chevy troubles

[aggieblazer07]

My truck is making a funny clicking noise when I drive it. It speeds up with RPMs. Is it possible that the torque converter is going out? It mostly does it in gear when I am driving or if I power brake.

[Doug Krebs]

Give us some help here... Edit, Which Engine, tranny, etc...

I'm going to ASSume a 350/350/203?

I personally have never heard of a torque converter clicking.

Oh and stop power braking :flipoff2:

[aggieblazer07]

I'm not sure where it is coming from. I thought it was the lifters, but I readjusted those and it still clicked.

[Doug Krebs]

I'm not sure where it is coming from. I thought it was the lifters, but I readjusted those and it still clicked.

Yeah sorry i was a little vague on what i meant, i edited before you responded.

[aggieblazer07]

it's got a 350 with an automatic. The T-case says NP 241-C

[aggieblazer07]

It's a 91 chevy 1/2 ton

[jerryg79]

I would think motor noise not torque converter noise, but I'm no scientologist.

Have you checked the oil? Could be all filled with water from a leaky intake, get ya every time :D

[aggieblazer07]

I changed the oil yesterday and added some Lucas oil stabilizer stuff.

[uglyota]

Do you have a limited slip?
Bad ujoint?

[aggieblazer07]

I'm pretty sure it isn't the u-joints because it seems related to the RPMs. No matter how fast I am driving.

[uglyota]

but only in gear?
It won't do it if you rev it in neutral?

[Doug Krebs]

Do you have a limited slip?
Bad ujoint?

Ugly's got a good point, I had a bad u-joint once and I thought it was my detroit messing up... but it goes with RPM and not speed?

[aggieblazer07]

It makes the same sound at 10 mph that it does at 30 and it speeds up when I give it gas. And it doesn't seem to do it in park or neutral when I rev it up.

[uglyota]

have you checked your tranny fluid?

[aggieblazer07]

I did that earlier, it was fine

[uglyota]

dunno man, btw you've probably got a 700r4, in which case a tranny problem is very likely :(

[fbronco86]

how about motor mount. The fan could be hitting the fan shroud.

[stx4wheeler]

It makes the same sound at 10 mph that it does at 30 and it speeds up when I give it gas. And it doesn't seem to do it in park or neutral when I rev it up.

im no scientologist either but since it doesnt seem to be doing it in park or nuetral i would think bad u joint, or something in the rear axle like a limited slip or something like that is messed up, and especially the limited slip if you power brake it alot.

[Graystroke]

I'm thinking ujoint too. Put it in gear and power brake the vehicle in drive and reverse to see if it makes a poping or clicking noise.

[aggieblazer07]

if it was a u-joint it wouldn't speed up when it downshifts

[agjohn02]

if it's rpm variable then its tranny forward, if its speed variable then its tranny rearward...or forward in the case of 4wd. so, if it's rpm variable then a bad u-joint isnt the problem. since an automatic transmission is a magical box to me, and im not sure what's inside, i dunno if it could be in there or not. never heard of a t converter tapping, but then again ive never had one apart and dont know whats inside. i know how they work and there should be no touching parts to be clicking.

check for exhaust leaks. it could be a small exhaust leak or blown head gasket that only shows up when the engine is loaded. exhaust leaks sound like tapping lifters all the time. when the engine is loaded, the cylinder pressure is higher because its actually having to push against something rather than just accelerating the piston. a good way to check for this is with a peice of vacuum hose. put one end in your ear and listen for small leaks around the heads and manifolds. like listening for vacuum leaks. of course not when your driving, just sitting in the driveway. unless you can find a buddy to drive for you and you can sit on the fender with the hood up and cruise around town.

[eight]

How did you adjust lifters? You swap in solid cam and lifters?

Or maybe it just likes to make noises. All 3 of my jeep motors have allways had ticks, and the latest one still runs.

[aggieblazer07]

I backed off the nut on the rocker until it started clicking and then tightened it until it stopped clicking. Then I turned them each a quarter of a turn. I did that trying to stop the occasional clicking, but after driving for a week the clicking happens everytime I drive it.

[agjohn02]

that could possibly be your problem. ive never adjusted rockers with the engine running. im not sure how the lifters being pumped up affects the adjustment. my guess is that they are fully pumped and if you adjust them this way then it leaves no room for error. kinda like running a solid lifter cam. could be the explaination as to why it comes back after a week or so. the way ive always done it is with the engine off, tighten the rocker nut until there is no up-down play in the pushrod, then tighten another 3/4 turn to center the lifter plunger in its stroke. you have to do this when the valve is completely seated. ive always done it by rotating the engine back and forth until i could tell there was no lift. but, if you wanna do it right, find TDC for cylinder #1 and do both valves for it and the intake valves on #'s 2,5,7 and exhaust on 3,4,8. then rotate 360 degrees and do 3,4,6,8 intakes and 2,5,6,7 exhaust valves.

edited to note: you rotate the engine 360 degrees, this does not involve doing the hokey pokey or shaking it all about

[BigRedFord04]

agjohn's method is what they use at Vilas when building SBCs.

