Gremlin in the radiator?!?!?

So I feel like I'm hearing a constant humming(whirring, pump motor running, poss. fan spinning, but not rad. fan) from the front of the radiator on the driver side.....

It's not the radiator fan, it's not the A.C., not the defroster.

In regards to the "1st start of the day";
I know what it sounds like when it's really cold or really hot. It's not that.

2017 Ram 1500, 5.7, 6-speed, 392gears. 4×4, approx. 37500kms.

I have been noticing my coolant temp fluctuating from 92°C(197°F), jumps to 101°C(213°C) then is suddenly/very quickly back to 92°C(197°F). It will do that not only driving, but at idle.

When this happens, the oil temp can(not every time), also fluctuate w/the coolant temp. 93°C(199°F) - 99°C(210°F) - 93°C(199°F).

After five days of this, I started to get a "low oil pressure" message flash(4 a split sec.) on the 1st start up of the day and only the 1st start of the day. Message immediately goes away, oil pressure gauge is right where it usually is upon fire up. Running RP 5-20, oil looks good, level is nearly perfect. Upper part of the cross hatch area on the dip stick. I got the message 5 consecutive days in a row. Didn't get it this morning.

No check engine light. It's kind of frustrating, cause the truck is running really good. But I still feel like somthing just isn't right.

Any ideas are welcomed. Thanks guys.

I have no idea about the noise. It's difficult to troublshoot anything remotely, especially sounds. Especially when you don't even include a sound clip or video.

It's normal for oil temp to track with coolant temp. The temps you posted don't seem unusual. What are your concerns with that?

Your oil pressure sending unit might be going out. Installing a temporary oil pressure gauge would be conclusive on whether your oil pressure really is dropping low enough to trigger a CEL. You could also just inspect the sending unit. Oil on the connector side usually indicates that it's bad or on its way out.

So my guess what you are trying to ask is can a failing water pump be the cause of a low oil pressure reading, because in your estimation there is no way it can be true. I don't the answer, maybe.

Go get rmi 25 and run it through your cooling system and check the overflow tank, if there is slime or gel this WILL remove it and deposit it in over flow. Also, run your heater and make sure this is getting through heater core. Replace thermostat, the whining can be the water pump, maybe this will free it up, and I say maybe. This is the cheap way forward and in theory might help if your theory is true that something in the cooling system is choking the engine creating an oil pressure issue, which is a little thin if I am being honest. There is no downside to adding rmi 25 and replacing t stat, these likely should be done anyhow.

I did make a video, but you can't hear the noise in said video! So I didn't post it.

In regards to coolant & oil temps. Yes, I am accustomed to seeing them change/track in unison. Just not so dramatically, that is my concern.

I am following this thread, as I love a mystery. My big question is how do you only rack up 3300 miles a year?!?
Hope this gets sorted for you

CalDad14 said:

I did make a video, but you can't hear the noise in said video! So I didn't post it.

In regards to coolant & oil temps. Yes, I am accustomed to seeing them change/track in unison. Just not so dramatically, that is my concern.

Click to expand...

If you can't hear it in the video, are you sure it's really making noise?

Just kidding (mostly lol). I can't say how much the temps should fluctuate, but there will always be some of that going on. I'd be more concerned if the temps were getting over the 220°F and up range, especially if it's not being used in extreme conditions such as towing heavy up a grade. The temperatures you posted are well within safe limits.