190SL oil change troubles

[hgupta]

I tried to change my oil for the first time today, and I can't seem to figure out how to get the oil filter housing out of the car. I was able to unbolt it, but there was not enough clearance to pull it down from beneath the car or to pull it up from above. I was able to turn the housing on its side to exchange filters, but I would really like to see if any gunk has built up in the housing. The car was on ramps instead of on jacks. Does that make a difference?Also, where is the primary filter (the metal one)located? I could only find the fine filter. Unfortunately, an oil and fine filter change did not fix my low oil pressure problem (pressure is only low after the car warms up). Is removing the oil pan to check the oil pump as simple as removing the bolts holding it up from underneath?

[bstreep]

Hemant,
If you turn the wheels all the way one direction (left? I can't remember), it makes it easier to get the housing out AND you can pull it straight down without spilling anything. I don't lift the car when changing oil. However, I've gotten it out when the wheels were straight, from above, spilling oil everywhere! While you have it out, check and make sure the housing has a little rubber thing at the bottom (I'm not sure on this, Jim Villers claims it's supposed to be there, and I don't remember seeing it on mine - I'll check next time I change the oil). Also, make sure that you have only 1 gasket (I found 2 on mine).

Oil Pan: Theoretically I'm told it can't be done without pulling the engine. My mechanic did it but did a little frame work while doing it... Either Jim or Robby's had theirs off, so they may be able to tell you.

As for the filter. I believe that there is only the paper insert. Older style filters had a screen, but all of the replacements are paper with a screen on them.

[hgupta]

Acutally I ended up finding the oil filter info in the service manual right after I posted (and unfortuantely after I changed my oil. It says to turn to the Right, to remove the filter. It also has the information on pulling the oil pan, but you have to jack up the transmisson 8 cm, and move some steering arm out of the way.
Last night I also greased 14 of the 27 fittings. Its nice watching new fresh grease push that old gunk out of the way. I found that it is easiest to grease if you first clean off the crud surrounding the bushings, otherwise the grease can't push through. There is so much old grease and gunk under my car. Is there a good way of cleaning the undercarriage of the car and getting all that gunk out? Any other greasing tips?

[bstreep]

There is no "easy" way. A pressure washer works ok, but you end up getting really nasty. The best way is to remove the entire subframe. Over the years I've owned the car I've had a chance to clean up most of the front end. About once a month when washing the car, I'll take a can of Gunk and squirt it underneath the car, then hose it off with high pressure. It takes a while, but the difference between now and then is amazing. Also, when I redid my pivot seals last summer I cleaned and repainted both sides of my front end. Unbelievable how much crud there was. Last weekend when I replaced a seal I'd torn last summer, it was still almost spotless. This summer (I live in South Texas, and we have Summer Projects instead of Winter Projects) I'm going to detail the engine compartment. I need to pull the carbs anyway, rebuild the generator, which means pulling the radiator (4 bolts, about 10 minutes, believe it or not!). So, I'll pull the heaters (I rebuilt the drivers side a few years ago) and clean and paint everything.

[Jim Villers]

Well Bill and the manual answered most of the questions. No I have not had my pan off while the engine was in the car. To improve you hot engine oil pressure, try 20W/50W oil. There is no magic to cleaning gunk, just get dirty and do it. When I pulled my front suspension ten years ago, I clogged up my parts washer with gunk (a lot of it).

I believe that there is a paper filter inside of the metal screen; at least it looks that way from the manual. In any case, there should be a rubber bumper in the bottom of the oil filter container that holds the filter tight against the top. I mentioned to Bill that I was missing mine for twenty years and for those twenty years, my filter did not filter because it wasn't held against the top seal, it just rattled around. My Acura, which has a similar cartridge filter, has a spring to hold the filter in place.

[hgupta]

When I was greasing the front end last night, I did notice than many, if not most, bushings were worn and needed to be replaced. Is it easier to pull the front suspension and check all the bushings or just replace them one by one as needed? Where do you put jack stands when pulling the front suspension or subframe? Any precautions I should take if I try to pressure wash the undercarriage?

[Edited by hgupta on 06-01-2001 at 02:55 PM]

[Jim Villers]

Rebuilding the front suspension bushings is an expensive and difficult job. Avoid it if you can.
I supported the car with axle stands under the body just in front of the doors. After removing the shock, I used small hydraulic jacks to hold the spring and lower A-arm in place while I unbolted and removed the lower king pin swivel bolt (or what it is called). With that loose, I could remove the spring and disassemble the rest. I did not have a spring compressor at the time. I think that a spring compressor would make the job a little easier (or at least safer). I always kept a 2x4 or some wood under the A-arms. If something slips, it can be very dangerous.

