How do you know when the timing chain needs service? or repair? What kind of noises to look for? How much should servece/repair be? Mine is making a slapping sound on the front head..near the radiator......Thanks in advance....

 

A loose timing chain makes an annoying rattling sound which is especially pronounced at start-up. A listening aid such as a length of small-diameter rubber tubing will help pinpoint the source. Replacement of the chain along with the tensioner and guides costs a small fortune.

 

Yes, it also makes the engine shake badly to the point where you see your dash moving.

Questions for Daniel B. Martin: What causes a timing chain to be loose? Does it affect the engine when the rattling and shaking happens?

 

There are several things which can cause a chain to be loose.
- worn chain
- worn chain tensioner
- worn or broken chain guides
- worn chain sprockets

We usually speak of a timing chain. Our 4Gen Maxima engine (the VQ30DE) actually has three chains: one timing chain and two camshaft chains. Any or all of these chains could develop a problem and become noisy. It's difficult to tell which chain is causing your noise without tearing down the engine. When replacing a chain it is prudent to replace the sprockets on which that chain rides, its guides and tensioner.

Timing chain failures are relatively uncommon and it's difficult to say what causes them. Lubrication failure, excessive engine speeds, materials defects, manufacturing errors. Mechanical parts wear out, sooner or later.

Sometimes a camshaft develops abnormal friction in its journals. This sharply increases the tension on the chains and hastens failure. Where did this friction come from? One possibility is that a failed head gasket has allowed engine coolant to seep into the engine oil. In this scenario the noisy timing chain is only one of several serious problems. Not a pretty picture.

[Edited by Daniel B. Martin on 02-19-2001 at 10:27 AM]

 

change out the water pump as well since your allready there.

 

Mine is noisy at startup. And the cam chain in the front most part of the engine bay is the one that does not quiet down. It keeps making a slapping sound. The engine runs as good as ever, it is just the sound that bothrs me.

 

That "slapping sound" is a warning. Ignore it at your peril.

 

Is it a warning for me to chainge the chain asap? How much will it cost?

 

It is a warning that something is wrong. At the moment, nobody knows exactly which parts are damaged. Therefore, it's impossible to make an accurate estimate of repair costs. However, removing the timing chain cover involves a lot of labor. I'd guess you are in the US$800 - US$1200 range, including parts.

I don't like to be the bearer of bad news. In this case, it is the engine sound which is the bearer of bad news. I just want to make sure you don't ignore it. If you do, the cost of repairs could be even higher. If the timing chain were to break you could do serious damage to the engine valves.

David Haygood suggested replacing the water pump. That's good advice. Maybe, just maybe, it is the water pump making all that noise.

 

My water pump has been leaking from time to time, so that is a sign it may be it. But the noise is coming from the cam sprokets. Nissan here charges 400 for timing chain service, what is service? Is 'service' just popping open the timing chain cover on the cams?

 

Are you seeing visual leaks or are you finding water in your oil? If not mistaken, the only place the water pump will leak is in the oil considering it is operated by the timing chain. In my FSM it shows that the timing cover is one unit and it encases the entire timing chain and the 2 camshaft chains so I don,t what they mean by "service" other then maybe taking off the cover and inspecting/adjusting. I highly doubt it involves any removal and installation of chains/sprockets.

 

Are you seeing visual leaks or are you finding water in your oil? If not mistaken, the only place the water pump will leak is in the oil considering it is operated by the timing chain. In my FSM it shows that the timing cover is one unit and it encases the entire timing chain and the 2 camshaft chains so I don,t know what they mean by "service" other then maybe taking off the cover and inspecting/adjusting. I highly doubt it involves any removal and installation of chains/sprockets.

 

I was just wondering, usually for most of the japanese cars that run on "timing belts", which need to be serviced at 60K intervals, the water pump is changed at that time. My question is what about for our Vq engines when the timing chain is supposed to last for a lifetime? are we also supposed to change the water pump every 60k as preventive maintenance or just drive until we see indicators such as leaks before taking action?

any good rules to follow?

thanks,

Brian

 

A good rule of thumb is:
- at 60K replace the water pump only if there is some defect (seepage, noise, doesn't spin freely)
- replace pump at 120K

I'm going to drive mine until there is evidence of a problem.

Why should there be a different water pump maintenance philosophy for belt- versus chain-driven? The answer lies in the collateral damage which arises from a pump with a bad bearing.
Timing Belt... The belt will overheat and break. The broken belt causes valve-piston collisions. No symptoms to warn you; the damage is done in two minutes.
Timing Chain... The pump will complain and leak but is unlikely to break the chain. Lots of symptoms to warn you.

 

On my 4th gen gxe, the car had well over 150,000 miles and never had any problems with the water pump. Althought the transmission was slowly begining to slip away. That car had fewer issues than my current maxima.