How to change the oil pan gasket in the M110 engine – W123 and W126

This has to be the most common oil leak area except for the valve cover on these engines. The gasket here is not rubber, but made of some sort of compressed fiber and they tend to start leaking after a few years. The leak from the oil pan will make oil spill from the front of the engine and oil will fly pass the whole length of the engine and on to the transmission, making oil seem leaking from everywhere. The MOT inspection might not like it either, although they usually will have more forgiveness towards classic cars. However you should not enjoy leakage from the front of the engine.

The leaking oil pan is usually not enough to drip on the ground while parking only for a day, but is surely noticeable after parking on the same spot over a longer time (like your garage). The M110 engines are notorious for some natural amount of oil consumption while driving, but a leaking oil pan will make this oil consumption seem worse. You should put a habit on inspecting the oil pan gasket for leaks every time doing an oil change. The chances are 100% likely that it needs replacing if you have never done it before.

I have noticed that simply changing the oil pan gasket without the proper procedure will make the oil gasket seem to leak after just a short while. This is usually due to lack of thread sealer on the pan bolts and improper torque. Sometimes the thin oil pan is bent slightly (due to bumping into rocks on a gravel road) and proper sealing is impossible to achieve, then you will need a new oil pan. Replacing the oil pan is something you might need to consider if you see clear scratches on the bottom side or noticeable dents.

The details on the specific oil change procedure for the M110 engine can be found in this article: How to Change Oil and Filter in the M110 Engine

Preparation

You cannot do this procedure without doing an oil change, so try timing it to your next oil change otherwise you will need to replace that new oil of yours.

Parts and supplies:

  • Oil pan gasket
  • Thread sealer (not the same as thread locker)
  • 6.5L oil + oil filter
  • Brake cleaner
  • Lots of shop paper/rags
  • zip ties

Tools:

  • Jack + Jack stands or ramps
  • Socket tools
  • Hex bits
  • Spanners
  • Low range torque wrench
  • Oil drip pan

Procedure

Start with warming up the motor to operating temperature and raise the front of the car for better access. Drain the oil from the oil plug and let it drain until the dripping stops. Then you can start the process of removing the oil pan.

draining engine oil
Draining the engine oil

After the oil is drained you can start loosening the oil pan bolts with a hex socket. There is a lot of them so be patient. And not all of them are the same length! There are a couple of bolts with longer length at the right front corner which also holds a bracket to an oil cooler line.

M110 engine oil pan
Disgusting oil pan with caked oil from leaking gasket.

Take care of holding the pan horizontal when you remove the last bolt, because there is still a lot of oil left in the bottom. Carefully lower it and then pour out the remains. There is most likely some sludge and debris left. Now the time has come to inspect the bottom of the oil pan. The leftovers in the bottom of the oil pan can tell the condition of the engine and if it has been properly maintained.

Bottom of M110 engine oil pan
Bottom content of M110 engine oil pan

A common denominator is that silicone or RTV debris are to be found due over use in valve gasket sealing. I do not blame them since the M110 engine is notorious to leak after a few years, but still this debris can clog the oil pickup and damage the engine. Also the engines tend to leak more if they are not used on a regular basis, sounds funny right? But it is the sad truth. Long time storage of these engines without usage will dry out the seals and the engine will leak more oil.

My engine (the whole car) had been parked for 1,5 years and only started intermittent and not driven. So the oil in the lower oil pan was very sludgy and you can notice that moisture has started building up, which can be seen from the white color. This is not good for lubrication obviously, and was the reason I did this job in the first place.

sludge in bottom of oil pan
Heavy sludge in bottom of oil pan due to long time parking.

Use break cleaner and clean the oil pan thoroughly so it is dust free inside. Also clean the outside so you can notice new leaks id they appear. If you have some small strong neodynium magnets you can attach them in the lower edge of the oil pan, otherwise the filter will catch most of the debris anyway.

Cleaned oil pan for the M110 engine
Cleaned oil pan for the M110 engine.

After the oil pan is cleaned, there is another matter to tend to. Grab the oil pickup strainer and pull it off. It is probably very clogged from debris and gunk, so you better clean it now or never.

Underneath the M110 engine
Underneath the M110 engine. Notice the oil strainer.

Whatever you do do not spray oil cleaner oil solvent into the lower engine since it can damage the rod bearings!!! Use only some paper or cloth and clean off the lower engine housing then pull off the strainer and use brake cleaner on your work bench.

