Coolant drain advice

No danger

 

I left mine partially drained (cleaning EGR cooler and pipe only, not the intake manifold yet, removed just a half gallon) over one night, and noticed no warnings of a problem. And I've experienced no problems since, though only 6 days (and driving only half of them) probably isn't long enough to be sure.

 

Yeah, you don't have to do a full coolant drain. You can if you want to, but it does create extra work, and doing the EGR you will be knackered. As @fuzzy1 said, if you drain just couple of quarts (at the radiator drain spigot, into a clean container), you'll have dropped the coolant level below the EGR components, leaving them high-and-dry.

When you disconnect coolant lines from the EGR cooler, there'll be no spillage. When removing the EGR cooler, don't tilt it, because there's a few tablespoons of coolant trapped at the lower back corner: once removed you can just pour that trapped bit into the previous draiined coolant.

When done with the EGR, everything reassembled, pour the coolant back into the reservoir. It'll likely end up slightly higher than normal. While pouring it back in you could leave the topmost coolant line disconnected (2013 lacks a coolant bleed screw IIRC), that might help air to vent as you add the coolant). If coolant starts flowing from the disconnected line, quickly push it back on and reinstall the clamp.

I found with a few days driving, the coolant level in reservoir settled back to normal level.

Also, if you remove the throttle body, say for cleaning and/or in the process of removing intake manifold, you can leave it's coolant hoses connected. There's enough slack to move it out of the way (maybe tie to the inverter), or to turn over for cleaning.

 

One more, a PSA for cooler removal: keep a hand under the back joint when removing the cooler; there's a loose gasket there, and it will drop.

 

I lucked out in having already dropped the front of the plastic underpanel to access the radiator draincock. So that gasket, and another part dropped during reassembly, were very easily fetched. But if I hadn't used Mendel's coolant drain path instead of clamping the hoses, or otherwise dropped that panel, retrieving those parts would have been much more work.

The NutzaboutBoltz maintenance videos, using a 2012 as a sample, didn't mention any bleed screw or disconnecting that upper hose, so I didn't, and haven't (yet) run into any problem from trapped air bubbles.

I did forget to not tip the EGR cooler during removal, so lost the portion trapped in there. And also the back bottom cooler hose slumped a bit and started draining some, so I had to prop up the end behind other hoses/wires/stuff to keep the end high enough to quit draining. So maybe one should drain a bit more than a half gallon / two liters?

After those loses, I has just able to get all the remaining coolant captured from the radiator, back in to the reservoir before startup. It didn't all go in at once, but flowed into the plumbing over a few minutes before the very last could be poured in.

The final reservoir level, after some errands and heater blasting to flush out air bubbles, is now about 3 inches below the initial reservoir level before startup.

 

I think for 2012 onward the bleed bolt was omitted. Maybe it wasn't very effective, not sure.

There are a couple of openings in the engine under panel, that appear to be expressly for acessing the radiator drain tap. The larger opening to the rear you reach your hand in, reach towards the front, and you can turn the wingnut to open the tap, which drains through smaller opening to the front.

That said, I also had the under panel removed, but when the rear gasket dropped, and I'd completely forgotten there was a gasket, it dropped, but hung up on something, didn't fall right through. When reassembling it occurred to me there should be a gasket there (largely due to repeatedly watching the @NutzAboutBolts video ) and I started looking for it, luckily found it and managed to fish it out.

Hmm, maybe that bleed bolt is useful then. Mine ended up at most an inch higher in the reservoir, and it all went in in one go. I had spilled tablespoons at most, when I first removed the cooler, not cognizant that there was bit still in there. I had the bleed bolt open as I poured coolant back in, and I periodically stopped and burped the main coolant hoses at the radiator.

I can't recollect now if coolant started coming back out, through that bleed bolt, at some point in the refill. Strange, I should remember, but it's gone, lol.

In the absence of bleed bolt, I would think removing the topmost hose over the EGR components, should accomplish the same thing. Again, just be ready to reconnect quickly, if it starts to flow out.

 

Yes, I'm thinking it is useful, even if possibly not essential. Opening one of those others likely would have helped too, just hope that any of the temporary bubbles where not in a troublesome place at the cylinders. Heater loop, EGR loop, top of radiator, no problems if any were trapped there.