About a week ago my truck ran out of gas and then I left the keys in the ignition and the battery died. I finally got a new battery and installed it today. The truck started up on the first try but after running for a few minutes smoke started to come from under the hood. It looks like some kind of fluid is leaking onto the exhaust manifold and is burning up. The fluid leaking is reddish and looks like tranny fluid which seems odd to me. But then again, I don't know much about trucks which is why I need some help. Thanks for any input

 

What engine? If the leak is coming from the driver's side it could also be from the power steering system, some people use auto tranny fluid in the power steering. You will have to get a flashlight and try to find out where it's coming from.

 

Did you turn the steering wheel with the engine off? If so it is sure to be P/S fluid. The Ford P/S pumps are notorious for pushing fluid out the filler if you turn the wheel with the engine off. For instance, yesterday we rolled Bruno's Bronco out of the shop and parked it beside the driveway. It left a trail of fluid and when we popped the hood to see it had squirted fluid all over the under side of the hood.

 

It is a 302 v8. The fluid appears to be reaching the right exhaust manifold and is burning up on there but I cannot locate the source of the leak. And I do not remember turning the wheel with the engine off although it is possible that I may have. If so, what can I do to prevent it from leaking?

 

By "right" exhaust manifold do you mean the driver's side? If so, that would probably mean it came from the P/S pump. They can leak several ways, but the one that showers everywhere is through the cap due to turning the wheel with the engine off. The only thing to prevent that is not to do it. But, if you have to then maybe pulling the cap and covering it with a rag would prevent it from spraying.

 

I did some more research and it seems like it could be caused by a vacuum leak or a bad modulator valve. However, the tranny fluid isn't low. (yet...?) But the engine does idle high and shifts late when driving. Maybe that helps some, thanks for any suggestions.

 

You may have missed the question, but which side of the engine?

 

Sorry, by "right" I mean the passenger side. The fluid is getting on to the spark plug and down from there, almost as if its coming from under the valve cover somehow?

 

Ok, forget the P/S pump. Which plug? If the back one that's sorta below the dipstick opening to the C6. If you have too much fluid or a problem in the tranny it could froth and come out there and drip. And, there's the vacuum line just above that, and it could have ATF in it if the modulator failed, but it should get sucked into the engine.

 

There are also the coolant tubes from tranny to radiator down on that side, too.

 

Yes it is the plug furthest back. Could fluid possibly be getting drawn into the vacuum line and instead of going into the engine it is leaking because of a leak in the vacuum line? And is it possible for the tranny fluid to be getting into the coolant lines?

 

The lines Chris is talking about are the tranny cooling lines, so would have fluid in them. And it is under pressure, so a leak would spray. But, IIRC there are no joints in the lines at that point so it would have to be be a hole in the line itself.

As for the vacuum line leaking, only with the engine off as it has vacuum otherwise.

 

Ah I see. I haven't noticed any spraying anywhere under the hood. It is all concentrated towards the back and there is no fluid on or above the valve cover. How can I check for vacuum leaks? Or should I even attempt to?

 

Actually, unless you know it is ATF, which is red when new but turns brown with use, I'd guess your valve cover gasket is leaking. That plug is at about the right point for oil to run down on it from the valve cover, and since the engine typically slopes down at the rear, a leak anywhere on the valve cover would show up at the rear.

I would clean the area and try to figure out where it is coming from. A rag or paper towel soaked with brake cleaner does a good job of cleaning, but may take paint off as well if you use much. But, with things clean you should be able to tell where the leak is coming from. And, if it is the valve cover that will be the easiest and cheapest fix of all.

 

I like the tranny being overfilled idea. Drive it down the road for about 15 minutes and get the tranny warmed up, park it on level ground, and with the engine idling, pull the tranny dipstick. Wipe it off and stick it back in and then pull it out and see where the level is. If it's high, then that's a problem. Gary is right, the fluid will get foamy and puke out the dipstick tube, and also when it gets foamy, it messes up the tranny and it shifts funny.

Just something quick to check and eliminate.