2004 V70 flywheel material defect Loud Starter, Chipped & Mashed teeth on flywheel/flexplate Topic is solved

[- Pete -]

Is there a way to check for crank float?
I strongly doubt that's what it is, and hope that's not what it is. Guess I'd rather replace the flywheel than tear the motor apart for an entire rebuild.

Seems to me if I pushed up on the flywheel I'd be able to verify if this was crank float or one of the infamous bad flywheels from the small batch of them that were produced & put into cars.

Plenty of old documentation on this it looks.

https://www.volvoforums.org.uk/archive/ ... 70148.html

My luck, oh wait, that ran out a couple weeks ago.

Guy we bought it from said he never noticed any abnormal starter noise. He drove it 61k miles before selling it to us at 128K 2-3 weeks ago. I replaced the starter when I got the car home from the purchase - no change in the noise whatsoever. Thankfully only spent $25 on the Volvo scrapyard starter.

Looks like I'll have to pull the engine afterall.

[oragex]

Also replaced the solenoid? Might be sticking causing the started to stay on

[- Pete -]

Both starters have the exact same sound, and it's clearly not coming from the starter.
The solenoid is piggybacked on the starter motor ya?
If so, and I think it is, yes, it was replaced and the sound is the same.
The sound has to be created by how the teeth of the bendix are mis-meshing with the teeth on the flywheel/flexplate.

[- Pete -]

Is there a way to check for crank float?

I'm pretty sure I can rule out crank float as the culprit for the teeth on the flywheel & starter mis-aligning. In reading that archived post I linked I don't really see what else it could be other than a sub-par flywheel. I'll know more once I can compare the two side by side & get a closer look at if the trans to motor mounting is wonky. I don't know if the trans to motor mounts are slotted & leave room for adjustment or not?

Another theory is that the machining on the trans casting for the starter nose is off. Again, not sure how this could happen, but this is me, so I'm not ruling out anything yet. If that were the case & I get this flywheel in there and it's still mis-meshing I'll need to shim the starter. I've never had to shim ANY starter, so will have to figure out the most appropriate way to do that with that alignment pin.

Regardless, that flywheel will need to come out of there at some point, because it WILL fail & since this is me, it will fail when I really need the car to start and it just won't, because it can't due to the 10 teeth that have gone missing & been collected by the tooth fairy.

Anyhow, this is what a healthy flywheel for a 2.5T should look like.

This is out of an XC90 2.5T with about twice as many miles as are on this 04 V70 AWD (128K).
There is probably twice as much material at tips of the teeth on this as there are on the one in the V70.
$40 at Stranberg.

The guy at the Volvo scrapyard in Centuria WI said it'd be easiest to drop the trans out versus pulling the motor.
I'm clueless as I've never had to dig this deep in any vehicle for repairs, but I'll take his word for it as he does this sorta stuff every day.

[jonesg]

I would try rotating the flywheel to check for runout.
Then actuate the starter with it unbolted so you can watch to see if the pinion gear stays out. It might be popping in and out from spurious signal voltage.

Come to think... I had a situation where my starter made a grinding squealing noise, I turned the key off and it kept on cranking the engine, I'm sitting there with the key in my hand and the starter is still cranking and grinding/squealing.

Turns out the ignition switch was not releasing.

You might be getting something similar. I would unbolt the starter and hold it, have someone turn the key and see if it releases with the key. Might need a temp ground wire to complete the circuit.

[- Pete -]

I'm sitting there with the key in my hand and the starter is still cranking and grinding/squealing.

Turns out the ignition switch was not releasing.

Holy cow, that would really pucker a guy up. I never saw your post, thanks for that tidbit.
This gear-mis-meshing noise is absolutely flywheel/ring-gear based.




I am mid-transmission removal right now. BTW, I have a really great tip for freeing the angle gear from the driveshaft collar, but will post a dedicated thread just for that, & link it here.

I'll be suspending the engine tomorrow, dropping the front subframe, then lowering the trans on a trans-jack - everything else is out of the way as of now.

Ultimately the purpose of this endeavor I've set out on is to replace a flywheel with inferior metallurgical properties.
Anyhow, I figured I'd revive this topic to see if anyone has any suggestions as far as other stuff to do/look for since I'm this far into the car.

All 3 motor mounts literally look like they are new. Three of our other P2 Volvos leak oil from the turbo return line, but this one appears to be very clean under the turbo so I won't mess with it.

[- Pete -]

Plenty of old documentation on this it looks.

https://www.volvoforums.org.uk/archive/ ... 70148.html

Here’s the flywheel at just over128K.

Here’s the flywheel at 130k, pretty crazy how fast those teeth have been reduced to sharp, jagged, barely-there teeth. I sincerely hope none of you need to do or pay for the repair I just finished. I firmly believe & understand why this would be a $1500-2000 repair at a shop. I paid $40 for a used replacement flywheel & did it myself with my father. We did it on a lift, used a transmission jack, engine bridge/support, and a good assortment of air tools & hand tools. I did learn a lot & no longer am intimidated by the thought of having to remove a bevel gear, transmission, or motor for that matter.

The bevel gear tip - remove the 6 bolts connecting the driveshaft to the rear of the bevel gear. I’ve read that these bolts need to go back in the same holes they came out of, but I don’t see how that can matter. They are all the exact same size. Anyhow, from the back side shoot Kroil (or whatever spray lube you have handy) in the 6 bolt holes. Then look at the front side of the coupler. You can see the backs of the 6 threaded holes. There are also 2 holes that are not threaded. Pop a junk bolt in both of those 2 unthreaded hole. I used 2 chisels to act as ramps on each of the bolt heads. Pushing on those bolt heads separates the driveshaft from the bevel gear coupler very easily. I wouldn’t try any other method than this. Prying on the front of the driveshaft runs the risk of damaging the grease cavity on the front of the driveshaft.

[tardcart]

there is no explanation for that sort of wear even if sand got in there and it was soft metal. the starter is engaged to the flywheel only about 1 hour in the life of a car. orangeX might be on to something, that the gear was always engaged, but that would create wear on the opposite side of the tooth than starting. I cant tell which side of the flywheel we are looking at but it does look like that wear is on the opposite side it should be on. looking from the back, the engine turns counter clockwise so the the starter would be pushing on the opposite side? unless its being dragged.

[- Pete -]

Nope.

There is an explanation & it is inferior metal on this flywheels ring gear. You don't have to take my word for it, but I've been beating my head against the floor, the wall, etc trying to accept any explanation other than the conclusion I have ultimately arrived at and my mind is not being convinced of anything other than inferior liquified metal in the casting process of the ring gear.

When you hit the key, the bendix contacts the worn face of the teeth on the ring gear. It is not dragging on the opposite side of the tooth faces.

As you look at the pictures of the flywheel, that face you can see mounts to/touches the crankshaft. That face you see is the one that spins clockwise, were you able to look at it while it was in motion, fictitious vantage point being from the crank pully.

The circled segment of teeth is where the starter initiates it’s purpose the majority of the time you hit the key. I know most engines like to stop in the same 1 or 2 positions, but maybe these are different being 5 jugs. There are 5 segments of teeth that are in bad shape. The one I pictured is by far the worst so this engine obviously likes to stop at that juncture most of the time.

[tardcart]

amazing that Volvo could have done this shody work, and also not have a deeper gear mesh. I just cant see how even an hour of spinning the motor over would create any wear even if it were aluminum,