2000 Corolla Engine Noise And Vibrating In Idle - Toyota Corolla, Chevy Prizm (1998-2008)

My 2000 corolla started to develop some more noise and vibrating in idle. It used to have some additional noise in highway above certain engine speed (will be lessened when AC was off). In this winter, when it was stopped and in "drive" shift, there will be this new noise sounds like related to belt or caused by more vibrating. It would be lessened when the fan was turned off, or turned to P shift.

I had some mechanic looked at this, he said the belt tensioner was not having a stable tension, so it need to be replaced and it will cost me $250. However, I watched belt tensioner for some time, didn't see any obvious problem.

I did found that there were 2 screw holes in sides of the radiator, maybe the mechanic who replaced the starter several months ago didn't put screw on? Now the radiator is vibrating a little bit when engine is running. I was thinking if the mechanic didn't fully tightened some screws when he replaced the starter.

I recorded a video for the engine. First it was in P shift, then was changed to D shift (the engine changed the angle a little bit). The noise I used to heard was not very obvious in this video.

http://www.youtube.com/watch?v=-GU69FGgngs

Or maybe you can see it more clearly in youtube site:

http://www.youtube.com/watch?v=-GU69FGgngs

Anybody have any advice? Should I find some screws to put on the sides of radiator?

Yesterday I had another mechanic checked this problem. They watched the engine movement while changing mode between P,D, said the right side mount was broken, there was too much movement in there. They replaced the right side engine mount, then the loud noise disappeared, but there is very obvious vibration now. When the car is stopped in Drive, the vibration is so big that the seat back vibration can be felt with hand on it, and I was really uncomfortable sitting there.

I took the car to mechanic again, he said that's because one mount is new, the others are old, and he'll have a look at it next Tue, maybe there will be new charge if other mount need to be removed.

I searched online about engine mount, found that they are supposed to absorb and control the vibration. I don't think when one engine mount is broken you need to replace all of them. Is that possible that they didn't installed the new mount correctly?

How long ago was the mount changed?

They take some time to "break-in" before they start to work properly. Technically, the mounts are referred to as torque mounts - older motor mounts were will filled with fluid to help with vibration. Vibration control in a torque mount is controlled by how much movement is allowed by the mount. It is possible that the new mount is causing reduced motion overall - which would mean a significant amount of vibration being transmitted to the cabin.

Personally, I'd hold off on the other mounts and give the new one a chance to soften up. You can also have them double check that the new mount is torque correctly. Sometimes, loosen it and retorquing the mount will help with vibration.

fishexpo101, thanks a lot! I think you replied every question of mine in this forum default_smile

The mount was installed yesterday. I'll take it to mechanic next Tuesday. Let's see what happens.

Today the mechanic told me that he found the problem of vibration. He said somebody who worked on engine before may overtightened a bolt for the ignition coil, then the bolt was broken, so the coil was dangling around which caused misfire of one cylinder, and unbalanced engine. To fix this, they need to drill a hole to take out the broken bolt, then make something to fill that hole, this will cost $150, plus other work, the total bill for the repair will cost $500.

But it have been a very long time since last time somebody worked on that engine. 1 year ago the Mass air flow sensor was replaced, but I don't think that will involve the coil. 5 years ago the engine was basically rebuilt by Toyota dealer because some walmart mechanic did something wrong when changing oil and oil filter. That all the repair related to the engine. So this problem was caused by the repair 5 years ago?

The engine vibration only appeared from this Jan and it only appears in idling. Other than that, the only thing I noticed about engine problem is there could be some small noise above 70 mph in highway.

I'm a little confused, the coil problem sounds like a severe one, but I didn't notice that kind of problem before, and the recent vibration problem only appear in idling, drive mode, never appear in driving.

Possible that the coil just recently got damaged enough to cause an intermittent connection with the spark plug.