Oil strainer M110 engnne
Very dirty oil strainer indeed.
Dirty oil strainer for M110 engine
Dirty ass oil strainer, must be cleaned! So black you cannot look through it even.
Clean oil strainer M110 engine
Cleaned oil strainer, you can actually see the mesh here.

After cleaning the strainer, put it back into the lower engine and start assembly of the parts! Put on the new flimsy gasket, since it will not stay n place use 3-5 zip-ties to secure it in place for assembly. After mounting the oil pan with some bolts on you can cut the zip ties.

New oil pan gasketf for M110 Engne
New oil pan gasket secured with zip-ties

Prepare the bolts with the thread sealer, start with two bolts, one on each side so the oil pan will stay in place.

Assembly of oil pan M110 engine
Assembly of oil pan. Fasten two bolts then cut the zip ties.
Oil pan assembly M110 engine
Cut and remove zip ties after some oil pan bolts are in

Put thread sealer on each bolt yo inert, all the bolts should be tightened to 11 nm. Remember that the two front right bolts have a different light than the rest due to a bracket with and oil lines.

Long oil pan bolts
Longer oil pan bolts due to oil cooler brackets
Torque oil pan bolts
Torque all oil pan bolts to 11nm. Don’t forget to use thread sealer otherwise they will leak.
M110 engine oil pan
New oil pan gasket installed!

After torque of all the bolts this job is well done. Hopefully it will not leak in a few years, well done!

Robs Out!

How to Change Oil and Filter in the M110 Engine

Changing engine oil is usually an straight forward procedure on most cars, however the location of the oil filter housing for the inline six cylinder M110 engine, makes the job a bit more messy and annoying than necessary. Now these cars with M110 engines are starting to get pretty old, which means more often oil changes with the increased mileage. My 280CE is of now 38 years old and I do regular oil changes at every 5000 km. This might seem often, but the little amount of actual kilometres this car is seeing it is usually only once per year.

If the car is parked for long periods, moisture will build up inside the block and the oil will eventually turn milky white, which can be noticed if opening the oil filler cap. If you are doing the oil change yourself, you will get a clear indication of the health of the engine. This you won’t get at a workshop unless it is a special workshop for classic cars. Who can afford that anyway?

This is an article long overdue, but since I did a lot of work on the W123 laterly the opportunity presented itself. Also got inspired by writing this since I already had an article on changing oil in the big brother M120 engine: https://mercbenz123.com/posts/engine-oil-change-m120-engine-w140-s-class/

More articles on W123 coming up soon too!

Preparation

You will need a few supplies and tools before starting on the job. Also it is best to change the oil when the engine is warm since this will let the oil drain easier. So make sure you take a short spin just before changing the oil. Changing the oil can be done in any season, so no need to wait until summer for this one. Just do it!

Supplies

  • 6.5L Synthetic Motor oil with viscosity for your climate and use: A good all-rounder could be 10w-40.
  • Good quality oil filter. I recommend getting a filter from Mann, since it will come with all new washers and gaskets. https://www.mann-filter.com/en.html
  • Paper towels or rags to clean up oil
  • Brake cleaner

Tools

  • Torque wrench
  • Sockets
  • Oil drip pan
  • Ramps or jack stands

Procedure

Make sure the engine is warm and drive the car upon ramps or raise the front of the car upon jack stands. The car is usually high enough just by itself to drain the oil without raising it up, but in order to reach under to the oil filter, you need the space to crawl under it.

280CE upon ramps
280CE upon ramps for the oil change

Draining the old oil

Normally you would open the oil filter can before draining the oil, but since this will literally spilling oil everywhere, you must drain the oil pan first. Open the oil filler cap to let the oil drain out easier. So grab your cleaned oil drip pan, or dirty if you do not care for inspecting the oil afterwards. It is your call. Grab your trusty 13mm socket and crank open the oil drip plug.

open oil filler cap
Open the oil filler cap before draining oil. Notice the white oil inside the valve cover due to moisture buildup. It is not because of coolant mixing with the oil. This ca has been parked for over a year due to reasons.
Draining oil from the M110 engine
Draining oil from the M110 engine

When the oil have stopped dripping, you can move over to removing the oil filter housing. If you have never seen it, it is a large aluminium canister located underneath the left side on the engine towards the back. See image below:

Oil filter housing location on the M110 engine
Oil filter housing location on the M110 engine. Mine says MANN on it, but it might not be the case for you. It is held in place with a single bolt.

