560 needs head gasket help!!

[coater]

I have an 89 560 SEL. One of the cylinders has very weak compression. Head gasket, it would seem, is a goner.

Here's my question: do I have to change the head gasket on that side only (seems there's a valve cover on one side, another on the other where compression was fine in those 4 cylinders)? Or do I have to change the head gasket on both sides? OR... am I a moron and there's only one HUGE head gasket?

I'm a-OK with doing the work. It looks, from what I'm seeing, pretty simple. Does anyone have any recommendations?

Does anyone have any kind of tech info or diagrams I might need? Or should I shoot the car and push it off the pier?

thanks again, all.

 

[paulcallender]

I'd recommend having a proper cylinder leakdown test done. You're probably right to suspect the head gasket, but you never know (until the cylinder leakdown test is done, of course...) The equipment to do this is expensive so it would be more cost-effective to go to an appropriately equipped local garage for this.

There's no real problems with this job, so long as you set aside a lot of time (I hope you have another car you can run around in in the meantime). You'll need to deal with the timing chain, its possible that its the type without a removable link, in which case you'd have to grind one off then obtain and refit the removable link.

A couple of the steps would greatly benefit from 2 people. For example, removing the bonnet; and lifting the heads off the block.