Head Gasket Issues

[colin evans]

Hi All
I haven't posted on here for a very long time as my 280SL has behaved itself for a few years! I need some help now as I am stumped, I will lay out all the details of what has happened.
I started the car one day and it hydraulicked quite sharply, then started ok. I was only fettling it so didn't drive it out that day. Next time out, I got a mile down the road and the temp gauge kept rising (it always settled at 180 before). I turned around and made it home in 5 mins but with a very hot engine. It was smoking white a little, but it always had done that a bit. I assumed it was the head gasket gone.
I stripped it down and had the head skimmed by a reliable local business and I fitted a new gasket (it took 2 attempts as the supplier sent the wrong one first time and stupidly I didn't notice until it was back together and water started coming out of the plug holes when I refilled the coolant. I got the correct gasket and torqued the head to 65 ft lb cold with new bolts. I never measured the head as my car is a genuine 50,000 miler and I made the assumption that it hadn't been done before.
It still smoked white more than I expected, but I drove around 10 miles fine with no overheating issues, although it seemed harder to start, which I put down to timing, I had somehow messed up the distributor position and had a big misfire on the first start up attempt. Once I corrected this it started and ran ok.
A couple of weeks later I took it to the local Merc garage around 8 miles away for MOT and to check the timing, which they adjusted. It ran ok on the way home but didn't idle as evenly as before and it white smoked at idle. By the time I got back there were clouds of white smoke at idle. I waited a couple of days and tried some K seal as a desperate measure but that seemed to be ineffective. I drove it down the road yesterday and noticed a loss of power, quite severe. I took the rocker cover off and there was mayonnaise everywhere. I retorqued the head to 80 ft lb warm after reading this forum but it when I started it back up it struggled to run and still smoked.
My thoughts are (and I am only an enthusiast not in any way a mechanic so please go easy on me!)
-Head was skimmed before so it is now under the minimum measurement
-Cracked head
-Cracked block
Is there anything else I should consider before I strip it down again to investigate? I did read somewhere that a porous inlet manifold could create the same symptoms, but it seems unlikely? My car is a manual.
Many thanks in advance for any advice!
Colin

[Pinder]

I think when you put the new head on you should have had it torqued down to 80lbs. its possible that water made it passed the new gasket as it was not on tight enough. also maybe have the head checked for cracks etc.  :(Im not an expert so lets see what the rest have to say on this).

Regards

[merrill]

i had a weeping head gasket issue.

purchased a new head gasket and some copper spray from metric motors.
pulled the head, cleaned the surfaces, sprayed the copper on the surfaces re installed and no issues since.

[Cees Klumper]

The 'mayonnaise everywhere' is especially concerning, given you drove it such short distances since putting the head back on. And of course the white smoke. I would remove the head again and have it tested for cracks, unless upon removal it is clear that the new gasket failed. Best of luck with the repair.

[colin evans]

Thanks guys. For reference if I look at fitting another gasket, what should I torque it down to cold? I used 65 ft lb as per the Haynes manual.
Thanks
Colin

[Pinder]

Colin  check the Haynes manual again for the 280sl not the 230 sl spec.  I took a Quick Look . I think hot engine it’s 80lbs and cold 72lbs. I think you have a 280sl?

Regards

 Pinder

[Pinder]

Here is a photo of the Haynes manual I have from 1977

[Cees Klumper]

The head needs to be torqued down in 3 successive stages and in a specific pattern.

[ja17]

Check the compression in all cylinders before you take the head gasket off again. Remove the plugs and spin the engine with the starter first to expel any water from the cylinders before the compression check. Your compression readings could give you a clue to where your problem is located. You might have a crack somewhere so try to find the cause and location of the failure or you might be wasting your time again. Head bolt torque on a M130 engine should be 80 ft/lbs. in three stages. After first warm-up re-torque the head to 80ft/lbs (warm engine). Re-torque the head again after 500 miles (warm engine). I also use the copper gasket spray. Replacement of the head bolts is not required on the M130 engines that do not have stretch style bolts like later Mercedes engines. Also realize that the blown head gasket allows engine coolant into the combustion chamber which then fills your exhaust system with engine coolant. As the exhaust heats up the coolant in the exhaust, white smoke will return for a considerable amount of time. Eventually the problem lessens and then disappears, as long as everything else is ok. You may need to change the oil twice to purge the water out of your engine or you risk damaging the engine bearings from circulating all the water through your engine.

[colin evans]

Thanks, will do. This is definitely new contamination and the power is well down so something is not right.

[MikeSimon]

Really stupid question (maybe): You are aware of the fact that there are two different head gaskets for the M130 2.8L engine?

[colin evans]

Hi Mike, thanks yes I found this out when the SL shop sent me the wrong one. I stupidly didn’t notice until I started refilling the cooling system and water poured out of the plug holes. Head straight back off and waited for correct gasket to be sent out!

[colin evans]

Joe, what would you expect compression readings to be?  Mine are;
1 105
2 107
3 106
4 98
5 107
6 107
So pretty even except 4 and that’s within the 10% rule, but not sure what the expected figures would be?
Cheers, Colin.

[Cees Klumper]

The tech manual lists values starting at a minimum of 120 and up to 175 psi compression ...

[Benz Dr.]

Those are some low compression readings. I would be surprised if it would barely start and run.

[colin evans]

Ok thanks. Guess I’ll have to strip it down again and get the head crack tested, as I am still none the wiser.