The oil filter is held in place with a single bolt, but be prepared for oil splashing when you start removing it, try balancing the filter into the upright position since it will be completely full with oil. So be prepared to get oil everywhere and keep you mouth closed. After the oil housing is removed, clean the mating surface and the area around.

oil filter removed from M110 engine
Oil filter removed from M110 engine. Clean surfaces and area around.

Replacing oil filter and washers

Pour out the old oil in the filter housing and notice the orientation of the old filter and washers. Take out the oil filter and throw it away. Now clean out the old gunky oil from the oil filter housing. Use some break cleaner and get all that gunk out and dry clean.

Mann Oil filter for the M110 Engine
Old and new filter. Mann filters are high quality and comes with gasket and new washers.

Hopefully your new filter has some new washers in the pack. Replace the lower washer on the oil filter bolt which goes on the outside of the filter housing (this not a copper washer). There is a spring and a spring retainer inside the housing below the filter, keep this in the same orientation before inserting the new filter. Place the new filter with the narrow hole down and the larger hole upwards. The side for up usually has a little handle on it. Do not forget to replace the new rubber gasket around the edge of the filter housing.

If you notice in the oil filter kit that there is an additional large copper washer there with an unusual shape. This washer is for the large bolt which holds the oil pressure relief valve right next to the oil filter housing. However this only needs replacing if you see oil seepage from the area. No need to replace this every oil Change. The torque for this bolt is 41 Nm.

Lower washer on the filter housing bolt
Replace lower washer on the filter housing bolt
Reinstall oil filter housing bolt
Reinstall oil filter housing bolt and place in spring and retainer before inserting the new filter.

Before reinstalling the oil filter, make sure you top up the oil filter completely with new oil. This will reduce the wear at the first startup after the oil change since more oil will be available for circulation right away. This is not possible in all engines, but here there is an opportunity in the M110 engine.

New filter inserted into the oil filter housing
New filter placed into the oil filter housing. As a last step top up the filter with new oil until the brim.

Reinstall the oil filter carefully not trying to spill out the oil from the new filter. Hand tighten so you can feel you do not ruin the threads. To tighten you will need to use a torque wrench and torque it to 35 Nm. This is pretty tight and will prevent leakage through the housing.. Too tight however and you will ruin the filter housing. Use a rag to clean up the filter housing and area completely so you can inspect for oil leaks later.

Reinstalled oil filter on the M110 engine
Reinstalled oil filter and torqued to 35 Nm. Cleaned for residue oil.

Adding new oil

Before pouting in the new oil, you can inspect the old oil and see if there is any residue and metal parts at the bottom of the drip pan. My oil looked alright, not any metal particles or excessive old oil, but because the car have been sitting for so long with only short starts now and then, the oil pan had built up some gunk which came out when draining the oil. Nothing serious, but it was a good time to replace the oil for sure.

Inspecting oil drip pan after oil change
Inspecting the oil drip pan after the oil change. No metal shavings or . Only some gunked up oil residue since the car has been parked for so long.

Then at last replace the copper washer on the oil drain plug bolt and torque it to 41 Nm. Very important to put this plug back before you pour in the new oil. The engine takes 6.5 L of oil, but do not pour in all at once, pour in around 5.5-6 L and start measuring, otherwise you will overfill and have to suck up the extra oil. There is always some old oil taking up some capacity. Remember to use a funnel to avoid unnecessary spills.

When the oil level is up to the minimum mark on the dipstick, pour another 100 ml between each measurement until you are between the minimum and the maximum mark. The correct oil level measurement is only made when the engine is turned off!

Now you can start up the car an let it idle for a few minutes, and while the engine is running, go under the car and check for oil leaks. Inspect the oil filter if it is leaking and the oil drip plug. If everything looks fine, you can lower the car and take it for a short spin.

Go on a short drive just to get the engine up to operating temperature and head back home. Now shut off the engine and re-measure the oil level. If it is between the minimum and the maximum mark, the oil level is good. If the oil level is still under minimum, then add some oil to get it back to the right level. However if the level is above the maximum, you should suck out some of the excessive oil. This might be unnecessary if the level is just slightly above maximum (a few mm), since there is a natural oil usage from the M110 engine and the level will be fine soon anyway.

So DIY you next oil change and become confident in fixing your own cars!

Cheers, Robs out!

Engine oil and filter change on the B-Class 180CDI W245

This is the most modern car which I have written an oil change procedure about. What is the difference here compared to the older cars? To be honest not much! The only difference is the car computer needs to be told that an oil change has happened and the service interval be reset through an OBD2 diagnostics unit. The OBD2 diagnostics unit can be found quite cheap online, but make sure you get one that works for this model with the capability to reset service intervals and fault codes. Since the more basic ones can only read fault codes.

