Well, winter is back. I am having the same problem I have the past 2 winters. When its cold (25 F) the temp gauge needle pinned to RED after 5 mins driving after start, no heat produced. I restart engine, the temp. gauge is back to normal, heat is normal for the rest of the day, unless I let the car sit for long period of time outside in the cold. This topic has been covered before. Everyone seems to be pointing at thermostats housing. I wasnt able to fix it the last 2 winters. I will have some free time coming before tha extreme cold return to the NorthEast, i want to fix it. Please confirm it is the faulty thermostat housing causing this issue. I will have it fixed this upcoming weekend. Thanks.

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2002 X5 3.0 Siena Red
Premium, Cold Weather, Rear Climate Packages, 19" Wheels
Aluminum Running Boards, Clear Tail Lights, Clear Side Markers
Titanium Kidney Grills, Titanium Trunk Lid, Xenon Headlights
4.6is X5 exhausts, 35% Tint, Aluminum Pedals
2005 530I Mystic Blue
Premium Package, Sport Package, Xenon Headlights
18" Sport Wheels, 35% Tint all around
Mods to come: M-Tech Front Bumper, M5 Side Skirts, M5 Rear Bumper
Quad Exhausts, Style 172 19" Wheels