75 c10 350sb clunking noise under acceleration

[c10dude75]

Yeah I got ramps too just doesn't seem like the greatest idea to do that in the middle of down pours be trying to look for stuff at the same time getting my man parts washed by Mother Nature trying to look for a break in the weather.

[Greybeard]

Could be worse, it could freeze the man parts right off...

I hem and haw at crawling under my stuff too, gravel drive, mud and no concrete or other solid area to work on my stuff. Gravel and grass. Drop a bolt or something and spend twenty minutes looking for it (not anymore though, I finally bought a strong magnet). I'm really seriously considering using pavers to make a solid, albeit rough, area to park my stuff on to work on it. Then get one of those $700 carport canopies to work under. Maybe lay some plywood down so the jack will roll.

[c10dude75]

Haha yeah something like that. I figure when I finally get a house of my very own I'm just going to pave over everything. Grass is over rated haha👌

[Greybeard]

I agree now, but 13 acres to pave is a bit pricey. 

[c10dude75]

Yeah that be a bit much ha.

[c10dude75]

Well I found a leak 1 of the freeze plugs or casting plugs w/e you want to call them is leaking water on my started which explains why it doesn't wanna start when I put a lot of water in. But anyway yeah think I could fix that without pulling the motor? looks like a tight fit defiantly would have to remove the starter out of the way. and  back to the knocking noise could it just be low on oil or cause there's probably water in there so it's not oiling everything up like it should and making that clunk noise? Found more chocolate milk lookin stuff haha

[Greybeard]

Take a small bright flashlight and look into the oil fill hole to see if that sludge is sitting on top of the rockers. If so change the oil and filter and keep an eye on it for a few weeks and change it again. As for the clunking/knocking that is never good coming from an engine. But there is always the slim possibility that the sound is being transmitted forwards from something else. Water on the starter doesn't hurt anything, it is after all out in the open anyway. I used to start my old truck when it was under water, in fact my throwout bearing seized and broke the front input housing nose off my sm 465 and drove the truck the rest of the week 4 wheeling and then drove it 100 miles home through St. Louis traffic to north county (all with no clutch and approximately 10.5/1 compression -450 horsepower- for the starter to turn over). And even that didn't kill the starter.

The casting plugs (most often erroneously called frost plugs) can be changed if you have the room. But that is a problem sometimes- getting the room. Maybe someone here that works on them more often than I do has new advice on how to do it easier than the way I know. No matter what, it is not hard, just takes some time. I say not hard once you get to the plug, getting to the plug can be a nightmare on an old engine with stock exhaust manifolds. Broken exhaust bolts will be the most common headache.

[bd]

Can't quite make out what that image is.  If the white accumulation is the "milk" you are referring to, there is water in the oil and the knock is a rod bearing - damage has already been done.  Under these circumstances, changing the oil is futile.

Procure a cooling system pressure tester, fill the radiator with water and pressurize it to 20 PSI, no more.  Remove all of the spark plugs and unplug the power lead from the distributor (HEI) or remove the coil wire (conventional ignition).  Pump up the cooling system pressure if it bleeds off.  After about 15 minutes, have an assistant crank the engine while you watch from the front of the motor to see if water blows out of a spark plug hole on the initial crank.  DO NOT stand over a fender or you could be drenched and possibly injured.  If water blows out through a spark plug hole either the head gasket has failed, or a cylinder wall is cracked, or a head is cracked.  If the cylinders pump clear then there is either a cracked block, a cracked cylinder head, or the intake gasket is leaking from the coolant crossover passages at one or more of its four corners.  There are other possibilities, but these are the most common. 

Don't waste your time with the freeze plug or any other superficial repairs until you determine what has failed and is causing that knock.

[c10dude75]

Shouldn't there be a bolt going through that hole?

[bd]

Yes, along with a matching bolt on the front of the crossmember and one down through the top for a total of three bolts retaining the diagonal brace to the horizontal crossmember on the right side.

[c10dude75]

So I take it every time I stomp on it while driving that's probably moving around making that noise? cause when I watched my little YouTube video it didn't quiet sound like it was coming from under the hood unless I was just thinking to much into it but like I said revs up fine but when I stomp on it while actually driving I get the noise

[bd]

A crossmember popping can make a loud disheartening sound, but normally will just "pop" once in awhile as the frame flexes.  The bolts that pop are usually the larger frame bolts passing through the side rail.  Actually, it's not the bolts that pop, but the large members suddenly overcoming the clamping friction between them, which allow the frame members to slip.  The video you posted sounds a lot more like a large rotating mass that is hammering.  That coupled with water in the oil are bad indicators.  But, being there you have the advantage in determining where the sound actually originates.  If you can reproduce the sound with a helper in or next to the vehicle, perhaps you can narrow it down.

[c10dude75]

Yeah thought about tapping a video camera to the hood then maybe under to see what's going on prob get best results that way that's if the camera doesn't fall off and get run over in the middle of the shoot ha.