What's this string do?... To those that are familiar with VQ40DE this is simple. For those like me who are new to this 4.0, not so much. "While you're in there..." Replacing rad, hoses, belt, tensioner, trans cooler lines, oil cooler liners etc. on my "new" Pathfinder, I noticed the passenger side timing chain tensioner (main) cover had a pretty good oil leak. (couldn't see it with shroud, fan etc. in place before hand). I had all the parts for everything else but as this was unexpected the wife had to run me to the store to get Permatex Ultra Grey RTV 82194, as I'm stranded while she's at work. No big deal, I'll pop the cover, clean it, scrape the flange, wipe down with brake cleaner on a rag and it'll be done, like I've done hundreds of times on other engines. Wrong! I was unprepared for what lay in wait. ( I actually double checked the fsm just in case there was something I needed to know and read through related forum topics for any tricks I could use. Nope, S.O.P.; onwards). I used a razor blade and a shim (for leverage) to carefully cut through the old rtv. Man that was no joke. Then the surprise. The case flange has a groove in it to form a thicker seal, where I thought it would be flat. The problem was that I didn't plan on spending that much time on it (sounds familier, huh. Wife wants "her" garage space back ) With dental picks, small screw drivers (the plastic ESD safe type used for electronics so as not to gouge), old credit cards, razor blades, paper towels, 600 grit sand paper and throbbing fingernails it took me 5 hours total to get the cover off, flange cleaned out/off and re-installed. Granted I'm festidious and was taking my time, but dang. After removing as much sealant as I could mechanically (I had a piece of foil in the hole to keep debris out of the timing case) I used brake cleaner on blue shop towels to get the rest. I didn't want to nuke it or hose it down with MEK (which is what I normally prep with) because of the plastics on the tensioner and guides. I didn't need to push my luck. Not a difficult job, with patience (until your back starts hurting, wah) if you're ready for it. I'm surprised Nissan didn't use a silicone rubber gasket here (reduce # of bolts needed by using RTV maybe?) Just wanted to pass it on to other noobs here.

Cheaper for Nissan to use silicone RTV for gaskets and, when applied correctly, tends to last for a long time. I can't remember the last Nissan timing chain cover that used gaskets; maybe the ol' L-series and NAP-Z engines? KA, GA, SR, VQ, QR and MR engines all use RTV silicone on the covers rather than gaskets. But, yeah, I agree that it is a real pain to clean out the grooves!

Good point. I didn't think of cost of a gasket, I was thinking of cost of driling+tapping for an extra bolt or 2. I wondered about an after market gasket, but that wouldn't be profitable because of low demand. (ie not needed too often other than water pump replacement, occasional leak like mine, just would make life easier when needed). The only other Nissan engine I have experience with was the VQ35DE on an 03 Infiniti, and that never leaked on the front (189,000mi when sold 3 mos ago). Great power plant, 255 rated HP and only (non-standard) problem was one of the darn cam pos. sensor connector. Heat would wreck that. Makes sense that they all use rtv. I can only imagine the work involved in prepping the entire timing cover for chain replacement as you mentioned in other posts. At least one could get more aggressive cleaning it with it removed.

You don't have to remove the entire front timing cover to replace the water pump. You probably noticed the two, black, stamped steel covers on the timing cover. One covers the primary timing chain tensioner and the other covers the water pump. To replace the water pump, those two covers are removed, the tensioner is removed to provide slack in the timing chain, followed by turning the crank pulley to put the slack at the water pump. Then the water pump 6mx1.0 bolts are removed from the water pump and 8Mx1.25 bolts are used to pull the water pump out while lifting the chain off of the water pump gear.

Thanks for the reply. No, you don't have to remove the entire front timing chain cover. All of that work I did was just for the primary chain tensioner cover on the passenger side of the timing cover that was leaking. The cover on the cover. Although after seeeing what the tensioner looked like a water pump job isn't as daunting as the fsm made it seem, knock on wood. I've already ordered new covers (tensioner and pump) just to save time cleaning them in the future. ($4 and change)

The covers are nothing to clean compared to having to do the front cover! Talk about a PITA!

I imagine quite colorful language being used during that! I know that the timing guides, chains, tensioners R&R are in the future (as I plan on having Pathfinder for very long time) at some point. I'll bet cleaning the timing cover might be the hardest part of the job; dreading that. I'm picturing the small area I did and multiplying it tenfold. I've read mixed reviews on rtv "dissolvers", (Permatex) but I don't know if anything available to the public anymore is even worth it. I remember trichloroethylene made it easy to soften and remove, but you won't find that on the shelves anymore! Brake cleaner USED to have that in it, maybe some brands still do? I wonder if the cover could be magnafluxed or some other "bath" at an engine shop, but cost would have to factor in. I thought I saw a new cover runs about $250? Tempting if one is in a hurry and the credit card is melting anyway

It's possible you may never need to do the chains. As many problems as there have been with the upper chains cutting through the plastic tensioner faces, it really all depends on what condition the tooling was when your upper chains' links were stamped as to when or whether you'll need to replace them. If the tooling was in good shape and your upper timing chains' links were stamped properly, they could last the life of the engine. So, unless you start hearing the infamous "whine," I wouldn't worry about it.

Thanks for the encouragement and sharing your knowledge, your posts across the board have been extremly helpful. Funny thing is that I've had Pathfinder for a over a month now, and most of that time she's been parked while I'm wrenching on her, and waiting for parts. Haven't really had a chance to put an ear on that timing cover, but from what I've learned (Ford power steering pump noise, man do I know that racket!!), if she's going to have that issue it will be obvious. After the exhaust leaks are tackled (Frickin' LOUD! Pipe connecting gaskets are virtually gone) I'll have a better idea. Fingers crossed. Thanks again!