https://imgur.com/nu2u342



I just took these pics 15 minutes ago, to me the oil seems normal. And from the testing I did with the coolant pressure tester the head gasket seems okay (post #1) I was hoping there's a similar test like this one that I could do on the Intake manifold to see if it's leaking. Somehow pressurize it to see if it holds? Also the the used LIM gaskets that I provided, it was the Fel-Pro part# that is recommended here.

 

I know from just changing out oil pans that the dip stick sits a couple of inches from the bottom of the pan. Unless you have got a good emulsion going, you're not going to be able to tell there is water in the oil. Best way is to change oil when the car is cold and judge what's coming out of the drain hole first since the oil will sit on top of the cooolant. If this turns out to be the case, I would expect LIM gaskets first. It could also be head gaskets or, as was my case, a cracked block. If you have the burning antifreeze smell, it sounds like an external leak. That doesn't necessarily cut down on the cause, but it's better than an internal leak. If the smell is not from the engine compartment, you could try an inspection camera through a spark plugs hole to see if you have a clean piston top. That still doesn't eliminate any of the potential causes though.

When I bought my truck, it has a new radiator. I'm presuming that it overheated as cylinder 6 was cracked in a couple of spots. Whatever cracks we're there let go on me and it dumped a lot of coolant into the cylinder and oil. The problem became very obvious upon changing the oil. I'm hoping yours is the LIM gaskets. There's a lot of rtv holding it in. There is also a lot of aluminum corrosion from the Dex cool on the LIM around the coolant passages. LIM is the easiest and cheapest place to start.

 

I did what you suggested and drained the oil after the truck was sitting overnight and the oil looked totally normal when I first took the plug out. I took this pic of the oil after it was sitting for several hours, I think if there was water in there the light would shine through, right? Thing is though, the coolant loss isn't that severe, maybe a quart every three weeks or so. Not sure if that's enough to make it obvious by looking at the oil.

I think I'm going to try to bypass the heater core, burp the system, and see if there's any change to the coolant loss/coolant temp.

 

That is interesting. I would think the oil would sit on top of the oil.

 

I've heard of water mixing with the synthetic oils but will eventually separate from regular oil. What type have you been using?

 

Mobil 5000 conventional oil.

 

Pretty sure you meant the oil would sit on top of the water, and yeah that's what I thought too. I was cringing the whole time I was loosening the drain plug thinking I would get a gush of water, but nope. And I even left the oil in the drain pan overnight and inspected it and there still didn't seem to be anything abnormal about it.

 

In case anyone reads this thread I figured I update to say that the P0128 was caused by a bad ECT sensor. Apparently the test with a scan tool that compares IAT, ECT, and ambient temps when engine has been off for a while isn't definitive (post #4). I needed the truck to pass emissions so I threw a new sensor and it is now running at normal temp.

Still losing coolant somewhere (not a lot). Kind of given up on that unless it starts to get worse.

 

My 2 cents here, check or change out your radiator cap, a weak cap will slowly mist coolant out and the mist will be small enough you will not feel it or be seen with your eyes

 

Cap is fairly new, but if I remember correctly it's an Advance cheapo brand. Not sure if OEM would make a difference but I can try swapping it out.