Hard to believe that this repair will cost $500. If the bolt requires that much work to be removed, be cheaper and easier to get another valve cover and new coil on plug unit. Pretty sure this model year has individual Coil on Plug igniter modules - one for each spark plug. Basically just sits on-top of the plug, no "dangling" here. I know on my car, the bolts were all aluminum, so should be easy enough to use a screw extractor to back them off. If they were cross-threaded - just drill out and use a heli-coil to repair the threads. An hours work tops - at the current going shop rate - between $85-$105 an hour.

Before you spend a single penny - have the plugs removed and compare the plug from the damaged coil to the other plugs. Basically want to "read" the plug ends. If the coil is bad, the spark plug associated with the bad coil should look significantly different than the other plugs. Maybe drenched in oil or fuel, have dark soot/carbon deposits on it. As if the coil was bad, the plug will not have a chance to fire - ending up with a fouled plug very quickly. Even under intermittent condition, the plug should show evidence of being significantly fouled.

Possible that the coil just recently got damaged enough to cause an intermittent connection with the spark plug.

Hard to believe that this repair will cost $500. If the bolt requires that much work to be removed, be cheaper and easier to get another valve cover and new coil on plug unit. Pretty sure this model year has individual Coil on Plug igniter modules - one for each spark plug. Basically just sits on-top of the plug, no "dangling" here. I know on my car, the bolts were all aluminum, so should be easy enough to use a screw extractor to back them off. If they were cross-threaded - just drill out and use a heli-coil to repair the threads. An hours work tops - at the current going shop rate - between $85-$105 an hour.
Before you spend a single penny - have the plugs removed and compare the plug from the damaged coil to the other plugs. Basically want to "read" the plug ends. If the coil is bad, the spark plug associated with the bad coil should look significantly different than the other plugs. Maybe drenched in oil or fuel, have dark soot/carbon deposits on it. As if the coil was bad, the plug will not have a chance to fire - ending up with a fouled plug very quickly. Even under intermittent condition, the plug should show evidence of being significantly fouled.

I'm with Fish on this one. It sounds like they are trying to hose you. The bolt for the ignition coil isn't even very big--should be easy to back out. If it really is as messed up as they say it is, a new valve cover isn't terribly expensive.

Thanks fishexpo101, dshadle1. I wish I can see your posts earlier, but I didn't receive any email notifications about new posts.

Anyway, I took my corolla to another mechanic to have second opinion. Several hours later, he called me and showed me all the spark plugs, said they have to be replaced immediately. I saw 2 of them have some white deposits, one is pretty clean, but he said all of them have to be replaced, and the plugs cannot be cleaned. He also want me to do a fuel injection cleaning. I asked him about the bolt and the coil, he said there was a bolt not totally fixed, but he can fix it easily with a bigger bolt or something(I'm not very clear about this).

It's so sad because I just began to have some trust on first mechanic when he found the real problem with engine mount (I went to several places before, they didn't find the problem since they didn't notice the vibration when the car was there). Now I don't believe him anymore.

As for second mechanic, I'm not totally convinced with spark plugs. I didn't notice any problem with engine running, and the mpg is less than before but not much. He said new spark plugs and fuel injection cleaning will make engine run smooth, but my engine's vibration and noise only appear with the engine mount problem. Right now there are some vibration, but I think it's still related to the new engine mount. At last I just asked him to put everything back, and he said he fixed the bolt.

Another problem I asked them to check is there is some noise on bottom when the road is not even, sounds like something is loose. First mechanic said something like strut is old and not tightened, but that is not emergency and he went to to urge me do the job on the ignition coil. The second mechanic actually didn't really check the problem, just because I mentioned the noise could appear more frequently when I apply brake, he said I need a new brake rotor because the rotor was not surfaced last time I changed brake pad.

Yesterday I looked at the bottom of corolla by myself, and found there was some plastic bottom cover broken loose from one bolt. I fixed the cover with bolt and some pad material, then the noise from bottom are almost gone. I also have a long time question, my car can be scratched on some normal bump, but I never found where. Yesterday I realized there were mud flaps which is significantly lower than the bottom of the car. I removed that mud flaps, and there is no more scratch on bump. I think maybe frequent scratches actually pulled the plastic cover so hard that it broken loose with the bolt.

