Doing Coolant Diagnostics, Any Advice

[WarrenBoostit]

This weekend I plan on doing a coolant pressure test, and just general diagnostics for leaks. Last oil change, Blackstone Analysis showed very marginal levels of coolant detected in my oil, not enough to cause wear or affect viscosity. At that point I remember my reservoir levels were ok, and I decided to keep an eye on it, but recently I noticed it was quite a bit below cold line.


I marked it as I know it can fluctuate slightly, but combined with some other symptoms, I knew it's time to take it more seriously.
Looking for any advice on diagnosing leaks, or general areas to look at. Nothing visible on the ground, but whitish watery exhaust on cold start (could just be e30, smells like e, but worth mentioning). I'm using orange coolant, so it's a bit harder to distinguish from rust.

I plan on first getting it on a lift and checking the water pump weep, oil cooler, and then doing a pressure test first when cold, and maybe a block test after. However I've heard the upper hose from the radiator is prone to leaks, and I wanted to run something by anyone who might have some knowledge to bounce off me.

Below is an image of where my upper radiator hose connects to the block


I circled in red a spot I initially thought was just rust, but now after smudging it I think is coolant. I'm guessing this should be the first spot I look? One thing in the back of my head is the prior owner of the vehicle installed a 170 tstat. Is it possible from either nicking an oring or the extra work that this could be the culprit? I have a tendency to connect unrelated issues, but the past couple weeks I've also been seeing a ton of rich correction on cold start on the rear bank (like 0.8 STFT while front bank is 1) until it gets warm, and I have to wonder if coolant vapor could be getting into the rear circuit and making the o2 sensor think it's over rich.

I feel like 80k miles is a bit early for water pump/turbo coolant failure, but you never know with these engines. Any advice or guidance is greatly appreciated!

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Black 2018 SHO Non-PP | GH e30 | PPE Catted Downpipes | DG2 Trans Mount | M-12405-35T plugs at .026 | H&R Springs | XDI-35 | Fuel-it Bluetooth ethanol analyzer | GH IC | EPP Gen2 CAI | Noisemaker delete | MSD coils | EPP Hot Pipes | Black AR924 w/ General GMAX AS 05 255/45r20 | MRT axle back w/black tips

 

[SM105K]

Traces of coolant in the oil is the red flag for water pump failure.

 

[Texas Marauder]

Traces of coolant in the oil is the red flag for water pump failure.

Agreed, should have no coolant in the oil. On a normal engine it would suggest head gasket seepage. On these engines it suggests water pump seal.

 

[WarrenBoostit]

That's my fear. Guess I won't know until I get it up on the lift, which is 30 minutes away so I'm hoping that's not a gamble. Blackstone's words were:

"...it's a marker for glycol-based coolant and it's high enough to indicate coolant, albeit just a trace amount. This
level isn't what we'd expect to coincide with noticeable coolant loss, for example, but it's contamination to
monitor all the same. Otherwise, this engine looks fine. We didn't find poor wear that might be related to
coolant. Check back in 3,000 miles to monitor -hopefully coolant remains minor."

Hoping that with such a small amount, and the lack of change in oil level or anything visible on the dipstick, I might be blessed with a cracked hose. Though doing mental gymnastics to explain coolant in the oil not being the water pump does not seem like it bodes well. I've learned these things typically tend to follow Murphy's Law. On the bright side if it comes to be, at least I could finally replace my phasers.

 

[luigisho]

A cracked hose for dimishing coolant level yes. For in the oil not so much. I agree H2O pump or headgasket are the most logical. You can fix the hose and then get another oil sample and send it out after a little while to confirm. Probably worth another check to keep from yanking expensive parts

 

[WarrenBoostit]

Did some diagnostics today. No trace of anything coming from the weep. We tried a block test, but initially used 16 year old liquid without thinking about it, test turned green with some bubbles terrifying me.

Checked plugs, looked decent enough for two year old plugs, scoped inside the pistons, nothing that screams coolant crust or steaming, but there was some outer ring soot and occasional soot buildup on the exhaust side of the piston which makes me think there's some leaking injector pooling in a couple cylinders.

Decided since I wasn't finding any smoking guns outside the horrifying block test, and didn't have time for a pressure test, best we could do was send another oil analysis out to see if levels had worsened.

While out buying oil on a whim we bought new block testing liquid just in case the 16 year old stuff had gone bad. Came back, and to our surprise tested it both below thermostat open and above, no bubbles, no color change, even with throttle stabs. So our best guess is that because we were testing the first old kit, maybe the bubbles were just from pressure imbalance because we were testing it right as the thermostat was opening (and I've had suspicions the system needs bled), and being 16 years old in an unwashed tester maybe it had been contaminated or gone bad. Or maybe there's a hairline crack in the head gasket that seals at operating temp.
If the oil analysis comes back as the same little to no coolant detected, I'll still plan for a water pump in the future but will slightly relax on that a bit for now. Going to keep an eye on the coolant levels daily and get a new cap just in case that helps, otherwise ultimately my new first priority will be injectors.