Engine Chatter When Accelerating?

My 2004 Toyota Matrix has been making a rattling/chattering noise when I accelerate. I took it to a shop (in nyc, where I live) who said it is a problem with the bearings and that my best bet is to replace the engine with a used one. He quoted me about $2500, parts and labor included. Also, he said it doesn’t really make sense to try to rebuild the engine - better to replace it.

Does this cost/analysis make sense? I know nothing about car repair, but a bit of googling does seem to confirm that this is a problem with the bearings (particularly the rod bearings?). Any advice would be much appreciated.



Bad bearings? Today, a rare type of failure unless the engine was run very low on oil at some point in the past…In any case, I would get an expert second opinion before I condemned the engine. You might mention the mileage on your Matrix…

Hmm, thanks for responding. I am definitely going to get a second (and maybe third) opinion/quote. Mileage is about 79k. I change the oil on schedule, but I bought the car used about 9 months ago, so who really knows how it was treated before.

Since we can’t hear the engine “chattering”, everything that we might offer is mere speculation, but…a bearing problem in your engine is not likely unless…
…there are…perhaps…over 250k miles of use on this engine…
…you were negligent regarding oil changes…
…you ran the engine with a very low oil level.

Are any of these scenarios true regarding your car?

My first thought was that your engine might be displaying “spark knock”, which could be the result of…
…badly worn spark plugs…
…an engine that is running too hot…
…a bad EGR valve

In the absence of being able to hear and examine your engine, we can only try to zero in on a possible cause-and-effect situation if you give us the following information:

How many miles are shown on the odometer?

What is the maintenance history (in DETAIL) of this car? Just telling us that it “has been well maintained” is essentially meaningless in the absence of actual details.

What are your usual driving patterns? (e.g.–mostly local short-trip driving, mostly highway driving, a mixture of these patterns, etc.)

Is the Check Engine Light lit up?


“I change the oil on schedule, but I bought the car used about 9 months ago, so who really knows how it was treated before.”

In the absence of maintenance records from the previous owner(s), you have to assume that maintenance has not been up to specs, and your good maintenance will not negate years of poor maintenance on the part of previous owners. That is why I would never buy a used car without hard copies of maintenance records, but that issue is just more “water over the dam” for you–unfortunately.

At this point, you need to get a second opinion about this “chattering” but, in the meantime, if you can provide at least some of the missing details that I asked about, it would help us to help you.

Edited to add:
The relatively low odometer mileage on this car means that, on average, it was driven less than 9k miles per year. If the previous owner(s)–there could have been several–changed the oil on the basis of odometer mileage, rather than on the basis of elapsed time, this engine could be the victim of sludging.
Oil changes need to be done at least every 6 months, regardless of how few miles were accumulated in that time span.

Thanks for responding, VDCdriver. And sorry for not including more in my original post.

I don’t have a video/audio of the sound, but I looked on youtube and it makes a pretty similar sound as this: http://www.youtube.com/watch?v=rcnBqe1LZ4k .

As I said in my previous post, I don’t know the full maintenance history because I bought it used about 9 months ago. It has about 79k (had about 72k when I bought it). I’ve given it regular (roughly 3k) oil changes, but I don’t know anything about previous repair history, as I bought it from someone who was just a reseller. Other than the oil changes, I haven’t had any maintenance done.

Check engine light is on. I commute about 15 miles round trip, 3-4 days per week. Mix of local and highway - but all in the city. Occasional weekend trip out of town, but nothing more than 150 miles.

Thanks again.

“Check engine light is on.”

That is a very significant detail, which should have been mentioned earlier.
If you take the car to an auto parts retailer (Auto Zone, Advance Auto, possibly Napa), they will “read” the stored trouble codes for you, gratis. Then, you can come back to this thread and post those codes for further advice. The codes will be in a format similar to “P0123”.

Wow, shows you how much I know about cars - I didn’t even know that there were different “codes” for a check engine light…

If it makes that sound on acceleration, I’d usually call it pinging, or pre-ignition. The knock sensor usually prevents that from happening. Get the codes pulled, post them here, and we can help further.

Ask a good local mechanic there to check it out as a second opinion. If there’s agreement the engine is shot – which seems unlikely in a 2004 Toyota unless the routine maintenance has been neglected by the prior owner – but if the engine is indeed confirmed kapuut, then the price quoted for a replacement engine seems reasonable. The mechanic is right, it is better to use a purchased replacement engine than rebuilding the existing one. Your old engine will probably go to a shop that does nothing but rebuild engines in an assy line. It will live a second life in a different car. Much cheaper that way than a shop mechanic rebuilding engines one at a time.

To be honest, I can’t really tell from listening to that on the PC speakers and it’s not helped any by my tinnitus and partial hearing loss.

The rap from an idle comes across as a rod rap but it sounds a bit tinny for that; keeping in mind my hearing issue. Maybe it’s a valve train issue but given the guy at the shop actually had his head under the hood I would have to go with him on this.

Seventy something thousand miles is a bit young for an engine issue but depending upon the oil change regimen in the past, etc. it’s also a possibility.
The mechanic is correct about the rebuilding because a proper rebuild can get very expensive even if all of engine basics are useable.

I listened to your link, and that is not a bearing problem. Engine bearings, because of their design, don’t chatter. Frankly that sounds exactly like a worn out timing chain problem to me. Pushing 200,000 miles are you?

Gat a second opinion. Definitely.

"Pushing 200,000 miles are you?

No, the OP already told us–after I pulled a few teeth–that it has only 79k on the odometer, but that he also knows nothing about its maintenance history prior to his purchase of it a few months ago.

I agree with you that it does sound very much like a timing chain that is at the end of its lifespan, but if my theory–that this engine has had too few oil changes in its lifetiime–holds true, the probable sludge in that engine could well have killed the chain by robbing it of proper lubrication. And, if the timing chain is near death, surely the bearings are not far behind.

Why people buy cars without evidence of proper maintenance is something that I will just never understand.

Lack of knowledge. Like I’d probably get screwed big time if I tried to buy a used bulldozer.

Ok folks. I took it to a second mechanic, who also said that the sound he is hearing sounds like a bearing problem in the engine. However, he said it isn’t that bad, and that I’d be crazy to think about replacing the engine right now. He said eventually I will have to, but not until it’s really knocking. He recommended having the oil changed every 2k miles, and using a thick Lucas oil.

Also, I had the check engine codes pulled at Autozone, and they are P0430 and P0133. The definitions given were:

P0430: Catalyst system efficiency below threshhold - bank 2.

P0133: Heated oxygen sensor - bank 1 sensor (HO2s11)

Thanks for any advice you can offer.



You don’t have a bank 2 catalyst. Your engine is a 4 cylinder in-line. Therefore you only have bank 1. Therefore you shouldn’t have a code p0430. You MIGHT have a code p0420.

Saying a bearing knock (or even a valve train knock) isn’t that bad is equivalent to saying that a recent heart attack was a minor one.
Running a heavier oil may help mask any problem but you don’t need to use the Lucas stuff and you should not travel far from home with the engine in this condition.

The advice you were given by that mechanic is pretty suspect, at least in my opinion.

“The advice you were given by that mechanic is pretty suspect, at least in my opinion.”


I still think that the problem is more likely to be a timing chain that is just plain worn-out from lack of lubrication, possibly stemming from a build-up of sludge.