2011 LX570 Intermittent Coolant Leak - What does this residue indicate? (10 Viewers)

[Chaldaean]

My LX570 has ~200,000 miles and has been losing coolant recently. I noticed that there is coolant residue in the area shown in the photo. Where it is likely leaking from?

 

[CanadianRockyCruiser]

Possible water pump leak, but given the location, it could also be a leak at the water by-pass joint (failed gasket pn1634138030?)...

Try to get a phone/camera in there to see if you can get a better view.

 

[GOLIGHTLY]

Water pump, thermostat housing, or the mother of all deferred valley plate leaks.

 

[Chaldaean]

Possible water pump leak, but given the location, it could also be a leak at the water by-pass joint (failed gasket pn1634138030?)...

Try to get a phone/camera in there to see if you can get a better view.

CanadianRockyCruiser, thanks for the guidance and I especially appreciate referencing the gasket part number -- that really helped visualize the area. I will see if I can get some better picture - I have access to an endoscope.

Water pump, thermostat housing, or the mother of all deferred valley plate leaks.

GOLIGHTLY, thank you! Yeah, the thermostat and water pump look like they could be culprits. I did stick an endoscope in the valley area a while back and didn't see any pink residue in there, but will keep that in mind.

 

[GOLIGHTLY]

CanadianRockyCruiser, thanks for the guidance and I especially appreciate referencing the gasket part number -- that really helped visualize the area. I will see if I can get some better picture - I have access to an endoscope.

View attachment 3544642



GOLIGHTLY, thank you! Yeah, the thermostat and water pump look like they could be culprits. I did stick an endoscope in the valley area a while back and didn't see any pink residue in there, but will keep that in mind.

View attachment 3544650

View attachment 3544658

View attachment 3544637

That’s great! Figured that much of a valley plate would have been very apparent by volume of disappeared coolant but gotta check that box. Glad it’s just therm/wp!

 

[Chaldaean]

To close the loop on this, I took my truck (2011 LX570 with 205,000 miles) to an independent shop and they determined the leak to be "the water pump" (that is the only detail I have to pass along). They fixed it for $600. Before dropping it off, I printed out this thread and highlighted all the potential causes for the shop to reference. Thanks all!

 

[Chaldaean]

To close the loop on this....

Scratch that. The loop is still open. My coolant overflow emptied again.

I crawled under the truck, removed the skid plate access door to the oil filter, looked up an saw this residue:

I'm bringing it back to the shop in a few weeks. In the meantime, I will keep a constant eye on the overflow reservoir.

 

[xeuxaz]

Well, thanks for the nightmare fuel. I'm interested to know what it ends up being once you get confirmation.