Sorry to hear about your experience. Just from what you mentioned here - the 1st mechanic sounds more competent than the second one. Actually ,if you combined the best aspects of each mechanic - you'll have a solid mechanic to go with. Unfortunately, even if you have a solid rapport with a mechanic, you always have be conscientious of being taken advantage of.

Here is a link to some sparkplug / ignition information:

http://www.aa1car.com/library/cm1196.htm

Not sure what was wrong with the coil with the 1st mechanic - but he was probably correct that the ignition issue was more important than the suspension. If the car continues to mis-fire - there is a very good chance that you could damage the catalytic converter, accelerate wear on the engine. That is because raw, unburnt fuel is being dumped into the combustion chamber and out the exhaust. Unburnt fuel will "wash" down the cylinder walls, reducing the ability of the oil to protect parts. In addition, that fuel will mix with the oil, effectively lower viscosity (low thickness, less protection) and accelerate oil consumption. Whatever fuel makes it past the combustion camber will "fuel" continued combustion down through the exhaust system. The catalytic converter is designed to operate within a specific temperature range - outside of that range, the substrate for the catalyst could break down from excessive heat.

The second mechanic is correct that plugs, especially these newer ones, cannot be cleaned. In fact, attempting to clean the plugs with the old trusty wirebrush - can actually increase the likelyhood of mis-fires, as the metal from the wires can get deposited onto the plug itself. So you are correct that you should hold off on the plugs, at least for a little while. If the plugs have more than 90K miles on them - I would personally just change them for piece of mind, but keep the old plugs for spares/diagnostic purposes. Fuel injection service is hit or miss - 90% of the time, more of a profit maker than something that your car really needs. Depends on how the injection service is done. If it is one where they take out each plug, ultrasonically clean them, flow test and balanced (each injector shooting the same amount of fuel), new gaskets - clean the fuel delivery system with a solvent to flush the lines and fuel log - run the engine with a cleaner solvent (disconnect the fuel line and run the car with the special solvent) to clean the top-end (decarbon engine) and slowly enough to ensure a decent cleaning - check fuel pump operation, pressure regulator operation, check for fuel leaks, clean throttlebody, check air flow, check for vacuum leaks, reset computer, etc. - then maybe it might be worth it. Chances are - they will plug in a can of solvent, run the engine for 10-15 minutes tops and charge you $150+ A little can of solvent run for a handful of minutes will not clean anything on the injector.

Good catch on the mudflaps and underbody splash panels. The can work loose over time - just takes a little bump/snag to pull them out of shape, then after enough fluttering at speed, they will break free of the screws holding them in. What I'm trying to figure out - what kind of bump did you run over / how much is the suspension sagging to have the mudflaps touch the ground. My car is lowered about an 1.5" and unless I try and slowly drive over a very tall speed bump, my flaps clear with plenty of space.

How can I tell by myself if there is a problem with misfire? I read the article you mentioned before, it was very helpful. But I don't have problem of difficult starting, check engine light on, or black smoke from exhaust pipe etc. Right now the engine is not as smooth as before in idling, I think it may related to these two diagnostics(4 plugs were taken out then put back), other than idling, the engine feels right.

The bumps I had problem with, is a normal speed limit bump in a strip mall, which looks just like any other bumps, but I always heard loud scratch noise when I went through it. I didn't have problem with any other bump. Besides, my wife's work place is a research institute by government, and the security checkpoint just had this newly installed gate, which will scratch my car too. The problematic mudflaps were right after front wheel, I think they will be more likely be scratched than the mudflap after rear wheels.

