Hey guys (and gals)

I have had this problem since about mid summer, and Im just now getting time to investigate it at it was not serious.

I have a sound, I dont know how to describe it, but almost like a pump sound, it lasts for 1-3 seconds and happens when I have EITHER the heater or the a/c on. it happens every few minutes, seems to be random intervals. I thought it might be the fan, but retracted that thought when I out the ignition in the "Run" (without the engin running) postion to run the fan, and the noise didnt apear. When I have the climate control to "Off" it dosnt happen at all.

I have NO leaking, nothing on the floor, no vapor on the window, and no sweet smell of coolant. So I belive my heatercore is alright, besides, it also happens when A/C is on too?

Although, I do have a light smell of mold that occurs when I engage the climate control, and lasts about 30 seconds, I believe these are unrelated problems though.

Anyone have some Insite?

 

Check your coolant level, If it has air in the system, you can hear a gurgling type sound in the heater core.
The moldy smell is from the stagnant water that isn't draining from the case, You might check the drain to make sure it isn't partially clogged.

 

Im sure iv checked the coolant, but will give it another check in the morning. I had a suspision of that to, posible air trapped in the system, but that dosnt explain why the noise happens when I have the A/C on too.

 

I believe coolant is running thru the heater core at all times.

 

Yes...the coolant is running through the heater core constantly. Even more so when the heater is on obviously, but also, more with the AC running. The engine then has a load on it, running a bit hotter, so the coolant is moving even more. Air in the system is really common but annoying. "Burping" the system would be the best first step, and of course the cheapest. Just throw your truck over your shoulder and start patting....

Remove the cap to the radiator and the resivoir and run the truck til it gets hot. As the fluid is exchanged around, you will see some bubbles rising. As you do, add more fluid first to the radiator til full, then to the resivoir if needed.

 

If you have a 2000 or newer truck the resevoir is part of the system and it automaticlly bleeds it self. as the fluid goes through the system.

Lance

 

I had thought that the colant ran through the heater core all the time, which would account for the noise.. but the thing that still has me questioned is, when I have the climate control in the off position, I dont hear anything. Regardless, I will blead the sytstem this weekend. I will let everyone know, thanks guys for your insight

 

Have you checked the temperature blend motor which controls the flap between the heater core and the evaperator, it should be on the evaporator case.

 

Racerguy said in another post that the hot coolant does go through the heater core all the time and that the blend door is what controls the heat and cold, so you are on the right track at checking the blend door.

Lance

 

Well, an update:

I did top off the colant, although it really wasnt that low below the line, and then drove it to work this morning, giving it a chance to cycle, and well, no luck. Infact, i noticed thismorning it seems to be increasing the occurance. The noise in question happens almost every 30seconds -1min, and as a result, I just turn the stereo up louder.

What is the blend motor, and can I get at it without ripping the dash apart?

 

The blend motor is a white box approximately 4" square and approximately 3/8" thick. There is also a metal lever that connects to the blend flap lever. It is located on the evaperator box. Should be able to get to it with out tearing the dash apart. I saw the same problem on a Taurus I worked on. I have not had the problem on my truck yet. I hope this helps.