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!

Changing the Exhaust pipes in the w123 280CE

There was this annoying hole in the exhaust from last summer. It was the thin sheet under front muffler that had cracked and I had it welded just before the MOT last year. Unfortunately the job was poorly done by the workshop. Another lesson learned on why we should fix our own cars…. The fix ended up costing almost as much as the new pipes, so that was also dumb. On the very day before this summers epic 3000 km road trip of crossing Norway I had to change the entire exhaust system. The pressure was on to get it finished before the trip!

The poorly welded exhaust only got noticeable few weeks before the upcoming road trip, but another car was planned to be used so there was no pressure initially. Then because of circumstances it was decided to use the 280CE after all and the exhaust leak needed to be addressed asap. I decided to swap out all the pipes since some rust was starting to appear in the pipe welds and its easier to just swap the whole thing at once.

I ordered the exhaust less than two weeks before from Germany and it arrived two days before the road trip was starting. Just in time. It only costed me 500$ which I think is a bargain for a classic car! The quality also seems very good as well.

Welded front muffler w123
Poorly welded front muffler. Now junk.

Stage 1 – Getting the car up in the air

You need some good space to wrestle with the large exhaust system under the car. I drove the front of the car up on ramps then lifted the back of the car on jack stands so the whole body was up in the air. I leave the tires on for extra safety and don’t lover the jack either. Also make sure to block the front wheels from rolling on the ramps. I’m a fan of redundancy and here I even placed a couple of jack stands in the front which is kind of unnecessary, but makes it feel somehow safer.

Car on jack stands
Car up in the air. Potentially dangerous and safety should be on your mind. Here I have redundancy by leaving the jack in place and using redundant jack stands. Not recommended to be under the car during an earthquake…

Stage 2 – Removing the old pipes

This is usually the most time consuming job involving rusted fasteners and wrestling with stuck pipes. I was planning to only change the pipes up to the down pipes, since the down pipes are in a really good condition compared to the rest of the exhaust. The issue then become separating the down pipes from the pipes underneath the car.

exhaust clamps
Front exhaust clamps

I started removing the clamps for the front pipes and loosening the system from the transmission mount. Then unhooking the four rubber donuts from the rear muffler. To avoid too much stress on the pipes I placed something under the rear muffler for it to rest on, in this case a tree stub.

rear muffler 280ce
Rear muffler resting on a wood stub

Then the issue with sliding off the exhaust system from the down pipes. They were extremely stuck and you’re not able to twist them since it’s a pair of dual pipes. I was first trying to push them out with putting my entire weight with my legs and kicking. Then I tried heating the outer pipes with a heater torch. After a while struggling with no success and them not moving at all I had to make a drastic decision. I needed to cut them out without damaging the inner down pipes. This would mean the old exhuast would be trash, but it’s old and not worth much anyway.

cutting the exhaust pipes
Cutting the exhaust pipes.

In order to get the old outer pipe off, it needs to be split and then removed. It would be impossible to try pushing them off otherwise. I started by cutting the pipes across a few centimeters before the mating point. Here I used an angle grinder with a thin cutting disk for about half the way, then a manual cutting saw blade for the rest. A bit tedious, but will get the job done. The best would be to use a hack saw which is much safer than an angle grinder and faster than the manual saw. However I don’t have one. Maybe now it’s a time to acquire one?

exhaust pipes cut
Pipes are cut and also a slit is made lengthwise with an angle grinder. Care is taken to not cut all the way through to th einner time.

After the pipes were separated I could remove the old exhaust system. The old stubs of the outer pipes are just as stuck and a slit have to be cut down the middle and care have to taken in order to not damage the inner tubes. The only tool for this is an angle grinder. Watch out for sparks in your face!

Split the pipes
Split the pipes with a sharp punch and drive it in with a hammer. Eventually the metal will split. Use ear protection since it tends to be very loud.

When there is a slit along the length of the pipe I could use a punch with a sharp end and drive it into the slit until it grew larger and eventually the pipe will split along its entire length. Then it was super easy to remove the outer pipe.

Splitting pipes with a punch
Splitting the pipes with a punch. Super easy!

I was surprised of how effective it was, and it was sour that I wasted so much time trying to free the pipes with different methods before I ended up doing this. I was also surprised to find that there was essentially no rust that was binding up the pipes, instead it looked like the metal had expanded into each other and exhaust coke had made this kind of glue between them. Now that the old exhaust was removed, I could mount the new system on.

Stage 3 – Fitting the new pipes

This was the fastest part of the job. It was basically lining up the three exhaust part components, putting on the clamps and tighten them. When the full length is assembled I could slide it under and mount it to the down pipes. Don’t forget to slide on the clamps before joining the exhaust pipes.

Hangers different from old system
Shape of hangers different from the old system.

I found having some help with the assembly part is useful due to the quite heavy and large part that needs to be aligned, but also doable alone if you plan all the moves ahead in time.

The exhaust kit came with four new rubber donut muffler hangers. These rubber hangers crack at an incredibly fast rate due to the heat of the exhaust and they rarely lasts more than 1-2 years before they break.