Their intermittent nature makes misfires very tough to diagnose. Even in a well running engine, there are occasional misfires - just a matter of statistics. In your case, since it affects idling - could be a number of things. If the engine is running roughly in idle, nearly constantly - you can test if you have a significant misfire issue by unplugging the signals from the coils, one at a time. The engine should run terribly with that missing coil, but the one that seems to have the least affect or no affect, when disconnected, is the likely culprit.

Misfires could be a result of a dodgy knock sensor - if the sensor is not reading properly, could be causing the car to pull timing all the time. That would make the car run "off". A bad injector, excessive cylinder deposits, damaged valve, or low compression could be other possibilities.

Can also check on this over time - if you have brand new plugs in the car now - pull them out, noting which cylinder they came from - either photograph or visually note as much as you can amount how the end appears (color, deposits, fouling if any, odor, etc.) Place them back in their respective cylinder - drive a few hundred miles or a thousand miles, repeat. Eventually, you will build up a "history" of each of the cylinders and how they are performing. If any are grossly different then their neighbors - could mean a problem with that particular cylinder.

Today the first mechanic called me again to urge me do the ignition coil fix. I thought the second mechanic said he used a bigger bolt to fix the coil, but still decided to have a look at it by myself. With borrowed tool from advance auto part, I found the second ignition coil do have a bolt missing(so it can move around a little bit), so the second mechanic didn't bother to do it since I didn't replace the spark plug immediately.

I'm really confused about that missing bolt. The last time somebody touched that part of my engine, is 5 years ago by Toyota dealer. How can an entire bolt gone under the engine cover? Is it missing 5 years ago, and we had driven it like this all the time? Or is it taken by the first mechanic itself? I have no idea. But I don't want to take it to him again.

I talked with the second mechanic, he said he can try to put a bigger bolt into it first -- he said the thread is stripped, I didn't verify it. Then if the bigger bolt don't work, he will use a helicoil insert (he mentioned something like "hex", I googled and guessed it will be this). The latter method will cost me around $100, and the first mechanic used to ask for $150 for this(plus other charges to make the total $500, he didn't say the details, I guess it will include a new coil).

Besides, the first mechanic said the noise came from right side bottom was caused by a weaken sway bar links.

Today I went the 3rd mechanic, who allowed me to bring my own parts. I purchased 4 spark plugs from advance auto parts. We found the missing bolt of the ignition coil actually was broken half, so there was some part of old bolt in the hole, and the thread were totally gone. He found a bigger bolt, cut to appropriate length, and tightened the bolt successfully. Then he changed all the 4 spark plugs, here are the picture of them

http://picasaweb.google.com/dracodoc/SparkPlugs#

From Left to right, No. 1,2,34

No. 1,2

No. 3,4

But I didn't feel anything changed after the new spark plugs. There were still the vibration in idling, and the engine was running rougher than before all these repairs.

This mechanic also looked at the sway bar links, said they were fine. I drove around and showed him the noise, he said it should come from stabilizer links.

Is this one the stabilizer links I need? From the pic, they were really small

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Suspension-Stabilizer-Bar-Link-Complete-Autopart-International_24012585-P_78_R|GRPCHASAMS_1024051863___

Today I found there was this big screeching noise when starting the car. It was just before the car started, sounds like the starter noise but much more big and harsh. I just replaced 4 new spark plugs. Could it be related to that job, or something with the ignition coil (one of them lost the bolt, then was fixed), or new problem of starter?

The noise sound like the screeching noise here

http://www.theaa.com/motoring_advice/audio/drive_belt_slip.mp3

But that audio clip have the noise after the engine started, in my case it stopped once I released the key..

EDIT: I just talked to the first mechanic, he said the noise is caused by the belt, we had rain yesterday, maybe the belt had some moisture. I didn't hear the noise after the morning.

That noise is definitely related to a slipping drive belt. Double check the condition of the serpentine belt, if there are any excessively shiny spot, severe cracking, missing chunks of rubber, etc. - might be time to replace the belt. Note that fine cracks in the belt are OK/normal. If a pulley was wet, it could slip in that manner. Think it was just coincidence that it happened after the sparkplug repair. If the belt has more than 60K-90K miles on it - highly recommend thinking about replacing it.

