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DIY Change The Oil Pan On a 1979 - 83 Mercedes 300D

Picture of DIY Change The Oil Pan On a 1979 - 83 Mercedes 300D
This instructable is how to on changing the oil pan and or the oil pan gasket.  there are a few reasons you why you would have to change one or both of these things. One being, not leaving oily patches where ever you might stop. Another may be the environment or spending less on oil.  this should also be done in conjunction with an oil change. And as it happens, I have done an instructable for that too.  Also do it when the engine is cold. there is little point in burning your self.

The reason you may have a leaky oil pan is simple. your car is 32 years old and it has a few dings in the pan. Which warps is, so there is no longer a tight seal. Secondly, the gasket is 32 years old. But if your reading this you already know these things, and just need a few tips to get the job done.

One of the side effects is improved performance dont you know.I gained a noticeable amount of extratra "pep" or a "few more scolded cats under the hood" after replacing the pan....

Do not under estimate how dirty this job is or how long it will take. Start it in the morning just in case something goes horribly wrong. like you accidentally fold the gasket or something. Some sites on the web say it takes no more than one hour, but thats if your have done it before.  It is a simple job, but as you will see, sometimes the car will through a monkey into the blender. If you know what I mean....
 
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Step 1: Tools

Ratchet driver,
Driver extension, 
13mm socket,
5mm Hex socket, 
6mm Hex socket,
Torch wrench (I got mine on the day from Kragens for $9.99, works good)
A 3/8 to 1/4 converter to go from the torch wrench to you Hex, (if you need one) 
Jack stands or a pile of 4x12s ( I used 4x12 railway sleepers until my neighbour saw me and was so shocked that he lent me his stands).
Oil catcher thing -- 4 litres plus , 
Disposable gloves -- Not a requirement, but useful.
Paper towels
Old cardboard boxes (to lay on) 

***WARNING***
All Mercedes  are in metric! Using imperial sockets or wrenches may work (sort of) but you'll just round the nuts off. And no one... NO ONE wants round nuts. 

These will do and they are cheap. http://www.amazon.com/Neiko-7-Piece-8-Inch-Socket-Metric/dp/B000IQNMQU/ref=pd_bxgy_hi_img_c


Step 2: Parts

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Order everything off the internet. It's SOOOOOO much cheaper that way.  I got all the stuff I needed from two places. Rock Auto and Parts Geeks ( dont fall for their Parts geeks phony attempts to con you out of all your particulars to get free shipping and money. They wanted everything down to the size of my undies AND my credit card number).

You'll need:
Oil Pan 
Oil pan gasket 
Oil filter
Oil

Step 3: Remove Oil Filter

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Use a 13mm socket and extension to remove the two nuts on the oil filter casing. Have a rag or bowl thing to catch the drips from the oil filter as you remove it. 

This is done so all the oil will drain out quickly 

***WARNING*** 

If your car is anything like mine or just about any older mercs, the vacuum lines are old, brittle and the rubber connectors hard and fragile. So it is a good idea to note the configuration or take a pic of them. But be sure to hold them out of the way as you remove the filter. One time at band camp, I knocked the vacuum lines off at the very spot you'll be working in. The car started alright, but I couldn't turn it off again with the key. It took us for ages to figure out the proper combination. It was like trying to crack a wall safe while suspended from the celing...or something.

Step 4: Time To Play Car Jenga

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Jack the car up and chuck the bits of wood under it.
Use the 13mm socket or a wrench to remover the oil pan plug. Oh and put the thing you plan to catch the oil in under the plug hole. 

Let the oil drain as long as posible.  You can put the plug back in to stop it dripping on your head.

Step 5: Removal

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On the back edge of the pan is the sway bar thingy that obscures several of the hex nuts. By removing the nut it will allow you to move the bar out of the way.  This bracket is not on every model.

Starting at the drain hole start unscrewing the hex nut in clockwise direction. It is a good idea to keep them in the order for the replacement since some are longer than others.

Step 6: Clean and Replace

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Take care to clean the rim until it shines like a pin. 
Position the gasket on the new pan and hold in place with a hex nut. 
Finger tighten the hex nut to hold the pan in place 
Lightly tighten/finger tighten the hex nuts ensuring that you replace the nuts in the same order they were removed.
Lightly tighten the nuts with the ratchet and 5mm hex socket IN A STAR PATTERN.

***WARNING WILL ROBERTSON, WARNING***
 
If you dont tighten in a star patten you WILL warp the pan and you will be in the same position you were in at the start. leaking oil.... and $36.94

Tighten to 11nm or 10 fp (foot pounds) with the torch wrench.  Put in the drain plug while you are here.
Drop the car and replace the oil. 

***Warning***

Because you have drained all the oil out of the oil lines as well as the pan, it will take more oil than you might supect to get it back to proper levels.  Pour one of your oil packs in and wait for it to settle.  

Start the car for 10-15 secs.  Check the dip stick and if it's low stop the car and add oil.

Check for leaks and good oil pressure. and off you go, slightly greener than before.  


userhck3 years ago
Great instructable. Only one thing though, I believe it is "Will Robinson"