It's -35 Celsius here this morning, and it's got me thinking about block heaters again. My 96 855 Turbo doesn't have one, but I park it in my garage at night, where the temp is about +8 C, so it's not a problem. It's when it sits outside at work in this weather. I've heard that the Volvo heater is very pricey and doesn't work that well. I remember years ago there was an in-line heater available that went on the heater hose (return line??) and it had a small pump that circulated the coolant to keep the block warm. They worked quite well, but I'm not sure if they are still available. Anybody know? Or am I stuck with the Volvo heater?

Many outside generators have inline heaters. The ones that I have seen sound like a coffee pot perculator. I think that coolant enters a chamber, is heated, then "pops" through a one-way valve, with new fluid entering. Each cycle takes several seconds.

We have three, two work well, and one generator has been through about two heaters a year for the last five years - go figure.
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3 8s & 2 7s 725,000 miles total

I've had the same weather here and have 2 Volvos, a '98 V70 & a '95 850, neither have block heaters but I think I'll install some this summer. Years ago I had an Isuzu (Chev. engine block) with an in-line heater, it worked just fine. I think they have a tendancy to shorten the life of the rad hose though (some thing else to keep an eye on). It's finally warming up today, a balmy -17*C!!

I noticed that Autozone sells a heater that fits in-line on either the heater hose or radiator hose. No experience with it, just noticed it behind the counter when I was purchasing something else.

Hi,
My wife has an 855T which has a block heater in it & it works just fine. It`s cold here~-31C. I don`t have any experience with the in-line heater tho` but the above works well. Pricey? I guess anything involving the dealer will be pricey: My wife just had a new thermostat installed at a cost of $135.($68. for the part) I think you can get a thermostat anywhere else for approx. $10. When will I ever learn?
Good luck!
Rich