It is weird that the car is running rougher - normally a car runs much better after a set of new plugs. Same make/model of plugs were used?

Also, nice clear close up pictures - thanks. Looking at the pic with all four plugs - assuming you mean cylinders #1-4, from left to right (cylinder #1 is closest to the pulleys/serpentine belt - passenger side of the car). My take on the condition of the plugs:

Overall - all four plugs show they have a decent amount of wear, probably could run them for a little longer, but the ash deposits are fairly excessive. They also show signs of running "rich" - though the factory tune of the car is fairly conservative and tends to err on running rich than lean. That grayish, powdery coating on the plug is the ash - these deposits form from the additives in gasoline and motor oil. A light coating of ash is normal, once they start to build up to that level, the likelyhood of a multi-cylinder mis-fire is greatly increased. From a quick visual inspection - #2 and #3 plugs have seen some mis-firing, possibly #1, more so on #3 plug. #1 and #4 plugs are better, with #4 being the best - perfect operation.

#1 - Heavy ash deposits, heavily worn center electrode (gap appears to be too open), dark, localized discoloration of porcelain and sooty deposit on the base ring indicate a possible issue with fuel injection in that cylinder. "Wet" base ring indicates a possible oil control/consumption issue with that cylinder.

#2 - Heavy ash deposits, heavily worn center electrode (not as bad as #1), dark, localized discoloration of porcelain and sooty deposit on the base ring indicate a possible issue with fuel injection in that cylinder. Again, "wet" base ring indicates a possible oil control/consumption issue with that cylinder. Due to the coloration - appears that this plug had issues with mis-firing.

#3 - Very heavy ash deposits, heavily worn center electrode (not as bad as #1), very dark, localized discoloration of porcelain and wet sooty deposit on the base ring indicate a possible issue with fuel injection in that cylinder. Again, "wet" base ring indicates a possible heavy oil control/consumption issue with that cylinder. Due to the coloration - appears that this plug had issues with mis-firing (worse that #2).

#4 - Light ash deposits, worn center electrode and ground strap (not as bad as #1, #2, #3), light localized discoloration of porcelain and medium, sooty deposit on the base ring indicates that cylinder and injector is running perfectly fine. Note that the base ring is much lighter in color, has less deposits that the other plugs - a well running engine will have all plugs look like this.

From this - I'd recommend that a mechanic run a compression test - make sure the engine is healthy. Possible that the piston rings are "stuck" or the valve seals are leaking an excessive amount of oil in to the cylinder. This is being transferred to the plug as ash deposits. If compression is good, then I would proceed to looking at ignition and fuel culprits. Possible that the intake side is clogged with heavy carbon deposits and/or the injector is not working optimally. Depending on the driving conditions - possible that the plug heat range is not matching up with usage of the car. Plugs appear to be too "cold" or the car is not driven enough. May just need a good blast down the expressway every once and a while, mix in some WOT (Wide Open Throttle) acceleration as well. Also monitor oil consumption, think about running a high-mileage motor oil (has additives that may help with stuck piston rings, break down internal deposits, maintain good viscosity, but can lead to more ash deposits - so monitor it closely). Do not be tempted to run a heavier oil - that just masks oil consumption and leads to larger problems down the road.

As for the stabilizer link - that looks like the right one. Unless there is obvious movement in the link, I would wait until you get some suspension work down before you replace them - i.e., when it comes time for new struts or springs, replace the end links as well - as they will need to come off anyways. Same goes to the rubber bushing for the sway bar - verify that the bushing is present and in OK condition.

I don't have a chance to compare the plug with that loose coil, because the second mechanic took them off and showed to me, and I don't think they remembered to put them in original order. The 1st mechanic said the loose coil was weak, and the $500 charge include the bolt job, replacing spark plugs and coil (he didn't tell me all these details at first).

