Hello,

This is actually my first post! I read a lot of threads and do a lot of research. Thus far, in regards to my 98 civic, I've had every question answered by using search. However, this time, I do not have a civic question. In fact it's not even a Honda question.

My roommate has a late model RAV4 with a 4 cylinder engine, and I have noticed that it has an engine rattle. I've looked at it a couple times to try and diagnose where its coming from but I can't tell. All I know for sure is that the noise is emanating from the passenger side of the engine. On that side of the engine is where most of the accessories are as well as the water pump and oil pump (I think). I do not believe it is valves unless one is severely out of spec.

Mostly I'd like to know what you guys think might be causing the rattle. I have uploaded a small video to YouTube that does a pretty good job of highlighting the rattle.
Because this car is not mine, and I have no experience working on it, I probably won't have immediate updates on suggested areas of concern. But if a couple major areas of concern can be looked at, I will of course respond with my findings.

Thanks and best regards.

P.S. f20b (f2b) or h22a (h2b)?

 

Really, no ideas? Do you guys hate RAV4s?

 

ugh that sounds almost like a rod to me.

I dont know if those engines are hydraulic or not, but I accidentally adjusted a valve .002in too tight and it sounded like that too.


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A valve seems more likely than a rod knock. It's not so much a knock as it is a rattle. And no, i don't think it's hydraulic, although I don't know for sure.

Also, wouldn't a tight valve make very little noise, as the cam would be in constant contact with the rocker?

I'm inclined to think it's something external to the engine. However, what ways are there to verify the noise is from the valves or connecting rod? I put a dowel rod on various parts of the head to try and see if I could hear the noise through it like a mechanic's stethoscope, but came up empty.

thanks for your input!

 

If you're talking about the slight rattle, it doesn't seem to vary with engine speed... Revving the engine seems to make more apparent. This makes me think its not in the rotating assembly.

To trace this you're gonna have to get a mechanics stethoscope and start probing. You can also put your ear on the end of a long screwdriver or a piece of hose.

If external, pull the accessory belt off it and see if it goes away. Look at the belt tensioner, had a similar rattle on a different motor...auto tensioner was blown but the belt still seemed tight.

 

well I had a chance to check out the car while my roommate was at work. Here are some things I noticed.

First, When I first started up the car and warmed it up, the noise was not there. let it run for about 5 mins revved the engine nothing. Went back out a few minutes later with the idea that it might be the AC. So I turned it on and I could hear the rattle. It was very random though, definitely not anywhere in the rotating assembly. I turned the AC on and it didn't change very much. Then I decided to drive the car to see if I could get it to be more consistent like it was in the video (the video was after the car had been warmed up and driven for a while). So I drove it down the road and back; engine was nice and hot. Definitely more noticeable but not like it was in the video. So I took a long screwdriver and started putting it on everything I could: intake, exhaust, mount bolts, idler pulley bolts, alternator bolts, et cetera. Nothing. I didn't get to all the pulleys, but I have convinced myself that it is somewhere along the serpentine belt. Either that or the timing chain/water pump area, which I have concluded is on that side of the engine.

Is it possible that the timing chain could be loose and occasionally hitting guides or something? Or if it is when the car is warmed up could it be the water pump? Would that have anything to do with it? such as the thermostat opening up? I'm taking a shot in the dark with that one.

While I'm not 100% sure it only happens when the car is warmed up, that's what I'm thinking. Unfortunately, my roommate's girlfriend took the car so that is all the diagnostics I'm going to get to tonight.

Thanks again for all your help.

P.S. stumpy, can I pull the serpentine belt off and run the car on just the battery, as it also drives the alternator? I know that the alternator provides the electricity after the car is started, so I wanted to make sure there wasn't some rectifiers or switches that prevented the battery from providing the necessary power.