GM truck noises
Question:
I bought my first truck about six months ago. It’s a 1986 GMC, and after fixing numerous little things that were giving up after 12 years, and rebuilding the tired 305 engine, it’s starting to look better than new. But I’m still having some trouble. As my great grandmother would say,"It’s a rattling good car". The first noise is pretty obvious; the speedometer cable needs replacing. The dial hops around alot, especially at low speeds and its accompanied by an annoying chirping sound. The second noise is much worse and more elusive. After the engine rebuild I started getting this ‘gawd awful’ squeaking sound from the engine compartment. It’s definitely coming from the belts, pulleys, or something. But I can’t figure it out, all the belts are new or in good shape. It squeaks when the engine is idling and by the time I’m up to 20 miles an hour it turns into a high pitched whine. I got a great Cat-Back exhaust system installed but all I can hear is the friggin’ sqeak! I guess I’m just going to have to take all the junk off and grease it, but I’m not sure if that will help. If anyone has any information about changing the speedo cable OR fixing the squeak, your advice will be greatly appreciated. —
Response:
> The second noise is much worse and > more elusive. After the engine rebuild I started getting this ‘gawd awful’ > squeaking sound from the engine compartment. It’s definitely coming from the > belts, pulleys, or something. But I can’t figure it out, all the belts are new > or in good shape. It squeaks when the engine is idling and by the time I’m up > to 20 miles an hour it turns into a high pitched whine.
Have you tried any belt lube? WD-40 will also quiet noisey belts. Or are the belts slipping? THAT will make a terrible howl… Scott
Response:
Check the condition of all the pulleys very closely, particular the one on the alternator. For whatever reason they seem to wear as they mileage piles up and even a new top quality belt will not grip properly. I have experienced this problem with 2 mid 80’s Monte Carlos, a Buick V6 rwd, and a Caprice w/ 305. Mostly it’s the alt pulley but on the Buick it also needed a water pump pulley. Also check to be sure you have the correct belts as some use a metric dimension belt and pulleys and others use standard inch size. The difference is slight but enough to cause the problem if the belt rides too low in the pulley grooves. BTW no amount of belt dressing will fix the problem for more than 20 minutes. — Mike ( Anti Spam Address ) "Opportunites are spawned from crisis" I bought my first truck about six months ago. It’s a 1986 GMC, and after fixing numerous little things that were giving up after 12 years, and rebuilding the tired 305 engine, it’s starting to look better than new. But I’m still having some trouble. As my great grandmother would say,"It’s a rattling good car". The first noise is pretty obvious; the speedometer cable needs replacing. The dial hops around alot, especially at low speeds and its accompanied by an annoying chirping sound. The second noise is much worse and more elusive. After the engine rebuild I started getting this ‘gawd awful’ squeaking sound from the engine compartment. It’s definitely coming from the belts, pulleys, or something. But I can’t figure it out, all the belts are new or in good shape. It squeaks when the engine is idling and by the time I’m up to 20 miles an hour it turns into a high pitched whine. I got a great Cat-Back exhaust system installed but all I can hear is the friggin’ sqeak! I guess I’m just going to have to take all the junk off and grease it, but I’m not sure if that will help. If anyone has any information about changing the speedo cable OR fixing the squeak, your advice will be greatly appreciated. —
Response:
– Hide quoted text — Show quoted text -> I bought my first truck about six months ago. It’s a 1986 GMC, and >after fixing numerous little things that were giving up after 12 years, and >rebuilding the tired 305 engine, it’s starting to look better than new. But I’m >still having some trouble. As my great grandmother would say,"It’s a rattling >good car". > The first noise is pretty obvious; the speedometer cable needs >replacing. The dial hops around alot, especially at low speeds and its >accompanied by an annoying chirping sound. The second noise is much worse and >more elusive. After the engine rebuild I started getting this ‘gawd awful’ >squeaking sound from the engine compartment. It’s definitely coming from the >belts, pulleys, or something. But I can’t figure it out, all the belts are new >or in good shape. It squeaks when the engine is idling and by the time I’m up >to 20 miles an hour it turns into a high pitched whine. > I got a great Cat-Back exhaust system installed but all I can hear is >the friggin’ sqeak! I guess I’m just going to have to take all the junk off and >grease it, but I’m not sure if that will help. If anyone has any information >about changing the speedo cable OR fixing the squeak, your advice will be >greatly appreciated. >–
Thanks for your help, I just went out there and it’s definitely the alternator. I assume bearings, but whatever it is it’s squealing like a stuck pig. I’m going to bring it in to a local rebuilder and see what they can do. Who knows how old the thing is, might be the original. Anyway, thanks for the help and if anyone knows anything about replacing speedometer cables, I haven’t tackled that part yet. Thanks again.
