1998 Ford F150 Heater Core And Evaporator Core Replacement – Additional Help And Information

F150 Headlight Switch Removal And A/C Evaporator Specifics

When you keep a vehicle for 15 years and over 250,000 miles you can expect a heater core replacement with a commensurate evaporator core replacement (or vice versa) will have to be done. It’s unfortunate that Ford F150 engineers could not come up with a better way to do that than removing the entire dash in an 8 – 16 hour job, depending.

The YouTube channel RealFixesRealFast has a 3 part series replacing the heater core on an F150 very similar to mine that was extremely helpful. Unfortunately, there is always more to know and his videos left some important points not covered (you just can’t do it all when trying to make how-to videos!).

In fact, I even commented that he almost makes it look TOO easy to the point that some folks might attempt what they are better off to leave alone. And remember, once you get it all torn apart and cannot finish it yourself your two choices are to hire a mechanic to come to your place or have it towed to a shop – it’s not exactly drivable.

Two of the more glaring omissions for me (noted, though, his video was on heater core only, so that resolves 1 of the 2 in a way) are how to remove the headlight switch in a Ford F150 WITHOUT BREAKING IT and the ADDITIONAL STEP of loosening and pulling back the entire heater housing to get the evaporator core out (in one piece) and the new one in (without ruining it).

I guess a third omission is him not INSISTING that a person replace BOTH heater core AND evaporator core when either one goes bad. If one is old enough to go bad, so is the other, and just how often do you want to spend a day or two repairing your truck or pay $800 to have someone else tear it apart?

Video Explaining Additional Steps For F150 Evaporator Core Replacement/Tips

The Culprits, Though They Did Last A Long Time!

 

 Ford F150 Headlight Switch Removal

I am guessing that very few people, non-professional mechanics anyway, would successfully guess how to remove a Ford F150 headlight switch without breaking it. I was shown how to do it many years ago when my switch went bad and I still had to dink with it for a little bit before it came back to me.

Basically, the procedure to remove the headlight switch from the dash is (remember, the battery has already been disconnected as step one of the heater core/evaporator core replacement):

• Turn headlight switch to on
• Pull the switch out to fog light position
• Insert small screwdriver in the slot now exposed on the back of the knob to release the knob (see photo below)
• Remove knob
• Turn knob 180 degrees and put back on, turning to off position as you do so
• Turn knob right to headlight on position which retracts locking tab (see photo above)
• Remove from dash and disconnect wiring connectors
• (Remove knob – no screwdriver insertion necessary – and replace in normal direction)

So, would you have guessed that on your own or broken it and reached for the super glue?

 

Heater Housing Photo, Screw Locations

The heater box cover comes off pretty easily, but the engineers did screw us over by putting on last screw in the back against the firewall, down in a hole that you cannot see and will probably be a pain to get back in without dropping it.

This photo is a view of the heater box cover from the top. A couple of those holes in the back are for plastic alignment pins, not screws.

 

Ford F150 Evaporator Core Replacement

In the RealFixesRealFast series of videos on F150 heater core repair the tech says basically “if your problem is the evaporator core, there it is too”. Not so fast. Again, you should replace BOTH anyway!

The evaporator core WILL NOT COME OUT without loosening and sliding back the entire heater box housing. Fortunately, that’s not TOO bad of a job, just complicated by some idiot Ford engineers who have obviously NEVER attempted this kind of repair themselves.

There are just 3 bolts/nuts that need to be loosened or removed inside the truck and 2 under the hood. Unfortunately, one of the ones under the hood has a bracket over it that must be removed requiring you to climb up in the engine compartment with a 10mm deep socket, universal joint, extensions and ratchet to LOOSEN – do NOT remove – a 3rd nut so you can remove the bracket in the way of the other nut.

See the photos:

Inside the cab, 1 on the driver’s side, 2 on the passenger side.

Now let’s climb up in there with the engine.

One bracket, two nuts. Different sizes, of course! (Thanks Ford engineers).

