2003 RL - Rattling engine noise
 

I have this rattling engine noise that developed slowly over the last 6 months or so (about 8k miles).

So I wonder if perhaps I’m lucky and someone else has dealt with that at some point and can give me some advice…

The rattling noise seems to be coming somewhere from the area marked in red in the photo.
https://cimg9.ibsrv.net/gimg/acurazi...d0f6d2fa47.jpg

And here is how it sounds. Like many mechanical noises it is a little hard to hear on a recording, but notice the different sound as I move from the passenger side of the engine to the driver side. The noise you hear when I move the video to the driver side is the more normal engine noise. When I record on the passenger side of the engine then the rattling sounds more pronounced.


The noise is a rattling noise with a little bit of knocking into it. To me it sounds sort of like a bad bearing shifting positions but I’m not that confident in my diagnosis.Anyone had similar experiences?

Opening the timing belt covers is quite a bit of work with all the electrical harnesses attached to it, even if I just remove just the top covers. Besides, once I open the covers it is no longer possible to start the engine to reproduce the noise. So getting some diagnostic hints on what it may be will help a lot.

Thanks much

A few other things I forgot:

I have observed that the rattling pitch and intensity only depends on the engine RPM. It does not depend on the engine load, acceleration/deceleration etc. It is less noticeable at highway speeds but that is probably because of the added road noise.

Engine power seems fine, gas mileage normal, no vibrations, rattling is the same in neutral as in gear, moving or stopped. No fluid leaks other than a small power steering leak that has been there for the last 100k miles (PS reservoir goes from high mark to low mark every 10k miles or so).

An automotive stethoscope is invaluable for finding the real source of the noise:

When were the valves adjusted last?

RL98, Thanks for the stethoscope suggestion. I did not know they made such things but it makes perfect sense. I ordered one, will have it in a week.

Ken1997TL, Thanks for reminding about the valves. The valves have never been adjusted in 245k miles. I sort of assumed it was not necessary since the 2003RL shop manual does not mention anything about valve adjustment in the maintenance section -- but I could be wrong. They do mention long term items like replacing transmission fluid and coolant at 120k miles and then every 90k and 60k respectively, or replacing timing belt every 105k miles but no word on valve timing. After reading your suggestion I looked at the valve description in the shop manual and seems like this car uses “hydraulic tappets” on the lifters, so perhaps those also act as automatic valve adjusters? There is also no mention in the manual of any valve adjustment procedure using thickness gauges etc.

Another interesting (to me) thing on valve adjustment: I remember valve adjustments in older cars. But starting with a 1987 Mazda 323 I once owned seems like they started using these hydraulic tappets, so I thought that valve adjustment had become a thing of the past. Now on my 2012 Honda Odyssey the shop manual mentions and describes a manual valve adjustment procedure using thickness gauges. So perhaps manual valve adjustment is returning once again…

It could also be something as simple as a catalytic converter heat shield that got loose, so don't overlook those things.

Valve adjustments work wonders on our cars, I remember on my older J30 Accord (6th gen), I didn't do a valve adjustment for 200K miles but on the second timing belt job, decided to do it and that baby purred so quietly afterwards.

I would definitely do it, it won't hurt at all!

That's funny, I just did a valve adjustment on my 4G TL yesterday. Took about 3 hours altogether. Also cleaned the fuel injectors. It didn't make much noise to begin with but it makes even less now. Seems to have better pickup though it could just be a placebo.

Does the noise level change by temp? If the noise changes when the car warms up, it could certainly indicate valve clearances. Not necessarily a tell-tale sign, but a common symptom.

I'd be happy to look into doing a valve adjustment on my RL, but I'm afraid there's no such adjustment to be made. At least I cannot find one in the shop manual. All I see is the "hydraulic tappets" at one end of the rocker arms, where the adjusting screw would normally be. There's a procedure on how to bleed the air out of these tappets before you (re)install them. That's all I see. I imagine that the purpose of the tappets is to dynamically maintain zero clearance, so no need for valve adjustments. It could very well be that these hydraulic tappets proved problematic and that is why manual adjustments have returned on my 2012 Odyssey (and likely other cars from what I gather reading the comments). But on the 1st Gen RL's there may not be any valve adjustment to be made.

Has anyone done a valve adjustment on their 1st generation RL?

OH wow, didn't realize the 1st Gen RL had a C series engine, and not the J . :sorry:

No, in my case the noise does not change with temperature. It is there at the same pitch and intensity from the time I start the engine until I turn it off. Also, it does not have that very regular rhythmic tapping that I imagine is characteristic of a valve. That's why it sounds to me more like a bad bearing. The balancer belt pulley or the timing belt pulley comes to mind, except that those are a little more centrally located and I hear the noise a little higher. But perhaps noise bounces around in the engine compartment, that is why the stethoscope may help. If it were a quick job I'd just open the timing belt covers, but it's not a quick job and once the covers are off the engine is no longer in a state that can be started.

Well, I poked around with the stethoscope (useful tool indeed, thanks RL98) and perhaps it’s the power steering pump. The bearings seem ok, there seems to be no play in the pulley, but perhaps the pump itself is noisy. I’ll take all the belts off next and start the engine, see if the noise is still there.

I bought the stethoscope that has two attachments, the metal rod and the small rubber funnel. They are both useful. The rubber funnel helps you identify where the noise is coming from. The metal rod is much more sensitive but when you use it you start hearing all kinds of other noises, so it can be confusing to discern the original noise.

It is the power steering pump that is making the noise. I removed the 3 belts (Alternator, AC, PS) and when I finally removed the PS belt the engine got very quiet.

Funny how the noise bounced around and initially appeared to be coming from the top of the engine. Things got clearer once I bought and used the stethoscope, and now the belt removal seems to leave no doubt that it’s the PS pump.

However I do not think it’s the PS pump bearings, there is very little play in the PS pump axle. I think it’s the pump itself inside making the noise.

Any tips on changing the PS pump?

I changed the Power Steering pump this past weekend. The noise is gone. Engine compartment is quiet once again.

It is not a difficult job. You just have to remove the air filter and the rubber air tube carrying air from the filter to the intake. With those two removed there is enough space to remove the two power steering bolts and the tension adjuster. The space is tight but it’s just a few bolts. It’s a messy job though because of the oil spilling. On the pump itself you just remove the rubber oil intake hose (hose from oil reservoir to pump) and the metal high pressure line (two bolts holding that one). I covered the disconnected hoses with a small plastic bag and a rubber band to prevent dirt from entering the system. I had also removed the bottom black plastic splash guard to have better access to the belts, because you do need to take out all three belts (Alternator, AC and Power steering). I got a remanufactured PS pump for about $100. I had to take the metal inlet out of the old pump and fit it on the new pump. The remanufactured pump came with the two sealing O-Rings. Another small challenge was to take out the pulley from the old pump and fit it on the new pump. You don’t need an extractor to do that however you need to hold the pulley still to loosen the bolt because it is tightened to 47 lbft. I cut two 3” of ½” allthread and squeezed them on the vise then put the pulley with the allthreads through the pulley holes to create enough torque to loosen the pulley bolt with a wrench.

Took me about 4 hours doing it for the first time, mostly because of all the messy details of dealing with the oil, then refilling, then flushing etc.

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There may be another problem though. I still see quite a bit of oil flow in the reservoir and a few air bubbles. But I’ll make a different thread for that because if it is a problem then it’s a somewhat different problem.