Valve cover gasket replacement on Infiniti I30 and Nissan Maxima:
As the VG30 gets older, and more of them get up there in mileage, a common problem has come to light. The valve covers and spark plug seals often leak oil. Both out onto the block, and into the spark plug tubes. This can diminish performance, as well as leave oil stains on your driveway.
Skill Level: 3 or 5
Time Required: 1 to 5 hours depending on personal skill. Take your time and do it correctly the first time.
Tools Required: A general mechanics tool set is a must, including but not limited to sockets, ratchets, wrenches, pliers, and screw drivers. Common sizes for Nissan and Infiniti vehicles are 10mm, 12mm, 14mm, 17mm, and 19mm.
I decided to replace the valve cover gaskets and spark plug gaskets on my I30 because they were hemorrhaging oil pretty badly. This job requires a lot of patience and I highly recommend labeling hoses and electrical connectors for a flawless one shot one kill start up. I suggest you set aside at least 5 hours to do both valve covers. I’m sure it can be done in a lot less time but why rush when you’re not getting paid to do it fast. I ended up going to the parts store to buy some replacement rubber hoses due to dry rot and also a new PCV valve because they are so cheap, albeit important to a car’s performance.
To start off, remove the airbox and intake hose from throttle body. Disconnect the throttle cables and then the two 10mm bolts that holds the throttle cable bracket on the intake manifold. Remove the two 12mm nuts securing the part on top of the intake close to the IACV. I have no idea what its called. Remove the IACV, and the four connectors that go to it,to get to the two 12mm EGR bolts (not actually the valve but an inlet from the EGR valve to the intake) at the front and right side of the intake if you’re facing it from the drivers side fender.
There are only two 12mm bolts and two 12mm nuts that you can actually see securing the upper intake. Then there are two more 12mm bolts that you’ll have to feel with your hands on the side of the intake by the firewall. These two 12mm bolts secure the side of the intake to two brackets. That’s 6 total bolts and nuts plus the two EGR bolts for a total of eight that you have to remove in order to take the upper intake off.
There is a U shaped rubber hose that is hard as hell to remove right behind the EGR inlet and another hose in front of that. Make sure you have some spray lube and long needle nose pliers to get to the clamps and to help you remove stuck rubber hoses. There is also a coolant line that goes underneath the throttle body and connects to the throttle body. I had to replace this hose because it was so swollen I couldn’t remove the snap clamps. I bought worm gear clamps to replace those(I forgot to tighten the side that is not attached to the throttle body and it causes a huge coolant leak that was hard as hell to see). Make sure you tighten those clamps. Those three hoses are pretty much the only ones holding the intake down. Once they’re off, lift up on the intake and remove. The gasket is rubber so it stays.
Make sure you cover up the lower intake to prevent foreign materials from falling in.You don’t have to remove the coil packs to remove the intake but you have to disconnect the connectors (rear bank). It is easy to remove the coil packs so I went ahead and did so. Be careful, or you might leave a boot in one of the spark plug holes, which I did. Now just remove the 10mm bolts all around the valve cover and lift it off.
The gasket on the rear bank was so dry it cracked into a bunch of pieces. Be careful removing the spark plug gaskets in the valve cover. I used a small pry bar to pry it out. Make sure you pay attention to which end goes up so you don’t install them upside down. I used a dead blow hammer to gently tap them into the valve cover. I also used super glue to glue the gasket into the valve cover because it kept falling out while I tried to put it back on the head. Just put a small drop in the corners and everything 3 or 4 inches around the valve cover and let it dry. This will make your life so much easier, especially on the front one because the damn wiring harness is a b… to get the valve cover under while trying to hold the gasket in place.
Make sure you clean the head where the gasket is gonna sit to provide a good seal. Hand start the bolts around the valve cover and tighten it from the inside towards the outside.Try not to overtighten. I use my Craftsman 19 volt impact driver because it is fast as hell and provides perfect torque for the valve covers.
Now is the time to put the intake back on. Make sure you reinstall the three hoses back on the intake. The two by the EGR inlet are tricky. The coolant line to the throttle body isn’t too bad. Once the three hoses are tightened, try to get the EGR inlet bolts started and then sit the intake onto the lower intake. Tighten the two 12mm bolts first and then the two 12mm studs last. Consult your FSM for proper torque specs. The rest is easy, just put all the brackets, IACV, hoses, and connectors back together.
The front valve cover is a piece of cake. You do have to remove the coil packs to remove the valve cover.
Remove all the 10mm bolts holding all the brackets and wiring harness on top of the intake in order to remove the intake.
Notice the blue tape labeling the connectors and hoses for easy reassembly.
This is the bracket holding the PCV hose and another vacuum line.I replaced the PCV while everything was apart.
These are the two hoses by the EGR inlet that I was talking about, they suck.
See the long hose underneath the intake, that is where you have to disconnect the U shaped hose and the other rubber hose. It is right next to the EGR inlet.
Notice the two brackets, that’s where the two 12mm bolts you have to feel for
attach to the side of the intake. Also, note the dreadful U shaped hose right by the EGR inlet.
Notice the IACV and the new and old spark plug gaskets and also the old, broken valve cover gasket.
This article was written by: Vu Bach Nguyen (Evil I 30)