280SEL questions

[Petercohen]

Hi
I've got a 1985 126 280SEL 110989 engine, and very noisey tappets. I've recentley changed to 20w40 oil due to excessive oil consumption (engine has done 131,000 miles) & this has reduced the noise abit, but when the engine is warm, its just the same as before!

I would like to ask how easy it is to adjust the tappets myself, and can anybody give me any tips?

Also does any body know what the fuel consumption for this car should be, as it uses so much fuel for a 2.8l! According to the on board computer at 50 mph i'm using 14 l/100km (which I don't believe). (I use premium unleaded).

Finally one last question, at 70 mph the rev counter reads approx 3500, is this normal for a 4 speed auto box?

Thanks for any help!
Peter

 

[Wolfram Halupka]

Hi,

the revs are ok. However, your fuel consumption is way too high. Does your computer agree with the manually calculated thirst?

Your valve clearance can be adjusted at home, if you´re careful.

Regards,

 

[Petercohen]

I havent really calculated the fuel consumption myself, but I know its high! For example £20 of fuel from empty will give me 40 mile trip including motorway and town travel, with an average speed of 50 mph.

I tried to adjust the tappets today, but quickley realised that I will need a special tool. Does anybody have any ideas on getting around this? Or if I have to take it to a garage, how much would I be looking at?

Regs

Peter

 

[Andy]

Hi Peter,

280's where never good on fuel. Although the cylinder head and piston shapes is as good as it gets for those days.

1. I would estimate about 20mpg around town. A little more on a run.

2. The engine is very "tappety" any way. You could adjust with a 17mm spanner. There is a special tool which is a long spanner with a couple of kinks in it to allow it to get in. Adjustment is a little tricky as the adjusters are very tight. Due to lack of people adjusting them. (Since a lot of the owners never get them serviced properly. Ie take it to a garage for servicing and they never adjust the tappet clearences.)  I cannot give you any tips on adjusting the tappets. They are an aquired taste. Try an adjust them a little on the tight side. But only just!!

3. The oil consumption is proberly due to the valve stem seals. They require replacement. Although its not a easy job on this engine, the cam housing has to be removed for acess.

4. As far as I am aware MB never had a onboard computer on this model!!!

5.Due you think that 3500rpm is high or low???
But seems about right to me. 80/85 it will be around 4500rpm.

Regards

Andy @ www.mercedesservicing.com

PS. As an aside. These engines are bullet proof. Weak point is that they use oil and their owners do not check them often enough. Then they blow up. The main cause of engine failure for this model.