New exhaust system
New muffler being very shining, almost looks fake.

Stage 4 – Road trip

Luckily I managed to sort it out the evening before and could leave the next day.The road trip went fine and went without issues all the 3000 km. The tail pipes of the new exhaust have a slightly different shape and the heat reaches the rear bumper a bit more making a subtle bluish tint on the chrome which is quite cool.

280CE in Lofoten

I have the habit of doing jobs in hurry lately where I needed to travel shortly afterwards. Unfortunately this introduces a lot of stress and takes the joy out of fixings cars a bit. I need to plan better indeed.

Cheers, Robs out.

How to do a fuel filter change on w123 – Petrol engine

How to change the Fuel filter

So how do you change the fuel filter? It is in theory simple, but in practice it can be quite messy and also tricky to fully access in the rear end fuel delivery system on the w123 chassis. You also need to make sure you have as low fuel as possible or drain the fuel tank dry.

WARNING:
There is a high explosion and fire risk when dealing with petrol fumes, so don’t light up your cigarette and avoid sparks!

Preparation

Make sure you inspect the fuel delivery system, since a lot of parts there might need to be changed along with the fuel filter, and since you are already draining fuel you don’t want to do this again in 2 months. See the older article on How to re-haul the rear fuel delivery system on w123 (gasoline)

Part requirements:

  • New Fuel filter
  • Optional parts:
    • Fuel delivery assembly rubber bushings – I highly recommend to change these
    • Fuel pump
    • Fuel accumulator
    • Fuel hoses
      • Main tank hose
      • High pressure hose
      • Low pressure hoses
    • Fuel hard line and fittings

Tools:

  • Spanners
  • Sockets
  • Hose clamp

Procedure

You need to access the rear end fuel delivery system on the rear right end of the car. It consists of the fuel pump, fuel filter and the fuel accumulator. They are suspended from 4 rubber bushings secured in a weird metal clamp. It is partly hidden behind a plastic cover near the right rear wheel.

Removal

Start by removing the battery, trust me, you dont’ want sparks while working under the car with petrol fumes! And don’t smoke!

Then jack up the rear end of the car up on jack stands and block the front wheels from rolling. As extra safety measure I always leave the jack in raised position on the same side as I will be working.

Remove the rear right wheel and you have better access to the fuel delivery system. Locate the plastic cover which is held by a few screws, use a long thin socket extension to remove these.

Fuel delivery assembly w123

Now you have to drain the fuel from the tank to avoid petrol spills and excessive fumes. This can either be done with using a vacuum pump with a  hose down into the filler neck, or by disconnecting the main hose to the fuel pump. It will also leak fuel from the delivery line to the engine, and this can be blocked from continuously dripping with a hose clamp on the high pressure hose. Make sure the clamp is of high quality with no sharp edges, since a new high pressure hose is quite expensive.

Fuel filter removed
Fuel filter removed. Notice the high pressure hose is clamped.

When the fuel is drained. You can start by loosening the 2 lines that connects to the fuel filter. The left side (from rear) is the high pressure line and the right is the hard line. Notice the position of the two copper washers on the hard line fitting.  A lot more fuel will now drain out from the filter so take care. It is possible to remove the filter from the cage without removing the whole assembly.

Rubber bishings fuel pump w123
Installing new rubber bushings for fuel pump assembly.

If you need to also change the rubber bushings, then change them one by one and you don’t have to take the whole assembly down. Alternatively to get better access you can secure the assembly with zip ties while changing them.

Fuel delivery assembly w123
New bushings installed

Installation

Installation is pretty much reverse of removal, but you have to remember to use the new copper washers that followed with the new filter. Also I found that you need to torque down the screw between the hard line and the filter for it to not leak.

After everything is put together and you have put some fuel in the tank, try to start the car, it should not take long for the engine to fire up after you crank it. The fuel pump is pretty quick pushing fuel through. When the car is running, go back and inspect carefully if fuel is leaking and check for any wetness.

New fuel filter installed on w123
New fuel filter installed.

If it’s dripping or you can see wetness, shut off the car. Tighten the bolts, wipe off the fuel so it’s completely dry and try again. I had to redo this step twice before it was properly sealed, and the leak was indeed between the new copper washers and the hard line. The copper washers will actually start to seal better when exposed to moisture and some small corrosion will start forming in the gaps.

Be sure to check for any wetness under the rear end of your car after you parked it the first times, since leaking fuel is bad for your wallet and is a potential fire hazard.

Cheers, Robs out!

How to change fuel injectors in the M110 engine

Ever felt that the engine is not making as much power as it used to? And that the fuel economy has been slowly decreasing? The first thing you should check is the condition of your injectors. Unless you have a pressure tester for the injectors, you would have to guess out from the age of the injectors. If they are more than 10 years old I would suggest to change them, that said if the injectors are relatively cheap since they vary a lot in price between the models. They are still relatively cheap for the M110 engine. E.g. If you have the rarer M100 engine, it will cost you nearly a new house to buy new injectors!

