Hello!

I am new to the 'zine, and am now in need of your collective assistance. These forums are great, I am already impressed with the depth of information and the great people! But I need some help, as I am running out of ideas. . .

PROBLEM: severe metallic grinding/harsh clicking engine noise of sudden onset for no apparent reason. Noise eminates (per mechanic's stethoscope technique) from rear of L-5 2.5 engine block, in the area where the block joins the trans-axle, worse (louder) on the driver's side, worse lower in the block than higher. NO noise from intake runners, various points on head around intake side or exhaoust side, so hopefully rules out dropped valves, etc. No noise from exhaust header or downstream pipes to cat con, etc.

BACKGROUND: Car is '97 2.5 TL deluxe, very cherry, all dealer serviced, bought from original "old rich guy" owner here in Florida. Timing belt changed by local dealer at 90 k miles; now 154 k miles. Have the apparently common shared issues of slow passenger window and burnt-out D4 light in dash, but other than that, the car has no other problems and is very clean and great shape.

OCCURENCE: Two nights ago, driving light load steady state 60 mph open smooth road, A/C on, headlights on, radio on. Without warning sudden severe, LOUD metallic engine noise, loud enough to be very alarming even over medium-loud rock-n-roll radio!

S__t pants, pull to side of road, look for disaster under hood, and in Mag-light beam nothing is apparent; no steam, fire, loose parts, debris in fans, leaks, holes in block, etc. No apparent loss of power, but noise increases with RPM, so ease on home last two miles or so at low speed, pop car on jackstands and started looking.

SO FAR: As mentioned, did stethoscope technique to try to narrow down source. Very loud metallic sounds almost like a coffee grinder, even at idle; louder from beneath car, seems to come from rear of block. Again seems louder on driver's side and lower in block. No change in noise or location when car in gear. Increases w/RPM. No apparent loss of power or any unwillingess to rev. Drained oil thru coffee filter looking for bits; nothing, all very normal. Transmission fluid normal. Pulled rear two spark plugs, both look great (only 5k miles on new plugs). Did not pull other 3 plugs yet, nor did I do cylinder compression checks yet (too many thunderstorms to get much done so far).

At this point I am thinking a broken/backed-out flywheel or counter-balancer bolt? Or seized rod bearing or rear main bearing? or what. . .? No loss of power and no noise in head seems to point away from valvetrain involvement (or does it?) What else rotates at the rear of the engine, when the car is not in gear? And how to get at it to check on a car on jackstands in a driveway? Yikes! The noise is so bad I am really afraid to even drive the car anywhere. . .

Any similar expereinces or suggestions on other things to check or how to proceed from here are greatly appreciated! Thanks!

Puzzled, in S.W. Florida

 

I don't know if this will help, but I experienced similar noise only when I started up the or stopped at a light, it turned out to be my crank pulley. It was coming apart.

Replaced it with brand new one and problem went away.

Your issue seems much more than than.

Good luck.

 

MEAZZ1,

Thanks for the suggestion, I will take off the belts and check all of the pulleys esp. the crank pulley; who knows, maybe the noise is resonating through the crank and it only sounds like it is coming from rear of block?

Thanks!

 

does sound like a bearing...

 

Not much rotating at rear of block except crankshaft, camshaft (up high), and distributor. Distributor bearing might make a nasty noise and I've heard of this in Accords, but it should be easy to isolate.

You have to be able to access the flywheel/torque converter bolts to remove trans, so you might check those. If a bolt got loose in there it might cause some nasty noise.

Agree w/ checking the harmonic balancer/crankshaft pulley. I had this one fail (rubber slipping) and caused all sorts of associated grief. check my posts trail for this one.

good luck

 

Thanks TexasHonda!

Will check distributor (hadn't thought of that!) and of course the crank pulley, as you and MEAZZ1 pointed out.

Will post results later this week as dicovered. . . has to work all weekend so no time yet to further diagnose.

swfl

 

On the 2.5 TL, the harnonic balancer and crank pullies are a one piece unit. The rubber holding the alternator pulley to the harmonic balancer dries out and fails. This is usually followed by the atlernator belt self destructing. (It might be a good idea to replace this on the timing belt replacement. Cost $300.00) I have also expereince the A/C idler bearing going bad. Sounds like a slipping belt noise or growl. I bought a $50.00 pulley assembly for our 2.5 at the dealer. The bearing is a 203. Very common in alterantors. Bought the bearing at Carquest and replaced with a hammer and sockets on the 3.2 for $10.00 in my garage. I counted the number of turns to loosen the idler and reversed the process after installing the new bearing. This also should be done during timing belt replacement. I also rebuilt the alternators during timing belt replacement on both.

