Phantom Coolant Leak...

[BrooklynGuppy]

Hey Folks,

I spent a few weeks looking for a coolant leak in my 2014 Tahoe PPV. Turns out, it was the reservoir. You would think the system being pressurized at 20 PSi, it be easy to find. Oil was clean and no white smoke from exhaust. Had a mechanic tell me it could be a gasket or cracked head. To save you a headache, just putting it out there in the event anyone is experiencing the same issue. Under the reservoir, there is a 3 sided block piece that sits close to the support arm. I found it by a youtube search. Hope this helps...

 

[Geotrash]

Hey Folks,

I spent a few weeks looking for a coolant leak in my 2014 Tahoe PPV. Turns out, it was the reservoir. You would think the system being pressurized at 20 PSi, it be easy to find. Oil was clean and no white smoke from exhaust. Had a mechanic tell me it could be a gasket or cracked head. To save you a headache, just putting it out there in the event anyone is experiencing the same issue. Under the reservoir, there is a 3 sided block piece that sits close to the support arm. I found it by a youtube search. Hope this helps... View attachment 411659

That's the overflow drain. It should only leak coolant out when the reservoir is either over-pressurized or overfilled. Aaaaand, it will also leak fluid if I'm sloppy when I add coolant because it drains from above the cap seal, but below the threads, so pouring coolant directly on the little hole there will cause fluid to come out through that port. So assuming you're not as careless as I am when you spill fluids , I suspect that you either have a hidden crack in the reservoir or the coolant cap on top is leaking under pressure for an undetermined cause.

 

[OR VietVet]

Make sure to inspect at the "tees" at the firewall heater hose connections. Seems that a lot of hard to find coolant leaks end up being that. I had that problem.

Come to think of it, does a PPV have rear heat?

 

[petethepug]

Thanks for posting this up. The coolant reservoir should be replaced every 80-100k regardless. The plastic is bizarre in that it only leaks steam at first so there’s no sign of a leak. It’ll take out the entire motor from an overheat if an inexperienced driver continues to drive it.

We only discovered our 08 YXL Denali leaking on 100*+ day with the a/c cranked up to full while sitting at idle for 20 min. When the truck was at speed it didn’t overheat. Of course after the expan tank was replaced the plastic end tank on the radiator revealed it had a crack too. Do the accessory belt while you’re in n there and water pump if you’ve got the budget. It’s basically an every 100k thing.

 

[Tozan]

Thanks for posting this up. The coolant reservoir should be replaced every 80-100k regardless. The plastic is bizarre in that it only leaks steam at first so there’s no sign of a leak. It’ll take out the entire motor from an overheat if an inexperienced driver continues to drive it.

We only discovered our 08 YXL Denali leaking on 100*+ day with the a/c cranked up to full while sitting at idle for 20 min. When the truck was at speed it didn’t overheat. Of course after the expan tank was replaced the plastic end tank on the radiator revealed it had a crack too. Do the accessory belt while you’re in n there and water pump if you’ve got the budget. It’s basically an every 100k thing.

I agree the tanks are very difficult to find when leaking. Mine leaked for a while and the trick to finding it is to pressurize the system. and look for air or coolant escaping.

 

[BrooklynGuppy]

That's the overflow drain. It should only leak coolant out when the reservoir is either over-pressurized or overfilled. Aaaaand, it will also leak fluid if I'm sloppy when I add coolant because it drains from above the cap seal, but below the threads, so pouring coolant directly on the little hole there will cause fluid to come out through that port. So assuming you're not as careless as I am when you spill fluids , I suspect that you either have a hidden crack in the reservoir or the coolant cap on top is leaking under pressure for an undetermined cause.

Yes, but if you notice the discoloration around it, it's weak in that area. Since I replaced the tank, no more leaking.

 

[BrooklynGuppy]

Make sure to inspect at the "tees" at the firewall heater hose connections. Seems that a lot of hard to find coolant leaks end up being that. I had that problem.

Come to think of it, does a PPV have rear heat?

I did. I actually bought the tri-hose for it. Everything looks good. And yes to the rear heat.

 

[BrooklynGuppy]

That's the overflow drain. It should only leak coolant out when the reservoir is either over-pressurized or overfilled. Aaaaand, it will also leak fluid if I'm sloppy when I add coolant because it drains from above the cap seal, but below the threads, so pouring coolant directly on the little hole there will cause fluid to come out through that port. So assuming you're not as careless as I am when you spill fluids , I suspect that you either have a hidden crack in the reservoir or the coolant cap on top is leaking under pressure for an undetermined cause.

I'm pretty careful with filling it. This wouldn't show any coolant anywhere. Until I seen coolant on the ground under the right front bumper. I felt under the tank and there it was, seeping out. All seems good now since I replaced the tank.