Funny Engine Noise

I drove my car to work this morning and as usual, it performed beautifully. When I started it up to go home, I heard an unusual rattle (very rhythmic), and a second higher pitched rattle (also very rhythmic and almost sounds like a cricket chirping) coming from the engine compartment.

Aside from the rattles (which I hear while idling and while driving), the engine performed perfectly on the way home. No heating issuses, no idiot lights, full power. The belts seem fine. Can anybody give me some advice on what to check? Thanks in advance for the help.

Brian

Check the tins?
My car used to have sheet-metal screws holding them together, not nuts and bolts.

Chirping

Two other possibilities: check fan belt or crank pulley hitting tin work.

Brian,
I had a similar "chirping sound" problem and it was driving me crazy! I eventually noticed my deck hinges were rubbing against the fan shroud. Just a thought - Mickey

I second what Alan said.

Does it change with RPMs? Is the internal (to cooling shroud) fan tight - check back of alt/gen.

Check your carbs make sure thay have not come loose. Maybe that they are loose on the manifold. Air comes in and creates a chirp...

Just rock the carb bodies to make sure there is no movement.

Check to see if your alternator strap hasn't come loose causing the alternator to tilt a bit making the fan hit the inside of the shroud.

HMMMMM, "funny engine sound?" There is no such thing as a funny engine sound....only cheap and expensive engine sounds! Maybe interesting and not interesting engine sounds? Even the cheap engine sounds cease to be funny by the time you find them.....I figure my last cheap engine sound ended up costing me about $10k and a years worth of spare time work......so maybe I defeat my own arguement, there are only expensive engine sounds....? Mine certainly wasn't funny!

I had the same thing on a VW engine...it was engine tin that had shifted a little and was just touching the pulley....it sounded rythmic because it was just close enough to only hit on the very hi point on the pulley

You're right, Jim...this isn't funny. I think that something has either shifted or a bolt has come loose somewhere, but I haven't found the problem yet. My fan belt is sqeaking a bit, and upon closer examination, it looks like the entire engine (fan shroud and carbs too) are shaking around more than normal, but they are all shaking in sync. I'll keep looking...

Thanks,
Brian

Brian -

You may have already done this, but check the small 10mm bolts/screws on the bottom of each side of the fanshroud (these secure the shroud to the upper engine tins). Sometimes they back out from vibration & you wouldn't know they're loose until a physical inspection.

Hope you get it all worked out!

Peace - Out!

- I see from your profile PICS that your running AC..., Please Please don't tighten down anymore than you absolutely have to on your Alt. and AC belt's, VW put out a notice 30 yrs. ago that this would preliminarily wear out the number 1 bearing on the crank. With that said..., Aluminum lower pulleys look real cool, but they slip more than steel ones. This might be part of your dilemma.

- Steal one of the wiffiees pocket mirrors and look into the inlet side of the cooling fan for debre.

- Make sure that you didn't drop a balance tube off the intake manifold of your Kardon's, this can give a whistling sound.

- Make sure the distributer cam lobe has white grease on it, when it dries out it can give a very high pitched whine..., as the point lobe wares down and the points begin to close the m o t o r g o e s d e a d .

- Does the sound quit or change if you shut the AC off..., if so, you know the problem.

- Looking at that stack of washers, and not being able to see the outer top front pulley, try another belt a 0.5" to 1" bigger in circumference like a continental brand.

- Have you sprayed the engine bay with a degreaser lately, whether you have or not, spay some oil on the front and back side of your AC idler pulley bearing and see if the sound quits.

- Take your shoe off and put the soul over your tail pipe to block out the engine noise, this will let you and localize the whine noise.

- Last..., I'll do some assuming: Does the sound change or quit when you push the clutch in? If so, you may be getting to much end play on the crank shaft. Thus is the reason it may be rubbing the engine tin when the clutch is released.

I'll stop rambling know..., David

David - don't stop now...I'm still taking notes!

David good stuff!

If the noise will be kind enough to repeat itself - here's a way to track it down quickly.

Take a broomstick handle, touch different areas of your engine (obviously don't touch the fan) while running. The other end of the broomstick goes to your ear. Put the stick alongside your ear held against the side of your head with your hand, not with the end of the stick in your ear like a giant q-tip... Safety... Trust me on that part (ha!).