There was also a recall on the transmission/differential about a bolt that would fall out causing the car to stop. I haven't expereinced this. Speaking to that end of the car, what was the service to the differential and transmission? Oil level? Was the noise only while the engine was running? With the car standing still?

We also had the speed sensor go out on the 2.5. This was a check engine light and loss of speedometer.

Has anyone seen any grounding issues? I noticed that Acura doesn't use star washers on any grounds. This will be my next thing to tackle. I have rear tail light alarm signals that are false. I don't really like the way the wiring is made. It seems too easy for corrosion to weaken in the electonic connectors. I solder mine to prevent corrosion.

Hope this helps.

 

I've never had any grounding problems.

I have had bad harmonic balancer and two failed vehicle speed sensor (VSS). I think the VSS may fail due to grease or oil blocking the signal. I recently had to replace the VSS for 2nd time. I replaced the "guts" w/ parts from an Accord VSS (identical) to avoid paying $150 for an OEM VSS. I started to clean magnetic rotor and sensor face in the old VSS and reinstall, but I had the replacement parts, and didn't want to have to do the job again,...if my theory proved incorrect. So I replaced the parts and VSS is working fine. If this problem comes up again, I'm going to try cleaning.

You can purchase Accord VSS for $25 on ebay for donor parts.

good luck

 

PROBLEM FIXED:

Turns out that the STARTER "return coil" failed, allowing the starter gear to partially engage the flywheel teeth, = 1/8 of starter gear teeth ground off and the resulting horrible grinding sound from the driver's side REAR of engine.

After pulling out the starter (bitch of a job) the marks from the metal probe I was using to listen to try to diagnose the source of the sound were all over the outside of the starter case = the old mechanic's stethoscope is an excellent technique. New starter installed and probelm solved!

Thanks for all the creative ideas, but it was something on the rear of the engine afterall!

swfl 97tl

 

Glad to hear that you found the problem! Could you tell if that was the original starter? Was it a remanifactured one? If it was remanufactured, does it say who remanufactured it?

Thanks!

 

how difficult was it to replace the starter?
I read a write up by Texas and it seems to be a very difficult task.

 

Starter was original with 154,000 miles, so at least it did last awhile. Interestingly, I had none of the other starter-related issues posted by others in other threads (intermittent starting, etc.), but when it finally failed, I guess it chose another interesting way!

Yes, it was a very tedious job to get starter in and out!
Bottom mount bolt was easy, regular ratchet/extension (in 17mm, I think) did the job with a littel wiggling around, but top mount bolt is tucked in up high underneath, with intake manifold blocking direct access (2.5 L inline 5cyl).

For top bolt, I used a regular open-end 14mm w/extender pipe for leverage to break top bolt free, then a ratcheting-end 14mm wrench for part of the bolt removal/replacement; then had to switch to a combination of extensions and u-joints on a regular ratchet, fished through the intake runners, inorder to get top bolt all the way out. Getting hands up in there was difficult, temporarily removed a vaccum hose routing bracket on the top right of the intake (working from the driver'sside fender point-of-view), and another bracket holding some misc. relays etc on the fender-well; left everything connected, just dismounted to allow movement out of the way of my arms. Still a bitch of a job, approx. 1.5 hrs out, 1.5 hrs in. Disconnected wires after bolt removal allowed old starter to be moved out where I could see it, then reconnected wires to new one while still in-hand but down under the manifold, before wiggling up into place and bolting on.

I could not have done this particular job without the ratcheting-end box wrench in 14mm, so if you're looking at starter r-r on 2.5L L-5, get one! I guess at a dealer they would probably r-and-r the intake to allow access, but I didn't want to do that!

swfl97tl

 

I hope you took some photos.
If so, can you post them?

thanks

 

I know its no easy to pull that stater out! I have the guys at Auto Alternative pull mine out when the put in the timing belt. They said that it was a fun job. They pulled the starter and alternator both. It is my wife's car and it has to start and run. I had to keep the down time to a minimum.

THANKS FOR THE DETAILED DESCRIPTION!

I had the alternator pulled out of the 3.2 when the timing chain was changed. The starter needs the exhaust pipes loosened or the drive axle removed. The drive axles will be pulled at 125K. They are starting it get loose. The starter has been replaced with a new one from the Acura Dealership from the previous owner.

When I get this done, I'll have the guys add a gound cable for the starter. I'll run this to the ground cable at the battery. I do this so that I don't have to rely on the aluminium block as a ground.

This weekend is grounding weekend. My service manual shows me all the grounds. I'll add them from the block to the fenders, block to the body, block to the battery, bolts at the alternator to the battery, and use star washers at each location. I did this on the Integra. Never had an issue. The TL's are having grounding issues. I'll post seperate post when I'm done.