Hello,

I have a 2007 v6 with 140k miles. I've owned the vehicle for about 4 years. This vehicle was owned by a family member from new before I bought it. It has been meticulously maintained from the beginning.

I recently had the oil changed by my mechanic. He said there was some water in the oil and to keep an eye on it and maybe change the PCV valve. I changed the PCV and the old one had some grime in it, but still rattled.

There is no white smoke, no check engine, runs fine, no oil mixed in coolant, coolant level is consistent.

I just checked the oil on the dip stick and there is no water or separation, it looks like pure clean oil.

Do you have any ideas?

Thank you,
Zach

Could've been sitting a while maybe? The head gasket issues were resolved in 2005, not to say there could potentially be a problem, not as common though. What does the coolant look like, level and condition?

You'll want to ask your oil change guy what evidence of water he saw.

If you're in a region where temps are cold, some carmel-colored accumulation at the oil fill cap is normal.

The oil in the crank case should still be normal black when changed...if the oil is emulsified with water mixed in, you have a problem.

Coolant level is normal and is bright pink, no trace of oil.

He said when he drained the oil he saw a little bit of water/milky substance.

BlackStone Labs has an oil analysis service that I like to use when I change my oil. They can tell you what is in your oil, like wear metals, fuel, coolant, detergents, etc. Since the oil is drained, it may be difficult to get a a sample from this past change.

Also the coolant will usually look nice on the top under the rad cap and in the expansion tank, so this isn't the best place to look for any intrusion. A shop recently put green coolant in my radiator with pink already in there. It was a total mess that I just fixed this weekend, but under rad cap was green, expansion tank pink, and out the drain it came out orange. Point being that a peek under the rad cap doesn't tell the whole story. Can try draining a little of the rad and see what that looks like.

+1 for getting an oil sample analyzed at Blackstone Labs.
In the meantime, you could check for exhaust gasses in the coolant system with a cheap test kit from almost any auto parts store.
As far as your "no white smoke" observation, you would be surprised how bad a head gasket can be without any visible smoke in the exhaust. I just went through the pain of diagnosing one in a 2UZ-FE in a Lexus LX470 (Another Misfire Thread - LX 470 | IH8MUD Forum) that was about as bad as it could be without any white smoke, although the misfire was very noticeable.

Since you weren't able to see the oil yourself and your mechanic didn't save any to sample, hopefully it was just a bad observation and everything is ok.