The broomstick handle will conduct noise to your ear. Move it to different places on your engine until you can locate the sound. You should be able to diagnose the area of the noise if not the exact component.

Makes troubleshooting much quicker. You look a little stupid, but who cares - what happens in the garage stays in the garage!

angela

Thanks Angela. I would love to respond, but I'm going to leave quips about what happens with broom handles in the garage that stays in the garage to the pros. Vince, take it away...

Hey Brian, without knowing a little more about the situation and assuming you have good oil pressure and the motor doesn't sound like you've got a gremlin trapped in your engine case and he's got a hammer in his hand, trying to beat a hole in your engine case to get out, I suggest stopping off at the closest convenience store and getting a cold drink and then go for a ride and enjoy life...

O'yea, carry a cellphone with good coverage, and a good towing package. This will ward off the evil car spirts. Har-Har. ( I say this in humor..., have a mechanic have a look at her ).

David

Nope, not a gremlin...it's the alternator. After watching the problem get worse as I tried to find it, I finally took it to my mechanic. I don't have any of the details yet, but apparently a weld (on or in) the alternator broke loose; thus the rattle and the squeal. They're re welding back it today and have ordered a new belt from Vintage (the engeine calls for a non-stock VW belt, of course). As always, thanks very much for all of the help and advice.

Brian

Brian; when you get the new belt just jot down and keep the number because with that you can get a replacement a lot quicker at your FLAPS.

I looked at those pictures of your "loose fan belt" ---nowhere can I see the strap that holds the alternator on (on either picture). The 4 - 10mm head bolts for the back by the fan aren't sufficient --- there should be a strap around the alternator just like on a generator model. Is there one there? but not visible in the 2 photos. Don't think you want your alternator welded on!

http://www2.cip1.com/ProductDetails.asp?ProductCode=ACC%2DC10%2D5784

Wolf; I think I saw the alternator strap a little on the second fan belt picture...

Angela, I will add to my list, one more thing you can do with a broomstick.....

I was wondering when you would chime in on this one Vince!! Couldn't resist, eh? Broomsticks - good for more than just a good beating! angela

I would lend you my spare broom but my "Ex" is currently riding it :)

I try to stay clear of the "Engine" or "Tech" threads cause I can add nothing but sarcasm...My answer to this thread would be to take the car to a mechanic and tell him to "fix the god-damn noise"
however with respect to all the grease monkeys out there, I usually just shake my head and move on when I read about someone having a problem that could be fixed by a "real mechanic" in minutes rather than spend hours looking for the problem......
I do respect those of you who do that, especially Angela, If I would have married her 30 years ago, I could have saved a fortune on repairs to my Jags, and Fiats...Not to mention the fact that she was probably 10 at the time....hmmmmm good..

Vince, that's exactly what I did. $90 and 24 hours later, the problem is fixed. Sorry I wasn't clear on what was wrong - There is a slight German/English language barrier with the mechanic, and I'm still a relative newbie, so please bear with me while I learn. What came unwelded was the tack weld that holds the back of the generator pulley to the generator. It came loose and cracked the back half of the pulley. Like I said, it's all fixed now and she's purring beautifully.

Brian

There should be no tack weld that you mention.
A key, shaped in a half moon configuration sets in the keyway slot on the shaft secures the back half of the pulley by sharing the same slot on the pulley hub. If the mechanic tack welded the pulley half, it may come loose again.

I hate to be the one to tell you this, but I think you've just had your wallet, welded.

As stated, there ain't no welds in that area!

A "tack weld" just doesn't hold the collar to the inner pulley half at all. I've had them separate twice on the drag bug and had to do a full parimeter weld in the end.

Even the original German pulleys will come apart at high enough revs. The belts want to turn inside out, the twisting movement puts too much stress on the stock press fit . . . then . . . doom.

Best to replace the pulley and be safe, keep the welded one as a spare.

Luck,

TC

According to the invoice, the $90 was for a new pulley and one hour (minimum charge) of labor. He said there was a tac weld, but it's not listed.

Brian

Brian - the bottom line is that you can now drive your car with some peace of mind!

Drive on - Be Safe - Peace- Out!