Water build up in Oil

burkie733 · February 13, 2018

I have a 2015 GMC Sierra SLT 5.3 with 10,500 miles. Within in the last month the engine has started to run rough miss firing, pinging, knocking etc.... Brought it in to the service center and they replaced the fuel pump, intake gaskets and changed the oil due to fuel smell. Pick it up, runs great for 200 miles and I start having the same issues. Bring it back to the service center and now they say there is a large quantity (8oz) of water in the oil that is causing the is miss fires, ticks, pings, clunks. Their "fix" if you want to call it that, was to just change the oil. Nothing else. I'm not a mechanic by any means, but I'm also not fool under the under the hood. I understand condensation build up with hot and cold but 8 oz on water in 200 miles in the oil? I'm not buying it. The dealership is playing this off as "Normal." I know this is completely bogus. Any thoughts, suggestions other than complaining and telling the dealership how ridiculous their answer to the problem is. Oh and the kicker! I had to pay for the oil & filter change because of the water in it.

Colossus · February 13, 2018

Take the receipts with you and go visit another GMC dealer. See if they can do better. If not, go by your local Dodge or Ford dealer and see what they'll give you on trade in.

Northman · February 13, 2018

Could be just condensation depending on the outside temps, the length of your commute, and whether or not you bring it into a heated garage after being out in the cold. More likely though it sounds like a a head gasket. Those sounds are likely related to small amounts of coolant getting into the cylinder. Have you been low on coolant?

burkie733 · February 13, 2018

I live in Minnesota, It's cold. I use a garage and it's not heated. My commute is not far, about 5 miles from work but I always warm the truck up before leaving. I cant be the only person that lives with a short commute that has issues like this. They said it wasn't coolant, it was water. But that much water since a oil change 200 miles ago?

burkie733 · February 13, 2018

I understand that usually when I get to my destination my engine is most likely not at the normal running temp but when its -10F non of the vehicles around here are.

Bash74 · February 14, 2018

I would go to another dealer and see if they will help. I would also do an oil sample. You must have a slow 5 mile commute for the truck not to get up to temp.

Loco-diablo · February 15, 2018

8 oz after 200 miles? Something is wrong. I agree with Northman. Check the coolant level. This could be the head gasket.

burkie733 · February 15, 2018

A sample was taken. Its not coolant, it's water. I guess they dumped some out and it froze. The dealer contacted GM and the solution was to drive it more often to burn off the condensation build up or have the oil changed more frequently. I understand the idea but this isn't the truck's first winter, I've owned it since 2015. I'm limited where I live with GM dealerships, I really don't have any other choice unless I drive 150 miles to another.

wforrest08 · February 15, 2018

So they want you to change the oil more often than every 200 miles? I think that’s what I’m understanding here.

MixerDriver · February 16, 2018

I almost wonder if the PCV is gummed up after all those short trips? If it's not venting properly, it could explain the excessive moisture buildup, and could also cause the rough running. May or may not be what's wrong, but just a thought...

Bash74 · February 16, 2018

Good catch with the PCV that the last poster said. Would definetly check that. If there is new oil in it i would purposely drive it alot more then usual and see if it still happens. If it doesn't then I guess that could be the fix.

burkie733 · February 16, 2018

Yeah Wforrest08, those exact words. I talked with them today and they did mention the pcv possibility before I could bring it up. For now I'll just drive it more often to see what happens. Thanks for all the help and ideas guys.

Hoginedgewood · February 17, 2018

22 hours ago, MixerDriver said:

I almost wonder if the PCV is gummed up after all those short trips? If it's not venting properly, it could explain the excessive moisture buildup, and could also cause the rough running. May or may not be what's wrong, but just a thought...

I agree, if it’s water then you are not getting the engine warm enough for long enough. Engine should get warm enough to turn it into steam. But make sure your not loosing coolant.

and make sure your pcv is not clogged.

Grumpy Bear · February 17, 2018

Pull the oil filler cap on the valve cover and have a look at its underside. Thick off white slimy foamy mess says it's not making it to temperature for long enough. Thermostat isn't stuck is it? PCV possible, yes.

160 is warm enough water temperature to vaporize water from oil IF it's that warm long enough. Normally an hour at peak temp.

If it had to 'boil' to vaporize you couldn't line dry cloths. (hint)

DONWT15 · February 17, 2018

Definitely go for the easy stuff first. Get it good and warm to get the water to "percolate" out. Check the oil fill cap for slime as stated above, clean it off and check it again after driving it up to temperature again a few times. If it keeps coming back, check the PCV for the same condition. Clean it or replace it if needed. It should move freely and will have a little oil in it which is normal. If your not seeing water build up in the summer, then it's probably not anything major.

Gotta run them hard every once in awhile to make them sneeze out the nasties.