Steam out the tail pipe

CHARLESCUMMINGS

MEMBER
2003 FORD F-150
4.2L
6 CYL
2WD
AUTOMATIC
150,100 MILES

My truck is in real good condition. I baby the vehicle. I have noticed that even after I do a lot of driving the steam does not ever burn off it continues to blow out a little steam the whole time the truck is running. It doesn't run rough and it is not much steam. Basically just like when you start it on a muggy day the problem is it never goes away even after the engine is warm. It has been going on for about a year. I have checked to make sure it is steam and not smoke. I also checked to see if I was losing antifreeze/coolant and I can only check the reservoir and it appears to be not losing any. I am stumped. I recently replaced my EGR valve and that did not fix it. The truck seems to be running fine. I change my oil regularly the only thing is it has been about 4-5 years since the coolant was changed. I know it is time. I was thinking it might be a leak in the TPS sensor or a small leak in the head gasket could you drive 1 year with a small leak in the head gasket? Is it possible if the TPS sensor could possibly leaking? I don't know. I know the TPS sensor regulates idle air, but I thought it has a passageway for coolant too. I'm probably wrong, but could you clarify?

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

It sounds to me like you have nothing to worry about at all. Water is a by product of the catalytic conversion process done by the catalytic converters on your vehicle. The steam is simply this water turning to steam in the hot exhaust system. In fact if you look at the tail pipes of a brand new healthy vehicle taking it's first drive off the showroom floor, when it takes off from a stop light or stop sign, there will be water pouring out of the tail pipes. Not a lot, but definitely noticeable. It is a sign of a healthy, properly working, exhaust system and catalytic converters. I hope this helps.

Thanks,
Alex
2CarPros