mikeyen

I finished my inner TC cover tonight, and the car sounds terrible, like it has bent valves.

The engine runs smoothly, and the sound goes away over 2,000 rpm, but below that, it has a really regular, extremely loud clatter. I don't think it's chain-slap until the oil pressure builds up.

What are the symptoms for bent valves on this car? And why would it run relatively smoothly over 2,000 rpm?

How long does it take for the clatter to go away after this job?

mikeyen

I wanted to point out one more thing: I was extremely careful about getting the timing right, to the point where I decided it was a good idea to check the valve clearances. All 24 valves were within spec. I'm not sure how you can have bent valves and still have the valve lash be correct. I'm pretty sure I got it right, although I won't guarantee that completely.

dwapenyi

iTrader: (3)

Post a youtube video of it.

mikeyen

The next thing is that I noticed a coolant leak last night, and figured I'd forgotten to tighten a clamp. Wrong. The coolant appears to be coming from behind the inner TC cover. What could I have done to cause that?

I have a feeling this entire thing is coming back apart. Maybe I damaged the inner O-ring on the water pump when I put the pump in...? I think the coolant is coming out through the weep hole.

mikeyen

Here's my video, sorry for the orientation on the screen.

https://www.youtube.com/watch?v=MkXkfuW9HN8

My very quick take: Doesn't seem like the sound is coming from under the valve cover. Seems like it's coming from the rear-bank gears. I think I torqued down all the gears... But what if I somehow did not? Obviously a recoverable error; that'd just be time.

It's a terrifying video. Rated R, for Redo.

theWalkinator

Sounds like slapping chain....

mikeyen

After my panic subsided, that's what I concluded too.

After reading other posts here, I see that people mention "priming" their tensioners. This is a step not mentioned in the FSM, as near as I can tell.

If it is a slapping chain, would you think it's the main chain, or the one that goes between the camshaft gears?

I am heavily inclined to not start it with this sound, especially with the coolant leak. I think I must have fouled up the water pump when I put it in. I thought I was being careful, but I guess not.

mikeyen

I now read this instruction in the AllData page:

"After installing the tensioner, race the engine at about 3,000 RPM under no load to purge air from the high-pressure chamber. The engine may produce a rattling noise. This indicates that air still remains in the chamber and is not a matter of concern."

So maybe the problem is I'm too chicken to rev the engine, given the noise level?

What is the "High Pressure Chamber"?

mikeyen

I think it'd be a bad idea for me to start this car again until I have a little more guidance.

In fact, I think it may be a good idea to not start it until I replace that water pump. A loose timing chain and the state of disassembly it's in are good starting points to do a water pump.

With that much coolant gushing out from behind the A/C compressor area, I can't see what else it can be besides a wrecked inner O-ring on the coolant pump.

max ride 41

iTrader: (4)

you don't know that until you take it apart again, did you check the tensioner/guides to make sure they're not worn? or did you replace them? imo that does'nt sound like a valve problem, your pump might not be lined up properly and for sure the seal is leaking or you have a bad pump.

dwapenyi

iTrader: (3)

Probably in or around the TC tensioner. It uses oil pressure to keep the TC from slacking. Racing the engine to 3k revs makes the gear driven oil pump develop more pressure to push the oil around, and hence push the tensioner more.

metalgod3082

I had the exact same sound when I replaced the inner timing chain cover o-rings and first started the engine. Everything I read said it was completely normal and just rev the engine to 3000. After I did that for several minutes (maybe 5 to 10 minutes off and on) it eventually went away.

cardana24

iTrader: (81)

I don't have a different suggestion, but I am curious if you did the job with the engine installed or if you took the engine out? If you kept it in the car did you document the procedure or have a clue how many hours it took? I have an engine that appears to have leaky o rings too, and I am debating on what to do.

M in KC

Is all that coolant on the ground leakage after you buttoned everything back up.? If so you have to solve that problem first. If you replaced the o rings on the water pump bear in mind they are two different sizes. Once that is done the rattle can be addressed. But as you have found and others have commented the engine will sound similar to what yours sounds like on your vid. until adequate oil pressure builds up and tension is put on the timing chain. I know when I did my water pump, TC tensioner and t-stat replacement and started the car up after all that goodness I swore the thing was going to cannibalize itself. But like you have found once the pressure built back up it sounded like a sewing machine once again.

cardana, there should be a how-to for the water pump replacement in the 4th gen How-To folder, or there are You-Boob videos for inspiration. No need to pull the motor to change the water pump's o-rings. Its an all day job for someone doing it the first time who has the ambition. You don't really need any special tools its just that the access is tight to relieve the tension on the drive chain and to pull and reinstall the water pump. Dozens of guys on here have done this repair. My advise, change your TC tensioner, t-stat, water pump, o-rings, rad. hose, new hose clamps and accessory belts since all that has to come off. You will also need oil and a filter for an oil change since it's about impossible to keep the coolant out of the engine once you crack the seal on the water pump. You might as well go back with new everything and be done with it. If you are ubber-paranoid like me you buy two sets of water pump o-rings in the event you were to gash one during installation. Good luck.

