My 2001 5.4 is leaking coolant at the thermostat crossover housing on the driver front right side into the #5 plug well. It seems to be seeping between the intake manifold & the gasket.

I have read a few posts & looks like the best option is to replace the intake manifold & necessary gaskets.

What is the best intake manifold to get? I have read the 1999 all aluminum will fit & is the best route to go? Is this true?

What do y'all think!? Opinions please if you've experienced this.

Thanks in advance!!!
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I believe in 2002 or 2003 they revised the composite manifold and dont have issues with leaking. Otherwise, 99 was the only year of aluminum PI manifolds.

 

if you go with the plastic one as far as i know the only choice is the doorman part. ford doesn't make it any more as far as I can tell.. Rock auto carrys it.

 

just took intake off 2000 lariat 5.4 for coolant leak. found a metal disc a little larger than a quarter with a dimple in the middle laying on the block underr where the intake sets. any ideas?? maybe a factory plug of some sort??
also- what is the very small flexible line that goes into the block under the intake. does it carry oil? if so, is it prone to leak? seemed like there was soem oil on the top of the block when i got the intake off.

all the coil boots on right side were coolant soaked. should i replace the boots. coils are not that old.
thanks in advance from a frustrated ford ower. it would be a great truck if it would quit eating coils etc.

 

All on the right? I'd be concerned about the heater hoses in fact I'd definitely replace them. The line at the bottom of the valley is the heater core line runs out of the back of the water pump. The o-rings fail you should replace them. You can also take heater hose and slide it over the connection and clamp it with worm clamps. Might have oil leaking from a head gasket but it usually leaks out of the passenger side down on the starter. Could just be spilt oil to.

 

I removed the intake manifold & there is a little corrosion where it was leaking....There was quite a bit of oil/antifreeze under the manifold in that well area under it....

I noticed that jbrew had a rubber hose with hose clamps on his? Is that where the oil could be coming from?

What yall think??

 

I did my intake on 2000 f150 about three weeks ago, it was actually pretty easy, I did a price match with advanced auto parts phone sells and rock auto, the upside to this is the free shipping from advanced that rock auto didn't have three weeks ago.

I tried my best to find a 99 alum intake to no avail. If you can find one I would do it..

I took the time to change the plugs while i was there..

I noticed a great increase in power gains since the plug/intake swap. Before I could not pull a hill in cruise without it dropping a gear, now it pulls large hills in 4th with no sign of dropping.

 

Again that line at the bottom of the valley is a water line. If you have oil it can only come from spilling it or a bad head gasket. valve covers dont generally leak that way. The line at the bottom of the valley runs out the back of the block and supplies the heater core.

 

been doing a little more digging. the very small line seems to be an electric line. it goes to a connector at the rear of the engine. there was so much dirt and gunk etc down in the valley i couldn't tell what it was.

also been driving the truck a lot and experimenting.
when i am going 60 mph and go to wot it goes up to 3500 rpom and just stays there. if i let up enough for it to shift it begins to accelerate on up to 85 with no problem and goes into lockup (converter ) when i ease up on throttle more. all seems normal unless i put it on the floor in high gear, it accelerates at wot from a stop good ,
it has a new aftermarket tpos on it and same as the old one. pulled a small trailer this morning and no change .

it will go fater than 85mph, i just stopped at that speed. it was still accelerating and with the trailer on it.
cleaned mass air flow sensor , new fulke filters, plugs aren't that old, new tps, new intake, new coils, and no check engine light,
could it be a bad new tps??
any help appreciated.
thanks