Sierra Ticking Noise

commercialgrade · June 3, 2010

I have a 2000 GMC Sierra with a 4.8L motor in it. The original motor was on its last leg so I snatched up a really good used motor and put it in the truck. Now that it is all back together there is the same sound that was present before I put the new motor in it. It sounds like an exhuast leak and is the loudest when under acceleration. The motor came with new exhaust manifolds and I used them. The noise is coming from the driver side it sounds like. You can hear a light tick when idling through the driver side fender wheel. I have replaced the gasket between the manifold and the collector and the exhaust manifold gasket on the driver side, still same noise. The only other thing that it could be wousld have to do with the intake or fuel injuectors becasue I used all the fuel injectors and the intake manifold from the old motor. Any way to pinpoint which injector or what is causing the noise. The noise sounds nothing like a ticking lifter but a lighter sound, like an exhaust leak. Have poked around with a stethoscope and cannot pinpoint problem. DId not know if this is normal or something to be worried about. Any suggestions are welcome.

pm26 · June 4, 2010

Did you replace the donut gaskets between the exhaust manifold and the front exhaust pipe (I assume the truck uses these types of gaskets, as many other vehicles do)?

pm26 · June 4, 2010

Did you replace the donut gaskets between the exhaust manifold and the front exhaust pipe (I assume the truck uses these types of gaskets, as many other vehicles do)? Also, are the exhaust manifold gaskets new and what type are they? If they are metal, the manifolds or cylinder heads must not be warped int he least, or you will have a leak. If they are fiber, they will be more forgiving.

jblakeney · June 4, 2010

What kind of replacement motor comes with NEW manifolds (GM Crate engine)???? Were they used bone yard pull???

If you have already replaced the donut gaskets and the manifolds are torqued up to the spec...... Pull the manifolds off, take them and get them resurfaced.... Probably they are warped........ Don't forget you will need new exhaust manifold gaskets and donut gaskets...

Also, CLEAN CLEAN CLEAN CLEAN THE FLANGE ON THE Ypipe..... If it is flat and has a metal ring as the donut gasket take a flat file and smooth it out.

Sometimes, it is really hard to get all exhaust noises to leave..... But at joints besides the manifold to head..... Walker Exhaust sealing compound and except no BRAND SUBSTITUTES... All the other brands on the market are trash and a waste of time.... Believe me I have tried them all.... The walker one is the best..

Jbo

commercialgrade · June 4, 2010

I changed the exhaust manifold gasket yesterday with a GM part and bought the new bigger headed bolts to go into it.The noise is still there, not necessarily coming from the manifold to head joint but you can still hear it when driving. Last week I bought a sheet of that gasket material made by mr. gasket and custom cut a gasket out of that stuff and installed it with no results. The motor was bought out of a wrecked truck with 15,000 miles on it and runs great. Oil pressure high and good power. The craziest thing is that I had the same exact sound with both motors? This is why I keep turning towards things that I put back on this motor from the old one, intake and injectors.

Willshire · June 4, 2010

I know on the 2000 there is a crush washer type gasket on the drivers side and a sleeved donut (flat on one side rounded on the other) or metal to metal contact (pipe directly to manifold) on the pass side. My 5.3 ticks too but i think it is coming from an injector or 2. Noisy solenoid in the injector. I don't worry too much about it.

commercialgrade · June 6, 2010

I changed that gasket already and nothing was fixed. I was thinking that it might be coming from an injector. Can these injectors be rebuilt or cleaned? I have an entire set of them but somebody let old fuel stay in the injectors and fuel rails so that they got stuck shut. I would like to change out the driver side injectors, this is the last thing that I can think of.

98 Z71 SLT · June 7, 2010

Are you SURE you don't have a hair-line crack in your Y-pipe??

That would explain the same sound with 2 different engines...

Also...does your truck have ANY holes drilled in the firewall?? Lots of guys have add-on stuff, and drilling holes in the firewall AMPLIFIES any normal sound the engine makes....

commercialgrade · June 7, 2010

I have checked the Y-pipe the best I can but I have not found any cracks in it yet. I started the truck up cold and ran my hand up and down the y-pipe and could not feel any air coming out, is there a better way to search for this type of leak? I do not have any actual holes drilled in the firewall but there is a couple of wires that enter the cab through the rubber surrounding the steering, I thought about trying to seal this area up also.

Willshire · June 7, 2010

Are there heat shields on your manifolds? Did you reuse your old manifolds? I replaced my manifolds with shorty headers, alot of guys say no performance gains but they are also not cast iron so less prone to cracking. Both manifolds were cracked on my 95, under the heat shields. Take a long screwdriver put the handle to your ear and probe as close to each injector as possible. The louder the ticking in your ear the closer you get to the noise producer.

jd1973 · June 8, 2010

One other cause could be a grounding problem. I had this issue on a former truck and added another ground cable from the motor to the frame. Noise went away.

jblakeney · June 9, 2010

Did you try filing the flange yet on the drivers side???? Could be the flange is warped... I have had this happen on several vehicles over the years. My friends tend to bring me stuff that makes racket and wants the odd noises fixed....

FLAT FILE the manifold flange and FLAT FILE the Y-pipe flange.... New crush Ring....

Jbo

attached is a picture of the y-pipe for a 2000 Silverado/Sierra w/V8... note picture for reference