Valve Cover Replacement

[2002 Maxima SE]

Need some advice:

Yesterday, I replaced the rear valve cover on my 2002 Maxima (requires removal of the intake manifold). The valve cover on this car is plastic with a rubber gasket that fits in a groove on the valve cover. Upon removing it, I discovered a dot of silcone in each corner of the valve body.

I requested some information from my co-horts and got varying answers on putting RTV just in the corners or around the valve body. I made the decision to put a bead of RTV all the way around the valve body where the rubber gasket sits. My logic was more would be better and would further seal the valve cover. I did the initial installation and torqured to 25 inch pds. I waited an hour and came back to re-torque to 72 inch pds. The torque wrench clicked almost immediately at 72 inch pds.

After reinstalling the rest of the engine I have let it sit for 24 hrs. I have not started the engine except for 10 sec to make sure I didn't get a CEL (lots of harnesses to reconnect).

Now my question:
I'm afraid there may be a greater chance of leackage at the valve body due to rubber on RTV seal. Is there any harm here? I'm trying to decide if I should just drive it or wait until I can get a new valve cover gasket, scrape off the excess RTV, put new RTV just in the corners and reinstall.

 

[Chris142]

WOW! That is a huge amount of Silicone on there! How much got squished into the engine when you put the cover on?

 

[2002 Maxima SE]

That is an odd question, obviously I cannot see inside the engine. As I said, I have not run the car.

 

[Chris142]

As long as the stuff thats inside the engine stays put your ok. If it breaks off and plugs the oil screen your gonna buy an engine.

Thats about 10x too much goop.

 

[Quest]

IMHO too much silicone! Seriously, if I were you, I would wipe off all those silicone and then just put 2 dollops (about the size of a soy bean) on the far end where the V/C gasket rubber experience an awkward twist (like a sharp 90degree angle, etc.)

This has been a standard practice meaning that whenever there's a sharp twist/angle involved in the rubber gasket sealing surface, that's where a small bit of RTV shall be involved. Also: if you happen to be dealing with a mating surface where another metal component (e.g. water pumpt body, etc.) forms a portion of the upper v/c mating surface, the small little gap formed between the the block and the additional water pump should have a small dab of silicone also before you start installing your rubber gasket.

Lastly, whenever possible, always resort to using fresh new gasket (felpro Perma-dry and mcCord are my best friends!) and try not to re-use any hardened/shrunk/deformed rubber gaskets.

BTW: For flat, continuous V/C gasket surface, rubber V/C gaskets are supposed to be installed dry, not with RTV (although RTV can be used in confidence but cleaning them out afterwards is a mess!).Besides, I have not seen any factory manuals calling on adding big dabs of silicone on top of the fresh rubber gasket material)

 

[2002 Maxima SE]

Thanks Quest. I have removed the valve cover and it came right off, so obviously not a good seal and a valuable lesson learned for me.

Some of the RTV got on the bolts, what is a good cleaning agent?

Any good practices to keep RTV from getting into the valve body when I scrape it out?

 

[Quest]

Maxima-

The only way to clean RTV off is to use brush/scrubbing or wiping with dry paper towels/cotton towels if possible, and then let it "skin" and dry before you can peel the remaining skins off.

Your best bet is to let those RTV to cure (takes overnite) bfore you can start scraping/peeling it off. watch carefully not to drop any RTV debris into the oil hole along the side of the upper valvetrain area into the bottom of your oil pan (clogging up your oil pump pickup screen).

Good luck!

Q.

 

[Merkava_4]

RTV is very finicky; it has to be applied just right and there's little room for error. I don't use the stuff unless there's absolutely no gasket available.

BTW, are they no longer installing heads onto engine blocks and installing valve bodies instead?

 

[2002 Maxima SE]

Thanks Quest.

The RTV was put on yesterday at noon, so it is fully cured. 90% of it came right off and none stuck to the rubber gasket. Using a blade and a cloth with isopropyl alcohol I have been able to clean it off the valve body.

I kept an old t-shirt over the cams, but did find a slither of RTV (paper thin and about 1/8" wide) on top of the cam.

Two concerns:
How can I get RTV out of the bolt holes?
Will any RTV debris that makes it into the valve body return to the oil filter and be taken out of the oil supply?

 

[2002 Maxima SE]

Quote:

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BTW, are they no longer installing heads onto engine blocks and installing valve bodies instead?

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Just my ignorance I'm afraid...

I assumed the valve cover went on a "valve body". Sorry, will refer to them as heads (always thought that was another name for the cylinder).

 

[XS650]

Please call it a head instead of a valve body. Everytime you call it a valve body some BITOGer's head explodes and we lose another forum member

To answer your RTV in the bolt holes question...Just scrape what you can out of the bolt holes then, with the cover off, see if the screw that belongs to that hole will easily (not much more than finger tight) go far enough into it's hole to clamp the cover in place. i.e less that the cover flange thickness left between the screw head and the surface of the engine head.

If there is a little RTV left in the threaded hole and the screw easily goes in far enough, it's not a problem.

Most RTV that falls into the engine will get caught by the screen over the oil pump inlet. Pieces small enough to get through the screen will mostly get caught by the filter. If a small piece gets by the filter when the filter is in bypass, it's not likely to do any harm. It's not a good thing, but odds are you will not have a problem.

 

[Merkava_4]

Quote:

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Just my ignorance I'm afraid...

I assumed the valve cover went on a "valve body". Sorry, will refer to them as heads (always thought that was another name for the cylinder).

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That's not ignorance; a head could very well be named a valve body since it contains the valves.

A head is another name for a cylinder if it's indeed a cylinder-head like on a Lycoming small aircraft engine; in that case, the cylinder and head are an integral part.

 

[Merkava_4]

Quote:

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Most RTV that falls into the engine will get caught by the screen over the oil pump inlet.

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That's exactly what you don't want to happen! You don't want your oil pump inlet screen getting blocked off by RTV. I think I'd have a vacuum hose at the ready while I was picking the RTV out with a pick.

 

[2002 Maxima SE]

OK, thanks all.

Again, a hard lesson learned on my part. I've got the head cleaned off, only a ring is left that was there from the old OEM gasket.

No RTV was on the OEM rubber gasket, but I do need to clean it off. What chemical can I use to clean the rubber gasket before re-installing (isopropyl alcohol and a cloth)?

 

[Merkava_4]

Quote:

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(isopropyl alcohol and a cloth)?

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Don't do that! Alcohol is not good for rubber, it dries it out; which in effect causes advanced ageing. Wipe it down with mineral spirits or WD-40 if you have some.

 

[2002 Maxima SE]

OK, WD-40 it is.

 

[2002 Maxima SE]

Before I claim victory and seal this guy back up...do I need to go over it with acetone or anything else?

 

[Merkava_4]

You could wipe that gasket surface down with some acetone or lacquer thinner yes, but that looks like it's good to go.

 

[2002 Maxima SE]

 

[Chris142]

See those spots where the corners meet? Where the flat part of the head turns and goes up? Clean that off with brakleen and put a small dab of silicone right in that corner. Thats probly where the Original stuff was.

The dab should be about the size of a kernel of corn.

As for getting it out of the bolt holes a reverse drill bit twisted with your fingers works well.