Milkshake on the filler cap

[steinbachphoto]

Okay so just doing some clean up and found milkshake on my filler cap and on the underside of my valve cover. However there's none on the dipstick and the car appears to be running fine.

What do you think is wrong and what should I fix/replace? Thanks

[Farbin Kaiber]

Could be signs of a headgasket failing.

[Pantless Spency]

i had the same thing, ended up being a blown head bolt, i thought it was blown HG.
drive your car around the block and check out your MPG needle, mine was acting up saying i was getting no more than 10 mpg, thats what lead to me finding the coolant under the filler cap and thats when i knew lol.

[Teaguer]

I second signs of potential or looming HG failure.

Spencer, you should seriously refrain from trying to give any tech advise ...for at least some years. Seriously.

[jlevie]

In cooler weather milky emulsion on the cap or under the valve cover is quite common and only means that the car is not being driven long enough, hard enough, or often enough to boil combustion blowby condensates out of the engine. A couple of runs each week of sustained highway speed driving for at least 30 minutes will keep the engine cleaner. If your driving pattern is mostly urban with lots of short low speed trips, cut the oil & filter changer interval to half or a third of normal.

[Pantless Spency]

I second signs of potential or looming HG failure.

Spencer, you should seriously refrain from trying to give any tech advise ...for at least some years. Seriously.

my bad.
op don't listen to me!

[davem]

In cooler weather milky emulsion on the cap or under the valve cover is quite common and only means that the car is not being driven long enough, hard enough, or often enough to boil combustion blowby condensates out of the engine. A couple of runs each week of sustained highway speed driving for at least 30 minutes will keep the engine cleaner. If your driving pattern is mostly urban with lots of short low speed trips, cut the oil & filter changer interval to half or a third of normal.

+1 when my car was sitting at the body shop i had milk under the cap after only a week

[paperplane94]

If it were me seeing this I would look for the other signs of HG failure and/or have some tests run (compression, leakdown, etc.)

Its still a possibility, just like its possible for the car to run normally with a HG leak.

Good luck

[steinbachphoto]

If it were me seeing this I would look for the other signs of HG failure and/or have some tests run (compression, leakdown, etc.)

Its still a possibility, just like its possible for the car to run normally with a HG leak.

Good luck

What are some other signs?

[smooth]

What are some other signs?

You might find oil in your coolant if the leak is severe enough.

If you've got white clouds of exhaust billowing out your tailpipe then you might have some more evidence of coolant getting into your combustion chambers but I don't know if that happens in colder climates regardless.

You can check to see if your coolant level is getting lower over time.

On the testing side of things:
You can do a coolant analysis. You can do an oil analysis, as well.

A compression test (fast, easy, inexpensive) will tell you something is amiss but a leakdown is definitive (with the disadvantage of requiring special shop tools and more expensive).

[Farbin Kaiber]

Any auto parts store will have a block tester, you fill it with the blue liquid, and place the rubber base onto your coolant tank with the engine running and watch the fluid for a change. This is testing to determine if emissions are present in the cooling system.

[hoveringuy]

Okay so just doing some clean up and found milkshake on my filler cap and on the underside of my valve cover. However there's none on the dipstick and the car appears to be running fine.

What do you think is wrong and what should I fix/replace? Thanks

This is a seasonal thing for me. It happens in the winter and goes away in warmer weather.

Monitor coolant level.

Drive hard occasionally.

Next oil change send a sample to Blackstone Laboratories and they'll tell you exactly how much coolant (if any) is in your oil. Order their free test kit now.