I had replaced all spark plugs but not coil, and the engine running was not better, actually it was not as smooth as before. The bottom noise are pretty obvious now, I'm waiting for the sway bar links I ordered.

Possible that the coil just recently got damaged enough to cause an intermittent connection with the spark plug.

Before you spend a single penny - have the plugs removed and compare the plug from the damaged coil to the other plugs. Basically want to "read" the plug ends. If the coil is bad, the spark plug associated with the bad coil should look significantly different than the other plugs. Maybe drenched in oil or fuel, have dark soot/carbon deposits on it. As if the coil was bad, the plug will not have a chance to fire - ending up with a fouled plug very quickly. Even under intermittent condition, the plug should show evidence of being significantly fouled.

I still hear the screeching noise every morning when starting engine, but not in later starting. The weather is hot now, I think the moisture should not that be difficult to be dispersed?

Is it possible to relate to the spark plug replacement? If there are some problem with the coil or spark plugs, make the engine difficult to start, so the starter made the belt screeching?

EDIT: I didn't see fisher's new reply when I was writing this. I looked at the belt but didn't find anything, I will looked at it again.

The belt probably have less than 30k miles, it was replaced in 2007.

Thanks a lot for the detailed analysis for spark plugs! As I mentioned, the spark plugs have been taken out and showed to me, so I don't think the order when I replaced them are exactly the same from all these repair before.

The spark plugs I used is this one

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Spark-Plug-NGK_15650071-P_960_R|GRPTUNEAMS_775181870___

NGK,Laser Series Iridium Spark Plug; IFR5T11; DOHC; @ Gap .044 @

I have a 2004 corolla manual which recommended NGK spark plugs.

My engine was basically rebuilt by Toyota dealer in 2005 because some walmart technician did something wrong in the oil change, then the engine run with low oil and black smoke, clunking noise. I think the rebuild was related to the piston and wall, so it's possible that they developed some problem after these years.

Before take it to mechanic, what's the simplest and easiest thing I can do?

more highway driving, full throttle acceleration?

use higher grade gas? I think all major brand gas have some additive to clean engines, does higher grade gas have more additive?

or do I need to buy some engine cleaning additive?

I use the same plugs in my 2002 Corolla - good plugs - no problems at all running NGK in the 1ZZ-FE engine.

Correct, all grades of gasoline have normal amount of additives - you can try a bottle of Redline fuel injector cleaner - that seems to work well for me. Then just take it on a good highway trip - running a few times at WOT (merging onto freeway, accelerating up to speed, etc.) is good for the engine as well (just watch your speed).

A good throttle body cleaning and cleaning the MAF can also help improve idle quality on the cars.

My MAF was replaced 2 years before by a Toyota dealer. Can I clean it by myself?

Yes, you can clean it yourself. They make a specific solvent (aerosol) - MAF cleaner. Sometimes it is sold as a combination throttlebody/MAF cleaner - just make sure it is O2 sensor safe and will not eat the plastic you want to clean. Just hose down the sensing wires - don't try and tough the wires themselves - let air dry and reinstall. There should be a couple of writeup here on the forum and online as well - as this is a fairly common fix/procedure.

I bought some Chevron fuel system cleaners, will try them first.

This afternoon I heard the screeching noise when starting the car again - not only in morning. I kept the key in ignition position for several seconds, it's the same noise. So I think the noise I had these days came from starter, not the belt. It's exactly the same noise that if you turn the key after the engine already started, and it will disappear once the key is released. I searched web, some said it was caused by the starter not disengaging after the engine started.

That starter was replaced last year. It was from Autozone. I'm not sure how autozone's warranty works.

I'm not a big fan of Autozone parts - they never seem to hold up for me. Most common issue with cheaper starters, is the bendix will not retract properly - leaving it to continue to engage the teeth on the flexplate or flywheel. This could lead to excessive wear of the teeth - so trying to get to the bottom of this noise - the sooner, the better.