Valve cover gasket replacement question?

[Mikey_ZX]

Should I drain the oil out of my engine before pulling the valve cover? Also, there are inlet/outlet elbows that connect to hoses that are on the actual valve cover itself, with mine I was actually able to pull those joint elbows out, are they suppose to be like this or should I seal those onto the valve cover?

[Lokim]

No need to drain oil for a VC gskt change, unless you get lots of schmutz/particulates into the head. If the elbows aren't leaking, put 'em back how you found 'em.

[Mikey_ZX]

Thanks you for your reply, I have one last question, what exactly are the half moons that I need to add RTV to?

[maxnix]

You will see them on the gasket. There are also two other places on the later VH45DE that require sealant. The critical thing is the tightening sequence with a good torque wrench and on the later VH45DE, new VC rubber washers.

[qship96]

Brian, I know you always mention how critical it is to replace the rubber VC washers, but I am not so sure they are really all that critical at all to replace,especially when you look at the added expense- t3 did my valve covers for the very first time,when the Q was over 11 years and 203K old- and did not replace them nor recommend doing so- it has now been almost exactly 4 years and 80,000 miles since and there is zero evidence of any leaks or seepage ????? What would I have gained by spending the extra $$$$ to replace them?

[Mikey_ZX]

I don't have the actual gasket, I'm using Permatex "The Right Stuff," I read a thread of someone using this stuff on their valve covers for the Q. So, from looking at the valve cover, are the half moons towards the front of the valve cover, in front of the timing gears or is it something more specific? Thanks for your help!

[Mikey_ZX]

I finally found the 2 half moons at the back of the engine, thanks for your help guys! Once again thanks for helping me guys!

[Q451990]

Brian is talking about the 94-96 style gaskets. 90-93 use RTV. Permatex gray has always been the correct cross-reference that I've seen on their packaging...

That's a back pain inducing job... good luck with it!

Heath

[Mikey_ZX]

Thanks, I finished the drivers side, my only problem is cleaning out the sparkplug holes and getting the oil out of the one closest to the firewall, I was able to get most of it out by using a pump that I have for changing my differential, but I can't seem to get the oil out from the very bottom of the hole, hope a little oil isn't a big issue. However, I'm working on the passenger side now, also I'm getting a code for a leaking injector, so I'm going to have to address that as well! But thanks again guys!

[maxnix]

Brian, I know you always mention how critical it is to replace the rubber VC washers, but I am not so sure they are really all that critical at all to replace,especially when you look at the added expense- t3 did my valve covers for the very first time,when the Q was over 11 years and 203K old- and did not replace them nor recommend doing so- it has now been almost exactly 4 years and 80,000 miles since and there is zero evidence of any leaks or seepage ????? What would I have gained by spending the extra $$$$ to replace them?

I think it is critical because with age not only do they deform but they also harden to hockey puck hardness. It is obvious that the FSM specifies the VC not torques with the elasticity of new VC washers in mind. Thus, not only is there less margin for torque force error with the old gaskets, there is no resilience to keep the VC sealed against the gasket as there is when new, so the VC will not last as long.

Just my take, but id the new rubber elasticity was not important, I imagine Nissan would have used something like Delrin.

[maxnix]

...my only problem is cleaning out the sparkplug holes and getting the oil out of the one closest to the firewall, I was able to get most of it out by using a pump that I have for changing my differential, but I can't seem to get the oil out from the very bottom of the hole, hope a little oil isn't a big issue.

Use a paper towel or two.

[Infinitiguy19]

Why did Nissan even use those half moon gaskets?

[Q451990]

I think the half moon cutout in the head is necessary for installing the cams... not sure though. It's been part of engine design for a long time for some reason.

Heath

[Lokim]

Its actually for align-boring the cam bearing caps. They install the rough-finished caps onto the rough-finish heads and run a bore down the center to ensure all the bores are the same size AND are straight.

If they didn't do this the cams could experience lateral stress between bearing and they'd snap. I've seen it happen to overhead-cam motors with severely warped heads. They overheat the motor and the resulting head warpage brings the bearing caps out of alignment and the cam shears in two.