Rav4, 170K miles, connecting rod noise

Was looking at buying a 2010 Rav4 with about 170K miles. Looked pretty good aside from needing new rear wheel bearings. Wanted a mechanic to take a look, so the seller dropped the car off Wednesday night at a local mechanic’s for a Thursday morning check-up. After sitting out all night there was a rattling noise in the engine in the morning on startup—very brief, then seemed to go away. Mechanic is 100% sure it’s the connecting rod. He said to me: “I don’t know if this engine will last 5000, 10000 miles, or more, but it’s going.”

Haven’t dealt with such a serious issue but this was a bummer after investing a lot of time in this car (good though, if we indeed caught a serious problem problem). Seller and I had been talking about selling for $4.5K—seller is now willing to go down to $4K. My priority is something reliable though, so think this is too much of a gamble.

Any thoughts? Any similar experiences?

In many of the the newer engines the block is bolted together and the oil pan is very small to where the rods can’t be accessed without separating the block. If you can access the bad rod, you can replace the rod bearing from the bottom.

Take the 4k you would spend to buy the car and the money you would need to fix the engine and rear wheel bearings, walk away and look for a better vehicle.


A brief rattle on cold start sounds more like timing chain noise than rod noise, which would make a knocking sound that would get worse as the engine warmed up. It wouldn’t particularly concern me, but I’m a mechanic who would fix it myself.

In your case, keep looking.


Another vote to look for a different car. @asemaster 's idea seems possible, but the inspecting mechanic is in the best position to make the call. Whatever you paid for the inspecting fee is money well spent imo.

Who here recalls the Andy Griffith Show episode where Barney buys his first car? … lol …

Andy: Barney, you should take this car to the local garage and have it inspected by the mechanic first.
Barney: Be quiet! It’s a cream puff

There are lot more cars for sale than a couple of years ago. Keep looking until you find a better bet.

Oil drains from the variable valve timing actuator, then makes a brief knocking noise during start-up. This is a common problem for the 1 AR, 2AR and 2GR engines, service bulletin below.
Someone is going to get a good deal on a Rav4 with a minor engine flaw.

MC-10133786-9999.pdf (nhtsa.gov)

Either way I’d find a different mechanic to inspect or work on your cars. What you described doesn’t fit the symptoms of a rod knock at all.


Whether it’s a connecting rod bearing or a timing chain rattle, or perhaps some other valvetrain noise really makes no difference. The noise bothers you, and the price is too high for a vehicle with unknown mechanical problems.

You are not a mechanic, and you cannot fix this engine yourself, so unless the acquisition cost is low enough to do one of two things (drive it 'til it dies, or pay to repair/replace the engine) it’s a loser for you.

I’d say if you can get this for $3k, it would be worth it, and I’d go as high as $3300. Even if you have to spend a few thousand on engine repairs down the road, plus the cost of new wheel bearings/brakes/etc. immediately, that makes sense. But not at $4500 or even $4k.

I think it is much more probable that this engine needs a new timing chain set, than that one connecting rod bearing is worn enough to make noise only on startup. Also, if you buy this vehicle, your mechanic could pull the oil pan and wiggle the connecting rods from below, and if one is a little loose, it is possible to replace the bearing inserts from below, especially if there is no constant knock.


When even car-knowledgeable mechanics don’t agree, I can see how that makes it hard for the car-buying OP to know what to do. .

Yep, you just stick around till you get the answer you want, or drop the pan and find out. Oil change history? I’ve never had an engine problem at a mere 170,000 except for the diesel, but then I change oil in excess of the mfg recommendations.

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Disable the cylinder with the rod knock, if the noise gets less then probably a rod, and if it gets worse when revving the engine and as it warms up, maybe a rod… A rod knock will normally lessen when you remove a plug wire, and get much worse with higher RPM’s not loaded (in gear)…

So how when and wear the noise is coming from is how you can narrow the noise down…

But also be careful, The older 2.4L not 2.5L Nissan Altima’s alternator would go bad and the overrunning clutch pully would make it sound just like a rod knock, so check it out really good… lol

Good idea. I wonder if that can be done using an OBD II scan tool these days? A 2010 is probably COP configured, so disabling a cylinder might be pretty complicated.

Just unplug the connector to the COP one at a time, if not covered up by the upper plenum, so not complicated at all…

Or just preform a cylinder balance test, but listen for the one that makes less noise…


Never got notifications on this! Just checked back and saw all the comments. Thanks very much to folks who responded!

My decision last week was to move on. I’m not a mechanic, this seemed beyond me, and I’d like something reliable for at least a little while. Again, the mechanic (who I had not used before—I was looking at this car about an hour from me—but who has an excellent reputation, and seemed honest and savvy to me) was 100% sure the engine was going. Like I wrote, he was confident the engine might last 5000 or 10000 miles or longer, but that it was going. We’re also going into winter here, in northern New England, so there’s that.

I hadn’t thought much of it since last week. Today the seller texted me again. She originally had asked for $6K for the car—she told me she’s got an offer from a dealership for $3750 and asked if I want it for $3500.

I still think it’s probably not worth it for me and financing something more reliable is the way to go. And I’m a bit tempted to just pay the cash and have it for however long it lasts.

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Really interesting. No idea if this is the case. Doubtful the mechanic was aware of this, but IDK.

I’d stay away from this car

Buy a car that doesn’t have ominous noises upon startup

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Nevada may be correct that it is the vvt but according to the repair bulletin would not be an easy fix. 7 cents a mile if it goes 5000, or 3 cents a mile if it goes 10,000. Why would she not sell it to the dealer though?

I ran across a YouTube on the vvt rattle. I’ve never owned a Toyota and likely never will but the guy had some interesting information. First he said to clean out the gunk on the oil passage filter and secondly the openings on the oil passages on the solenoids. These restrict the oil flow.

Secondly when replacing the valve cover gasket he found the o rings harden over time and heat. Replacing the o rings stopped the rattle. Saves the estimated $3-5,000 repair cost or engine replacement.

Otherwise I know nothing about it but looked interesting. Other engines also seem to have oil starvation at start up.

Oil leaks from the camshaft gear while the engine is off for several hours. Without oil between the lobes in the camshaft actuator, there will be a metal-on-metal knock until oil is pumped into the gear.

Lexus recalled 101,500 vehicles for this problem 10 years ago:

RCMN-13V395-4590.pdf (nhtsa.gov)

The bolts used to secure the housing and sprocket of the intake-side VVT gear assembly could become loose due to abnormal impacts generated within the gear assembly immediately after a cold start-up.