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Discussion Starter #1
HI, just became a new X owner, bought an '08 rwd with 138k on it for a decent price with an engine knock. It knocks like a piston with a skirt broken off, not a rod bearing but it happens at both ends of the stroke, so the knock is 2x engine rpm. Runs great, makes good power, smokes under hard acceleration, of course the knock is loudest then as well.

Looking at used engines from salvage, found quite a few under 100k and under 2k with 90 day warranties, some have 6mo warranties. The choice ones are all 3 and 4 hundred miles from me which means expensive shipping or at the very least a road trip to go get one, I found one local with 81k on it for $1750 and 90 day warranty, opinions?

For what it's worth, I can get my core rebuilt by Poteat in Kannapolis NC for 2800, this is just a work vehicle, nothing fancy, doesn't have to be a new engine.
 

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If you do get a used one I would consider doing the timing chain tensioners before putting it in. just for piece of mind of not having to do it later while its in the vehicle.
 

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Discussion Starter #4
If you do get a used one I would consider doing the timing chain tensioners before putting it in. just for piece of mind of not having to do it later while its in the vehicle.
That would make perfect sense. I'll look into the SMOD issues as well, my coolant is green and ATF is a nice red color, need to see what part # my radiator is, who knows if this has ever been replaced.

It was brought to my attention that these motors can also experience oil usage through the PCV system siphoning oil and burning it, there is a fix for it but it's easy and cheaper to use a catch can and empty it periodically.

Might as well kill all the rats while the engine is out. The cat is full of oil now, and I have a P0420 Catalyst System Below Bank 1 code. A buddy said I could run some brake clean through it and try and clean it out, but would this work or should I look at replacing it too?

Any other suggestions?
 

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i mean, if money were no issue i'd say yeah ,replace the cats I suppose it wouldnt hurt to try the brake cleaner, but i wouldn't bet on it.
 

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Cheapest advice is take 2 oil changes and call me in the morning. Otherwise you have some major issues that can be most easily solved by a motor change. There are some folks that can pull the oil pan and do new bearings but it's a gamble that is only a fraction of a full motor change.
EDIT: I see you're dumping oil out the exhaust....that really just calls for a motor change when it does finally give up the ghost. Go ahead and cut the rats out and deal with the light while you are at it if you can do that where you live.
 

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That would make perfect sense. I'll look into the SMOD issues as well, my coolant is green and ATF is a nice red color, need to see what part # my radiator is, who knows if this has ever been replaced.

It was brought to my attention that these motors can also experience oil usage through the PCV system siphoning oil and burning it, there is a fix for it but it's easy and cheaper to use a catch can and empty it periodically.

Might as well kill all the rats while the engine is out. The cat is full of oil now, and I have a P0420 Catalyst System Below Bank 1 code. A buddy said I could run some brake clean through it and try and clean it out, but would this work or should I look at replacing it too?

Any other suggestions?
I just got a call from my dealer as they have my X for a cold start engine rattle fix. While I had the rattle every morning since owning it (1mo), they could not reproduce the sound. They saw my video and believe me, but there's nothing they can do (under warranty) unless they can reproduce the problem.

I'm sure that it's the timing chain tensioner as the rattle goes away with acceleration/driving.

No cash right now, so I'm stuck with the warranty rules and cannot do elective surgery w/o paying out of pocket.

If your engine is out, REPLACE the tensioner! It's a cheap part and apparently wearable.

I suspect humidity plays a role. Very wet and rural, here compared to the shop an hour away in the city.
 

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Discussion Starter #8
Have got a VQ40 on the way to swap in, before it gets dropped in I plan to replace the tensioner, maybe the galley gaskets, all of the cats since this old motor is dumping LOTS of oil out the exhaust, and check the radiator part # to see if it is one that might fail or if it has been replaced.
 

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Have got a VQ40 on the way to swap in, before it gets dropped in I plan to replace the tensioner, maybe the galley gaskets, all of the cats since this old motor is dumping LOTS of oil out the exhaust, and check the radiator part # to see if it is one that might fail or if it has been replaced.
i'd probably do the valve cover gaskets, plugs, coils..if budget allows.
 

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Discussion Starter #10
What might be the kicker is the new (used) 4.0 is coming from a salvage yard with 90 day warranty. They may say that by doing anything to the engine besides dropping it in, putting oil in it and running it, voids the warranty. The more I read on doing the timing chains and the VERY extensive list of parts needed to do it properly, including the gallery gaskets (which apparently have to be made by hand for the VQ40) and the likelihood of the gallery screws breaking off, the more appealing the $2800 cost of a new motor from a reputable rebuilder becomes. There is literally hundreds of dollars worth of parts and labor that does not have to be done.
 

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There were issues ( example: timing chain tensioner) which were a problem with the earlier 4.0 engines that were addressed and resolved for the newer engines.

I believe the problems with the tensioners affected the 2005-2010 years.

IMO, If your purchasing a 2011> engine, I would leave it alone and install it asap.
Re: Use your warranty time to determine if the engine is a keeper or not.

Used engine warranties can be a gamble for the average Joe.
The warranty tends to be short and the provider knows it will take a while for you to get a mechanic to install your engine. While this is happening, time is ticking away.
 

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Discussion Starter #12 (Edited)
I went and picked up the motor, it had some Gravely's heat tabs stuck onto the heads and block so I called them and got some history of the motor they sold my salvage dealer. It is a 2008, from an X with 86k miles on it, their records show it was run tested and if there had been anything wrong with it, noisy timing chain or a leaky gasket or something, they would have fixed it and added the cost to the price of the motor, or they would have parted the motor out if it would have been too much cost to repair it then resell it.

My gut feel says yeah, you could go in and swap out the tensioners and the water pump, but why fix what ain't broke? Plus I have the 90 day warranty. The guy at Gravely's said the same thing, it has been run tested he would just drop it in, prime the oil system and run it.

It's a work truck. Used locally so no long interstate trips, my last work car only got 62k put on it in 10 years, so if this one follows suit, in 10 years it will only have 50k - 60k added to 86k for a total of 140k - 150k for lack of a better guess, and in that time I might totally retire, beat cancer for the 4th time or some other illness takes me out of the work force so I will take my chances and run it as is.
 
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