white past on oil cap after a overheat condition

[Ross]

My friend’s 2006 Hyundai tiburon (GS) overheated recently and stranded him on the side of the road. I drove down to check things out, It was acting fine until he hit a highway on-ramp where the temperature gauge suddenly spiked to “H” within 30 seconds, which he then pulled over and stopped the engine. When I got there there was coolant still in the system and the engine was cooled off as we were about an hour away from home.

I couldn’t find any coolant leak, and the car started up drove fine, but when I took off the oil cap there was some white past on it, and the oil on the dipstick seemed milky. I told him he has coolant mixed with his oil and that the overheat likely blew the head gasket and/or warped the cylinder head (cast iron block, aluminum cylinder head).

Here’s where I’m left un-easy, the mechanic he took it to replaced the thermostat, which solved the overheating problem, but his explanation for the white past on the oil cap was condensation. What I’m told he said is that city cars (I’m on the highway 97% of the time, my friend is in the city 90% of the time) can have condensation build up on the inside of the engine during winter, and that the white past on the cap could be that.

we just did an oil change for good measure, what came out looked ok but I’m very un-easy about the mechanic’s explanation for the white past. of my commuting .5 of my 17 mile commute to work is city, and maybe 1 mile of my 70 mile commute to collage is city, so I really have nothing to use against the city driving claim. my instincts say that there shouldn’t be any amount of white past on the oil cap EVER, but maybe I’m overreacting.

Anyone have any experience with “condensation” in the winter? I appreciate the help!

Topic

[Richard Kirshy]

What the mechanic said is true.
Vehicles that only do short trips are prone to have condensation build up.
Especially in the winter time.
This is due to the fact the oil does not stay at temperature for a long enough time to “dry out ” .

Is there any evidence of excessive smoke out the tail pipe?
If your concerned about a possible head gasket failure, you can always do a leak down test.
You can also inspect the plugs, if any look especially clean, that is a sign if coolant getting into the cylinder(s) and basically steam cleaning the carbon off.

[Ross]

as far as I can tell the engine is operating normally, No smoke coming out of the tail pipe. I can’t say what he does in his free time, but I know he drives less than a mile to get to work, and his coolant gauge never leaves the cold mark.

I’ll see if I can inspect the plugs in his car sometime soon, Thank you!

[Richard Kirshy]

[color=#00bbff][i]as far as I can tell the engine is operating normally, No smoke coming out of the tail pipe. I can’t say what he does in his free time, but I know he drives less than a mile to get to work, and his coolant gauge never leaves the cold mark.

I’ll see if I can inspect the plugs in his car sometime soon, Thank you! [/i]
[/color]
That being the case, I’m not surprised that the thermostat got stuck closed, or that it has condensation build up.
Might suggest he install a catch can.
May help to remove some of the water vapor build up.

[Rich]

Given that the water in the engine oil was accompanied by an overheat condition, a leak down test is essential. Don’t assume the water is condensation.

[Author]

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