The heater core is inside the dash, so that coolant is coming from somewhere else. It is still possible that your heater core has a pin hole leak. The heater core is not difficult to change but it is very time consuming, basically the entire dash has to come out.

It could be a heater hose, the heater core IN and OUT go through the firewall on the passenger side. I would also check for coolant on top of the engine under the intake manifold. There is a heater pipe under the intake that connects to the back of the water pump. When it leaks, coolant will pool up on top of the engine until it overflows off the back passenger side of the engine. Passenger side is a little lower so it always overflows off that side.

There is no factory cabin air filter in your truck, 97-03 F150's didn't come with one but it is possible to install one.

 

ok, good to know about the cabin air filter, I had seen online that one was available, but needed some kit to be installed.

I watched a couple of videos of the dash removal, oh joy.

I will start looking at the firewall area, but that whole area is tucked way back up in there, DOH!

Just going to order the heater core, and the special tool for the quick releases things.

can you point me to a picture of this area, as I am not sure of it's exact location, and don't want to start tearing into things blindly

I hope I didn't screw something up when I installed my Spectre CAI, that thing was a pain in the butt....

Maybe I need to jsut leave my vehicles stock

 

Scroll down to jbrew's post

https://www.f150forum.com/f6/coolant...stions-344101/

Here is what I used for info when I did my heater core.

https://docs.google.com/document/d/1...sBaH8IdJ0/edit

 

ok, so is it possible that it isn't my heater core at all?

here is what I found, there is a hose that comes straight up off the front of the motor that goes back to the firewall for the core, and that hose is fine, the one to it's left, that goes down, I can't see.

there is a big void below the upper half of the motor, behind the fan clutch area, and that appears to be wet, has what looks to be oil and coolant in it.

the oil level of the truck is ok though, and so is the coolant level, so not sure?

I think I have that valley issue thing that one of the threads I read about has.... great, so the top end needs to come off. If I take it to a shop, what is an acceptable price for it? Anyone local to Fremont, CA want to come over for a wrench session? I have tools, and can buy you beer and food

this may be my issue? I think it is.... but how can I confirm for sure?



not trying to spend tons of $.... but should I get a new intake at this point? the guy in the video said dorman, but I heard dorman was just good enough to get by... I want to keep this truck as long as possible

 

It is possible that your heater core is fine but from the symptoms you described in your first post it could have a pin hole leak.

I would tackle the leak you have under the hood first, refill with distilled water, then determine if you need a new heater core. I wouldn't add new coolant until I was sure there is no more leaks.

On my truck the location of the leak was obvious because the valley was full of coolant and I could see it leaking with the engine running.

Rent a cooling system pressure tester from a parts store if you are unsure where the leak is coming from, that way you don't waste time/money.

I think Dorman is the only company who makes a replacement intake for your truck. I wouldn't buy a new intake unless you actually need it.

 

really can't see anything other than the puddle in the valley and the puddle o nthe floor... this engine is way up there, and tucked halfway into the firewall.

I did pick up an endoscope, so I might try to dig around with that. it was like $8 and attaches to my cell phone.

would this tester be fine?

just hook it up, pressurize it to what? and try to see where it is leaking from?

 

is this tester sufficient?

https://www.harborfreight.com/radiat...kit-63862.html

to what pressure? I think the thermostat opens @ 16 psi if that matters

I really can't see anything other than the pool of coolant and some oil in the valley under the intake. I don't have coolant in my oil, or oil in my coolant. I am not losing any oil. the motor is half sunk into the firewall and up pretty high, I have 35s on it.

Going to try and pick up a step stool too, haha

I did pick up a waterproof endoscope attachment I can use on my phone, it was $8 from tmart. it's clarity isn't the greatest, but it may be sufficient

 

So trying to get a little further with this, but it's slow going.

picked up a radiator pressure test kit today

 

You probably could have rented a kit for free from an auto parts store but owning specialty tools is never a bad thing.

If you have a decent size leak, it should be easy to find with just a little pressure. The cooling system cap should have the max pressure on it, don't go higher than that number.

 

the auto parts stores around here make you pay full retail for the rental, and refund you when you bring it back (you have 30 days, if you don't return it, you just bought it)... it was <$80 so I wasn't tripping too much.... and who knows when I am going to get to work on this thing. I work about 60 hours a week, spanning 5-6 days usually.... really hectic, and random schedule.

 

so....... going to try and look @ this thing this weekend.....

is there any place in particular that it would be super obvious once I set up the tester?

what psi should I test it to? I think the radiator cap is 16 psi, so less than that?

I really can't see anything other than right behind the alternator... the back of the engine at the firewall area really can't be seen by me... I mean it is very tucked up in there.....

 

Just don't go over the max psi listed on the cap, too much pressure can damage the cooling system. It shouldn't take much pressure if the leak is bad enough.

You should be able to hear air escaping and see coolant bubbling from the leaking spot.

Use a step stool, flashlight, small mirror and poke around until you find the leak. The 5.4 is a tight fit but when your standing on a stool looking at the engine from the top down, it's not that bad.

 

pumped it up to 15 psi. didn't hear any bubbling no noises, nor could I see anything. Looked around with an 800 lumen flashlight. under the truck was dry, and no wet spots on the firewall like in my pictures above.

 

Watch the pressure reading over time and see if it drops.

 

Had it on about 15 minutes and didn't see a change.

I am going for a drive right now. Local errands. Maybe once it's flowing....