Hello everyone:
I have a 2000 f-150 4.6. yesterday i changed the thermostate because it was stuck open,and i changed the oil and filter.Well to make a long story short. now it runs like crap codes PO307&308 i know these are 7&8 cyl. misfires. Also now i have a coolant leak under the intake manifold.
It ran good prior to doing these things,just didn't have much heat coming out.
Any help or suggestions would be appreciated.Also by the oil filter there is a plug unhooked it is on the same wire harness as the oil pressure sending unit.
It dosn't look like it was hooked up in a long time if ever.Were does this wire go?
THANK KEN

 

How did you know the thermostat was stuck open? Sounds like youv'e got something else going on.

 

Becuase when i pulled it out it was still stuck open.

 

Do you have plug wires or just coil packs? - I think 01 is were they got rid of the plug wires.

You must have wires because the coil packs would be in the vicinity of thermostat in that case.

Check the wires were they plug into the pack - you had to get them wet or pulled them loose.

Coolant leaks behind the water pump is a common problem. The Haynes and Chilton's manuals both show a picture of a Reman block with that fix.

All you do to fix that is modify pipe where it plugs into the back of the pump using a section of heater hose and two clamps.

Heres mine -

 

Thanks for the info and picture. My truck has coilovers/no wires.The leak seems to be farther back on the engine under the intake.Just puzzled as to why changing the thermostate and oil filter would make such a drastic change in the way it runs.It doesn't seem to run to bad idleing but as soon as you go down the road it starts cutting out and the check engine light starts flashing.

 

I don't know - Thermostat isn't even close to 7 and 8 . There is No reason for that to happen.. ? Must be a coincidence is all I can figure.

There is nothing further back to leak . That heater tube is solid and 90's up behind the passenger side head . It's bolted to the back of the head . Your heater core hose connects right there between the head and firewall . It would have to be leaking their then. You should have a puddle under the truck if that's the case and your starter would have anti-freeze on it. You might want to get under the truck with a light and look up at it for evidence of it leaking their.



See the heater core hose back by the firewall - That's where it connects to pipe. The pipe isn't in this pic. -



See the water pump stem in this pic - the o-rings are removed, but that's what leaked in my case -

 

Thanks again;
It's definitly leaking in the vally on top of the engine from some place because i can see coolant laying in there.
Do you know what the wire is thats hooked in with the oil pressure plug it also has a plug with 2 terminals but its not plugged into anything.It's by the oil filter, front lower right of engine.
I'll be diving back into it when i get off work.

 

Oil pressure sender ?

 

I would go to Autozone and get their coolant pressure tester to check for the leak. Remove the alternator for a better view under the intake. I think the thermostat and the leak are high pressure related.

 

The plug i'm talking about is is on the same harness as the one shown in your pic.A wire comes down with the oil pressure plug and the one i'm asking about.

 

Oh , I know what your talking about - That's an extra connector used for the "WABS" - 4 wheel brake steering which you don't have. I think that was on the Navigators or Expy's only. You should have just one connector thats used down on that side - It's an all "White" connector and it's a b^tch to get to

That one is just an extra in the harness for something your vehicle isn't equipped with. Don't worry about it - I would tape it up or seal it off though.

 

Is this it ? -

 

Thats sorta what i thought it was for something else.
Going home to work on truck. thanks for all the help it is greatly appreciated.

 

Heres what you need to -

You need to update your COP system on your 2000. A set on new COP's are $85

You probably need new plugs - Motorcraft ONLY.

You need to pull your intake and fix that tube - The O-Rings always go bad about now . While the intake is off , it's real simple to do the Plugs and COP's. Let us know when your about to do the plugs, theres certain precautions that should be taken..

Don't forget to purchase NEW intake gaskets along with all 3 TB, Plenum and EGR gaskets.

Clean the MAF sensor.

Do all that at the same time and it will feel like a new truck when done - lots of power and she'll be quicker..

That's where your at - Do this or your problems will most likely get worse with that old ignition system..

 

Hello again i'm back, Well iremoved the plugs and they were pretty bad.
In the previuos thread you stated that i needed to update my cop system.
You said that that a set was $85. I'm not really understanding what you are talking about as the plugs are about $40 and the coils are $60 each.Is there something i'm missing? What does updating my cop's include.
Thanks KEN