99sagelimited

So I recently decided to replace both of my leaky valve cover gaskets and clean the engine bay up a bit. I ran into some problems that I would like to share to forewarn some members.

1. When I removed the upper intake to get to the rear cover, I had to cut two coolant hoses that connect to the back of the intake. I couldn't reach the clips so this was my only option. These hoses are a Nissan only part, so I had to wait a bit to get them.

2. I decided to replace the lower intake manifold gasket since it came as part of the intake gasket kit. I didn't relieve the fuel pressure beforehand, so I simply pivoted the fuel rail assembly out of the way. The first time I put the rail back onto the lower intake, I forgot the spacers and torqued it down. I noticed my mistake, removed it and added the spacers only to later find out that the fuel rail tabs were bent from my mishap. This caused a MAJOR vacuum leak that stumped me for several days. To fix this, I ended up installing smaller spacers to properly seat the injectors in the lower intake in addition to new injector insulators.

3. The fuel rail to lower intake bolts strip easily! I stripped one and ended up re-tapping it with a 3/8-24 bolt.

4. You MUST use RTV at the sharp edges on the front and rear valve cover. Most members know this, but I neglected it and ended up doing both covers twice. I also recommend using the OEM Nissan gasket or the Felpro one.

All in all, I removed the upper intake and re-assembled it 4 times. By the last time, I could disassemble and reassemble in 1 hour. I did all of the following while I had it apart, and the car runs AWESOME now:

-Replaced Valve Cover, EGR, IACV, Throttle body, and all Intake gaskets.

-Painted front valve cover, ornament cover, and upper intake.

-Polished rear valve cover.

-Cleaned IACV, EGR tube, upper intake, and throttle body.

-Replaced ALL coolant hoses.

-Replaced blow-by hose and all cracked vacuum lines.

-Replaced lower intake insulators.

-Replaced PCV valve.

VisciousMo

iTrader: (4)

Great write-up, need to do this soon.

phatboislim

iTrader: (27)

i fail to see a 'write-up' but i do appreciate the precautionary measures. bay looks good man.

99sagelimited

I think I will add a write-up and parts list while it is fresh in my memory.

phatboislim

iTrader: (27)

you can do that but i believe there is already a write-up on this, but i dont think having another would be a bad thing

tigersharkdude

iTrader: (20)

Just FTR you can get those two rear UIM hoses at any parts store. Take the two pieces of the hose(s), measure the length and get corresponding size hose/length

99sagelimited

I was worried about bending a hose in the u-shape and having it crimp. I was ordering stuff from Nissan anyway, so it didn't hurt. I did replace the blow-by hose with some cut-to-length stuff from pepboys. That worked great and saved me a few bucks.

Trini Boom

iTrader: (5)

Best thing I did was go to the local parts store, get the right diameter and buy 1 foot long and install it back there. Much easier access for me and it is not touching anything when installed.

tigersharkdude

iTrader: (20)

same here...i just did this a few weekends ago. Those hoses werent bugging, had to cut them off

ef9

iTrader: (8)

I am doing the same as we speak. I also checked valve lash since the valve covers were off.... that's a whole story on it's own.

I also needed to change the steering rack, so I decided to change the headers and y pipe since I was already there. I had to replace the RTV for the lower oil pan, so I decided to remove the aluminum oil pan to change the RTV there as well. Front and rear motor mounts were torn, I plan on addressing those soon too. Since I have all of that apart, I decided to change the water pump, tensioner and half-moon seals and crank main seal. I also decided to change the crank pulley as well as the two drive belts too.
I needed to change the sway bar bushings and lower control arm bushings too.
Like the original poster stated about changing the hoses, I too ordered a plethora of hoses from Courtesy Parts.

A $100 fix became a $1000 fix.

Todd in Atlanta

Those hoses on the back of the UIM are tough. You can make this easier though by disconnecting the longer one from the end that connects to the throttle body, then you only have to mess with the litle U-shaped one. That one becomes a whole lot easier after the first time, since age seals it to the little tubes. If it has been on there a long time, definitely cut it. For replacement hose, fule injector hose at parts store works well. They also sell a lubricant that you can put on there, makes it easier to put on and take off. I usually replace the hose clamps with ones with the screw as well for the U-shaped one, found its easier to get to again if you position it correctly

svezarov

I have been wondering, since the Rear VC always leaks at the back corner, has somebody tried to clean the surface around the leaking area and smudge lots of RTV there to see if it will continue leaking. When you think about it, there isn't really pressure that pushes the oil out - it is the opening that appears from the old gasket + RTV when they age.

350zMaximaownr

^^ Do you have to RTV the intake gaskets for plenum, and the valve cover gaskets? The Z doesn't so I am working backwards in years here for my winter DD

Thx

tigersharkdude

iTrader: (20)

When I did mine, I put RTV in the groove for the gasket on the VC and then laid the gasket on top of that, and then ran a small bead around the mating surface on the head, i put a slight build up on the back corners.

99sagelimited

I replaced all of the hose clamps with screw type clamps. They were much easier to work with. Good to know that fuel hose would have worked, but there's something that makes me warm and fuzzy about using a Nissan part, even if it is a stupid little hose.

