Heating Problem!?

[spookykl]

Hi,

I have a 91 Jeep Cherokee I6, 4.0L. I live in Toronto, Ontario Canada

On warmer days, when I turn on my heater, I can feel the heat coming out and it can get quite hot...in no time.

On colder days (-5C or -10,-15 etc)....even when I crank up my heater to the max, I can barely feel any heat at all! (that's also after 20-30min of driving, including highway/freeway driving). The heat is either @ min...very min..or it's like cold air coming out....

What's wrong!? =\

[Jeepme]

How's your thermostat? Should be a 195 deg. F. I'd check it first before I would suspect anything wrong with the heater.

[spookykl]

I have swapped my thermostat to a lower rated one over the summer, due to overheating problems...

is this why!? damn..which means i'll have to bust out the pan/tools to take change the thermostat? friggin'!

[Jeepme]

You could try the old standby- a piece of cardboard in front of part of the radiator. See if the heat works better. Blocking off part of the radiator will make it run hotter suppling hotter water to the heater. If you get more heat, you know it has to be the thermostat.

[spookykl]

Originally Posted by Jeepme

You could try the old standby- a piece of cardboard in front of part of the radiator. See if the heat works better. Blocking off part of the radiator will make it run hotter suppling hotter water to the heater. If you get more heat, you know it has to be the thermostat.

you mean place a cardboard in between the grille and the radiator?

[Jeepme]

Yes. Put it against the outside of the radiator behind the grill. Block some of the air flow through the radiator. Don't cover it all, just half to begain with. Watch the engine temp and if it gets too hot, cover a smaller area. You should see the engine temp go up and if the heat from the heater comes out hotter, you will know that you need to put in the correct thermostat. Or at least change the cardboard for a fresh piece as it ages.

[glennco1]

Yep, in northern MN, the cardboard trick is used pretty regularly to get the temp high enough. Works great.