W209 2004 2.7 CDI oil dipstick tube - Does it act as a breather?

[236572J]

Hi, I am about to re fit the inlet manifold on my car. The oil dipstick tube runs between one of the branches in the manifold. The car doesn't actually have a dipstick fitted - only the tube. When I service the car, I measure the amount of oil that comes out and match that with the same amount of new oil to be replaced. The dip stick is a "Mercedes Special Tool".
When trying to remove it - when detaching the inlet manifold, it fouled the starter motor and made removing one of the inlet manifold screws very difficult.
My question to the learned members of the forum is, is the tube necessary? Does it provide any element of crank case breathing? I know that there is a crank case breather on the top of the cam cover. If I was to cap the dipstick hole on the engine case, would this cause any problem, please? It would certainly make refitting the inlet manifold easier! Thank you in advance for any advice you can give.

 

[umblecumbuz]

When a dipstick is fitted in the tube, it basically seals the top, so no practical crankcase breathing occurs.
Dipsticks are not difficult to obtain.
The potential danger of simply refilling with the same amount of oil extracted each time is the obvious one of not getting the level right - an error that will increase with each oil change.
I seem to remember that the dipstick tube is an interference fit in its drilling, and you should therefore be able to remove the tube and refit it after you have installed the inlet manifold.

 

[ajlsl600]

I very much doubt it has any breather function.I believe its only there as an aid to servicing at the dealers. Otherwise I suspect it would already be capped.you can buy.make a dipstick . I would get some flex curtain net piping at b and q and mark that at correct level from the bottom of sump.did this on my clk W208 trans Then benz screwed that plan with the daft idea of today.just makin things more aggro for diy.bizzare as my 2013 om651 actually HAS a dipstick...

 

[236572J]

I very much doubt it has any breather function.I believe its only there as an aid to servicing at the dealers. Otherwise I suspect it would already be capped.you can buy.make a dipstick . I would get some flex curtain net piping at b and q and mark that at correct level from the bottom of sump.did this on my clk W208 trans Then benz screwed that plan with the daft idea of today.just makin things more aggro for diy.bizzare as my 2013 om651 actually HAS a dipstick

When a dipstick is fitted in the tube, it basically seals the top, so no practical crankcase breathing occurs.
Dipsticks are not difficult to obtain.
The potential danger of simply refilling with the same amount of oil extracted each time is the obvious one of not getting the level right - an error that will increase with each oil change.
I seem to remember that the dipstick tube is an interference fit in its drilling, and you should therefore be able to remove the tube and refit it after you have installed the inlet manifold.

Thank you very much for your replies. It is frustrating not having the dipstick fitted. I check the level with the electronic system so I am careful to maintain an acceptable level of oil.
I can lift the tube about 10 cm when fitted between the inlet manifold before it hits the starter. I guess I may just have live with it being awkward!

 

[236572J]

I very much doubt it has any breather function.I believe its only there as an aid to servicing at the dealers. Otherwise I suspect it would already be capped.you can buy.make a dipstick . I would get some flex curtain net piping at b and q and mark that at correct level from the bottom of sump.did this on my clk W208 trans Then benz screwed that plan with the daft idea of today.just makin things more aggro for diy.bizzare as my 2013 om651 actually HAS a dipstick...

Thank you for taking time to reply. Yes, Im sure that the tube is only for the dealer. The certainly make it expensive to buy if you want a "real" one! Thanks for the advice.

 

[umblecumbuz]

Ebay - about £8. Several sellers on there.

 

[mioba]

Get the calibrated stick off ebay. It will be provided with a sheet for the correct level for your car.
dont get me wrong but capping it off totally questions basic maintenance.
I got a stick off ebay, was about 10 quid.
make sure you get engine stick - red, i think tranny are blue. i think machine mart also do them.

As for it being a breather, no. simply too little force holding it down otherwise it go flying in the sky.

 

[236572J]

Ebay - about £8. Several sellers on there.

Gosh! Really? Last time I looked they were about £80 aftermarket. Thanks.

 

[236572J]

Get the calibrated stick off ebay. It will be provided with a sheet for the correct level for your car.
dont get me wrong but capping it off totally questions basic maintenance.
I got a stick off ebay, was about 10 quid.
make sure you get engine stick - red, i think tranny are blue. i think machine mart also do them

Thank you. I appreciate it. I do the maintenance myself and I am very careful about when and how much. But a dipstick would make it so much easier.

 

[mioba]

Get the calibrated stick off ebay. It will be provided with a sheet for the correct level for your car.
dont get me wrong but capping it off totally questions basic maintenance.
I got stick off ebay, was about 15 quid.

Thank you. I appreciate it. I do the maintenance myself and I am very careful about when and how much. But a dipstick would make it so much easier.

Just to be clear. the sticks of ebay - oil level measuring workshop stick are not be left in the car. they are a meauring stick only. dip, measure and then recap with the red cap. hang the measuring stick somewhere in the garage they are pretty long and MB use them in the workshops for many cars of the era where there was no proper dipsticks.

you can also accuratly measure the level electronically. 5 mins after shutdown. key in position 2, 3 times press R, and flick through menu and the sensors read oil level. a very reliable system

 

[236572J]

Just to be clear. the sticks of ebay - oil level measuring workshop stick are not be left in the car. they are a meauring stick only. dip, measure and then recap with the red cap. hang the measuring stick somewhere in the garage they are pretty long and MB use them in the workshops for many cars of the era where there was no proper dipsticks.

you can also accuratly measure the level electronically. 5 mins after shutdown. key in position 2, 3 times press R, and flick through menu and the sensors read oil level. a very reliable system

Yes, I certainly know how to measure the oil electronically although mine takes much more than an hour to actually measure after draining and refilling. However I really appreciate your advice, especially about not leaving it in the tube.

 

[ajlsl600]

Thank you. I appreciate it. I do the maintenance myself and I am very careful about when and how much. But a dipstick would make it so much easier.

Just another. Issue made harder by the maker. Replaced with something.more expensive and far far more likely to fail.!!.now,WHY would maker want to do that ?! Pretty sure I know...

 

[236572J]

Just to be clear. the sticks of ebay - oil level measuring workshop stick are not be left in the car. they are a meauring stick only. dip, measure and then recap with the red cap. hang the measuring stick somewhere in the garage they are pretty long and MB use them in the workshops for many cars of the era where there was no proper dipsticks.

you can also accuratly measure the level electronically. 5 mins after shutdown. key in position 2, 3 times press R, and flick through menu and the sensors read oil level. a very reliable system

Hi Mioba, Actually re reading your advice for the electronic system, that isn't how I do it but next time I will try the method that you say. At the moment I just press the "to the right" arrow once on the left side top of steering wheel with the ignition on.

 

[236572J]

Just another. Issue made harder by the maker. Replaced with something.more expensive and far far more likely to fail.!!.now,WHY would maker want to do that ?! Pretty sure I know...

Me too!!