280 Sel 1984 ??? - PeachParts Mercedes-Benz Forum

gvanhouten · #1 11-01-2005, 07:56 PM

Just purchased 84 280 sel and need a couple of things for the car. It has 65,000 original miles and the valve cover is leaking along with the lower gasket. It is not the headgasket but a lower valve cover gasket. Need to know if any year had the same engine american version.

As you probably already know this is a grey market vehicle meaning made for europe but imported to the states. Also looks like the o2 sensor is bad. Question is in europe do they have O2 sensors?? Wiring does not look oem? Any comments would be greatly appreciated.

t walgamuth · #2 11-01-2005, 08:56 PM

about the o2 but most parts are the same including i am sure the head and valve cov gaskets.

i have an 84 280e euro.

sweet car.

tom w

gvanhouten · #3 11-01-2005, 09:04 PM

I am not sure of your answer but I need to know what car has the same valve covers as you are referring to.

ctaylor738 · #4 11-01-2005, 09:22 PM

This is an M110 engine, basically the same as on a 1977-81 280E or CE, both of which were US cars. It sounds like your leak is from where the cam box joins the head. It is very common and you don't want to mess with it unless it is really bad.

The O2 sensor was probably added when the car was federalized. You can use a generic Bosch single wire sensor as a replacement.

PaulSpringmann · #5 11-02-2005, 08:32 AM

I agree with Chuck, don't mess with the leak between the cam housing and the head unless it is really bad. I had a 126 280SE for many years, and it always leaked at that joint, even after I re-assembled after a valve job w/ the foil gasket.

My car was also federalized very poorly. The generic O2 sensor will work; or you could just remove the added stuff for "testing".

ctaylor738 · #6 11-02-2005, 09:38 AM

We exchanged emails on this. I thought I would add it here, since it has some additional info on the M110:

Email from gvanhouten:

It seems to be leaking pretty good front right side of the engine. Making a mess. Why do you recommend leaving it? How complicated is it?? As mentioned before the car has 65,000 miles on it. Also while I am at it I hear the valves tapping. I suspect that they need to be adjusted. Any advice would be great. Thanks

My reply:

It's not complicated, but it is a big job. You need to remove the rockers, two slide rails, the chain tensioner (which means removing the AC compressor), and two cam gears. You need the right valve spring compressor and a puller for the pins that hold the rails in, and two very large hex bit sockets (17mm and 19mm) to get the tensioner out. You need to remove half of the head bolts. Plus the damn thing is heavy.

Before you do this, you might want to clean the engine and make sure that the cam box - head joint is where the oil is coming from. It is two flat metal surfaces with thin aluminum gasket between them. Normally it seeps, not leaks badly. You might look around the tensioner on the pass side of the head, because there is an o-ring behind it that can dry out and leak.

The valves are not hydraulic. The intakes are set (cold) at .10mm and exhaust at .025mm. You need a 17mm crow foot to turn the adjuster. You rotate the cams with a remote starter switch and adjust when the lobe is straight up. There are spring clips that need to be removed. Sometimes the adjuster will not turn with a wrench and you need to take the rocker off and put a deep-well socket on it.

I suggest that you get Haynes manual 63025, which has a good section on the engine and explains things much better than I.

Good luck,

Chuck

PaulSpringmann · #7 11-02-2005, 08:23 PM

Chuck's comments are spot on.

The main reason I am wary of installing the cam housing to cylinder head foil gasket alone is becuase is does require removing at -least- half of the head bolts am I am just not comfortable disturbing the torque against a 20 year old cylinder head gasket. With the overall labor involved, it's not much more work to remove the head, have the surface and valve guides checked and install a new head gasket. Maybe I am paranoid, but I did this job all over and went down to the the head the 2nd time becuase of an oil/coolant mix problem after I RnR'ed the cam housing. To add insult to injury, I never acheived a leak free cam-housing to cylinder head! It was improved, but not perfect.

Also, if you do the job, make sure you reset the chain tensioner prior to re-installation. The tensioner is the racheting type, unlike the V-8. It also might be stuck in the head; I had to puchase a large metric bolt to thread into the tensioner in order to remove it for resetting. On the 126 cars, you can unbolt the A/C compressor and swing it out of the way; I would recommend unbolting the the lower brace from the block and not disturbing the bolt which connects the brace to the compressor. On my car, the upper brace bolt which goes thru the brace into the York compressor was also the bolt the held on the lower compressor head. This may have been non-factory, but it was the case on my car.

On the valve adjustment: I have always been successful adjusting the valves with a regular craftsman 17mm open end wrench, but you do need to remove the spring clips. My M110 seemed to always have had the need valve adjustment at every 10k miles.

The factory M110 manual which is included on the 123 and 116 CDs is an excellent resource.

These are fun cars; I wish I still had mine.