When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Ive been searching for a solution for abiut 3 weeks now and i cant find one. My problem is about a month ago i noticed my temp gauge was going dwn then back to normal while i was driving (flat ground and criuse set at 60) it never went up it only went dwn. So i decided i was gunna replace my thermostat. It fixed the problem. After that the weather was nice out and i didnt have to use my heater, then the cold came about the same day i was driving from mich to NC so the whole trip(about 15 hrs) to nc my heat would blow hot for about 1 min then cold for about 2.5 min and it did it the whole way there and back. Andi cant figure out why. I put a brand new heater core in it and another new thermostat. Itll blow warm and somtimes hot when the out side temp is in the 20s but below that itswitches from warm to cold. I got EGR delete and head studs, i did a head gasket test and it passed. I have new clue what it could be. Any help would be greatly appreciated
There is a vacuum powered valve that controls coolant to the heater core just behind the oil fill neck in the engine compartment, sitting on top of the passenger side head. It is on the heater hose that runs from water pump to the heater core! There is a small 1/8" grey poly-tube with a black rubber connector going into the front of the small black plastic valve and pulls off quite easily. Mine had a small crack in the rubber connector and did the same thing to me, it kept losing vacuum which closes the valve shutting off heated coolant to your heater core. If you have manual temp control there is no heater valve.
There is a vacuum powered valve that controls coolant to the heater core just behind the oil fill neck in the engine compartment, sitting on top of the passenger side head. It is on the heater hose that runs from water pump to the heater core! There is a small 1/8" grey poly-tube with a black rubber connector going into the front of the small black plastic valve and pulls off quite easily. Mine had a small crack in the rubber connector and did the same thing to me, it kept losing vacuum which closes the valve shutting off heated coolant to your heater core. If you have manual temp control there is no heater valve.
I dont have anything on the hoses that go into the heater core. Do you have any pics or is there a way i can add some to show you what im looking at??
When you go to that YouTube link, there are a bunch of other videos with more of the same issues you can check out. You should be able to find something related. If not, let me know and I'll give you my email address to send pics to so I can see what you've got.
When you go to that YouTube link, there are a bunch of other videos with more of the same issues you can check out. You should be able to find something related. If not, let me know and I'll give you my email address to send pics to do I can see what you've got.
We need make, model, trim level and type of heater controls? Do you have an XLT or below with the he manual controls, or do you have the automatic HVAC with temp settings and automatic mode? Really need this to help, because it's either this hot water valve under the hood, or simply the vacuum line off or it's something more related to your water pump or the thermostat....