8.1L Weird Grind at Startup

kanton1 · February 12, 2002

Upon the first startup of the day, about 10 seconds after the truck has been running, there is a distinct loud "grinding" type of noise that seems to be coming from the left side of the motor. The noise only lasts about 1-2 seconds and then is gone. It does not happen any other time, just the initial startup of the day. It has done this from day one.

Anybody else experience this? Any suggestions?

Thanks in advance,

Kyle

Shaners · February 12, 2002

Welcome to the forum Kyle... I hope some of these bigblock guys can help you.

This isn't somethng I have heard about before. Sorry

CMNTMXR81 · February 12, 2002

You sure it's not more of a buzzing? That's a pulley on the seprentine, most likely the power steering pump.

jethrobodine00 · February 13, 2002

I have noticed the exact same problem on my truck. Like Kanton 1 said it only happens on the first startup of the day and only lasts a couple of seconds. I have not been able to track it down yet. I will check into the pulley mentioned. Thanks

Heavy Cruiser · February 13, 2002

My suggestion is ABS System self-testing?

CMNTMXR81 · February 14, 2002

With the ABS testing though, you'd feel it in the brake pedal just as if the ABS were engaging, so if you feel it, you know this is the problem.

I believe GM has a few TSB's on the ABS module sensitivity.

kanton1 · February 14, 2002

CMNTX...

you know... the grind noise is sort-of like a buzzing noise, however looking at the motor from the front it is on the left (passengers) side. isn't the power steering pump on the right?

I would take it to the dealer, but they wouldn't be able to hear it unless I left it over night. then they would not be able to reproduce it until the next morning. right now I don't want to leave the truck there for a couple of days. know what I mean?!!

any more thought and suggestions would be appreciated,

thanks

Kyle

Heavy Cruiser · February 14, 2002

CMNTMXR81,

You won't feel anything on your brake pedal when ABS is in the test mode, testing done after master cylinder.

:music:

CMNTMXR81 · February 15, 2002

CMNTMXR81,

You won't feel anything on your brake pedal when ABS is in the test mode, testing done after master cylinder.

:music:

That's funny, whenever we've tested the Kelsey Hayes system through a TechII, the pedal has always pulsated! Essentially, we are testing that the electronics are engaging the ABS system, as such, the pedal will pulsate as it would normally under ABS engagment on the road.

As to the pump, it is on the driver's side of the 8.1 below the thermostat housing. Almost inline with the exhaust manifolds.

ClawSS · February 15, 2002

I am experiencing the same thing. I did break my PS pump just a couple of weeks ago, so I have a new pump now, but the noise still exists at startup for about 1-2 sec. then you never hear it again. If I wait about 8 hours it may do it, but it usually takes the standard "overnight" wait.

I have no clue as to what it is, but it is on the passenger side.

Inquiring minds want to know.

CMNTMXR81 · February 15, 2002

It's the bearing on the pump itself.

kanton1 · February 18, 2002

I went to the dealer today, took a walk with the service manager and started both the 8100's they had on the lot. Truck #1 did not make the noise that mine does. Truck #2 made the same noise, but much fainter (mine is much louder). Service manager has no idea what could be causing it. It is so brief, I doubt they will be able to determine what it is even when I leave my truck over night so they can hear mine. Service manager was going to look at bulletins and let me know.

Any other opinions or similar experiences will be helpful

Thanks,

Kyle

Heavy Cruiser · February 19, 2002

CMNTMXR81,

Thanks for the education!

CMNTMXR81 · February 19, 2002

No problem. I remember going through several ABS modules on one of my trucks because it's engage the ABS if I breathed on the brake pedal.

Now I think I have a wheel speed sensor going. Does it ever end?

kanton1 · February 24, 2002

Well, I crawled under my truck this morning and had by fiancee start it. This grind noise seems to be coming from the bell housing of the tranny. Definately coming from the rear of the motor/front of the tranny.

Any suggestions?

Thanks

Kyle