What takes longer?

[ADFD1]

You start up your car and begin driving, cold engine builds moisture in the oil and the exhaust. What takes longer to boil off, the moisture in the exhaust system, or boiling off the moisture in the engine oil?

Does the season and outside temperature matter?

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[mechtech2]

Normally, your exhaust will get up to temperature faster than your engine oil. Not that it means anything.
15 F below zero on a Chicago morning will cause both to heat up slowly and not fully.

 

[ADFD1]

Thanks. I sort of figured that. I was wondering about those cars you see in the morning with water literally pouring out of 2 tail pipes. It has to take some time to boil that water off, especially what gets caught in seams, or in the mufflers, far away from the engine.

 

[AdRock]

Water vapor is one of the byproducts of the catalytic converter doing it's job. That's part of the reason for so much steam on a cool early morning with a lot of humidity. It's not all just condensation from being cold & warming up.

 

[ADFD1]

I realize that, but for short hops that moisture can really rot out an exhaust system, especially an after market exhaust system. I wondered if the water boiling out of the exhaust took about the same 20 minutes it takes to get engine oil hot enough to boil the garbage out of it.

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[AdRock]

It'll clear out of the ehaust much quicker because the exhaust gets much hotter much faster. The oil temps don't get as hot as the exhaust temps. I agree that the moisture can really rot out a system but that's just how things are. This is why you see a lot of aftermarket companies making stainless exhausts. Quite a few higher end cars also come with stainless from the factory.

 

[ADFD1]

Thanks. I thought in the winter time (NW or NE USA) the moisture at the exhaust parts at the very rear of the car would take a long time to boil out. Time wise about as long is it would take the oil to reach operating temps.

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[Gary Allan]

I had a modified Toyota chassis (it was a dual rear wheeled mini "cube van" sorta -1980). It had about 5 or 6 feet of additional exhaust. If I had any extended idling in the cold weather (winter) it would condense moisture in the exhaust while running the whole time. I'd start moving and heavy vapor would form a decent cloud behind me for a bit.