Sega_Sonic

Hello everyone,

I joined this forum because my mother's 1997 F-150 truck has been having some issues for about a year now and we have had multiple people look at it and no one seems to know whats wrong with it.

Its a 4.2 V6

It has been making a tapping noise when you start it and white smoke comes out of the exhaust when it sits idle. It lets off a sweet smell. After it has been driven for awhile the noise quiets. The funny thing is the truck drives fine, but just makes a lot of noise. The noise is coming from the front of the motor by the timing chain.

If anyone can please give me some input on what could possibly be wrong, please let me know. Thank you.

Half Breed

Does it show any signs of oil useage? How many miles does it have on it? Has the engine ever been opened up on the front end?

torkum

You have a blown head gasket. Of the 'multiple people' has a leak down test not been done. The sweet smell is antifreeze and the white smoke is water vapor. The tapping is the wear caused by the antifreeze breaking down the oil and wearing the crank and rod bearings. Check your oil and its probably overfull.

wde3477

First, welcome to the site.

Is the truck using any coolant - white smoke and sweet smell can be signs of a leak. It can also be typical water condensation from a cold engine and cold catalytic converter operation.

Does the engine oil look good (not milky) and at the proper level?

Another forum discusses some bad news with this engine - don't know about its validity:
http://www.aera.org/fm/archive/index.php?t-407.html

Sega_Sonic

Thanks for the welcome and the help. This is a wonderful forum.

We are going to check the oil again and see if it is overfilled or looks strange but here are some more facts:

The truck has a 85,000 something miles on it

The motor has been pressure and litmus tested and passed both those okay

One place we took it to down the street from us said there was no leak but then another place said there was. The coolant looked okay when we last checked it.

We also heard that the 4.2 engine has a reputation for bad head bolts and there was a recall

Its just weird. The vehicle drives just fine, but I know that whatever is wrong needs to be fixed before it causes further damage, and no one wants my mom driving her truck taking a chance at it breaking down on the highway.

transmaster

Ditto, I had a Dodge truck with the excellent 225 slant 6 with a blown head gasket sweet small and steam. The knocking can be made by the coolant causing a hydrostatic lock in the cylinders. Look for gray goo at the bottom of the crank case, and in the valve covers. I am surprised your mechanics didn't pick up on this.

Mister Mitch

Sega_Sonic,

did you find out what was wrong with the engine?

When you said the exhaust has a sweet smell to it, I also thought that there is a problem with the head gasket, or worst, a cracked header, or worst yet, a cracked block.

If you have white exhaust and it ain't cold out, it could indicate that your head gasket has shrunk and is allowing small amounts of coolant into the cylinders. You said it was mostly during start up, right? Then it tends to go away? You said that the truck seems to run fine otherwise.

Did you check the oil? Is it milky? I hope it ain't. Much $$$ to fix.

Did you check to see if the headers were torqued down properly?

Keep us posted.

Mitch

transmaster

When you have a blown head gasket is one of the few times a flat head engine is cool. Had a flat head Ford V8 years ago, what a sweet sounding engine. It was so easy to pop off the heads on it.

rootsbrd59

the 4.2 ford had a intake problem, would leak water into i think #3 cyl.

DJsF150-4X4

It sounds like a cracked head vs. blown head gasket. A cracked head can be microscopic in nature, thus your internal preasure will look OK, but steam is escaping into the engine. The head can be x-rayed to find the crack.