Where's my heat?

My 2001 Honda Odyssey used to warm up on cold days after about 5 to 7 minutes of driving. Now it doesn’t heat up at all, even after 30 minutes. Except that sometimes it decides it will, usually after I’ve parked it and restarted it later. What could this be about? Can I fix it myself?

First check your coolant level. If it’s low, you’ll need to refill it through the radiator fil hole and get it to a shop for a cooling system pressure check, to see of you can locate the leak.

If the level is good, your thermostat may be sticking, and may at this point be stuck open.

My money is on the thermostat, because of the “sometimes it decides it will, usually after I’ve parked it and restarted it later” comment. That erratic behavior would not be uncommon of a sticking T-stat.

OK. Thanks!

Are you going by the temperature gauge on your dash or by the amount of heat that comes out of your heater? (Or both?)

By the air that comes out of the vents (I don’t have a temperature guage on my dash) and it’s either dead cold or, if I’m lucky, working fine.