Heat and air weak at idle - 2004 Volvo XC90

crw4bama · Post by **crw4bama** » 18 Dec 2017, 09:21

My 2004 Volvo XC90 t6 the heat and air blows fine whe at consistent speed however when idling or just getting going it bogs down and doesn’t have the same strength

Post by **jvl** » 18 Dec 2017, 09:28

Does the blower itself bog down (blows air at same temp but not as powerful?)
Or is the blower consistent and does the temp lerature vary?

The first would indicate electrical trouble that arises at lower voltages (lower revs --> less alternator output). Could be a bad ground or corroded connection. Or dirty/faulty switch.

The latter would indicate a problem with coolant flow: thermostat stuck open, failing water pump, clogged cooling channels.

How is overall performance? Does the engine get up to temperature? How's the coolant level?

Post by **oragex** » 18 Dec 2017, 09:31

I would also think first electricals. Maybe check the controller on the blower

Post by **jimmy57** » 18 Dec 2017, 11:23

cabin filter plugged?

crw4bama · Post by **crw4bama** » 18 Dec 2017, 12:00

Same temp blowing but does idle rough has error code low air flow circuit

crw4bama · Post by **crw4bama** » 18 Dec 2017, 12:06

jvl wrote: 18 Dec 2017, 09:28 Does the blower itself bog down (blows air at same temp but not as powerful?)
Or is the blower consistent and does the temp lerature vary?

The first would indicate electrical trouble that arises at lower voltages (lower revs --> less alternator output). Could be a bad ground or corroded connection. Or dirty/faulty switch.

The latter would indicate a problem with coolant flow: thermostat stuck open, failing water pump, clogged cooling channels.

How is overall performance? Does the engine get up to temperature? How's the coolant level?

crw4bama · Post by **crw4bama** » 18 Dec 2017, 12:08

Bogs down when rpm drops I do have check engine light on and it low airflow circuit a

Post by **ggleavitt** » 18 Dec 2017, 12:39

Original battery? If not, how old is it? (With Volvo part marked batteries, sometime you'll see the manufacture date in YYWW stamped on one of the terminals). My vote is on battery and/or alternator regulator until both can be omitted as causatives.

Post by **cn90** » 18 Dec 2017, 16:51

Tstat and heater core are the usual culprits. I posted some DIYs in forum.

Post by **oragex** » 22 Dec 2017, 02:56

Maybe the alternator doesn't charge well. I'd test the voltage at the alternator and battery. 8'd also check all pulleys on the serpentine belt for turning smoothly by hand with the belt off. Also the timing belt tensioner should not shake and it's needle should be correctly positioned