I have a leak higher than the oil filter (according to the mechanic who put it up on the lifts long enough to tell that it wasn't the filter). I have a few drops on the floor in the morning, and it seems that the belts have been throwing motor oil onto and around the alternator.

Admittedly, I have not taken off the wheel and plastic shields to look myself because I've been to sick or too busy, but even if I did, I'm not so sure I'd know what I was looking at.

Thanks for any help.

 

Front crankshaft seal. If it's indeed oil. If it' grease, then it might be CV joint boot leaking.

 

Thanks emax, I'll try that tonight if I get the time.

 

The best way to find a oil leak is spray the area down with brakeleen and then the whole area will be clean and oil free. After you do that see if you see where new oil is leaking from, if you see none turn the engine on and keep a close eye on spilling oil. The oil leak could be a coming from lots of different areas like a pully seal or crank case cover leak. Well see if you can figure it out and I or someone else can tell you how to fix it.

 

whoa, my response to emax, instead of following his post, replaced the one HE responded to. how did that happen?

 

A leaking oil pressure sending unit has been mentioned by several Maxima owners.

Raise the front of the vehicle and support it on sturdy jackstands. Slide under. No need to remove any plastic splash shields. The OPS is easy to see and reach. It is "just around the corner" from the oil filter, in the rear face of the block. Peel back the protective rubber boot. Wipe the sender and everything near it. Start the engine, let it idle for ten minutes, then turn it off. Slide under and look at the sender for evidence of leakage.

Replacing the Oil Pressure Sender is a job which can be done by the home mechanic. Press and wiggle to disconnect the electrical connector from the OPS. You may use a special sending unit socket such as Blackhawk #30634S or ordinary 12-point 1-inch deep socket such as craftsman #47531 to unscrew the OPS. A few ounces of engine oil will dribble out, not much of a problem. You can do the whole job in half an hour, including cleanup time.

 

You got me? LOL

 

Daniel, would oil leaking from the OPS easily make it to the belts and onto the alternator?

 

respond with the OPS.....the whole "belts and alternator" comment didn't sound like the OPS. Plus, an OPS oil leak is fairly minor........

I vote with Jeff on this one.

 

If it's a 4th gen, it's the oil sending unit. Mine leaked and I had it replaced under warranty by the dealer.

Daniel, I was wondering how you had those tool numbers so handy. Do you have them committed to memory, did you go look at your own tools, or did you look them up online?

 

*sigh*

Yes the front crankshaft seal will most definately throw oil on the belts and thus all over the bottom of the engine compartment(depending how severe the leak is). That is why I suggested the seal. Also I have had this exact same problem. Leakage from the main seal dripped into the belts caused the oil to be flung all around. I think also it's the alternator's cooling vents that also blow oil everywhere.

I would NOT spray brake clean over everything. It's pretty caustic stuff. Just take a rag and clean as much as you can. After you get everything fixed, you can use engine degreaser to clean it up later.

 

Daniel's brain to a Nissan FSM.........then it makes sense to me.....

 

A leaking oil sending unit can be one of the probable causes. I went through two oil sending units until I found the culprit (leaking timing cover from the top rear of the engine). Coincidentally, it developed the leak a few months after I switched to Mobil 1 10W-30.

 

No. However, oil tends to be blown around by the air which swirls under the car during normal driving. The place you see evidence of a leak may not be the actual source. That's why you can't really tell about the source of a leak by the location of the drip spots under the car.

 

Upon reconsideration, I vote with Jeff on this one too.

Let's not overlook the possibility it is power steering fluid.

 

My own tools.

 

Ok, here's where I stand:

Jacked it up, took off the front right wheel and the shields covering the crank pulley and the one under the front right bumper. Sprayed everything that looked non-electrical with engine brite (sorry Jeff, I'd have taken your advice if I'd had it before I logged off this afternoon) and wiped everything down that I could.

Then I called my brother who is a self-taught DIYer, and who has worked on Maximas in the past. He mentioned that often the culprit is the valve cover, so he suggested I loosen all 10 bolts and tighten them down to spec. OK. Well, all 10 were VERY easy to loosen, but the only one that seemed to have any oil *near* it was the bottom left one, the one above the oily alternator. And it didn't look caked in oil, just like some had splahed up there in the past and collected dirt. My brother said that maybe it was a slow leak, ran down the block onto the alternator and that was my culprit.

So as I tighten the bolts, they all tighten to about 15-20 ft/lbs, then pretty much spin in the threads. I'm swearing, call my brother back, and he said it sounds like someone overtorqued the bolts in the past, flattened/ruined the gasket, and I was bottoming-out the bolts. Does this sound right to anyone?

Ok, so I bolt everything back on at this point and take the car out for a hard drive to build up some pressure and hope I don't find a leak. I get back after a 20-25 minute drive on back roads, park it in the garage, and put a clean rag under the front right corner to see if anything fresh hits the floor.

I'm sorry this is so long...

It should be mentioned that I checked the oil sending unit, and it may be leaking, slightly, as it was somewhat oily on the bottom half of the unit and the wire sheath.

Also important is that I noticed oil sitting in the small lip behind the crank pulley, where the semicircular seal is made below the pulley itself (does this sound familiar?), but that may simply have been a collection place for spattering oil.

