took the car in for a diagnosis

[ad356]

i had them further diagnose the problem. the suspect a bad flexplate. they unbolted the flexplate from the torque converter and the noise changed. it didnt go away but changed pitch. he said further diagnosis would require R&R engine or transmission. i would have never guessed that. in all of the years i have owned cars i have never had a bad flexplate. i dont know if this is something i would want to tackle myself. i have never removed the engine from a FWD car, i cannot use my cherry picker and have the stove on in the garage at the same time. i dont have a long enough building for that. further diagnosis cost 10 hours at $84 per hour, $840. i dont know what to do know and i have now idea how this happened, its not like i beat the snot out of this car.

[J Wikoff]

What was the problem?

[ad356]

they suspect bad flexplate but have no futher answers without removing the engine or trans

[J Wikoff]

I guess a better question is, what were the symptoms?

[Jfridge92]

http://www.pontiacbonnevilleclub.com/fo ... 41309.html

I don't know if I would be pulling the engine quite yet. That gets expensive quick, and there are easier ways to diagnose a dead engine before ripping it out haha.

[ad356]

so was this another case of taking $45 from me and not giving me real answers. my wife drives this car i want answers. are they full of it and just trying to sell a $800+ job. my parents have used this mechanic before and he was good to them, i just have a problem trusting any of them and for good reasons. i, myself have doubts about the flexplate explanation. IF, IF it was a flexplate, WHY WHY would it be effected by engine operating temperature?? i asked the mechanic this and he said it was harmonics?? engine temp effects harmonics?? seems to me that if it was a flex-plate it wouldn't care how warm or cold the engine is. it makes no sense to me. i was never really good at pinpointing noises most times i just try to figure it out. at this point with this car im guessing.

also the with the flexplate theory, WHY does it sound like the noise is coming from the passenger side when the flexplate is all the way on the other side of the engine. i think its nothing more then another guess.

[00Beast]

Can you please re-tell us what the car was doing?

Almost sounds like a bad balancer?

[ad356]

balancer was new 5 thousand miles ago. car makes that aweful noise once it is up to operating temperature. it only does it after you rev it past idle. the noise will then typically not got away. it is not in the accessories, since i ran the engine for a minute without the serpentine belt, noise presisted, i did not run the car very long like that i understand the water pump doesnt circulate with that belt off.

[00Beast]

Hmm. I wonder if there might be something wrong with your timing chain?

[MattStrike]

I could be wrong, but I'm not convinced it's a timing issue. You can pull the oil pan, and remove the main bearing caps to check. But you need a torque wrench and a way to measure an angle to re-install bearing caps. You can get torque angle meters cheap, but I still say you need to at least try my method of using a ~2 foot rod to listen to the engine that I posted in the other thread.

BTW, unbolting the flywheel from the TCC makes it idle faster = changed pitch. So they are Captain Obvious, but did eliminate a transmission issue from the list of possibilities.

[ad356]

not familiar with measuring angles when installing bearing caps. i installed bearing caps on a chevy 350 and i rebuilt a couple of kohler K series single cylinder engines but with all of those you just torque them down with a torque wrench. if i removed bearings caps and find bad bearing then what would i do, have the engine replaced??

i removed the inspection cover and looked at the flexplate. it seems to be in good condition. no signs of cracks or damage no metal pieces. you cannot see the hub of the flexplate but i really dont think thats the problem. does the oil pan come off of these cars without dropping the cradle. it seems like there is enough room.

[rustyroger]

I think your mechanic has got it right. Flexplates do crack, often near its centre where it is under greatest load, right where you can't see it!. It's not common but far from unknown. Could well be it makes no noise until you speed up the engine, then the plate flexes (there is a clue in its name) maybe touching the back of the engine block, staying out of line until the engine stops, returning to its normal position when the load is removed.
Removing the engine and/or transmission isn't a hard job for a competent mechanic, but it takes time. This is reflected in the price you were given.

