nitrous360

I did some searching but found too many different opinions. I've had an oil leak for some time. First, I thought it was the power steering pump, so I replaced it. Still had the leak...damn it! Then I tried tightening the screws. It stopped leaking. Nice! Then my injectors went...Super! So, I replaced them, changed every hose in site, cleaned everything, new gaskets throughout. It's running great now. A few weeks pass and the leak appeared again. Today I again tried tightening the screws. Well, they are tight. So, I just moved the car and there is a nice puddle now. The gaskets are now gone. Question I have is what gaskets actually need to be replaced when I pull the plenum? I know I need the upper plenum gasket. The lower plenum doesn't need to be removed. Does the EGR need to be removed or will it clear if I just unbolt the pipe? The air intake pipe (in front of throttle body), can that be left on? From what I can remember if the intake pipe and egr can be left on I should only need the upper plenum gasket, right? I want to make sure I have what I need when I do this. I can't afford to have it sit waiting for parts. I'm thinking I'm going to replace the cover screws with some bolts. I hate screws.

maxinout93

HI, had to do my valve cover gaskets once, and it was pretty easy! The one in the back went out first, and I was tired of smelling oil through my vents all the time, and also to save my exaust manifold. So that one was done with ease, I just had to slide the cover out and slide it back on. Then a few months went by and the front valve cover started to leak. That was not good, as I never removed the intake plenum since I bought the car, and had no idea how to do it or what parts would need to be replaced, but to make a long story short, I went to several mechanics who wanted to charge almost $200s each. So i came to the Org. and also bought a repair manual. The first attempt, I had a stripped intake manifold bolt, and could not get it out, but the second attempt was a success. You only need to purchase a UPPER INTAKE PLENUM GASKET, the parts store wanted to charge me 50 bucks for the whole set, which you dont need. I got the upper plenum gasket from the dealer for like $16. Make sure you mark the position of the distributor before removing it, as there is one bolt right underneath the distributor. After that the cover comes right off most of the time, and then just seat the gasket in and put it all back togather.

1993-VG30E-GXE

Every time I remove the upper plenum I unhook the EGR Valve, so that means replacing that small 80 cent gasket. I disconnect the EGR flare tube at the bottom - where it connects to the exhaust manifold, and remove the 2 hex nuts attaching the valve to the plenum and slide it out. The throttle body gasket you talk about I leave alone, as the dual duct part just disconnects from the rubber accordian air tube thing and lift out with the upper plenum.

It's all discussed in the Injector Removal section of the FSM or Cylinder Head Disassembly...the beginning part.

So to answer your question the only other gasket you need besides the upper plenum gasket, is the small 80 cent EGR Valve gasket - and you only need 1 of them.....although order a bunch if you can so you don't run into this problem again.

nitrous360

Thanks for the replies. I should have just replaced the valve cover gaskets when I did the injectors. My Max is just spewing fluids out right now. Crusty fuel/brake lines are toast. The oil leak is the worst, so I have to tackle that first. Oil leaking all over my new A frame,CV joint,power steering pump,etc. I hope I can get to a point where I don't have to fix something for a while. I've been fixing for the past two years....

maxitech

iTrader: (7)

It's a never-ending battle with old cars...Trust me, I drive two!

1993-VG30E-GXE

Your so right. It truly becomes man vs machine...maybe that's what we all suffer from - some battle complex

I guess if you replaced EVERY SINGLE PART in the FSM, you would do OK for awhile....but then again.

nitrous360

Yeah, or I just like the punishment. The truth is I actually owned a nice 89 GXE before this one that I got for $2200. It was mint and had 50k on it. My ex girlfriend got pissed at me one night when she was drunk and decided to steal my car and smash it smack into the middle of a telephone pole. True story. Nevertheless the Max was done, and obviously so were we. So, I guess she still haunts me because I would of never bought this car if she didn't total it.

I'll probably be at the point soon when everything WILL be replaced, so hopefully at that point it will be reliable enough until I have the cash to buy a new Max.

GRNMAXDMON

iTrader: (1)

WOAH! damn them ex-g/f's. what a shame for your previous maxima. i usually undo the big bolt from the exhaust manifold to the EGR so that i won't to unbolt the EGR from the UIM so in reality just replace the UIM while in there.

burhan92SE

wow thanks god my gf only broke my sunroof cover clips by punching on it...

nitrous360

Do you think putting some blue locktite on the new valve cover bolt threads would be a good idea? That way they won't loosen up over time. I know the rubber will expand and contract over time but just thinking. Any opinions?

