Starting the engine at -25C

[June]

Most people in Sweden who live where winter actually means winter buy the car with a engine heater installed from the factory.

Are these the coolant warming heaters? I've found a video on internet. However this device only seems to me it fastens up a little the coolant warming by heating faster the coolant once the engine fires up. The way it's installed in the middle of the hose, it doesn't seem like it will warm the entire coolant around the block unless the engine is running and the water pump is spinning ?

It would work like on a old car that blew a water pump belt. The hot water flows to the highest point pulling the cooler water behind it causing a flow. June

[Rattnalle]

Most people in Sweden who live where winter actually means winter buy the car with a engine heater installed from the factory.

Are these the coolant warming heaters? I've found a video on internet. However this device only seems to me it fastens up a little the coolant warming by heating faster the coolant once the engine fires up. The way it's installed in the middle of the hose, it doesn't seem like it will warm the entire coolant around the block unless the engine is running and the water pump is spinning ?

The Volvo OEM heater for P2 and P80-models is like a clothes iron stuck onto the side of the oil pan - not very good although it does make the engine go hot a little earlier when you start driving.

There are lots of aftermarket heaters which are a heat coil in a piece of tubing that is inserted in the coolant loop. It's true that while they don't mechanically move the water around the heat itself will cause some movement and the heat will generally rise into the top of the engine. It doesn't get very hot since most are only 500 W or so but even lukewarm is an improvement over -20. The oil will often still be cold but when the oil hits the warm oil channels in the top it'll warm up quite quickly. The thermal mass of the top and the coolant together is much larger than that of the oil making it more effective than warming the oil which will get cold again when it hits the top.

Quite a few people also instead a battery charger and/or an electric cabin heater in parallel with these electric warmers. Calix who make the OEM heater in the video have a large range of accessories with compatible plugs.

The latest of these after market heaters combine stronger heating elements of up to 2000 W with a small pump.

Then there are the fuel operated heaters which often have a rated power of 3-4000 W. They also move the water around in some way else the power would just boil the water locally. With these you can in most circumstances have heat in the cabin and an engine halfway warm within 15-30 min depending on temperature.