Preparation

Get the necessary parts and oil. Here you need a filter kit, which contains the oil filter element, two rubber gaskets for the filter housing and a new drain plug with a new copper washer. Make sure to not get the cheapest filter you can find, since in my experience the filter element can start to deteriorate if you have long service intervals. This car is rated at 15.000km between oil changes, but I suggest doing them at 10.000km.

Parts:

  • Oil filter kit
  • Oil: Keep at least 6L on hand- The car needs around 5,4-5,8L

Tools:

  • Jack and jack stands
  • Sockets
  • Oil drain pan

I tend to use Castrol’s oil picker to find which oil I need for any car, but if you prefer other brands then I have no objection. Anyway Castrol recommends Edge 0W-30, but this could change if you plan to use the car in more extreme weather conditions. Refer to the owners manual if in doubt.

New engine oil for 180CDI
0W-30 Oil for 180CDI

Procedure

The engine should be at operating temperature to make the draining more effective. So prepare the oil change after a trip, either back from work or after the store.

I’m always a bit shocked when checking the oil on diesels since it’s usually pure black in color after a relatively short time. This car had some time since the last oil change and the level was quite low. This did worry me a bit since the car is at 250.000km already. It is always a good idea to check the bottom of the oil drip pan for sludge and metal shavings to assess the condition of the engine every time when changing the oil. So with that in mind, hoist up the front of the car on jack stands. This car has a very low ground clearance and it’s impossible to access anything under there.

Start with locating the oil filter element in the engine bay. It is on the right side of the car just behind the turbo. It is a bit cumbersome to reach with a socket, but you don’t need any special filter tool to remove it. The access will be much easier if you have a socket with a joint as shown in the picture below. Take out the old oil filter and then move to beneath the car.

Oil filter 180cdi
Oil filter location. Use a socket with a joint to get better access behind the turbo

If you haven’t seen under this car, everything is hidden beneath plastic panels. You have to take at least 2 of the panels off to get access to the oil drain plug. The oil drain plug is also a joker to find, since it’s not where you expect it to be traditionally. It’s at the very rear of the engine far behind the front wheels. It is the most left plug on the engine block (see image).

Oil drain plug location B180CDI
Oil drain plug location on the 180CDI. You need to remove some plastic panels to find it.

I’m not sure what the plastic panels are for except aesthetics and hiding the under body. Also it can trap moisture and rust. They have some very subtle sound dampening effects and can keep some of the dirt away. Maybe it decreases air drag at high speeds? But I didn’t bother to put them back on. They were quite cracked and had a large hole due to the low ground clearance. I prefer seeing whats going underneath the car and the ability to wash off the salt underneath there especially in the winter.

Now that the drain plug is located. Start drain the oil and try not to loose the plug into the pan when opening it. The oil should drain a while until the dripping stops. Then take the new drain plug with the new copper washer and use that to plug the drain. Do not overtighten! Maximum 30Nm.

Draining oil from 180CDI
Draining oil from the 180CDI

After the drain plug is secured. Then it’s time to change the oil filter. The oil filter cap contains two rubber seals, remember to change both of them! Use a rag to clean up inside the oil filter housing for old oil. Mount the new filter onto the oil filter cap and then reinsert the filter cap into the filter housing. Tighten the filter housing to max 25NM. Over tightening will ruin the plastic so be careful.

Oil filter kit parts B180CDI
Oil filter kit parts. Note the two rubber seals, along with new drain plug and washer. See the old filter how deteriorated it is, it’s almost falling apart. Indicating cheap filter and overdue service interval. The new filter is a honeycomb structure and not a cheap paper filter like the old one.

Recheck that you actually secured the oil drain plug under the engine before you start pouring in the new oil. The car needs 5,4L to 5,8L, but there is probably some residue and the actual amount might be a little less. Start by pouring 4,5L. Level the car in order to make a proper reading of the dip stick. Then pour little by little until max level on the dip stick is achieved.

Oil pan with old oil from diesel engine
Inspect oil from the oil pan. Since this is a diesel it’s completely black. This is normal for a diesel. Also use your smell, does it smell really burnt? This could indicate overdue interval. Also check for sludge at the bottom of the pan which can indicate old oil. Check for metal shavings which can indicate bearing wear and poorly maintained engine.