The flexplate is more or less in the middle of the engine bay, pinpointing the source of a noise is notoriously difficult.

Roger.

[MattStrike]

When my flex plate on the '86 cracked it sounded like a piece of the trans drive chain being slung against the case, and then a pop and it broke from the bolts on the crank. From the time it started making noises to the time it broke was about 2 minutes. Most of the other cracked flex plates I've heard really sound more like a rod knock as opposed to the squealing noise your engine is making.

So you can see what to look for: You should be able to easily see the cracks, there are 4 radial cracks and a 5th one starting:


Yes the oil pan can be removed without dropping the subframe cradle or anything. Usually if there is a bearing that's spun there will be what looks like a fine powder of sparkles that have been spraying out from the ends, which gets all over the cap and adjacent part, so you might not need to actually remove the caps to find a spun bearing. Take some clear photos and post them before pulling off any bearing caps, post them up here if you can. There are 4 main caps (keeps the crank mounted to the block) and 6 rod caps (connects the piston to the crank), one main is on each end, and there are 2 rods between each main. #1 main is at the harmonic balancer, #1 rod is the first rod after that. The rods you can feel for play in the bearing, it can slide a little side to side along the crank but should not move otherwise.
This is basically what you will see;

[ad356]

im familiar with what a rotating assembly looks like. i knew that a bad rod bearing will have movement, but if its a main bearing the crank isnt going to move is it? if this engine is bad, is a replacement engine nessary or can you go with a crank kit? i was going to change the oil anyways, would the evidence be found in the oil or do i have to remove the pan. removing the pan seems like no more then the cost of a pan

[MattStrike]

When a main bearing fails it sometimes leaves the babbit sparkle trail on the side of the cap but there should be evidence in the oil pan. Coppery or silvery flakes, babbit sparkles, etc. Most of the flakes will settle in the bottom of the pan, so unless you capture a quantity of the oil and see the sparkles you won't know without pulling the pan. You are correct that you won't be able feel it like you can with a rod bearing.

Depending on which bearing(s) it was and how much damage was done to the bearing bore in the block/rod/caps will determine if you only need a crank kit. But most of the time all you'd need is the crank kit, a timing set, gaskets, and assembly lube, and a good block cleaning. Because you don't want leftover metal flakes getting in the new bearings, or abrading the cylinder walls.




Here's a picture of what I'm talking about when I say tiny sparkly things in the oil. You might need a magnifying glass and will need a good light and just the right angle to see it on the dipstick. It's nearly invisible without a good light on it:

[ad356]

honestly this car has been running literally thousands of miles with this noise. at first i assumed it was just a water pump, so i had one of these " i will change it when i get to it moments". now im running the car because i refuse to drive my nicer cars in the nasty, slop hole that im living in right now. constantly snowing constant salt. i really wish that this would have happened in the summer, its allot easier to deal with when i'm willing to use my other 2 cars. i really think if it was a flexplate it would have left the car stranded already. its probably been making the noise for 4,000 miles already. i just want to get through the rest of the winter, at least i would like to

[MattStrike]

its probably been making the noise for 4,000 miles already. i just want to get through the rest of the winter, at least i would like to

If it's been that long a main/rod bearing issue should have left you stranded too.

[SuperHbody]

I've listened to your video several times and I can't help but feel it's a bearing going somewhere on your accessory side. A pulley maybe or the alternator. That and it sounded like you have a vacuum leak somewhere.

[RJolly87]

As i mentioned in your first thread on this, i want to see whats behind the timing cover.

[ad356]

a vacuum leak would explain why my check engine light is on. i thought it was a loose connection at the purge selinod but i pushed that vacuum line back on. its not the alternator, its been replaced not only that but the noise exists with the serpentine belt removed, completely removing the possibility of any accessory related noises. what do i have to do to remove the timing cover. altenator has to come off, serpentine tensioner, alternator, water pump, power steering pump? what im i missing? how long would the job take?