Fatboy98maxima

nice write up ill be doing this soon

jholley

iTrader: (13)

Turns out you're not the only one who had to do it more than once. When I replaced my valve cover gaskets last month I had to disassemble it twice due to a clicking valve in the rear bank.

http://s1224.photobucket.com/albums/ee376/jwholley68/?action=view&current=VID00005.mp4


I first tried changing the oil twice along with adding some CD2 oil detergent but that made no difference. I removed the rear valve cover again and saw that the valves were well lubricated so I just poured CD2 onto all 12 valves. After starting her up again the clicking noise went away in about 30 seconds. Taking her apart the second time took less than half the first time.

Removing the nuts off those rear mounting brackets was not hard using a 3/8" ratchet.





The only struggle I had during disassembling was removing those coolant hoses connected from the TB to the EGR guide tube mounting. I didn't have to cut them but it still wasn't easy. Like others suggested I replaced the clip-on clamps with screw-on clamps to make it easier next time.


I replaced those injector o-rings along with their cap spacers, pintle caps, and side mesh filters. I didn't use the injector spacers that came in the felpro kit because they were narrower. I just left the wider OEM spacers sit in the LIM.


I also cleaned it up and did some painting

infinimax96

I was able to get the rear hoses off with out cutting them. A pain yes, but it is possible.

phatboislim

iTrader: (27)

nothing was cut when i did mine

Maxnub

actually just did this today and got to the 2 coolant hoses and after about an hour of trying to grip those rusty clips i finally cut them. A whoppin $2 for a foot of hose at the auto store wish i would have cut them right away

GGENIUS

iTrader: (1)

didnt have a problem with the coolant hoses when i did this. all you need to do is what the other dude said disconnect the one on the throttle body end. hose clamp pliers and twist the hose back and fourth. people forget to twist

Snypa

iTrader: (35)

neither mine. I hate cutting **** !

wirelessdude04

iTrader: (24)

I ended up replacing the coolant hose coming from the throttle body. I didn't cut it, just got a little bit of a longer hose so I can have some more play in it next time. Btw everyone def cover your LIM I dropped a few bolts down there FML

phatboislim

iTrader: (27)

lol thats standard i figured...actually tore pieces of newspaper and stuffed it down there

agreed...if it needed replacing i would have replaced em, but everything was good

Ninety9gle

did u get the bolts out?

infinimax96

I ended up changing the valve gasket because cylinder 3 spark plug gasket had fallen out of it's place and slid down the plug tube. It was frighteningly close to the valves

Something about cutting the parts when taking it apart bothers me. I've replaced most of my pinch clamps with screw clamps so that I don't have to fight with removing them if something needs fixed again.

asand1

iTrader: (1)

If your gonna drive/work on imports you need these. I was able to remove and reuse my hoses. also use a pick between the hose and nipple and work it around.

http://www.google.com/products/catal...ed=0CFIQ8gIwBA#

ddcoons

I got my valve cover off easily. The gasket came away clean.

But the spark plug seals seem to be nearly impossible to remove.

Am I missing something? can they possibly be this hard to deal with?

ddcoons

I saw some posts that indicate that with some valve covers, the plug seals are built-in. Is that true for 1999 4th gen?


They certainly seem to be permanently atttached, but I have damaged one now. If I can't replace it, I'll have to replace the whole valve cover.

Why would the gasket kit include these seals if they are not replaceable?

jholley

iTrader: (13)

They don't come out easy. I sprayed them with PB blaster then knocked them out with a large screwdriver and hammer.

When installing the new seals coat the outer sides with engine oil then force them in. You also want the curved side of those seals facing down towards the spark plugs.

ddcoons

Thanks. I'll keep trying, but it's incredibly stuck, so I'm having trouble imagining how I'll get six of them out.

ddcoons

Big screwdriver was the key! Popped them out by using a large screwdriver as a lever. from the inside of the valve cover, I stuck the screwdriver under one side of the ring and pressed down using the other side of the ring as the fulcrom. Had to be carefull to no gouge the wall, but all three in the cover popped right out.

Thanks for the tip.

BigLou55

iTrader: (6)

I used a hammer and screwdriver to get mine out, it can be a but difficult to get them out just be careful not to mess up the valve cover because it's scratches easy(aluminum)

phatboislim

iTrader: (27)

glad you got them out, i was fortunate to be able to do my VC replacement at a friends shop and when i tried to pop them w/ the hammer and screw driver out i'd break them, so i had him pop them out

Justaguy

My car also needs a new gasket but besides a little leak of oil, what other benefits will I benefit from replacing the gasket? I'm planning on keeping my car forever. Currently at 270,000 kms.

Thanks

phatboislim

iTrader: (27)

you're doing required maintenance that will also help keep your engine clean...what other benefits do you need?

BigLou55

iTrader: (6)

you'll save money by not buying quarts of oil to keep it at the proper level.

burts

I was trying to get 15 posts so i could make a thread but i know you guys can answer this since your in the area i need to know about..

From under the car I see oil leaking from the general area of under the intake manifold. What sources can it be coming from? I see oil on some intake bolts from underneath the car?

phatboislim

iTrader: (27)

you feel oil behind the rear VC?

ddcoons

Get a flashlight and try to find the source of the leak from above the engine. Since the oil should flow down, the leak source is going to be at the highest point that is oily. When the engine is cool, try to feel for the leaky area since it will be wet with oil obviously. Likely spots will be the corners of the valve covers. There are two valve covers. One in the rear underneath the intake manifold and one in the front (which should be obvious).