I am sure there is a post already similar to this but I couldn't find it.
I have a 2001 F-150 XLT and started it up the other day and started gettingthe smell of coolant in the cabin. I have read a couple of threads and saw people had issue with coolant on the passenger side floor which indicates a bad heater core. I do not have that problem. I have pressurised the system and it does not bleed down. I can not find any leaks under pressure and it doesn't appear that the coolant level is going down.
Suggest that if you're getting a coolant smell - there's almost got to be a leak somewheres. A smell in the cabin is almost always the heater core, or its inlet or outlet tubing. It doesn't take much of a leak to get the smell. Perhaps the leak has not progressed to the point to be noticeable in the overflow tank level.
Perhaps something odd is going on - such as you've got a hairline crack in the heater core that won't open up until it's hot?? As things cool off, the crack seals back up. Or the leak may have still been there when you pressurized it - it just wasn't bad enough (yet) to be seen.
Another sign of a heater core leak is that the inside of the windshield will begin to develop a film or haze on it - from the air going to the defroster.
The leak could be in the engine compartment - may want to give the engine a good look-see for any trails, puddles on the manifold, weeping out the water pump, etc.
The different engines looked the same, but you can go and change them to make sure. I suggest getting a haynes or chiltons to help you out. As for where and price?? Dunno but I am sure someone will chime in.
Heater core replacement can be a finger snap or an all day sucker. Suggest looking at a manual for your year, make and model. Not to mention color, size of tires, trailer tow package (or not), bumper hitch, moon roof or what ever.
I called around a couple places and it is going to cost about $500 in labor alone. One place said it cannot be done without removing the dash. Is that a fact? I am willing to try if it is possible, for $500.
Don't have the book to tell me different so if it says so then believe it. If this was an early to mid eighties mustang. Remove floor shift console cover, block wheels and put shifter in low, all the way back. Seats full back, remove instrument cluster, unfasten steering column from dash and lower to rest on front seat. Remove screws securing dash to firewall below windshield, (1" stubby screwdriver), remove side kick panels for access to lower panel bolts. Should be it, lower inst panel to floor. It was not necessary to undo any wiring stuff. In engine compartment, drain freon, remove AC lines, drain coolant, remove heater hoses, undo 4 bolts securing AC Plenium chamber to firewall. Pull same back and lift out over instrument panel, there you go. Three or four screws to remove core from plenium. Easy, nuts and a hole bunch of bolts. Time for a beer or two. In reviewing what said forgot the heater control cables, you will have vacuum lines. Just conferred with my Miller lite service manual, and it suggests to keep all fasteners in groupings according to task. Like the floor shifter console for example, keep those screws by themselves so as to not get mixed up with the instrument cluster screws. Get the picture.