Head gasket ?

[rwaw]

Dear all,

Yet another problem: had my car now for 2 months and have noticed thin line/few drops of moisture along head gasket from cylinder 4 to 6 on left hand side of engine.
It's blue/green and slightly oily so almost definitely cooling fluid.

It doesn't pour out, the level in the expansion tank doesn't go down, the oil level on the dipstick doesn't go up, the car never overheats.

Reconditioned head/new gasket/re-torquing all done (presumed correctly through previous owner) about 18 months ago.

Before blaming a blown head gasket at the least and embarking on head off etc thro' local dealer I wonder what other members' thoughts are. :?:

Further update: decided to bite the bullet and took car (280SL) in to dealer's to take head off.
Just been to see it:top of engine block very dirty and obviously not well prepared when previous reconditioned head+gasket put on but more importantly the head gasket itself.
The impressions made by the head show an incomplete seal around several of the coolant passages that surround cylinders 5+6 so would definitely account for the leak.
This probably confirms that fitting head+gasket it is a very specialized procedure to perform accurately.
Thanks again for your suggestions.

[Cees Klumper]

This is just a long shot, but sometimes oil leaks through the threaded holes located just above the spark plugs, that the valve ball stud adjusters are seated in. It can look like the leak is coming from the spark plugs. You can check higher up the head, to see if maybe the fluid is coming from above (one of) the plugs. You could also try re-torqueing the head, never hurts. Here's a procedure for that:

Before you retorque, make sure there's no pressure in the cooling system. Loosen the overflow canister cap and re-fit. The sequence of the bolts is from the inside out, there's a diagram in the Haynes manual. Loosen each bolt for at least a half a turn, then tighten to 60 lbs (double check your engine specs to be sure). Use a bit of oil on the threads and washers so they screw down evenly. It's easy to do with a relatively long 10 mm Allen key. Don't forget the bolts in the timing chain housing. Modern head gaskets are said to not need re-tightening, but do it anyway to be sure. After you do the bolts, check the valve clearances.

Cees

white 1969 280 SL

[ja17]

Hello rwaw,
I am not sure which model 113 you own however, the coolant passages in the block especially on the (M130) 280-SL, come very close to the edge of the block on this side. Engines which freeze-up because of no or low antifreeze will crack and leak coolant in the area of the block you mention. Lets hope not. Try a re-torque first with engine hot. My factory "Technical Data Book" gives the torque specs on the M130 (280-SL) as being 11 kpm with engine hot.(one kpm equals 7.23 ft. lbs). Earlier 250 and 230-SLs, require 9 kpm with engine hot. If you are installing a new gasket re-torque in three or four stages. When re-torquing as Cees metioned, remove coolant cap to relieve cooling system pressure. Loosen one head bolt at a time then re-torque to specs. follow the correct sequence.  Modern replacement head gaskets are improved and seal better than the original.
Good Luck!


Joe Alexander
Blacklick, Ohio

[Naj ✝︎]

My suggestion is that if you are re-torqueing only, do not loosen the bolts more than a couple of turns. The threaded holes in the block are 'dead end' and could fill up with oil. Then you could end up torqueing against the oil.
If you replace the gasket, be sure to take all the oil out of the bolt holes. Then lightly oil threads and washers as suggested by Cees. I prefer to lightly grease the threads.
Also thoroughly check the bolts along the shank. 2 of mine were quite badly pitted.
naj

naj
hobel 65 230SL
jalopyno 68 280SL