no cabin heat

[rclapper]

Temp gauge reads 12 o'clock but no heat to the cabin. Blower work fine, trace amounts of heat detectable at vents. The car has to be parked next to a long needle pine that sheds buckets of needles and the cowl grill and water drains are exposed to them. Drains can be cleaned by hand for the most part, but I'm wondering if needles have been ingested into the heater case and are blocking damper doors. Could that happen and if so, what's the procedure to inspect?

[RickHaleParker]

Try removing the Cowl Grill and Rain cap, see if you can get a peek into the climate unit.

[rclapper]

Looks like plastic pins and a couple of metal clips at the bottom and a plastic channel at the base of the wind screen. The wiper posts go through as well. Is there more than that securing the grill/cap?

Thanks Rick

[cn90]

If you have more than 100K miles, then get new Wahler thermostat. I posted the trick in XC90 forum without the need to remove the PS Pump. Very easy if you follow the DIY. Flush the heater core too (from firewall).

PS: Re leaves, pine needles, this is a bonus: open the FRONT doors, look inside the FENDER crevice, there will be tons of leaves/debris. Get a garden hose and spray in there to flush all the crap out. You may have to sneak your hand in there (make sure your hand is small to get in there!).

Below is a video from a different Volvo, but you can see the CREVICE I am talking at time marking 3:26:

[oragex]

wondering if needles have been ingested into the heater case and are blocking damper doors. Could that happen and if so, what's the procedure to inspect?

Yes, they can, but if you hear the blower spinning at full speed, it shouldn't be a problem. Maybe have a look at the cabin air filter, how is the air flow at the vents with the blower at max ? (be it warm or cold)

As mentioned, it's time for a thermostat even with the needle at 12h (you can test it like this www.youtube.com/watch?v=sOjfjCIemVY

But if you think the airflow is too weak despite the blower's speed, I would rather look into the actuators/hinges at the climate module unit.

If however the airflow blasts as it should but it's only lukewarm, my first guess it a clogged heater core. Happens now and then from using tap water mixed with coolant. If replacing it, use only Behr as other brands won't give really hot air (Behr is genuine and has more fins). The thermostat can also cause cooler coolant, but unless it's stuck wide open I wouldn't blame it in the first place - and even then the coolant will still get quite warm from the engine. But as mentioned, it is time to replace it at 10-12 years old

[richardgengle]

my heat is weak too. So i would like to test the actuators/hinges . below is the image of the
blower vent opened up. Under the big white wheel, behind the long rod bottom, is where there would have been a rod that opens up the
flow from the blower thru the evaporator in the back, to go thu the heater core. it must be the lower of the 3 controls, no? but it looks like that rod would not have connected there, the servo that was there just runs a rod up top... .



have u seen a description of the theory of operation of the heater core ducts actuators and hinges?

Also, it would be nice to see a video of how much flo normally goes thru the heater core out the output hose, as mine seems lower than i would suspect

[cn90]

All the tricks, brand of heater core, linkage arm (Volvo PN 9171544) are in the thread below that I wrote a few yrs ago...

DIY: 2005 XC90 Heater Core Replacement

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