Check the oil drain pan for assessing the health of the engine and if the service interval have been overdue. Luckily there were no sludge or metal shavings from my oil, but it smelt strongly burnt. Which with the low oil level may indicate an overdue oil service interval. Thankfully I switched this oil in this before doing any driving at all after getting it. The engine is quite strong and starts easy without any smoking indicating a healthy engine still. Phew!

Now the last part is to tell the engine computer that an oil change have been done and reset the service interval. The annoying wrench and reminder every time you start the car will then go away. Unfortunately I didn’t take pictures of this process, but it’s really a straight forwards procedure.

  1. Connect the OBD2 to the connector underneath the steering wheel.
  2. Select the car and engine type with manufacturing year
  3. Go on the menu which you can reset oil service interval. These can be different depending on the type of reader, but should be pretty obvious
  4. Set that oil service have been done, this will remove warnings on the dashboard
  5. While you’re at it, do a scan of error codes if any

Now you can do an oil measurement while the key is inserted and the engine is off. You can access this through the interactive computer in the dashboard through the buttons on the steering wheel. The car will then tell you if the level is OK or not.

If everything is OK and no service interval warnings. It’s time to start the engine. While the engine is running. Inspect underneath and see that there are no oil leaks form the drain plug and also check the oil filter housing for leaks. If no leaks, go for a small 5min drive. When back, recheck the dip stick level when engine is off. Refill more oil if necessary. Also recheck for leaks underneath and at the oil filter housing.

Robs out!

Changing Filters on the W245 B-Class 180CDI

There are quite a lot of filters on this car. Diesel fuel filter, air filter, oil filter and pollen filter. I will cover all of them but the oil filter in this article (the oil filter will be addressed in a separate oil change guide). You can buy complete filter kits which include all filters. I recommend doing that to save some hard earned rupies and then changing all of them in one go, they probably are all overdue anyway.

Pollen Filter

Having that dampness and weird smell in the cabin gain? It’s not always a fart. Changing the pollen filter might address the issue. It’s also the most overlooked filter on the car. Many people does not even know it exists. Especially if you have been around older cars which do not have them! There you have the good old fashioned unfiltered atmosphere straight into the cabin.

So where do you find the pollen filter? Start by opening the hood. At the plastic cover above the engine is a narrow plastic lid. Open it and there you will find the filter.

Pollen filter location W245
Say hello to pollen filter

The pollen filter is a flimsy piece of paper which you can easily swap without any tools. Mess this up and you are a clown.

Old vs new pollen filter
Can you spot the old filter?

Well done you completed 1/3.

Air Filter

Time to step it up a notch. Now you will require some actual tools. Some torx bits to be specific. The air filter is located at the top of the engine and you can’t miss it. You have to loosen the plastic cover which is held in place by torx screws all around it. Be careful not to loose the screws into the engine bay and you will never find them again.

Air filter løocation w245
Location of air filter box

You don’t have to loosen the air intake tube going to the turbo. And if you do, it’s important to get the seal completely tight again. Not so easy.

Can you spot the new filter?

Now you have done 2/3, well done. Maybe you’re not a clown after all? Lets step over to the diesel filter.

Diesel Filter

The final and hardest part. Here you will utilize at least a screwdriver. You should also consider getting new hose clamps if the old ones are rotten. In older mechanical diesels injection systems it was a pain to change the filter, since you had to manually pump and bleed the injection system for air after changing filters. Now the car will do this for you with the electronic injection system. To be honest I did zero pre-studying before doing this job and wasn’t 100% sure if this would happen, but it was no issue starting the car afterwards. So no worries!

Locate the diesel filter on the right side of the engine. It should be easy to spot. It’s a canister with two hoses going into it. Note the location of each hose, take a picture so you don’t cross them when installing the new filter.

Diesel filter Mercedes W245
Location of diesel filter.

Unscrew the hoses and beware of diesel pouring out, prepare some paper to catch the spilling diesel. You should be extra careful of spilled diesel here since the exhaust is just beneath. This can catch fire if a lot of diesel is spilled, and I don’t want you to blame me for you burning up your own car.

The filter canister is clamped tight by a couple of spring clamps which you can loosen by hand.

Filter canister secured by two clips.

After installing the new diesel filter. Start the car and inspect closely for diesel leaks. Tighten the clamps if you see seepage. Alternatively the hoses might need replacing if they have started to seep from cracks. Diesel leaks here might cause engine fire and you have now been warned!

If you managed to complete this 3/3 step, you are already at novice DIY level and congratulations! Who said fixing your car was difficult? Hardly need any tools at all.

Robs out!