Lastly, and most importantly, the large, flat, vertical aluminum part that's on the left side of the engine, as you face the engine from the front of the car, seems to have dripped one drop since I got back. It ran down the arm that connects to the top portion of the alternator. Could this be my explanation? What is this part? It's two flat vertical pieces bolted together on the left of the block. It's rather large.

Ok, thanks for being so patient and sharing with me what you know. You all know how valuable you are to us who are relative beginners...

 

Ok, that broad, flat, vertical and nameless part I told you about ... it's got fresh oil on the underside of the front end. That's where the _drips_ are originating. I have no idea yet how the oil could get there. Is it coming from inside that part? Is it dripping on from somewhere else, then just running down the under-slope of that part to the tip, where it drips on to the alternator?

In any case, if I have only one leak, I've found where it leads.

Now, what's the next step?

Thanks!

 

The valve cover is supposed to be Tourqed to 8-11 LB's, also you are supposed to take them off in a coun ter clock wise fassion. ABout fixing the leak I can't tell exactly because I would need more info or to see it in person. I can't think of any places above the alternator that could be leaking, the only thing above the alternator is the Super charger, hmm?

 

I followed the Haynes diagram for tightening the bolts in a particular order, and it said to tighten them in two rounds: round one is 9-25 lbs, and round two is 48-6X lbs (can't remember the number).

 

Jeff, Daniel, what do you think?

 

In an earlier post you said this:

So as I tighten the bolts, they all tighten to about 15-20 ft/lbs, then pretty much spin in the threads. I'm swearing, call my brother back, and he said it sounds like someone overtorqued the bolts in the past, flattened/ruined the gasket, and I was bottoming-out the bolts. Does this sound right to anyone?

The torque specification for those bolts is 4-5.4 foot-pounds. You overtightened those bolts and probably stripped the threaded holes. That might not ruin the gasket, but it would eliminate the clamping force that any gasket needs.

The usual remedy for stripped threads is to drill the damaged holes to the next larger standard size and tap new threads. I hope these particular holes have enough "meat" around them to accomodate this repair technique. If you undertake this, take care to prevent metal cuttings from getting inside your engine.

 

Did I misread the Haynes manual? I don't have it in front of me...

Now, as for the leak, any ideas?

 

If the leak is, in fact, from the valve cover gasket then you have to
1) Verify that the installed gasket is okay, or replace it.
2) Perform whatever thread repair may be required.

Each spark plug hole is sealed with a gasket ring. If the valve cover is not held down properly your plugs may be "swimming" in oil.

 

Daniel has it right on the money. Those head cover bolts sound stripped. Remember your tightening into a soft aluminum head. Very easy to strip threads.

It's very hard to diagnois oil leaks over the internet and since you confirm the valve cover gasket could be suspect, I doubt that anyone could really say what it is until you get this fixed first. Get the holes retapped or helicoiled, buy a new cover gasket and o-rings for the sparkplug holes(this could be part of the gasket but I can't remember), then tackle this pesky oil leak.

Good luck and keep us posted!

 

Well, I checked it out and the valve cover gasket seal still looks in tact (I didn't just keep spinning these bolts in the threads -- I backed off as soon as it felt funny).

a.) What is that part to the left of the head cover I mentioned? Looks aluminum, sitting up vertical, running along the left side of the engine?

b.) How would oil get onto it and run forward if it's not the valve cover leaking?

 

a) Sounds like a timing chain cover.

b) Well there is a chain tensioner under the cover tha supplies oil to the tensioner and the chain. This cover should either have a gasket or sealant behind it to seal it from oil leaks.

 

If it's the timing chain cover, brace yourself for an expensive repair, somewhere around a grand.

 

Daniel:

I eventually need to do mine too. Just snug it up till tight or should a torque wrench be used? Also, I notice the FSM mentions thread sealant.

Thanks

 

Wow!~ You guys are talking about the little plate on the side of the engine which allows you to gain access to the timing chain right? If this is the case I replaced that peace when I installed my SC and about month later I got a massive oil leak there. Well my car was in the shop getting my Clutch installed and the guy said it would cost $600 to fix the leak, LOL. Well anways the moral of the story I fixed it my self, I had to remove my SC and then belt tensioner rod, then I got to the damn plate and cleaned the area down with brakleen then I undid the 4 bolts, removed the plate and cleaned the area somemore. Next I got some , Liquid sealer{i.e. Permatex Form-a-gasket#2, Loctite 518}. Anyhow I put that on the plate and reinstalled it back onto the engine tightened the 4 bolts and the leak is gone! So really if thats the problem and if you don't have a SC it is pretty darn easy to fix{for my anyways}. With the removal of my SC it took me about 4 hours to do.

 

The torque spec for the Oil Pressure Switch is 9-13 foot-pounds. I would not bother with a torque wrench, just snug it up. My FSM does not call for sealant. I'm looking at the '99 Maxima FSM, page EM-13.

 

Daniel:

My 95 FSM does in fact call for a thread sealant. I wonder when it was eliminated in later years. I found some sealant made by Loctite and intend on using a dab of it on the sensor threads.

Thanks for your help.

 

Loctite makes an extensive line of threadlockers. They range in tenacity from low strength to permanent. Choose carefully.

For more information about Loctite threadlockers, see http://www.loctite.com/catalog/categ...ProductLine=10

 

Thanks Daniel:

I researched this carefully and found a thread "sealant" as opposed to threadlocker. They have a very nice website and I studied the product data sheets.