Sign up for The Wire Newsletter!

Freightliner m2 A/C problem. Heater core all frozen/ icy

Discussion in 'Truck Talk' started by kamilski, Jun 25, 2013.

  1. kamilski

    kamilski New Recruit

    Every now and then my ac stops blowing the right way and it happens because the heater core gets all iced up and frozen and doesn't let the air to flow thru. I was wondering if anyone has experienced this and if there's any way to stop this from happening. Thanks
  2. davekc

    davekc Senior Moderator Staff Member

    That is usually from low freon. Second cause would be a bad expansion valve.
  3. BobWolf

    BobWolf Active Expediter

    You might be low on refridgerant or have a blockage. First thing you need to find out is what the specs for your truck and the ammount of refridgerant, line preasuers. After that you need a guage set to check how much freon is actualy in the system, and preasures on the high and low side both with the compressor idling and engaged. I dont recomend just adding refridgerant too litte as well as too much can destroy your systeme.

    Any aditional reading and or doing is at your own risk
    If your truck has alot of mileson it, and you have owned it for at least a few months, and you know the pressure specs, and you have the guage set, and the tools, and the knowhow you can try adding one can of refridgerant to the low presure side
    and see if this inproves things if you dont get good results take it to an AC shop.
  4. hossman2011

    hossman2011 Rookie Expediter

    I just replaced the compressor, dryer, expansion valve in my M2.. compressor was bad and leaking. Be sure to have them look at your hoses while it is apart..... Great people in the Houston area... Jordy's truck and trailer parts.. fair and fast...know what they are doing
  5. spongebox1

    spongebox1 New Recruit

    My m2 does the same thing, I just replaced the evaporator coil, condensor and it would freeze up from time to time, I took the cab filter door off and found debris blocking the drain hole, cleaned out the drain tube and seems to be working better now

    Sent from my VS910 4G using EO Forums mobile app
  6. Dynamite 1

    Dynamite 1 Moderator Staff Member

    There is also a resistor that can be bought that plugs inline in the temp probe that is in the front of the cabin filter housing that also helps with the problem. Was common when the M2's first came out. Any dealer that does expedite units should know about and have or be able to get the resistor. You can google the problem and find info on it but by all means check out everything else also.
  7. Monty

    Monty New Recruit

    Consider what is freezing ..... (that will be the humidity in the air). An occasional "thaw out" of the system by turning the a/c off for a bit can be helpful.
  8. BobWolf

    BobWolf Active Expediter

    Have you checked BOTH A/C coils Condenser behind the grille and Evap in the heat/airbox and any cabin filters. If theyre crudded up you wont have airflow and you will turn your A/C into an icemaker. Most hardware stores sell a condenser brush th clean the coils use the brush and a shop vac. You will have to disassemble the dash to get to the evap coil.

    Bob Wolf

Share This Page