I am replacing the valve cover gaskets in my 1999 Range Rover 4.6 this coming weekend and started reading up on the procedure in RAVE and on this site and ended up with more questions. The first step in RAVE for the RH valve cover gasket is to drain the cooling system, however, in all my searching and reading other people's posts on this site I have yet to see anyone mention draining the coolant as a step they took. Did they leave that out because it's supposed to be obvious, is this a difference between a Range Rover and a Discovery, or is the RAVE manual just being excessive?
Should I apply Hylomar or something similar to the gasket for a better seal? And what should I do about the intake manifold gasket, I didn't buy a new one as it is significantly more expensive than the valve cover gaskets, would it be acceptable to reuse the existing gasket if it is good condition? Would I want to use Hylomar on this gasket too?
Thanks again for all the wonderful help, thanks to this website I have become much more confident at working on my Rover, and am getting towards having a respectable and reliable ride!

 

They say drain the cooling system because the heater hoses run directly over the top of the passenger valve cover.
But here is a little tip for you, tighten the valve cover bolts, 8mm 12 point socket, only worry about the ones you can reach, that will stop 98% of all valve cover leaks.
I snug mine at ever oil change, no leaks...from them.

 

The intake manifold gasket should not need to come apart in order to replace the valve cover gaskets. Basically what you do is clear all the hoses and pipes and everything above the valve cover so you can lift it off. The intake manifold and it's gasket surface should be under the valve cover over the lifter valley. There's no reason to do anything with it unless it's also leaking. It would be leaking coolant or air/fuel and probably not oil.

So clear out the stuff above the valve covers and they should lift off fine. I would not use hylomar, but would do one of two things: either use a preformed rubber gasket from the factory without any gasket maker; or use no preformed gasket and Permatex The Right Stuff elastomeric gasket maker. Right stuff makes very good gaskets, especially valve cover gaskets and oil pan gaskets. I'm not that familiar with the Rover valve covers and gaskets but if the valve cover was cast (not stamped) and had a groove for an o-ring type gasket, and the gasket surface was clean and smooth, then I'd go ahead with that. I think the Rover valve covers use uncaptured thick rubber gaskets which is probably why the rubber flows and some have found a need for regular tightening.

 

Thanks gentlemen! Spike I found your tightening tip searching last week and while that seemed to slow the flow, it didn't stop the bleeding entirely. So as long as I'm not overzealous removing the passenger side rocker cover and yank it up into the heater hoses I should be able to get by without draining my coolant? Because I've drained the stuff twice this year, once for a full flush, the other time to replace hoses after one blew, I have had my fill of messing with the coolant for 2011! And as far as I can tell, I have to remove the upper IM to get to the other bolts as well as to provide enough clearance to lift the valve cover off. Is changing the intake manifold gasket really necessary, it costs nearly twice as much as the gaskets I actually need to change.

 

I have never changed the valve cover gaskets so I cannot say for sure, but if you can get the cover off without draining the system more power to you.
And you would have to drain the whole thing, just enough so the heater hoses didnt leak if you did need to remove them.