Anbody Know 5.3 Liter GM Engines?

[mscher]

Have s 2001 Silverado, leaking coolant.

I need to get the snake-cam in there, but as best as i can tell, it appears to be leaking from a screw-in plug in the block, on the front left side, behind the water pump.

It looks to be a screw in plug about 3/4" or so, that needs a hefty hex driver, to turn.

Anybody know what this plug would be for?

It's not easy to get to, at all.

I'm hoping this is the place that it is leaking.

 

[TilliamWe]

Re: Anbody Know 5.3 Liter GM Engines?

The only thing I know about those engines is that the thermoplastic intake manifolds leak. And GM has had intake manifold gasket issues for YEARS on various engines. You sure it's not leaking there?

 

[rockyrude]

Re: Anbody Know 5.3 Liter GM Engines?

I do know the 5.3's have intake warpage issues resulting in coolant leakage.

 

[mscher]

Re: Anbody Know 5.3 Liter GM Engines?

The only thing I know about those engines is that the thermoplastic intake manifolds leak. And GM has had intake manifold gasket issues for YEARS on various engines. You sure it's not leaking there?

Yes, painfully.

Spent the whole weekend replacing the intake gaskets (made 4 trips to town), then the throttle body gasket.

Come to find out, 5.3s have no coolant ports (at least in 01'), between the intake and block. All coolant that is circulated through the intake plenum, is pumped through the throttle body (in and out).


At least I got it put back together right. I learned to work on a fuel injected Chevy, only cost me $150 (had to purchase a torque wrench, too), for this mechanics class.

 

[tswiczko]

Re: Anbody Know 5.3 Liter GM Engines?

It's probably the water pump gaskets leaking. They're a couple of bucks each, and while you're changing the gaskets you'll be able to inspect that plug better while you have the water pump off.

Also there are plastic adapters on the heater core connections, check them. I looked for a leak all summer and could not find one till I grabbed the heater hose and the adapter broke. I think they were about seven dollars each. you'll need a disconnect tool for them. They were a PITA to remove, and a little dish soap helped them go on pretty easy though.

 

[mscher]

Re: Anbody Know 5.3 Liter GM Engines?

Too easy for it to be a leaking plug.

The coolant seems to be leaking between the water pump and block, near where the head is mounted, so I'm still not sure, where to turn next, short of pulling the pump. Worried, that it might be leaking from the left head.

I can still a do a pressure test on the system, even with the loose pump, right?

 

[mscher]

Re: Anbody Know 5.3 Liter GM Engines?

It's probably the water pump gaskets leaking. They're a couple of bucks each, and while you're changing the gaskets you'll be able to inspect that plug better while you have the water pump off.

Also there are plastic adapters on the heater core connections, check them. I looked for a leak all summer and could not find one till I grabbed the heater hose and the adapter broke. I think they were about seven dollars each. you'll need a disconnect tool for them. They were a PITA to remove, and a little dish soap helped them go on pretty easy though.


View attachment 174173

I just saw a diagram of these water pumps and where the gaskets are.

Feeling a little better, already.

Not too exited about tearing into the head, or paying someone else to do it.

 

[bigriver79]

Re: Anbody Know 5.3 Liter GM Engines?

You might make sure that water pump does not have a weep hole its leaking from. I had a 350 do that that several times and at first glance it looked like the gasket...