[uglyota]

hows about putting the rear end on jackstands, put it in gear to get the wheels spinning and see if you can hear something different then?

[stx4wheeler]

hows about putting the rear end on jackstands, put it in gear to get the wheels spinning and see if you can hear something different then?
mr saftey says yikes this sounds like a bad idea :flipoff2: . i would try what ag john says and yes exhaust leaks can sound like a lifter tapping my damn bronco has two exhaust leaks and sounds like crud.

[agjohn02]

hows about putting the rear end on jackstands, put it in gear to get the wheels spinning and see if you can hear something different then?


have you ever seen ferris bueller's day off when they were trying to rewind the odometer on the old ferrari?

[uglyota]

I didn't say to throw every stitch of common sense you have out the window, stick your diff on a pile of firewood and throw 'er in reverse. :flipoff2:
ask kopecki how he balances a driveshaft

[aggieblazer07]

I'm pretty sure it isn't the lifters, I adjusted them and nothing has changed. It might be something loose on one of the pistons. It doesn't sounds pretty at all. I have made some more observations, it only does it when the rpms are steady or speeding up, not when it is slowing down. I might be putting a new engine in this weekend. 267,000 miles isn't too bad on one engine.

[uglyota]

did you check the simple stuff? Fan clutch? A/C compressor?

[agjohn02]

I have made some more observations, it only does it when the rpms are steady or speeding up, not when it is slowing down. I might be putting a new engine in this weekend. 267,000 miles isn't too bad on one engine.


Nooooooo, you cant just put in a new engine without finding out what's wrong with it. we'll never know if we were right or not. plus, the fact that the engine beat you will eat at your heart and soul for all of eternity. be a man and find the problem, fix it if its cheap, then put a new engine in it. not only beat it but master it like the beast master you are. muuhahahaha

ahem, ok, your recent observations tell me that its more likely an exhaust leak. trust me, they usually dont sound like exhaust leaks. they have more of a mechanical sound

accelerating rpm= open throttle more air flowing through the engine and increased dynamic compression ratio results in higher cylinder pressure and intensifies the exhaust leak.

steady state rpm= still lots of air flowing, same result but not as severe

decreasing rpm= closed throttle, less air, etc. etc.

check your oil for coolant and your coolant for oil. if none in either it could still be a blown head gasket, just not by a coolant or oil passage. could be between the cylinder and outside.

scout guys always give me guff over putting a chevy engine in mine. this is yet another example of how a chevy powerplant is good for 300,000 miles as well.

[aggieblazer07]

If any of ya'll want to listen to it I can come by and we can go for a ride in it. It's hard to explain the sound with words.

[StevenAg03]

i concurr with agjohn....exhaust leaks sound exactly like a lifter knocking when the engine is under a load...they are variable with RPM and not speed...and you wont be able to hear then very easily when slowing down. the ol' tube to the ear trick is very easily and will allow you to pinpoint where it is coming from.

if you decide to replace the engine and use the same exhaust system, you will more then likely still hear the same noise....unless it is coming from where the exhaust manifold/header mates to the block


it is not worth replacing the engine for such a noise. you should only do somethign like that when it leaks 6 quarts a week or has a whole in the side of it or something of the like.

[aggieblazer07]

It only leaks about a quart and a half a week. I crawled under the truck and couldn't hear any exhaust leaks.

[agjohn02]

just remembered, my dad had a similar problem, thought he had major problems. asked me about it and i took a look. ended up costing $20, including labor, to replace the donut gasket between the manifold and exhaust.

[aggieblazer07]

I'll check that

[StevenAg03]

It only leaks about a quart and a half a week. I crawled under the truck and couldn't hear any exhaust leaks.

you not gonna be able to hear them very easily while the engine is not under a load. you are gonna haveto get a piece of tube and check the exhaust...or if it is a auto, you can have someone sit in it...putit in gear with their foot on the brake and revthe engine up some....they will be more apparent then

[aggieblazer07]

would an exhaust leak cause the check engine light to come on?

[uglyota]

generally not
now that your computer's throwing codes, take it to Autozone and have them read the codes for you.

[aggieblazer07]

do they charge for it?

[StevenAg03]

do they charge for it?

they shouldnt...but depending on the year model and where the leak is i think it could throw a code....if it is a big enough leak the O2 sensors might not be getting correct readings....


as ugly said...go to Vatozone and have them check the codes for you. then come back and tell us what they said...