1993-VG30E-GXE

I don't think that's necessary. Just use some anti-seize on the bolts...don't forget those rubber grommet things. And check the FSM for the torque - it's so low it's just snug if I remember. I hope you can get the old corroded phillips head screws out. You have the spec for the new hex head cap screws right?

nitrous360

I got the gasket kit and it comes with new rubber washers, so I should be good. Got a great deal on the upper plenum gasket from partsgeek for $3.31. I will probably use my impact driver to break out the old screws. Worked well on the fuel rail screws. I don't have the bolts yet, what do you mean by spec? The size/diameter? If so, no. I was going to take one to the hardware store and see what I could find. I have a good hardware store in my area. They even carry crome hardware which is rare nowadays. Unless you know of a place...

nitrous360

Any tips removing the distributor so I don't have to worry about timing being off? Should I line up the timing marker with the mark on the balancer and also mark the rotor in the position it's in? If so, I should be able to pull it out and put in back in without messing up the timing right??

GRNMAXDMON

iTrader: (1)

go ahead and line up the marker on the crank pulley with the lower timing cover arrow and make sure the rotor in the distributor is in piston 1. once all that is lined up the timing will be fine but before you remove the distributor get white out and mark the rotor position in the distributor and then make another mark on the distributor to the cylinder head.

nitrous360

^^^^^Thanks. Much appreciated.

My valve covers are leaking so this needs to be done. I'm only hoping that my cam seal isn't leaking because the steering pump is soaked and I can't tell if it's the valve covers leaking or the cam seal. The timing belt was done about 30k miles ago, and at that time the seals were dry. Crossing my fingers because after this I have to replace all my lines (fuel/brake) from the engine compartment back because they are exploding with rust and the brake lines are starting to weep and that's a safety issue. Man this car just won't let up. After that, I have to replace the struts,mounts and springs all the way around......

GRNMAXDMON

iTrader: (1)

ok so before you start taking things apart, clean the engine where oil seems to be leaking and then let it dry. after it all dries, start the car and let it idle for about 20 minutes or so and see if you can trace the leak. once you can find the leak start taking things apart. or just take off the timing covers and see if you can find the leak like that just don't start the car though .

nitrous360

The valve cover gaskets are junk so I know they need to be done. I can see where they are weeping on the front and back. I tried tightening them but they are bottomed out. When I took out one of the screws to match them up with new stainless bolts, the rubber washers were cracked and squished to nothing. The new ones I have are like 1/4" taller that's how squished they are.

After this project I will degrease and see what else I find. Hopefully the cam seals are not leaking because I have another 30k to go on the current belt, but with my luck it won't be the case. Also noticed the bolts holding the timing belt cover have rubber washers also and they don't look so good either. What's up with rubber washers on this car????

Lucky for me though I have the tools and ability to do the work. If not then I'd be screwed.

1993-VG30E-GXE

Rocker Cover Fasteners:

M6X25 CAP SCREW COARSE (18)

1993-VG30E-GXE

Does anyone remember which side of the new valve cover gaskets face down and which side pushes into the valve cover?

One side is rounded and the other is flat. Old ones were squished to death and thrown out.

CapedCadaver

iTrader: (8)

i would tend to think flat side up. is it even possible to install them upside down? i was not aware that they were symmetrical in such a way as to be able to install them upside down

1993-VG30E-GXE

I'll try that, swap them to the other side upside down, see if they fit. From looking at them they look symetrical.

I called one machinist right now and he suggested I should install the rounded part into the valve cover and the flat side on the cylinder head flange. I put them on flat side up, but didn't tighten them down yet, so i'll do more investigating and call around too.

I figured with the round side down onto the cylinder head it would seal better.

CapedCadaver

iTrader: (8)

i think it is round side down.. i will look at my Z's valve covers that i removed to paint, and see how the gasket is set into them. i didn't remove their gaskets yet.. it was handy having something to keep them elevated while the paint was drying.

bigleman

iTrader: (4)

you should PM capedcadaver about your car problems

CapedCadaver

iTrader: (8)

your car is not hawt anymore

1993-VG30E-GXE

I'm curious what your Z covers are like.

I talked to a second machinist, a 67 yr old guy, and he advised me to install it round side onto the cylinder head flange and flat side into the valve cover. He claims it's round so it compresses slightly when you tighten down, and if I installed the round side into the valve cover it would be putting a round piece of rubber in a square hole - if you notice in the valve cover it's square in that gap where the gasket goes.

300zmax

not a bad idea since vibration loosens them over time. i would look in to getting some new bolts for it, socket hex cap heads would work well. or just regular hex.

300zmax

they are near identical only major difference is they have diferent releafs in the top for different intakes.

CapedCadaver

iTrader: (8)

well and the different oil filler (flat vs neck) and the differnent vac/blowby hose bungs.

300zmax

true true i almost forgot