[bstreep]

When you say the "bushings" are worn, what are we talking about? If you are talking about the rubber seals, let me know, I did all of mine last summer (and one I tore weekend before last)... As for where to put jackstands, I did the same as Jim, I put 2 on the frame behind the wheel and in front of the jackport. Make SURE your frame isn't rusted and it will support it. I also put blocks under the oilpan, just to be sure...

I don't have a coil spring compressor (I bought one for the job I just did, and it didn't fit). WHAT FOLLOWS YOU DO AT YOUR OWN RISK. I MAKE NO CLAIMS ABOUT IT BEING SAFE IN ANY FORM OR FASHION: I made one out of a heavy piece of threaded rod and some BIG washers and nuts, and some bar stock I bought at Home Depot. I cut 2 pieces of the 3/8 inch bar stock about 5 inches long, drilled a hole in it for the rod. Cut the piece of rod long enough to go from the top of the shock to the bottom. Remove the shock absorber and substitute the rod for it. Put 2 nuts on each end along with plenty of washers. Keep a close eye on the rod ends and make SURE the nuts don't turn off. I use a floor jack to compress the spring a little at a time, and then tighten the nuts as it compresses. When you get the rubber bumper hitting the top (you might want to look at whether any of these need to be replaced...), you can then remove the bottom pivot pin by removing the 4 bolts. You can then slowly relax the spring by jacking and unscrewing the nuts. Be very careful here... Once the spring is relaxed, you can remove it. Now you have access to everything and it shouldn't be under pressure. If you remove the bushings from the pivot pins, be SURE and keep the front and back separate - they ARE different! I also marked them with a file and counted the turns to come off - it becomes useful when assembling (I learned this the hard way). Examine the pivot pins and the stampings on the control arms. You likely have to replace the seal, at about $1.30 each. Check your kingpin out, hopefully it's in good shape. The kit for it is about $55 for a reprodution ($220 for a real one). Take the time to clean all the gunk out of everything. I cleaned mine up, primed it all, and then painted it. When putting it back together there are 2 main problem areas: 1) getting the pivot bushings back on evenly, and 2) getting the pivot pin back on the subframe. For the first problem, make sure you mark them and count the turns to get them off. On the second one, first compress the spring as above until the pivot pin is close to where it belongs. I then take a big phillips head screwdrive and wrap some masking tape around the tip. I then insert it into the hole in the pin, and then into the threaded hole in subframe and strong arm it into place to put one of the bolts in. It may take 2 screwdrivers, but it works. The tape protects the threads. The manual says that Mercedes makes a threaded pin for this job. That sure would help! It took me a couple of weeks of evenings to do both sides. Most of it was cleaning and painting rather than doing the actual work. As a note again - be careful with the springs. Don't depend upon 1 single thing to protect you. Use both the spring compressor and a jack or piece of wood or something to be safe. Watch your fingers too - the control arms tend to "move" in fits and starts.

Also might be a good idea to get some disposable rubber gloves. I LOVE the way they keep your hands clean (so does Mamma).

Good luck.

[Jim Villers]

Bill ... Great description. I would only add that the hydraulic jack to lift the lower A-arm into position might be easier to adjust than the threaded rod. I do like the threaded rod for safety. I echo Bill safety words. The front springs are dangerous!

[hgupta]

Thanks Bill for the detailed directions. This is one thread that is worth bookmarking. I had no idea it might take that long! I'm still out there cleaning out gunk and regreasing stuff tonight. I'm tryin to keep track of everything that looks damaged or missing in the front suspension. I will probably save a complete subframe/ suspension removal until late this summer. My roommate just got a summer job with a mechanic so hopefully by then he would have gained enough expertise to help me with it.

[bstreep]

Just to clarify: The first time I did this I used the homemade spring compressor to compress the spring. Then, DUH, I figured out that I could use the floor jack AND the compressor. When I did just the one seal a week or so ago, it probably took me 3 or 4 hours total (including beer breaks!). MOST of the time I spent originally was getting 40+ years of gunk removed from the suspension, wheel, and fender well. Also, when I did it last, I had gotten good at using the jack/compressor. But please, for about $5 you can build a spring compressor - don't try and do this without some kind of safety device. These things BITE.

[bstreep]

when I look at my summer projects, they take about 4 times as long as they "should". It's hot down here. All jobs take twice as long as they should, and I spend at least as much time cooling off sipping a cold one as I do working... so, it takes 4 times as long as it should!