07 xc70 no cabin heat or a/c

dcmike · Post by **dcmike** » 09 Dec 2023, 08:26

I purchased a 07xc70 over the summer. When winter came the heat did not work. This summer the a/c did work as it should have.

The two hoses that go through the firewall, for the heater core, are both hot but do not feel like fluid is circulating through them. Is their a valve on the heater core that is not opening?

The other things i have noticed is the the engine cooling fan comes on as soon as the engine is started and constantly runs until the car is turned off. Also the coolant reservoir never gets hot when the the temp guage is at 12 o'clock. The upper hose never gets soft. I m thinking that the thermostat needs to be replaced.

My son drives the car daily but its for a 10 minute trip to work. He really does not drive far so maybe he car does not come up to temp.

Any help would be great.

Post by **abscate** » 09 Dec 2023, 08:46

10 minutes driving will get a P2 Volvo engine hot, definitely sounds like the thermostat has pooped out. Not a bad job but use OEM Volvo or Wahle

Post by **erikv11** » 09 Dec 2023, 09:12

Also: the coolant is always circulating through the core in these cars, there is no valve. And I’d replace both the thermostat and the ECT, not do a thermostat-only job.

dcmike · Post by **dcmike** » 09 Dec 2023, 09:21

We replaced the thermostat and housing, purchased one from NAPA. The fan still runs when the car is started but the reservoir is circulating and increasing in temperature. Still no heat in the cabin from the vents. Both the hoses are nice and hot when the car is up to temp .

I will look at the cabin air filter also. I was really hoping that the thermostat would fix the problem. Only thing left would be the heater core, correcrt?

Any ideas on why the fan constantly runs? Or is this normal? I have read that their is not a relay or module for the P2s for the fan.

Post by **jonesg** » 09 Dec 2023, 15:59

did you change the coolant temp sensor next to the thermostat?
that will cause the elec engine fans to run constantly if bad.

with the cooling fan blowing at this time of yr in your state i wouldn't expect the coolant to go above 140F.
and that isn't gonna give much heat.
vida or even a $12 elm327 widget will give you the realtime coolant temperature.

dcmike · Post by **dcmike** » 09 Dec 2023, 16:38

The ECT was also replaced, it came with the housing already installed.

dcmike · Post by **dcmike** » 09 Dec 2023, 16:43

The fan comes on as soon as you start the car even if it has been sitting overnight. No matter the coolant temp the fan is on. The fan does turn off when the ignition is turned off. It does not keep running as if relay or module breaks and fails closed.

Post by **cn90** » 09 Dec 2023, 16:58

It is very rare to see a bad actuator motor, but the way to test it is:
- Turn off all noises, radio off etc.
- Close the door.
- Key turned to position II, no need to crank engine.
- Now cycle the temp dial from COLD to HOT, the arm (the linkage arm that controls the flap)
should move and you can hear the noise. Or better yet, get down on your knees and look for
the linkage arm movement.

- During the heater core replacement (might have been replaced previously), it is very common
for the linkage arm to be knocked off. Info in forum. The electrical motor that drives the linkage
arm: it rarely goes bad.

dcmike · Post by **dcmike** » 09 Dec 2023, 17:07

I will check this tomorrow.

Post by **jonesg** » 10 Dec 2023, 02:24

dcmike wrote: ↑09 Dec 2023, 17:07 I will check this tomorrow.

before doing surgery under the dash...

unplug the engine cooling fan, start the engine, drive around , do you get heat now ?