Changing Valve Cover Gasket replacement.

[gamellott]

I've read a few strings on this topic, but I didn't see anything specific for it. This is the first time that I'll be doing this and I believe that I have all of my bases covered, but I thought I would bounce it off of the experts

 

For the VG30E, I know that I'll be doing the Valve cover gasket with grommets and the intake plenum gasket. Aside from some RTV, is there anything else that I should be aware of that usually bites you in the butt when you do this work??

 

Thanks!!

[Citron]

There are a number of vaccum and coolant hoses that connect to the intake. Plan on replacing those, a few run under the upper intake so while the intake is off would be a great time to replace them. I believe a few are molded, so you will need to get them on order.

 

You need to pull the distributor to access one of the valve cover bolts, so you will need a timing light to verify timing when it goes back together.

 

Also a great time to replace spark plugs if needed. #6 is so much easier without the intake on.

 

Careful when removing the air ducting, it can be stiff a tear a small hole.

 

That's all I can think of right now.

[adamzan]

You don't need any RTV to do this job. Clean all surfaces and use the gaskets only.

[level9]

Intake:

 

Personally I don't like to use RTV here; although I'm sure plenty of people do it without issue. Reason being, the RTV will squeeze out into the intake runners and there's not much you can do about it. If you go this route, make sure you use O2 sensor safe RTV as bits and pieces will brake off over time and could foul sensors.

 

With the intake off, it's a good opportunity to clean off the carbon buildup. I use a can of Seafoam with a flexible bottle brush like OXO Good Grips Bottle Brush to clean the intake runners. Then clean the idle control valve, EGR, throttle body and idle air bypass with CRC Throttle Body & Air Intake Cleaner.

 

You might consider replacing your PCV valve while you are at it. Personally, I will only buy an OEM PCV valve and they are pretty cheap. Make sure to seal the threads on reinstallation with thread sealant (or O2 safe RTV would probably be fine here).

 

 

Valve Covers:

 

Be careful with removing the hoses from the tops of the valve covers unless you intend to replace them. This is part of the crankcase ventilation system and it is a special fuel/oil resistant rubber and at least the front, pass side valve cover hose would likely need to be replaced with OEM only version due to it being premolded with a very tight radius bend. Also the hose connected to the PCV on the intake is the same - premolded and I'm not sure you can bend an aftermarket hose into that radius.

 

Before removing the distributor, mark the rotor position relative to the body with a marker. Then align it back on reinstallation. This should avoid the need to check timing as Citron mentioned; although it's never a bad idea to confirm. EDIT: Almost forgot.. you need to mark the timing adjustment bolt as well. I did not have to do this on mine as it left a very nice clean spot when I removed the bolt so it was obvious!

 

During reinstallation, make sure to clean the surfaces and bolt the covers back down using the proper pattern as noted in the FSM. It is also recommended to torque to spec. As I recall, there is actually 2 different torque specs combined with the bolt pattern to effect a 'proper' installation; although plenty of people don't do this and have no issues, so it's up to you.

 

Some people also use High Tack Gasket Sealant on the heads to lock the gasket in place and help prevent future leaks as added insurance.

 

 

If you want to implement some performance mods while you are there I can also make some recommendations as well, but it's extra time and $$. Good luck!

Edited March 31, 2017 by level9

[adamzan]

Yeah, aftermarket PCV's suck. I replaced the one on my SC xterra, and it started blowing blue smoke at startup, put the old factory one back in, problem gone.

 

The one on the wd21 is pretty stout. I would clean it with brake cleaner and if it still rattles I would just re use it.

 

Level9 has it right. Do what he says and you'll have no issues. I have done this job a couple times now on a pathfinder and an Xterra (same engine style), goes fine. Finagling the hoses on the back of the intake is always a good time though. Lol.

Edited March 31, 2017 by adamzan

[level9]

Yeah, I cleaned my PCV valve originally, shook it back and forth and it seemed fine. I saw how cheap the OEM one was and said what the hell and bought it anyway. I then compared the new OEM to the clean one and there was a quite noticeable difference in spring tension. So I just recommend replace now.. they will still mostly work once cleaned up but the after moving back and forth a zillion times over 10+ years, the spring just starts to wear out. This can sometimes contribute to increased oil consumption as you might not get quite the same/consistent level of crankcase vacuum which can hurt with ring sealing (increasing blowby, hurting fuel economy, etc.). Some cars are more sensitive than others. The use of low tension piston rings in later model years causes more problems with malfunctioning PCV systems.

[gamellott]

Ok, Thanks for the heads up on the numerous hoses. Sounds like I need to plan for it to be down for more than a day since I'm sure I'm going to run into other issues. Not exactly what I was thinking when I was preparing and thinking this can't be a big deal... Sounds like I was wrong again . Thank You for your input

 

I have no idea if this is a JDM engine or if it is actually 25 years old, I just know that the valve covers are leaking... If it's been 25 years since this has been pulled off, that'll be amazing... we'll see how the rubber crumbles

 

I've read that the distributors wear out. Guess I can look to see if it's wobbly or whatever while I have it out.

 

 

[level9]

I had another thought since we were on the topic. You may want to start off checking/replacing the PCV valve first and see if that solves your issue. If it is severely plugged up this can contribute to oil leaks. Reason being, the crankcase pressurizes due to blowby and this can push oil out the older/weakened gaskets. The blowby will exit the wrong way - on the breather side (hoses connecting valve covers to intake boot). Evidence of a plugged PCV would be a lot of carbon buildup on the throttle body. GL

[Slartibartfast]

I meant to do my PCV while I had it open, but the one Rockauto sent didn't fit. I just blasted my old one out with carb cleaner and reinstalled it.

 

For the manifold gasket, don't get the stamped steel ones. The first time I did mine, I got these awful stamped-steel Victor Reinz gaskets. Nothing lined up, it didn't seal, and I had to tear the bugger apart again and put Fel-Pros in there. Start with the right gasket and save yourself some headaches! And yeah, no silicone required.

 

The exhaust connection to your EGR valve may be a bugger to get out. If all you're doing are the valve cover gaskets, you can probably get away with just unbolting the valve from the intake and leaving it supported by the pipe going down to the exhaust. There is a gasket for that. IIRC I reused mine without issue, but I'm sure they're cheap enough new.

 

+1 on doing the plugs while you're in there. Not only are they easier to get to, you can vacuum the dirt from around them before you pull them so it doesn't end up in the cylinders.

 

Also not a bad idea to lay a couple strips of masking tape over the holes in the lower intake manifold as soon as you've got the upper off, just so you've got six fewer places for a stray valve cover screw to explore.

[Citron]

+1 on the masking tape. I was very glad I did that after dropping bolts a number of times. Same with spark plug holes. Don't leave them open for an extended time or something will fall in. Pull old plugs and put new in.

 

I completely forgot about the egr, deleted mine over a year ago.

[gamellott]

More good info. Thanks guys. I spent the day, since it was nice out, doing yard work. Actually, I was slinging poo from the goats and alpaca that we have. The chores never end!!