Coolant Leak Disappeared

[OlPensy]

2017 PW with ~103K miles.

I came out to the driveway the other morning and had about a pint of coolant in the driveway after the truck had sat overnight. Couldn’t tell from where it was leaking, but it was a slow drip pooling up in the middle of the truck.
I topped off the coolant and drove around. The leak stopped completely. I let the truck cool and sit overnight and in the morning, nothing. I am noticing though that coolant temps are fluctuating between about 185-212 deg. Is that normal? I took it to the dealer and they pressure tested the system. They found no leaks and say the truck is good to go, but I’m not convinced. Any ideas?

Thanks all.

 

[rzr6-4]

coolant temps are fluctuating between about 185-212 deg. Is that normal?

My Sierra does this, but that's because of a bad thermostat. Normally no that should not happen.

pooling up in the middle of the truck.

In my mind "middle of the truck" would be under the feet of the back seat passengers, but that wouldn't make any sense. Do you mean more like the middle of the engine bay? Middle but closer to the front I might think cracked radiator but true middle of the engine bay being roughly below the oil pan, I would think maybe the water pump. They have a weep hole at the bottom that tends to be the first thing to show signs of them failing.

 

[OlPensy]

Hey, yes I meant “middle” in reference to side-to-side. It was dripping from directly under the engine. Thanks for the response!

 

[buckeyexx]

I suspect the water pump. Had a similar situation when mine started leaking. I was 1000 miles from home when it happened. I came out the first morning and found a small puddle under truck so I too topped it off and drove around. It didn’t leak on that drive and couldn’t figure it out until I climbed under the truck and could see it wet coming from the lower part of water pump. It would only leak enough to see a puddle maybe every couple of days. I actually drove the 1000 miles back home without issue but it definitely had me worried. If it is the pump they aren’t the easiest to replace. They have a coolant hose that runs under the intake manifold.

 

[buckeyexx]

Adding to my previous post. It is a very doable job in your garage as long as your comfortable working on your on truck. Most water pumps are just a simple pull the belt off and unbolt pump which the 6.4 is that way, it just has the line running under the intake that makes it a little more challenging and involved.

 

[OlPensy]

Awesome info, thank you.

 

[OlPensy]

I suspect the water pump. Had a similar situation when mine started leaking. I was 1000 miles from home when it happened. I came out the first morning and found a small puddle under truck so I too topped it off and drove around. It didn’t leak on that drive and couldn’t figure it out until I climbed under the truck and could see it wet coming from the lower part of water pump. It would only leak enough to see a puddle maybe every couple of days. I actually drove the 1000 miles back home without issue but it definitely had me worried. If it is the pump they aren’t the easiest to replace. They have a coolant hose that runs under the intake manifold.

Dealer just called and said, “Actually we found the leak from the weep hole in the water pump”. I think you were spot on. Thanks again.