Chain tensioner removal

[mulrik]

My car lost excesive amounts of coolant, and overhaets. At first we thought it was the thermostat was not working, and caused the overheating. Well, we were right....... but it wasn't the only thing which was wrong. It still loses coolant, but doesn't overheat as fast as before the new thermostat. So now the working hypothesis is a blown cylinder head gasket, or, doesn't dare to say it, a crack in the cylinder block, hope NOT. I got most of the engine apart to get to the gasket, but I can't figure out how to remove the chain tensioner shaft out, the one with the little spring. Could anyone help me on this one?
THANKS!!!
Ulrik


'67 250 SL Papyrus White 113043-10-000023

[knirk]

Mulrik,

You screw a 6 (i think)mm threaded bolt into the shaft. If you add some washers between the bolt head and the cyl. head you will then pull the shaft out while screwing in.

Per G. Birkeland
69 280 sl aut 834
Norway

[Cees Klumper]

Per is right, inserting a threaded bolt and then gently pulling on that should remove the shaft. Cracks in the engine block are rare as far as I know. If you have overheated the engine repeatedly, it is not unlikely your have a problem with the gasket or worse: the cylinder head could be warped or otherwise damaged. If so, I believe you may be able to use an early-style 280 cylinder head instead, but this would have to be checked. 280 heads are more common than 250.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[ja17]

Hello Ulrik and Cees,
 The chain tensioner unit bolts to the right side of the head near the thermostat. The chain tensioner sprocket has the spring and a pin holds it in place as knirk has stated. I believe knirk is correct in that a 6mm bolt can be used to extract it. You can also buy a special factory tool.

Cees the 250-SL  head can replace a 230-SL head, but neither version 280-SL head will interchange with a 250-SL.



Joe Alexander
Blacklick, Ohio

[mulrik]

OK here's a tip for the future. YOu do NOT have to take out the chain tensioner to unscrew the two bolts below in order to remove the cylinder head. You can unsrew and remove these bolts using a long thin extender with a 6 mm in the end. The Haynes manual says otherwise, but I just did it without removing the chain tensioner.

Regarding cracks. I actually had cracks going from the two middle bolt holes outwards in both directions to the coolant channel. My "mechanic consultant" says it is no problem since the only cylinder I had water traces in was cylinder # 1.

'67 250 SL Papyrus White 113043-10-000023