Having troubles with my 1997 Ford F-150 with a 4.6l in it. Never had a problem with the truck, then woke up one morning with check engine light on. Well I ran the code and it was a cylinder 4 misfire. Replaced plugs there seemed to be coolant on the number 4 plug. Well I reset code and two days later it pops back up. Also, my heat gauge was heating up, well I went and loosened up the reservior and heat gauge dropped instantly. Anyone have an idea of what could be wrong?

 

Check the heater lines, they hang above the number 4 cylinder and were common to leak. Sometimes the leak is not completely noticeable until it is at operating temps or what not. But that should be where it's coming from. Fix the leak. Not sure what is going on with your heat gauge heating up and going back after you release the res cap. Could be the thermostat is hanging up.

 

Also I put a tester on my coolant system and pumped it up to 16psi. Left it for 5-10 minutes and never dropped any. Don't know if this helps any...

 

sounds like the no 4 piston could have some water leaking under the head gasket. would not think the engine light would come on if it was external like a heater hose.

 

The heater hose is the only way antifreeze can get in that hole=its leaking. It can hold pressure for quite awhile when its only a pin hole leak and it may only leak when the engines hot. the head gasket is not something in this engine design that could cause plus failure like that. its the heater hose.

 

just wandering if i could change out a 4.6 L triton with a 4.6 L engine. i have a 1998 ford f-150 and a 2001 crown vic both with 4.6 can i swap these engines

 

yes.

 

if there is water on the plug and it is showing a code and the plug is screwed in then how can water get in the hole to the plug? or why would it throw a code into the computer? if the plug is not sealed then it would also lose compression as well if that is the case. or looks like it would to me, water on the outside should not be able to get inside the engine,unless there is a leak in the head.either way he has a problem.

 

looks like it would have to have leaked a lot of water to have caused it to heat up too.

 

jethat, could water sitting around the plug cause it to misfire? When I pulled the plug the threads and outer part looked as if there was moisture or liquid around it.

 

the antifreeze would leak down from above and yes it can (and does) cause misfires. The only sources for water are external (you washed the engine or drove through a huge puddle like that) or the heater hose and it being #4 that the hose commonly fails and causes missfires in that hole leads one to think you have a bad hose..

 

Also I just looked underneath and have water coolant leaking down from somewhere dripping off the starter. I imagine I have a leaking hose somewhere. Any possibility that it is a head gasket?

 

that could be either the head gasket or the tube that s for the heater core that runs under the intake is leaking or the heater hose is leaking pretty bad and it filled the intake valley to the point its running out the back there.. So yes the head gasket IS a possibility there..

 

May be a dumb question but if it is getting coolant around the spark plug, would it be able to get there from a leaking head gasket?

 

absolutely not.