I will describe how you change the injectors with new ones. Refurbishing the old ones is a bit more cumbersome and it needs a pressure tester which you can clean them with and test for release pressure and spray pattern.

Theory

Changing the fuel injectors is not difficult and you don’t need much preparation except acquiring new injectors, gaskets and o-rings. There are two gaskets per injector you will have to change or you will end up leaking fuel which is expensive. You can change the injectors easily in an afternoon. I also recommend to change the fuel filter at the same time to not clog up your new injectors.

Practice

Removal

Start with opening your hood and disconnecting the battery. Sparks can make explosions from gasoline vapor when you are working with the fuel system, and we don’t want that to happen.

mercedes m110 engine without air filter housing
Remove air filter housing to gain access

Remove the air filter housing to get access to the fuel delivery system.

The four front injectors you can now access without removing more stuff, but to gain access for the last two, you have to remove throttle linkages, fuel hard lines and a fuel regulator. We’ll come to that later.

Two and two injectors are held in place by a single metal plate, to remove the metal plate loosen the injector hard lines first. The injector hard lines should not sit on very hard unless they corroded over time or they have been over tightened. Use two spanners, one 14mm to loose the line nut and one 12mm on the injector itself to to keep it from rotating.

fuel injector removal
Loosen fuel injector hard lines with two spanners.

When two hard lines are loosened you can bend them a little to the side to get more access and then remove the injector hold-down plate.

injector removal
Loosen the injector hold down plate

After the plate is removed you can pull out the injectors with you fingers, they sit loose in there. The injector housing will be left, This plastic housing you can just pull out straight too, but be warned, do not use excessive force and pull only the housing straight out with you fingers, don’t use tools or you might damage it. It most likely have become quite brittle by heat over the years. If they are in such a bad condition they are cracked, you have to replace them.

Most likely some of the injector housing gaskets do not come out with the housing, but is still sitting in the injector hole, use a small flat screwdriver and pry it carefully out.

After removing the first four injectors, the two back injectors are left, now the big job starts. See in the picture below that these things blocks access to the fuel injectors.

fuel injector access
Throttle linkage, hard lines, fuel stuff blocking access to the injectors.

Start with removing the throttle linkage. Remove the pin and the c-clip along the ball joint. I use a wide flat screwdriver to pry the ball joints off. Remove some more linkages and then you are ready to remove the regulator.

throttle link removal
Remove the throttle linkage.

Warning:
Get a small collecting can of some sorts and tilt it towards the injector line shown in the picture below. Loosen it and fuel with shoot out with high pressure. Wait until the fuel stops flowing, then loosen the second fuel line connected to the regulator.

fuel line disassembly
Fuel will shoot out when you loosen this line so be prepared with a can of some sort.

Also loosen the vacuum lines before removing the fuel regulator, it is fastened to a bracket with two small bolts.

removing fuel regulator m110
Unbolt the fuel regulator.

Now you should have clear access to the last two injectors.

fuel injector removal M110
Clear access for the last two injectors.

Inspection

Now is the time to inspect the old injectors and look at those old brittle gaskets. It is a reason why your car was using excessive fuel…

injector o-rings
New vs. old, looks can deceive.

My old gaskets were super hard, especially the round outer ones. No wonder why there was a lot of dirt around the injector area by the engine, they have probably been leaking a while. This job should have been done years ago. I didn’t notice it when the engine performance still was very good, but obviously not optimal when looking at this leaking issue. The old injectors I don’t even bother testing, I will just throw the old ones and put in new ones.

brittle old injector o-ring
Just look how brittle the old injector o-rings were. They must have given little sealing when they are hard as rock!

Assembly

This is how you should assemble the injector with the gaskets:

  1. Pop on the big rubber gasket on the injector itself.
  2. Pop on the little rubber ring on the injector plastic holder.
  3. Pop the injector holder into the engine block until you hear and feel a nice pop.
  4. Slide all the injectors into the holders. Put the hold-down plates over them and tighten.

injector assembly M110 engine
Injector assembly

The injectors will now have a good seal and no fuel will leak. It is also a good idea to clean up the area around the injector holes in the engine before assembly. Also try to be super clean with the new injectors, keeping the plastic cups on as long as possible before fitting them.

No you also have the perfect opportunity to lubricate all the throttle linkages, such as the pivot points and ball joints, I know they have been neglected for years and we are all guilty as charged. However now is the perfect opportunity for redemption. Remove all the linkages and pivot plates, clean them and apply new synthetic grease that will last a while and hold up to water and heat from the engine.

When everything is bolted back together, there is no such thing as dreadful bleeding like in a diesel. Just crank the engine over a few times and the engine should start, it will run rough for a little while until the pressure have settled, and you might experience hard start the first couple of times before the first drive. This is the time when you realize if the electric fuel pump needs replacement or not, mine is some years old and still going strong, although it have been replaced a couple of times the last 15 years.

Cheers, Robs out!