change.

No, I've never reached in to see how smooth the cam is while in operation. . .