Hi guys, need a little help..I recently had to start driving a '00 that's been sitting in my driveway for about a year. Everything was fine for a few days, then noticed the temp gauge drop to about 180 while driving, also lost cabin heat. Checked coolant level, it's fine. Flushed cooling system, flushed heater core, good flow out of out both ways, changed thermostat even though it was new. Same results.

If I let it idle it will climb to 210, but still no heat. Upper and lower rad. Hoses are hot, heater core hoses are not, so no flow...but why?? Rad. cap also not hot to the touch, but again level checks fine. What am I missing?

 

Could be a weak/bad water pump........or maybe the flapper door under the dash in the heater box not moving.

 

^^ This is what I would start with.^^

 

Water pump, radiator, hoses etc are all brand new...will check on the flapper door

 

jlk hi if that doesnt work you will have to forward and back flush 6 times like i had to it took me bloody ages hun,had to attach a foot pump to hose to help me get presure to push crap through,couldnt believe how much came out.hope this helps

 

Thermostat. When they fail, they usually fail in the open position which is the same as not having a t-stat at all, which means the engine takes much, much, much longer to heat up.

 

If you read the first post he already said that he has changed it.

If you are not getting any heat conducting off of the coolant hoses to your heater box I would double check to insure that you are getting sufficiant flow. As in fast enough that the box doesnt cool it down to much before it comes back out.
You also didnt say where you got the water pump from but have personally had bad experiances with having to pull of and replace brand new water pumps before i even get a chance to test drive the vehicle. So I would check the pump next. Good luck. Its starting to get cold.

 

Can I even get to the blend door without pulling the whole dash?

 

Make sure the valve on the heater hoses are working properly with the heat switch in the cab... I have no thermostat right now ans it runs about 140 or so... 180 is fine... 210 is fine... Your not getting water to your heater core when your dash ia asking for it...

 

There is no heater control valve on '97 up. Operating without a t-stat in a OBD-II motor is likely to set a CEL.

 

There has to be something somewhere then... Thats acts the same way... Cant blow AC through a heater....

 

I agree, OP says good flow thru heater core and new water pump but heater hoses are not hot......sounds strange.

 

It's controlled with the bled door.

 

So, do I have to pull the dash?

 

Before u dig into the dash, r u positive the water pump is spinning counter-clockwise, there is a "R" stamped on the pump impeller, flushing thru the heater core yields good flow, coolant level remains in the top of the rad (motor cold) but heater hoses r not hot?