First remove the battery, then take off the OUTSIDE nut (11mm) on the stud behind the battery. The bracket holding the A/C hose will flip out of the way. The other slotted bracket for the A/C component will not come off until you LOOSEN (no need to remove and drop or lose) the nut down behind (10mm). The other end of the bracket is also slotted and it will now come off.

Then remove the inner nut and you should be clear to go inside the cab and wiggle the heater box about 1 inch away from the firewall and now get that con-founded evaporator core out (presuming, naturally, that you have had someone remove the freon from the system – if any – and with those special tools disconnect the A/C lines (another contortionist’s job).

Parts I Bought For Repair Job

There are cheaper brands you can get, but considering how big of a job this is I was recommended to – and agreed – that genuine Ford Motorcraft parts would be a good idea.

I was disappointed, though that the heater core did NOT come with the wrap around foam. Ameriseal Part#11140 (available at NAPA) is some camper foam that should work. I’ll find out tomorrow I hope. (Edit: Yes it seemed to be fine)

The Ford dealer parts guy told me that the gasket that fits between the evaporator core and the heater box (firewall side) is no longer available from Ford. The bottom portion of mine was stuck to the core and tore off.

I removed it and silicone glued a piece I cut to fit from the camper foam into the housing in its place.

Without that gasket I have heard from several sources that it may well leak inside the cab when it rains.

 

These Parts Fit MY Truck

These are the parts I ordered to fit my truck. This is one thing I like about Amazon automotive, you tell it what vehicle you have and it will tell you if it fits or not! Make sure and get the ones that fit YOUR vehicle!

Motorcraft HC-15 Heater Core

Get the blend air door like RealFixesRealFast said (I just don’t understand why he didn’t tell viewers to always replace A/C AND heater cores for the same reason he suggested changing the blend door).

Dorman 902-207 Blend Air Door

Motorcraft YK183 New Evaporator

Problem Installing New Dorman Blend Door

Unfortunately, even after taking an exacto knife and cleaning out the hole for the steel collared Dorman blend door it would still not slide all the way down. What I found is that I had to carve a little off of the bottom “stop collar” so that it would slide all the way down into the corresponding channel in the heater box.

I’m guessing maybe I carved off about 1/8 inch from the semi-circular guide on the bottom of the blend door shaft. Basically, it’s like the guy says in the RealFixesRealFast video, if the blend door is not flush at the top, it’s not in right.

Helpful Tools I Bought

When it comes to taking out trim pieces (without scratching or breaking anything), and those fasteners that I talk about in the video, here are some tools I bought in addition to the heater hose removal tool shown in the RealFixesRealFast video 1:

For removing those heater hoses with “quick” connects, this is the tool shown in the RealFixesRealFast video: Wilmar W83108 HEATER HOSE DISCONNECT TOOL–FORD & CHRY.

Set of plastic trim fastener removal tools: 5 pc. No-Scratch Tools for Removing Fastener & Molding

Metal fastener removal tool I show in my video: Lisle 35260 Plastic Fastener Remover

Additional Resources I Found Helpful

RealFixesRealFast 3 part video series for Ford F150 Heater Core Removal: Part 1, Part 2, Part 3

Word document for 1997 heater core repair (NOT prepared by me), here

Ford F150 Forum thread on heater core repair

Ford F150 Online Forum thread on additional steps (with pics) for F150 evaporator core removal

The Wrap

I put a lot of time and effort into the video, pictures and post; I hope it helps someone. Forums are fantastic and this is one way of giving back for all the help I received from forum threads (old & new) and YouTube videos others have done.

If this did help you, could you please share it up socially? Thanks. And leave a comment too, if you like.

More Pics Of Heater Core Replacement/Evaporator Core Replacement, Interior Removed

With the dash pulled back just far enough to work on:

How About Some Pics Of My F150 With The Interior Removed?:

Here is the carpet after being cleaned with dish soap, baking soda and LOTS of WATER!:

Takes a while to dry, though, especially in ILL-inois in December: