Engine noise - like a pressure cooker - some coolant loss

[DonnieBrasco]

2003 Yukon 240k miles. Not sure if these are related, but I'll give all the info I can...

Last week had a massive coolant leak. Like, add coolant and can see it pouring out right around the water pump. Investigated and I'm 99% sure it was the water pump. Changed out the water pump and thermostat, belts were fine, added coolant, drove it some, all is fine.

Last night driving home, the engine started making a noise. It wasn’t a hard ticking like a baseball card in a bicycle spoke, it was more like a pressure cooker. You ever heard the older pressure cookers that have the rocker weight on top? That’s what it sounded similar to. It was directly related to engine speed, i.e., it sped up as I accelerated, and slowed down when I wasn’t. In fact, it’s almost non-existent when I’m idling.

This morning I head out to work and dash says low coolant. WHAT! I checked and sure enough it was a little low. I topped it off and can’t see anything draining out or dripping. I head on to work and the pressure cooker sound starts up again. It doesn’t happen when I first start the car. I think it only happens when the car gets up to normal temp. Sooooo…

(1) Where/how am I losing coolant?

(2) Are these issues (coolant loss and engine noise) related?

I’ve thought of everything. It could be a collapsed lifter? Could be a spring? Maybe an exhaust leak? Otherwise everything seems fine. Oil pressure is good (and I just changed oil, filter, and air filter less than 500 miles ago). Check engine light is on but I know it’s for the evap canister that I am fixing next week (the bigger charcoal canister underneath; I’ve already switched out the one on the engine block and the smaller one underneath the car).

I can’t get it to my mechanic until next week. This is obviously something I can’t diagnose myself so I’ve gotta take it in. Any thoughts?

 

[Z28TWITCH]

Almost impossible to diagnose over the interwebz. Gotta get some more info from you. Having a little coolant missing after changing out parts is normal in my experience. Motor runs through a few heat cycles and works all the air out, coolant level drops. Now, is it still leaking anywhere? Can you find an area where its making the noise? Maybe a bum water pump bearing? Pull the belt off and start it real quick, but don't let it run for too long.

 

[Chubbs]

Since the 'Check Engine' was activated previously, there could be new fault codes in addition-to the EVAP that you are aware of. Have you scanned the truck since the WP replace to verify presence of new faults, or just assuming nothing new could have come up? Either way, a few sessions of air-purging tactics may help. Keep an eye on coolant temps, spec' with a computer via OBD if applicable. My only experience of such a noise was an overheating episode. Not good.

 

[RET423]

Pull your dipstick and see if the coolant is going into the block, you may have blown a head gasket when you lost the water pump.

 

[Chubbs]

@RET423

Quick & easy. Good call. Like he said, look for signs of oil contamination immediately.

 

[Doubeleive]

check you ac compressor they will make a noise like that when they take a dump, usually they will end up kicking the belt off, but you can try and take the compressor belt off and see if that is it, wont hurt anything to try.