metalgod3082

And if you were referring to replacing the o-rings behind the inner cover I was able to do it with the engine in the car. I followed the upper oil-pan walkthrough on here and then used the FSM to finish the rest as far as torque specs, setting the timing, and sealing the covers. Took me about a week working on and off and cleaning everything and kind of limited room when reinstalling the timing covers and not smearing the rtv all over but was able to do it

cardana24

iTrader: (81)

Thanks for the replies guys. I have done all of the work before including replacing the o rings behind the tc cover, but I have always had the engine out of the car. I can pull the engine in a few hours so I am wondering if pulling the engine would be worth the saved frustration of doing the job while the engine is in the car.

mikeyen

To clarify, I made the mistake of using the water pump I took out, along with the O-rings.

Bad idea. This is a lot of hours to spend working on a car, and you're going to have the water pump in your hand. If it has less than 20k miles on it, fine, put it back in... But replace the O-rings, at least. I think that was my mistake; re-using those O-rings.

This water pump felt great, but I know it had close to 100,000 miles on it. Not replacing it was dumb -- even though it seemed fine.

I'm now on to my next problem. I have to replace the water pump. But as a matter of taking this apart in the first place, I updated the tensioner and the guide. I also used the gasket they now supply. In removing that tensioner, just a few minutes ago, I dropped the gasket in there. The bolts came out, and I heard a little clink. Very disappointing. Outer TC might need to come out now.

Do I have any hope at all of fishing that thing out?

Also, I can't believe how much tension there is on the main guide side, even with the tensioner out. It's as though the camshafts are trying to turn clockwise. What is up with that? Is this normal? The FSM doesn't have you park it at TDC or anything like that; you just take the covers off.

This is all with the engine in the car, and because I work 2 hours here, 2 hours there, the amount of time I've spent is meaningless. It's been too long, but I'm very slow. No answer I give would be relevant.

The coolant on the ground is after I started the engine. It's a completely shot inner O-ring, I'm just about completely sure. It's all coming out the weep-hole.

mikeyen

Has anyone ever tried one of these?

http://www.oreillyauto.com/site/c/de...0722&ppt=C0374

metalgod3082

I've heard of people retrieving a lost tensioner spring or piston with one of those so it is definately worth a try. Is the tensioner gasket metal? Been awhile since I did mine and can't remember.

Fakie J Farkerton

iTrader: (51)

I would just replace the o-rings on the water pump..and if you get a new one, Oem will outlast aftermarket any day.

mikeyen

That gasket is metal.

I found this thread:

https://maxima.org/forums/4th-genera...g-problem.html

It's the photos in that thread that are useful. The text doesn't really pertain to me.

I figure the thing slid down behind the slack-side tensioner and is now in the vicinity of the lower pivot point of the tensioner. There's no direct path to the sump from there.

There's a good chance I'm taking this all the way back to the outer cover.

I also managed to drop a water pump bolt. That one had a direct path to the sump; I could hear the splash, and you can see the inside of the pan from there.

All in all, not a good night. Although when things land in the sump, there's probably no reason it can't stay there forever. Not as worried about the bolt.

I wonder even how concerned I should be about the tensioner gasket. If it ever did get picked up by the chain, it'd be obliterated and the bits would end up in the sump. It's not ideal, of course, but it's not a substantial enough piece to cause any damage. The strainer and the filter would take care of these bits.

mikeyen

Now I really can see the cause of the leak -- two huge nicks in the impeller-side O-ring.

In my mind, you add this to the list of "must change" when doing an outer or inner TC job: Over X miles, water pump; under X miles, at least do the O-rings.

You're crazy if you don't.

mikeyen

I got it running, and it sounds great. The video doesn't really capture how good it sounds.

https://www.youtube.com/watch?v=eEr1jnqd8ZM

mikeyen

I have one thing left to do. The idler pulley sounds very janky. I'm leaving it on the stands not because I need to, but because this job is slightly easier with the car off the ground and the under-covers off.

mikeyen

Here's my suggested shopping list for an inner TC cover job:

Water pump
Thermostat gasket
O-rings between block and inner cover
Updated tensioner and guide
Grey RTV
Black RTV (just enough for the steel oil pan; use grey everywhere else)
Drive belts
Idler pulley
Check your motor mounts before you start; at 200k miles, you're very likely to need 4.
8mm by 1.25 bolts to remove the water pump
New bolts for the transmission motor mount
A low-pressure PS pump hose
Two new copper rings for the PS high pressure hose
The little U-shaped coolant hose that goes behind the intake manifold
A new ring for your hidden oil drain plug
A new gasket for where the EGR tube connects to the intake manifold
A new intake manifold gasket set (I only used the rubber one)
A new throttle body gasket
New gaskets that go between the manifolds and the Y-pipe
New valve cover gaskets
I like to replace the frustrating spring hose clamps where possible when I work on this car

I think that's about it. It's probably close to $500 worth of items.

