Engine overheat and cool air -thermostat?

Yesterday coming home from work in -10 C, a 26 km drive,
I was getting just cold air through the heater. I was watching the temp
guage all the way home and as I got near my home about 20 minutes in,
the temp guage on my pickup was at the red line.
Once parked in driveway, I noticed the rad pushingbubbling fluid into the overflow and could smell hot antifreeze.
I have noticed the past few weeks that the temp guage has been rising but then would suddenly start to go down esp. if I turned on the heater and it seemed unusual at the time so I have been watching it. --yesterday was the first time, it did not go down. I went for a little drive later that evening and this time, the temp rose even faster -7 minute drive to move temp guage close to red and still no heat from heater.
I assumed/read that you would have one or the other, that is, engine overheats so thermostat is stuck in closed position No heat in car so thermostat is stuck in open position.
I seem to have both scenerio's going on.
Any thoughts -is it even the thermostat? if so, I know the thermostat is relatively inexpensive? should I buy 3rd party or from dealer and finally, how long/shop time to replace one (I am assuming one hour or so) and is it worth trying to do it myself?
many thanks in advance
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snipped-for-privacy@yahoo.com wrote in
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If you have no heat, there's no coolant flow.

Sounds very much like it.
Secondarily, it could be a bad head gasket causing low coolant level. Check the rad level when the engine is cold. Is there air in there? Reservoir level high?

Dealer ONLY. NEVER buy an aftermarket thermostat. There are some good aftermarket 'stats out there, but it's crapshoot to find the good ones.
OEM is about $20. OEM is the best.

If you've never done one before, get the Helm manual for your car www.helminc.com and plan on at *least* three hours.
And get some Honda Premix antifreeze while you're at the dealer.
--
TeGGeR®

The Unofficial Honda/Acura FAQ
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