Grinding noise from the engine

[fc321]

Hi guys,

My car has 32k miles and has begun making this strange noise from the engine as if the engine is under a great load. I feel a vibration coming thru on the steering wheel

It just started happening about a week ago out of the blue. I have not made any changes other than the new tires installed about 3 months ago.

The engine has become 40% louder than it used to be. Is there anything you recommend me to check? I lifted the hood but nothing looks different. I have the manual transmission and have not yet changed the fluid of that (still has original fluid).

Even when the car is coasting in neutral at 30 mph the engine is loud and has a low pitched grinding sort of roar.

The only thing I could think was maybe its the new tires that are what is making the sound but it doenst seem logical because I have already put almost 2000 miles on them and the noise started just like that one day.

[Fummins]

This might be a lot of back and forth questions and answers.

Are you sure it's your engine?

Does it get worse the faster you go?

Does it vary with rpm or does it vary with speed?

Is it a grinding noise or more of a humming?

Is it still there if you shut off the engine while coasting?

I had one Mirage with a weird vibration that I've never seen before. Under load it would shake really bad, if you let off the throttle it still shook but not as bad. It seemed worse over 30mph up to 50(I didn't go faster than that). It was really bad. Just for sharts I replaced the one cv axle that had slightly more play in on the inner joint(the rh side in this case). Problem solved.
I recall another forum member had a similar problem years ago, I didn't believe it at the time.

Other guesses are possible wheel bearing? Could be a bad tire, maybe one is turning into a China bomb?

[fc321]

This might be a lot of back and forth questions and answers.

Are you sure it's your engine? I THINK SO BUT EVEN WHEN COASTING IN NEUTRAL IT MAKES THE SOUND

Does it get worse the faster you go? YES

Does it vary with rpm or does it vary with speed?

Is it a grinding noise or more of a humming? I WOULD SAY ITS A DEEP BASS TONED GRINDING

Is it still there if you shut off the engine while coasting? I WILL CHECK AND SEE

I had one Mirage with a weird vibration that I've never seen before. Under load it would shake really bad, if you let off the throttle it still shook but not as bad. It seemed worse over 30mph up to 50(I didn't go faster than that). It was really bad. Just for sharts I replaced the one cv axle that had slightly more play in on the inner joint(the rh side in this case). Problem solved.
I recall another forum member had a similar problem years ago, I didn't believe it at the time.

Other guesses are possible wheel bearing? Could be a bad tire, maybe one is turning into a China bomb? YES I AM THINKING IT MAY BE THE TIRES BUT AFTER 1 MONTH WHEN I HAD PUT THEM ALL AT 40 PSI IT HAD ONLY GONE DOWN TO 36 PSI ON ALL 4 TRES

tHANKS FOR THE GUIDANCE I WILL KEEP MONITORING THE SYMPTOMS. I took a big hit on fuel economy since changing to these larger tires. Down to a 36 mpg average from the old 40 mpg average

[CROSSBOLT]

Easy to check is lug nuts/bolts holding the wheels on. Tire shops in the US have been noted forgetting one or more wheels tightened up. To belabor the point, jack each wheel and try and turn each bolt/nut. You will know if you find a loose set....

[7milesout]

fc321 - The next time you drive it, bring it up to the speed you hear the noise the best, and then, toggle the A/C OFF, wait a few seconds, then ON, wait a few seconds then OFF, etc. Let us know if it's the A/C compressor. I say this because mine makes a lot of A/C noise, but I think it is normal.

I don't listen to the radio all that often, so I hear the A/C compressor noise. My A/C compressor makes a noise like you describe.

[Mark]

tHANKS FOR THE GUIDANCE I WILL KEEP MONITORING THE SYMPTOMS. I took a big hit on fuel economy since changing to these larger tires. Down to a 36 mpg average from the old 40 mpg average

It could be something as simple as wheel weight falling off causing one of your front tires to be out of balance. Given new tires is the most recent thing you have had done, I would lean toward something like that being the issue for you.

[7milesout]

I took a big hit on fuel economy since changing to these larger tires. Down to a 36 mpg average from the old 40 mpg average

fc321 - Part of my theory is that maybe recently, when you noticed the noise and you know, soon after putting on the tires, you started using the A/C about the time the weather started getting much warmer. The A/C will effect your mpg a bit as well. But my theory could be all whack. You might be using the Mirage's A/C year round. You do live where the heat is on.

In my case, when it is cool out (75° or cooler, or a bit over 80° and cooler if not in direct sunshine (like night or cloudy conditions), I drop the windows, and enjoy the breeze and sounds. You may not do the same.

[MetroMPG]

tHANKS FOR THE GUIDANCE I WILL KEEP MONITORING THE SYMPTOMS. I took a big hit on fuel economy since changing to these larger tires. Down to a 36 mpg average from the old 40 mpg average

Did you post a thread about switching tires? Link? My 2nd Mirage had a tire with a broken belt. It made a lot of noise.

I was going to place a bet about what I think is wrong, but we don't have enough info yet!

Does it vary with rpm or does it vary with speed?

He's got a manual trans. Easy to test.

Does the noise change (loudness or frequency) when you shift gears while holding the same road speed? EG: find a stretch of road where you can hold steady at 45 mph. Try 5th gear for a while, then 4th & 3rd.

[fc321]

Hey Guys I was out of the country for a few weeks. But seems the noise was from the cheap tires I had selected (Fortune Brand). They are very loud about 4000 miles in. I should not have been such a cheap-skate trying to save $20 per tire and it a dumb decision.

Better to go with a reputable brand. Now Im stuck with these things until they wear out. I wasted money on an alignment as well (right after I installed them) so I gave the tires every opportunity for success.

They should change the brand name to MisFortune

[fc321]

Hmmm, I never considered that. I do know for sure that the bolts are at the correct spec because I used a torque wrench myself when I got home.....to loosen and tighten them to the correct spec.

Yeah that theory actually............ would perfectly explain my symptoms.

Ref: It could be something as simple as wheel weight falling off causing one of your front tires to be out of balance. Given new tires is the most recent thing you have had done, I would lean toward something like that being the issue for you.
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Update: I just came back from the tire shop. The guy put the car up on the lift and inspected the tires and he declined the theory of wheel weights coming off and said it must be the wheel bearing on the passenger side front tire. And quoted me $420 for the job.

Then also advised me that the rear drives side "wheel" has suffered some sort of impact injury and will need to be replaced as well. Then he spun that same tire and the wheel did look a bit wobbly.

But I bought this car from Dealership and it has never been in any collision although I have hit a couple of violent potholes in the past 3 years and gone over some speed bumps "too fast" and perhaps not slowed down enough at train track crossings.

But anyways I told the chap that I will "think it over" and anyways my next step in the troubleshooting is to rotate the tires myself here at home and fill them to the 35 psi and also to torque all the bolts to the 80 ft lbs. And then we shall see if the noise remains.

Because there is way too many people changing wheel bearings for unjustified reasons. And my car only has 32k miles so it doesnt seem very likely that the wheel bearings would need changing so soon.