The fact that I replaced all these parts probably goes a long way to explaining why the car now runs better. I bet I have a far better seal on my intake manifold now, for example.

mikeyen

By the way, I think the main difference between the new tensioner and the old is that the new one has a far stiffer spring in it. The housing is about 5mm longer than the old, probably only to accommodate a stiffer spring. I bet that's the only difference.

Since it's longer, this very slightly alters the geometry of the pushrod, so the guide is slightly different. I couldn't see any differences between the two guides, but you might not notice if the rod on the guide was rotated 5 degrees.

theWalkinator

So how did you get the gasket and bolt out? It happened to me that I dropped a water pump bolt, cannot fish out with that flexible magnetic so I have to drop the lower oil pan. I re-use the water pump, but replaced both inner and outer o-rings, the original water pump is 180k miles but no problem since I replaced the o-rings, no leaks.

mikeyen

I know you'll think this sounds crazy, but don't worry about the water pump bolt. I confirmed the heck out of this: That leads directly to the sump. It's now sitting on the bottom of the steel pan, miles below the crankshaft. It won't hurt a thing down there.

That gasket is wedged in there somewhere. Again, the strainer is pretty fine, and that gasket is not very substantial. If it ever does find the timing chain, that chain will win, big-time.

Study some of the photographs and you'll see it really can't go very far. I was even thinking of this: Pulling the harmonic balancer and the seal and see if it's between the pump and the front case. You might get really lucky and find it there.

I wanted to get that gasket out. I tried. If it ever does find the chain, the chain will win that battle in a huge way. I suspect that one day, it'll get caught in the chain and get crunched, then pieces of it will drop into the sump. None of the pieces would be large enough to go into the strainer. So basically, I don't think it'll eat much.

A bolt would be a different story.

That's my story and I'm stickin' with it.

mikeyen

Man, if my water pump had 180k miles on it, and I actually had it in my hand, I'd replace it. Final answer. I got an AC Delco one on amazon for $32. 90% chance of overkill, but that's a huge job, and 180k miles is a lot. Half a chance you'll be back in there in 40k miles.

Fakie J Farkerton

iTrader: (51)

Should have gone OEM if you're replacing the water pump.
The only thing that fails on OEM is the o rings.
The aftermarket actually fall apart.

mikeyen

I hate to bump this at this late a date...

I'm positive I cross-threaded a couple of the steel pan bolts. Luckily, this is one of the easiest parts to reach on the whole car. My plan is to drive it for a while -- maybe 1,000-2,000 miles, then change the oil, and while it's empty, remove the lower pan, and use heli-coils to repair about 2 holes.

Yes, it's leaking a bit. Not gushing, but dripping.

Just hoping anyone might have good advice for doing this task. I'm open to ideas.

mikeyen

The one I had in there was an AC Delco, which is why I bought another one. Like I said, the bearings were silky-smooth. That one had around 100,000 miles on it. Maybe the AC Delco is one of the good ones.

max-nutcase

just wondering if the oem pumps never fail, why replace anyting but the o-rings?

Fakie J Farkerton

iTrader: (51)

Sometimes people run water or badly neglect their engine's cooling system and the fins on the water pump rot.
That's the only reason I can think of at the moment.

max ride 41

iTrader: (4)

hellz yeah, have'nt you ever seen a water pump that's got he fins worn off of it? causes overheating and major issues.

aackshun

iTrader: (3)

Wait, so your fix for the tensioner noise was what again? Replacing it? Was it the main? or one of the secondary tensioners?

Some local here got that noise once upon a time, we narrowed it down to the camshaft tensioner, and ended up replacing it... Even though he claims he let it soak in oil overnight before installation.

mikeyen

I know it's awfully late in the game to bring this up, but...

I AM DONE!

Finished last weekend, when I successfully installed the 6mm helicoil and new oil pan. Zero leaks, not a drop.

And I'm kind of wondering now if changing the steel pan isn't something you just do on these cars, when you have to take it off for any reason. I could not get mine off without bending it. I'm sure I'm not the most patient mechanic here, but that thing was on there, but good.

I put on the $30 eBay pan. I could not tell the difference between it and the stock one. It's really well made.

I guess if you're confident in the condition of your pan, then don't change it. But if you have any questions at all, I mean, how much time is $30 worth to you?

This car now runs better than it has in 3 years.

In sum:
4 new motor mounts;
one new tensioner and guide;
New o-rings behind inner TC cover;
new belts;
new half-moon seals;
new water-pump;
new low-pressure PS hose.

I figure this would have been $2,000 parts and labor in CA. I think I spent $500, and I bet I spent 60 hours (because I am slow). That's okay, though, because I need projects; I'd rather lie out under the car saying, "Oh, shoot; now what??" than watch endless episodes of pointless television.

Anyway, if anyone needs a 6mm helicoil kit, let me know. I used it once; these are $40 at O'Reilly, or $20 at amazon. If you want my leftovers, let me know. I also have about 1/2 tube (the caulking-gun size) of gray RTV left.

CS_AR

CONGRATULATIONS! You make it!