Sitting, idling at a light, or just cruising slowly around town, and you get this pungent odor through your windows or vents of burnt oil. A common issue with the 4.2l wet sump and dry sump motors, whether a GS, GT, 4200, or Quat is the valve cover gaskets. Basically they begin to seep, then leak down on top of the exhaust manifolds. Then you always have this oil smell when hot idling or cruising around at slow speeds. Sometimes when you start it up there will be smoke coming from the front of the car from the oil burning off on start-up.
The pictures above gives you an under the car perspective of what’s happening with the valve covers. This particular Maserati had 58,xxx miles on it when I performed the service. Pretty sure it was done before I did it as well. Again a common occurrence with the 4.2ls.
Here are a few more pictures, but these are the spark plug holes. You need to make sure when you perform this service you order the correct gaskets for the spark plug holes as well. The valve cover has a gasket and each of the spark plug holes underneath have separate tube style gaskets. As you can see below with the oil sitting inside the spark plug cavity it’s very important this is addressed and doesn’t ruin your coils in the process.
Where to Start?
So first things first, you should order the parts and get them ready. You will need the valve cover gaskets, the spark plug hole gaskets, and the secondary air injection gaskets for both sides. You can go to Ricambi, or Maserati Parts USA to obtain them. Secondary Air Gaskets is Part # 186781 (x4), Valve cover gaskets #198927, and 198928; Spark plug hole gaskets # 187706 (x8). Also, this is just my personal opinion, instead of replacing the press clips, purchase the worm drive clamps instead. Throughout you will notice I am using them, it will make any subsequent service easier on all parties involved.
You will need to remove all of the plastic trim around the engine bay.
After removing all the Trim, we will start with some of the easier components.
The intake tube, throttle body, and MAF.
Now you might notice I have worm drive clamps already on my intake. You will need to use a straight screw driver, and pliers to initially remove the stock clamps as they are crimped on there. Also if you are doing this on a wet sump motor, like the Gran Turismo, of course all of this set up will be slightly different. I will add photos of the Gran Turismo/ later Quats set up (when I can later) to make it easier for those replacing valve cover gaskets on those.
You will notice that there are actually clasps you need to unclamp to remove the MAF housing from the air box housing. You will then remove the MAF wiring harness. After removing all of the press clips you’ll see all of this comes right out including the Throttle body below. You can either clean the throttle body now, or when you get ready to re-install it.
Spark Plug Coils and Cam Variator Plug
After you have removed all of the intake hoses and connectors, etc.
Above you will see I removed the “Maserati” logoed wiring harness cover plate. This is necessary to access a few things, first you are going to want to remove the spark plug coils. With the plate removed above you can see all of the harnesses that run underneath it, including the numbered fuel injector harnesses, the cam variator C clip holding the wiring harness plug to the valve cover and of course the coil harnesses. There are three small hex bolts holding the two cover plates on.
Now you’ll notice I just placed the coils on the fender cover out of the way. But if you prefer, you can also unplug all of the coils by the wiring harnesses that run right next to the fender.
Next, disconnect the fuel injector wiring harnesses. Just push up on the clip underneath each fuel injector plug. If you’ll notice I never said anything about numbering the coils of the fuel injector harnesses. Mainly because common sense dictates you’ll see that’s a nice factory added benefit: they are already numbered.
Just pull the harnesses back out-of-the-way so they don’t snag when lifting the valve cover, or worse, get caught underneath when you put them back on.
Next up Cam Variator plug.
It seems simple enough, but wait until you get to the connector, because it’s a bit untraditional and you will need to pull the catches outward with either two pics or small screw drivers.
Above just pull the C clip off, and you can push the plug seal slightly inside. Then below, unplug the connector.
Now inevitably, I’m going to forget to tell you this later on, so remember this, clean every plug connector and put dielectric grease on them before re-installation.
Next, up towards the back of each valve cover toward the fire wall you’ll see the Cam Phase sensor like above. These on either side also need to be removed. Again, I’m going to forget to tell you replace those O rings on both the sensors and Variator Solenoid hole plugs.
Just slightly above each Cam phase sensor, you’ll see a metal elbow with the hose on it. Pressed clips like all the rest. This is your PVC system.
Take those clamps hoses off and replace them upon re-installation with worm drives.
Secondary Air Injection System
Okay, so now you should pretty much have everything out of the way before we pull the bolts and the valve covers off. I really saved the worst for last because it’s going to require careful attention to detail to prevent frustration with this process. If you removed everything else and thought that wasn’t too bad, this next part will make up for it, not to mention you’ll love reinstalling it as well.
So I’ve included a few photos above. First what you will notice is that you cannot detach, even if you wanted to, the valve cover bolts on the lower part of the cover until you remove these valves out of the way. The second thing you will notice is you have bolts that attach the above elbow going down, and also coming up. So you will have to use an allen wrench key or something similar for the limited space, to especially detach the allen bolts that are facing up.
Small tip: if you are prone to drop your tools, tie it to your wrist or something similar.
Next tip: detach the clamp fit hose clips and hoses from around the valve to give you easier access. Remember to replace the gaskets on both sides of the elbow or you will get secondary air injection codes in the CEL on the dash.
I use swivel sockets and such, as you have seen above, for the hex head bolts facing down, with long extensions. If the car is on a lift you might be able to get them for the ones coming up as well. I just do this from the top.
Just want to include these photos above as well. The secondary injection piping runs around the front of the motor. The hold downs should be loosened so you have movement, again the clamps like the above photo for the driver side also need to be taken off so you have movement.
Once you get all of this stuff taken care of you can pop the valve covers off. Now, be very careful, as I usually just push the air injection system out of the way, turning the valve cover to bring it up. On the Passenger side it can be tight and tricky, you should use duct tape or painter’s tape on the cover so the secondary air injection doesn’t accidentally dig up the valve cover. Take your time, don’t get frustrated. If you see any potential contact, put painters tape underneath it on the cover. Make sure you make it thick if you are concerned you will scratch it.
Seen above is a plastic trim removal tool, no metal to metal contact to pry up the valve cover. No metal to metal anywhere. Don’t have one? Wrap black electrical tape a few times around the tip of a screw driver. Before you pull these off, I’m assuming you’ve already cleaned all around the top to make sure you aren’t dropping loose nuts or anything else a previous Tech left up there. This includes dirt/debris.
There you have it, you removed the valve covers!
Okay before we go any further, we want to clean the valve covers properly, they have dirt/grime, etc. all over them. You don’t want to pressure wash them or use any harsh chemicals. You’ll want a soft bristle brush or you’ll mess up your finish.
The cleaner above works good, but also Simple Green which is basically what this is. I’ve included a side by side to also show how vibrant the color is after it’s been cleaned. You can air dry it, or blow it off with a compressor.
It’s the reverse of what I just walked you through…..lol. I love that in service manuals.
Now you are going to clearly see how the gaskets are removed from under the valve covers, both gaskets have different part numbers and align differently so you cannot get them mixed up. I also use a product like Permatex Red High Temp RTV gasket maker to make sure I don’t have to do this again. Do not use any quick-setting Gasket maker (like products that come in a can), it will not give you the time you need to place the covers back on.
The replaced valve cover above, nice vibrant red and ready to run without the smell of oil.