I have a 99 S70 T5 with 75K miles on it. We got our first freeze down here last week and I noticed my car not putting out heat like it used to. I also noticed that the temp gage on the dash never really exceeded the 2nd mark when it usually runs right in the middle. The heat had a slight burning smell to it.

Then after go over some rail road tracks the temp gauge shot up and heat came out great.

I took it to a Jiffy Lube to get a radiator flush (which they said they couldn't do in the Volvo's sealed system) but they said it's most likely my water pump going out.

I'm hoping someone more mechanically inclined could give me some pointers here. Obviously I'll be taking it into the dealership but I like to go in somewhat knowledgeable. I got raked over the coals on the whole ECU/Throttle body problem while they had me get a bunch of service I didn't need before finially fixing the problem.

Thanks in advance.