[aggieblazer07]

The codes were 32 and 43. 32 is the EGR code and 43 is a knock sensor error. Someone suggested that the pin connecting the piston to the connecting rods could be going out. Any new ideas?

[agjohn02]

a worn wristpin would definately make click click sounds and trip the knock sensor. is the engine way short on power? if it detects a knock it will retard the timing and kill the power. i know the pre-vortec 350's arent known for their output, but i think you would notice it. not sure how the egr works on those motors. i think its something like the old stovepipe off the manifold and enters the air cleaner housing. that could be a bad valve in the cleaner housing but not whats causing the noises.

an exhaust leak can cause the comp to throw o2 sensor codes because it will scavenge atmospheric air through the leaky spot and make the o2 think the engine is running lean. it would fatten up the mixture and hurt gas mileage and power.

[fbronco86]

what about flattened lobe on the cam?

[uglyota]

is there an egr valve that's cheap and/or easy to replace?
I'd start there
Think you could have gotten a batch of bad gas? Maybe top off your tank and hit it with some of that octane booster stuff

[fbronco86]

so has any one heard this noise? Cause they is a big difference between an engine miss and valve train/wrist pin problem.

[fbronco86]

is there an egr valve that's cheap and/or easy to replace?
I'd start there
Think you could have gotten a batch of bad gas? Maybe top off your tank and hit it with some of that octane booster stuff

egr valve and cheap not so much. I think for the one for the bronco/mustang motor is like 80 bucks at horeilys

[agjohn02]

egr valve isnt your problem. it'll make it run terribly if it gets stuck, but wont make noises. i wouldn't worry about it until you get everything else niched first.

if it is a ping (bad gas) and it's that bad, and you have been driving it for a while now. it's probably not a ping anymore. if thats the case then it may be a wristpin because the piston top has burned away and its melted the wristpin. ;)

just thinking out loud, could be a spun bearing

[aggieblazer07]

I think it is a wristpin. I'm going to have a guy listen to it friday morning and see what he suggests. If I need a new engine what are some good places I can call around here to get prices?

[agjohn02]

ok, two more ways to troubleshoot mechanical problems:

if you suspect its a bearing or wristpin:
sounds cooky but works (usually). remove one plug at a time and crank it over or drive it around the block. when the suspect noise ceases, thats your cylinder with the bad bearing/pin

if you suspect valvetrain problems:
such as a stuck lifter or valve out of adjustment. get a screwdriver (put one end to your ear and the other to the engine, preferrably the blunt end to your ear and the sharp one to the engine), peice of hose, or a stethescope and listen to the valve covers while its running. move it along the valve cover and where it gets loudest is the problem area. i picked up a auto stethescope at o'reilly's once to see which of my injectors were stuck. they're great to have to troubleshoot engine noises. they have a probe on the end instead of the pad thing doctors have.


to get your engine rebuilt: vilas

to get a pull-out motor: doggett auto salvage (i think thats the name, the one on the SE corner of the hwy6 and 190 intersection)

to get a new engine: the dealer :flipoff3:

[StevenAg03]

I think it is a wristpin. I'm going to have a guy listen to it friday morning and see what he suggests. If I need a new engine what are some good places I can call around here to get prices?

where are you from?

nothing agienst vilas but i havent heard very good things about them(no offense austin)

[agjohn02]

i had a head for my old 258 rebuilt at napa in bryan. they do good work, i just didnt like the guys' attitudes there.

[fbronco86]

I think someone is going to have to hear this "noise" to understand what it is. are you in cs?

[aggieblazer07]

until about 3. Then I'm heading home for the weekend

[BigRedFord04]

nothing agienst vilas but i havent heard very good things about them(no offense austin)
i'd like an explaination of that. between the guys there there's probably 50+ years of experience building engines. cooks doesnt do very good work. they cut corners and their method of cleaning a block fills the water jackets w/ shot peen, which they dont try very hard to get out. hows that for a cooling system?

[StevenAg03]

i'd like an explaination of that. between the guys there there's probably 50+ years of experience building engines. cooks doesnt do very good work. they cut corners and their method of cleaning a block fills the water jackets w/ shot peen, which they dont try very hard to get out. hows that for a cooling system?


thats what i hear from most of the mechanics here

[BigRedFord04]

what is what you hear? from mechanics where?

[Fredo]

I remember we were getting a couple of ball joints pressed into some 44 knuckles one time in CS and we were looking for someone to press them in since we didn't have a press. Took them to Cooks, and I **** you not, they said, "what are those?" Then, they said they "thought" they could do it, so we dropped them off, came back a half hour later and they were like, "well, we couldn't figure out how they were supposed to go in there." We proceeded to take them and walk out and drive directly to Vilas where they pressed them in while we waited. I wouldn't trust Cooks to make me a peanut butter sandwich.