bgkast
bgkast GRM+ Memberand PowerDork
4/15/21 4:16 p.m.

I've been looking for a 3/4 ton Suburban and found this one with "engine noise" at auction. It's not bid up very high because of the noise. 

 

It sounds like it could be an accessory to me, and if it's not a terminal engine issue it would be a good buy. I like the color and the low option "government spec". It's a gamble though, because it's too far away to get eyes on it.

LS engine experts, what say you?

noddaz
noddaz GRM+ Memberand UltraDork
4/15/21 4:27 p.m.

I am no expert, but I would guess a cracked exhaust manifold.

And that is a nice color yellow.

DjGreggieP
DjGreggieP HalfDork
4/15/21 5:06 p.m.

Is it 6.0L or 5.3L?

bgkast
bgkast GRM+ Memberand PowerDork
4/15/21 5:27 p.m.

In reply to DjGreggieP :

6.0. The 2500s didn't come with cylinder deactivation

DjGreggieP
DjGreggieP HalfDork
4/15/21 5:44 p.m.

In reply to bgkast :

It sounds like my 6.0L and it is missing some manifold studs, but it goes away when warm. I usually let it warm up a bit before driving so I am unsure if rpm affect it's rythmn or not. 

Placemotorsports
Placemotorsports GRM+ Memberand HalfDork
4/15/21 6:06 p.m.

Definitely sounds exhaust related

Stampie
Stampie MegaDork
4/15/21 6:31 p.m.

I agree with exhaust but from the last auction I followed up in that area don't expect the prices to stay reasonable.

QuasiMofo (John Brown)
QuasiMofo (John Brown) GRM+ Memberand MegaDork
4/15/21 6:50 p.m.

I think I would name that noise Kyle. It's a little annoying at first but once you realize that its okay and then all can hang and have fun.

akylekoz
akylekoz SuperDork
4/15/21 6:56 p.m.

I agree Kyle is a good name.

Frank would be my next choice.

ShawnG
ShawnG UltimaDork
4/15/21 7:43 p.m.

Can't help. I'm only a for-real mechanic.

bgkast
bgkast GRM+ Memberand PowerDork
4/15/21 9:25 p.m.

Thanks guys. Very true that the prices often don't stay reasonable on these auctions.  There is a local boring white one up for auction tomorrow, but if the price on it goes crazy maybe I'll roll the dice on Kyle.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
4/15/21 9:45 p.m.

On rare occasions the plastic lifter retainers will break which lets a roller go sideways and wipe a cam lobe.  I don't think that's the case or it would be running terribly.

Exhaust manifold is possible, but it sounds more metallic to me

Collapsed lifter or piston slap is possible but not likely.  The rockers and pushrods are pretty bulletproof but it's possible that a pushrod tip snapped off.  Again, unlikely, but I'm trying to give you the worst case scenarios.

It does not sound like a bearing to me.  Too "clicky" and not "clunky."

I would bid on it with the worst case scenario in mind.  Let's say it's a bad rod bearing or a broken piston skirt (but it isn't).  $1000 buys a low-mileage LQ4 or LQ9 from the boneyard.  So bid up to it's market value minus $1500 and you kinda can't go wrong.  That way you won't be disappointed, but you might be surprised to find out it's something like a cracked manifold or one collapsed lifter.

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