Wobbly Crankshaft flywheel/rumble from engine block

Hi all,

I noticed a rumbleing noise coming from my engine and saw that the crankshaft pulley is wobbly.

Is this as simple as changing the pulley, or is there a bigger problem in the engine that is causing the flywheel to wobble.

I can't tell if it's the wobbly pulley that's making the rumbleing sound or the cranksaft itself.

Am I looking at a new engine.

Please help

Thanks in advance

 

if your crankshaft pulley is wobbling maybe its just a tighten up job on the pulley bolts, however, if your crank shaft itself is wobbling, then yeah that is NOT good. possible bearings and or journals have a problem? Which can be repaired, ie new bearings, and grind or buy new crank but yeah that gets expensive real quick if you are not doing it yourself. Also, just thinking out loud, if the whole crank is wobbling from fly end to pulley end then yeah you sound like you have some sort of serious internal problems i would say. Must sound pretty rough though? Also, your crank its attached to you pistons, conrods, conrod bearings and ultimately those pistons if wobbling because of the crank will be causing additional wear in your bores if the pistons are not on the right planes. Journals could be lose on your big end bearings. Wont know until you ostrip the engine, so it kinda sounds like might be a new engine if you dont have the means to repair it yourself. Also, making a repair might end up more expensive than new engine (depending on what is bad inside yours)……. just simply because of the labor time involved, ie engine out, strip down, fault find, new parts, rebuild, then install repaired engine, etc. vs Engine swap is possibly cheaper, ie old engine out, new engine in. (as long as you know you got a good new engine to put in.)  

Thanks Shubbs,

for the time you put into your reply, much appreciated.

By the way when I said 'flywheel' in the subject heading that was my mistake, I meant to say pulley.

I checked the pulley bolts and they are not loose.

The noise is not that loud it's like a low rumble, a bit like a diesel although my car is petrol. Initially, I thought the noise was the alternator bearings  but I eliminated that.

If you don't know Mk1s you may struggle to hear it, but I know my car and what it should sound like and it doesn't sound right.

Thanks again for your help, even though your opinion is what I feared.

I think I'm gonna have to book it in for a full diagnosis and pray that they say that the cause of the rumbleing is just the pulley and changing that will fix the problem. I should be be able to tackle that , but realistically I think I may be in the market for a new engine. Any suggestions around NW London/Middx area would be greatly appreciated
 

Sure thing Zod, no problem. If the pulley is on right then that may lead you down the path that the pulley hasbeen damaged, and may not be 100% round which could possibly cause vibration and may account for the low rumble. I hope that's the case but I suspect that you maybe have beginnings of engine knock or something like that. The longer you leave it the worse it will get. Defo a good idea to get someone to check it out. Lots of places won't know your vehicle as well as you do they may not detect the subtle change in engine tone, so make sure you use a good place that knows VWs and their engines pretty good.

Unfortunately I can't refer any good places I do all my own work and I'm in USA, so no clue what's good places there around London mate, sorry. I'm sure other on this forum can point you in right direction for that though.

Also last stupid question, do you 100% know that the crank pulley is wobbling? Or you just think it is? If it's not wobbling, the noise you described could also be that maybe your timing belt has jumped a tooth and your engine is just slightly out of timing. Seen that before a few times also. I would check all your timing marks and see if everything is lined up where it should be.

Hi Shubbs,

Thanks for coming back.

Yes the pulley is definately, visibly wobbly and I'm the only one who asks stupid questions.

I don't think that the timing belt has jumped a tooth. The car is my daily drive so I think I would have noticed, unless the difference of a jumped tooth is very subtle. I haven't noticed a change in performance since I noticed the noise.

I first noticed the rumbleing sound at the end of a 30 mile journey at 60 - 70 mph during which the car drove as it had always done.

Thanks again
 

Hi again Shubbs or anyone else who may be monitoring this post.

Do you know the correct torque setting for the crankshaft pulley bolts?

I think I'll try replaceing the pulley first and eliminate that and hope that that's a cheap and quick fix.

Thanks
 

Yeah prob a good starting point as least expensive. sure thing, i'll check the torque settings when I get into the shop a little later today and send you that info. It's still early here in Houston………need some coffee first.

Actually, found a photo on my phone, Looks like 20Nm (15ftlbs)

Wow, thanks!

I don't like s[ending money if I can avoid it, I would try taking the pulley off and cleaning the mating faces of all rust etc so that it goes back on square.

I'm not sure the engine would even run if the crankshaft bearings were worn to a point where the pulley wobbled, the oil pressure would certainly be down.

Hi cedar,

Thanks for weighing in, you have put my mind at ease.

I hope that it is just the pulley that needs attention, but I'll just get a new one, I don't trust my inspection skills.

I will of course clean off the mating surfaces first - that much I can do.

Thanks again

You have to remove the pulley to get access to change the cam belt so could be just the bolts have come lose?

TVD, rubber deteriorated in the centre

Thanks guys,

The pulley bolts were the first thing I checked and they are not lose.

The rubber in the centre seems OK also. If the rubber had deteriorated would there be an oil leak?  I'll check again when I take the pulley off.

Thanks again

oil leak would damage the rubber

Hi,

Are you saying that I should replace the crankshaft oil seal as well, while I've got the pulley off?

Is that not a sump-off job?

Thanks

You'll end up rebuilding the whole car if you're not careful, if there's no excessive oil leak I would just sort out the pulley wobble.
The pulley has to go on the right way so the TDC mark lines up, is yours okay in that respect.

Thanks Cedar,

From what I can tell there are no oil leaks from the crankshaft, and I'll double check the timing markings.

So I'll take your advice and just change the pulley first and keep my fingers crossed.

Thanks again.

Hey something else I just thought about when you say 'pulley' I assume you are talking about the "assessories pulley" etc. So it just crossed my mind, I think the crank pulley actually has a specific key 'o' in it that fits over a little knobbley bit that sticks out from the crank timing belt, gear so to speak. Therefore, if the pulley has been put on wrong that would certainly cause a wobble because the hole in the pulley has to alig n with the little knobbley bit that sticks out from the timing belt gear which would then fit flush because one fits inside the other. If they are not aligned the accessories pulley for sure would off and could cause your wobble. Just something else to check. See red circle in my photo of the knobbley bit I'm talking about on the crank "gear" so to speak.

Hey something else I just thought about when you say 'pulley' I assume you are talking about the "assessories pulley" etc. So it just crossed my mind, I think the crank pulley actually has a specific key 'o' in it that fits over a little knobbley bit that sticks out from the crank timing belt, gear so to speak. Therefore, if the pulley has been put on wrong that would certainly cause a wobble because the hole in the pulley has to align with the little knobbley bit that sticks out from the timing belt gear which would then fit flush because one fits inside the other. If they are not aligned the accessories pulley for sure would be off and could cause your wobble. Just something else to check. See red circle in my photo of the knobbley bit I'm talking about on the crank "gear" so to speak.