V70 Thermostat
 

2009 V70 Mk3 2.4 D5 205

Guys
My car heater is a bit disappointing. The blower works fine but even after a 30 minute motorway drive there is no real heat even with the climate control set to high also. It's not freezing but it's no better than mildly warm. I'm guessing the thermostat is the issue. Am I right? If so, is this a simple or a tricky fix?

I'd start with the basics first...

1. Check your coolant level in the reservoir. Check that its the correct level & if not, add coolant as required. If you do add coolant, keep your eye on the reservoir regularly because if you have to add some again, you may have a leak in the system.

2. Check your cabin air filter, which is located in the footwell area/behind the centre console. If its clogged up, that may also affect your temperature inside the cabin because air can't flow through it properly.

3. The heater core/matrix could be leaking. Check the pipework at the bulkhead behind the engine to see if you can see any visible leaks.

A good way to test the thermostat is to bring the car for a short drive, say a short spin around the corner for a few minutes so it gets luke warm, not to full operating temperature though. Open the bonnet whilst the car is running after your short drive & feel the hose that is connected to the radiator. This hose shouldn't be piping hot after a short two minute drive say, it should be relatively cool to the touch if that makes sense. If the hose is really hot to the point where you take your hand away to avoid a burn, then that's an indication of a faulty thermostat because the coolant isn't being circulated properly.

The thermostat isn't really a hard job & I imagine there's plenty of videos on YouTube giving clear instructions.

How do you change the cabin air filter? Is it relatively easy to do?

It's quite easy, but on some cars you need to be a contortionist. There are you tube vids available that show you how.

Thank you Kev, your suggestions make perfect sense 👍


I found this video of the cabin filter replacement ... https://www.youtube.com/watch?v=4pUIWEPywnQ

Am I right to assume that 1 and 3 above are linked,i.e. that if there was a leak then the coolant would be leaking through the heater core/matrix?

Hi Kev

I took the car for a short drive (about 3 miles) and on my return I checked the radiator hose. It was a bit warm but not roasting. Hopefully this suggests the thermostat is fine??

There are no obvious leaks around the bulkhead and the coolant level is fine. Having said that it doesn't appear to have much of any colour in it. Could that be an issue? And if so which colour coolant would I need to use?

Many thanks for your help

The temperature of the radiator hose appears normal then, so your thermostat sounds as if its working okay. If the hose was piping hot to the point where you couldn't touch it, then I'd say your thermostat was dodgy.

It sounds to me like your coolant is old if it has no colour to it as such. My car has a green/blue coolant in the reservoir, but a Volvo specialist changed mine for me. If you're doing it yourself, nip to a dealership & buy genuine Volvo coolant. Its made for the car & then you have no issue of mixing an aftermarket brand with what's already in it.

Thanks Kev. I tested the coolant with one of those little things that has 3 floating balls in it. When I filled it all 3 balls went to the top of the tube then 1 started sinking slowly back to the bottom. This may be a stupid question ... does coolant have a potential impact on the car's heater???

The temperature inside the car heats up as the coolant heats up. Your coolant absorbs the heat of the engine, which is transferred to the heater core & then through your vents when the blower fan is on. The coolant level will definitely affect the heater, particularly if its low. Old coolant isn't much use for your car either, as your engine needs it for protection in the winter months & to stop overheating too.

I'd recommend getting your coolant flushed, particularly as you state it has no colour. That indicates that its either the wrong coolant has been used, or its old & degraded.

Great info Kev, and much appreciated.
Mu understanding is that the draining process requires 2 separate drain point: one under the radiator and one under the engine block. When these are both drained what quantity of coolant and water should be added?