Response:
– Hide quoted text — Show quoted text -> I bought my first truck about six months ago. It’s a 1986 GMC, and >after fixing numerous little things that were giving up after 12 years, and >rebuilding the tired 305 engine, it’s starting to look better than new. But I’m >still having some trouble. As my great grandmother would say,"It’s a rattling >good car". > The first noise is pretty obvious; the speedometer cable needs >replacing. The dial hops around alot, especially at low speeds and its >accompanied by an annoying chirping sound. The second noise is much worse and >more elusive. After the engine rebuild I started getting this ‘gawd awful’ >squeaking sound from the engine compartment. It’s definitely coming from the >belts, pulleys, or something. But I can’t figure it out, all the belts are new >or in good shape. It squeaks when the engine is idling and by the time I’m up >to 20 miles an hour it turns into a high pitched whine. > I got a great Cat-Back exhaust system installed but all I can hear is >the friggin’ sqeak! I guess I’m just going to have to take all the junk off and >grease it, but I’m not sure if that will help. If anyone has any information >about changing the speedo cable OR fixing the squeak, your advice will be >greatly appreciated.
if you think the noise or squeak is coming from a belt or pulley try removing one belt at a time then start the motor. if the squeak dissappears then look at what was driven by that belt. hope this helps h.v.
Response:
I would look first to the A.I.R. pump. This is a small round belt-driven air pump that supplies air to the exhaust manifolds as part of the emissions systems. Those things are notorious for locking up after a time. If that is the case, I am surprised the belt didn’t burn into from the friction. Roy – Hide quoted text — Show quoted text -> I bought my first truck about six months ago. It’s a 1986 GMC, and >after fixing numerous little things that were giving up after 12 years, and >rebuilding the tired 305 engine, it’s starting to look better than new. But I’m >still having some trouble. As my great grandmother would say,"It’s a rattling >good car". > The first noise is pretty obvious; the speedometer cable needs >replacing. The dial hops around alot, especially at low speeds and its >accompanied by an annoying chirping sound. The second noise is much worse and >more elusive. After the engine rebuild I started getting this ‘gawd awful’ >squeaking sound from the engine compartment. It’s definitely coming from the >belts, pulleys, or something. But I can’t figure it out, all the belts are new >or in good shape. It squeaks when the engine is idling and by the time I’m up >to 20 miles an hour it turns into a high pitched whine. > I got a great Cat-Back exhaust system installed but all I can hear is >the friggin’ sqeak! I guess I’m just going to have to take all the junk off and >grease it, but I’m not sure if that will help. If anyone has any information >about changing the speedo cable OR fixing the squeak, your advice will be >greatly appreciated. > if you think the noise or squeak is coming from a belt or pulley try > removing one belt at a time then start the motor. if the squeak > dissappears then look at what was driven by that belt. > hope this helps > h.v.
Response:
Glad that with a bit of suggestions you were able to locate the noise. It is a pain to go through a bunch of work and then have a problem that wasn’t there before you started. — Mike ( Anti Spam Address ) "Opportunites are spawned from crisis" Tom Morris> wrote in article >… ( referring to all who replied I assume ) Thanks for your help, I just went out there and it’s definitely the alternator. I assume bearings, but whatever it is it’s squealing like a stuck pig. I’m going to bring it in to a local rebuilder and see what they can do. Who knows how old the thing is, might be the original. Anyway, thanks for the help and if anyone knows anything about replacing speedometer cables, I haven’t tackled that part yet. Thanks again.
