M112: Using transmission dipstick to check engine oil level?

[rich1068]

2003 W209 CLK 240

Like many I have to rely on the car telling me when it needs oil. No dipstick. Hate it. This may be fine for tight, new engines but imo not for higher mileage, 20+ year old ones that inevitably do weep a little. I'd really rather not wait until the car tells me it needs an entire litre putting in.

Now, I do have the aftermarket transmission dipstick. With the correct oil level measurement table could I use that? I've found a few mentions of the OE workshop dipstick and also a Baum Tools alternative. I've also found a table for the Baum tool which indicates my engine oil level should be between 148mm and 168mm using their tool. Unclear at this point whether that's low/high or cold/hot, further investigation is required.

Any reason why I shouldn't use my transmission dipstick?

 

[Trickythemerc]

I bought a set of three dipsticks that cover most MB requirements. I think the transmission one may not be much use for the engine, as the plastic bit will have the wrong increments on it and will be at the wrong level in the sump.

 

[markjay]

Mum/Max is just that.

It should read at least Min when cold, and no more than Max when hot.

Best to check the oil level when hot, it should be just below the Max.

 

[rich1068]

I bought a set of three dipsticks that cover most MB requirements. I think the transmission one may not be much use for the engine, as the plastic bit will have the wrong increments on it and will be at the wrong level in the sump.

I thought I could just ignore the markings on the transmission dipstick and simply measure how far the oil travels up the bendy coiled bit.

Mum/Max is just that.

It should read at least Min when cold, and no more than Max when hot.

Best to check the oil level when hot, it should be just below the Max.

Check the level when hot? Really? I've only ever checked engine oil when it's cold and on the level.

 

[Bellow]

I thought I could just ignore the markings on the transmission dipstick and simply measure how far the oil travels up the bendy coiled bit.

'Calibrate' that dipstick ie, when the engine oil is at a known level, notch the stick where the oil comes up to and that's you new engine oil dipstick.

 

[rich1068]

'Calibrate' that dipstick ie, when the engine oil is at a known level, notch the stick where the oil comes up to and that's you new engine oil dipstick.

Had thought of that but unfortunately I'm between oil changes. Last one done when I purchased the car a few months ago and I'd rather not do it again just yet.

 

[Trickythemerc]

If you do buy a dipstick, be aware that some of the cheap ones can drop the plastic bit in the sump.

 

[W1ghty]

I thought I could just ignore the markings on the transmission dipstick and simply measure how far the oil travels up the bendy coiled bit.



Check the level when hot? Really? I've only ever checked engine oil when it's cold and on the level.

Yep , hot , wait 15 mins after driving to allow it to settle ….that’s normally what handbooks suggest

 

[markjay]

I thought I could just ignore the markings on the transmission dipstick and simply measure how far the oil travels up the bendy coiled bit.



Check the level when hot? Really? I've only ever checked engine oil when it's cold and on the level.

It's best to check the engine oil level when hot, the textbook says to do that at the end of a refueling stop i.e. after the engines was switched off for 5-10 minutes or so, giving the oil the opportunity to drain back into the sump and for the oil level to settle (and the surface near the pump will be level ground).

Engines are equally at risk from low oil level as they are from overfilling (Diesel engines more so than petrol), and so checking the oil level when the engine oil is at operating temperatures (95⁰C to 105⁰C, varies by engine type) ensured that the engine won't encounter an overfill situation when the oil gets hot and expands.

On Modern engines, you'll get a warning if the engine oil level goes up too much when it gets hot, to protect the engine.

In fact, some mechanics say that the optimal oil level when hot is right in the middle between the Min and the Max, as an additional safeguard against overfilling.

Personally, I prefer to have the oil level just a smidgen under the Max mark when hot, though you could argue that it's unnecessary with modern engines that consume very little oil between services.

 

[WilliamParsons]

I bought a set of three dipsticks that cover most MB requirements. I think the transmission one may not be much use for the engine, as the plastic bit will have the wrong increments on it and will be at the wrong level in the sump.

You're right, the transmission dipstick may not be suitable for checking engine oil level and should be used only for its intended purpose.

 

[rich1068]

You're right, the transmission dipstick may not be suitable for checking engine oil level and should be used only for its intended purpose.

Fair enough.

Might pop down to see my indy, see what he uses. Can't imagine he relies entirely on the electronic display.

 

[Trickythemerc]

He will probably use the Sealey dipsticks that I use. They are not dear to buy and are of decent quality.