03 V40 Struggling to get up to temperature fully

[Fabi05]

I haven't had time to change the thermostat yet but before buying one I decided to plug into the OBD port using a basic obd app to get a somewhat reliable temperature on my morning commute to London.

It took about 3 minutes from start up to 50c, another 3 from 50 to 60c and from 60 it gradually went up to high 60s (did not reach 70) until I pulled over at a service station in London and sat idling for 2 minutes (this was about 35 minutes of driving average 70mph and another 30mins at around 50mph.)

The demister was on, but I noticed the reading for the operating temperature was 80c. Is the OBD/app wrong or is that a normal temp? I was under the impression it would be 90c as thermostats I've seen that supposedly fit my car open at 90.

Can anyone confirm if the thermostat im supposed to replace it with is supposed to open at 90? Dont want the risk replace overcooling with overheating 😅

I recorded the app and made a video to keep track of time stamps; if anyone is interested ill add it below.

https://youtu.be/3IxESxwrJN4?si=4KBAUGDSBfzR7WtB

[lynns hubby]

I do not know what the temp spec is on the new stat you need to fit is. If you go to a factors with your reg they will be able to advise or get a genuine Volvo stat. To be honest, if it were me, I would go Volvo, may cost a bit more but at least you know it will be the correct one for your engine.
You can get genuine Volvo stuff on Ebay now at reasonable prices if you search GENUINE.
The times you give above does look like your stat is stuck open to me.

[canis]

Yeah, as above, it sounds like the thermostat. Mine did slightly the same, but in cold weather.

While driving in the winter the heater just didn't work. When I'd finally put all the clues together, on one snowy journey I had to stop a couple of times to let the engine warm up enough to heat the cabin. The reason was the rush of air over the radiator was sufficient on it's own to cool the engine to such an extent. Which was a suprise, but there it is. The thermostat was stuck open, so the engine was never getting properly warm because the radiator wasn't being bypassed. I just bought a thermostat from a motor factors.

It's entirely possible your thermostat is stuck half-way. That might explain your 50-60+ readings. Aware that the FAN MIGHT START, how does the radiator feel? And it's hoses? Be aware that the air-conditioning fan will cool the radiator, if it's a seperate one, so if you're using that you'll be affecting your result.

Penetrating oil can't hurt, but overdoing it can. It harbours dirt, therefore moisture, therefore corrosion. It can also make tools more slippery. I'm not talking safety here, it means they get less purchase on the thing you're trying to move.

EDIT: Oh, I meant to say... flushing. Yeah, do it. Tap water is fine, you're not leaving it in there. Take the radiator out, attach a hose to one end (of the engine) and flush it out. Do the same in reverse too. You can do the same with the radiator, both directions, but over a drain or something. Which brings me to a very important point:

DRAIN IT FIRST! Volvo make this very easy, there's a tap on the radiator, use that to drain all the coolant out into the wife's washing up bowl. Use a funnel to put it into old coke bottles. Do the same when you disconnect the hoses, really, try to catch as much as you can. It's not what you think! It tastes sweet, you see? And animals love it. Nobody cares about the weeds between the slabs, true. But when you poison your own cat...

You can flush water onto the ground, but catch the coolant. The first couple of flushes are best caught and drained manually.

Torx - hate them! I hate them!

While we're here, the gasket on the thermostat housing is one of my favourite bits of volvo design. It is so beautiful, and like all machines, only properly appreciated when in bits. While you're in there, take the time to appreciate how beautifully the two pieces marry, and how they squash the rubber seal without pinching it. Gorgeous!