Discuss NO HEAT Troubleshooting Guide - Page 2

chaniii · #16 12-01-2011, 10:35 AM

Your troubleshooting guide looks good. I tried following it, but am now stumped. Here is the issue: I do not have heat in the cab of the truck. Following your guide, I topped off the radiator, and let the engine warm up. The temp gauge is middle normal. Seems to me that only one of the hoses to the heater core is hot, but it is not the in hose, which seems to contradict what should be happening. I verified that the hot water valve is not stuck closed, as it does close in the off and max AC settings, and is open otherwise. Both vacuum hoses are hot (I believe I am looking at the correct hoses.) I would really appreciate some additional guidance. Thanks a bunch! (I'm new to this forum/posting/thread thing, so please forgive any hiccups on my part)

chaniii · #17 12-01-2011, 11:25 AM

A little more info: 1998 Ford Ranger XLT - If I understand what I am looking at under the hood, it appears that two vacuum lines connect to the two water lines connected to the heater core. Both vacuum lines are hot, but only the water line coming from the core is hot. The input vacuum line is connected to the water line with a plastic T connector. Both the vacuum and water to that point are hot, but after that point the water line is not hot. Could it just be the T is broken/clogged?
Thanks,

FireRanger · #18 12-01-2011, 12:10 PM

Hot vacuum lines??? Does your truck have the 4-Port hot water valve or that single in-line valve down by the pump?

chaniii · #19 12-01-2011, 12:29 PM

I may not know what I am talking about, but I can try to attach a pic to show what I am describing. Will take me a little while to do it.

FireRanger · #20 12-01-2011, 01:20 PM

That would be best.

chaniii · #21 12-01-2011, 03:15 PM

I'm sorry, but for the life of me, I cannot figure out how to insert/attach the pic.

FireRanger · #22 12-01-2011, 03:39 PM

Strange, the attachment feature seems to be missing. You can e-mail them to if you want. lawrence dot matt at gmail.com

FireRanger · #23 12-01-2011, 07:28 PM

Got it. I did some art work on your picture to illustrate the water flow.

None of those are vacuum lines. Those are hot water lines to the intake manifold. One is the supply, the other is the return. The discharge from the heater core is hot because of that return line from the intake manifold. The hot water from that is going into that hose and making it hot.

Your problem is a block after the split to the intake manifold on the supply. Either the valve is jammed shut, or the heater core is clogged. If you can see the lever moving on the valve, chances are it is your heater core that is clogged.

Disconnected the hoses at those T's and try backflushing the heater core with a garden hose.

mrwolff · #24 12-08-2011, 05:15 PM

Great flow chart. My question is simple. How hot is HOT when checking the hoses going through the firewall. I think I am just feeling the heat coming from the engine.

FireRanger · #25 12-08-2011, 08:23 PM

The coolant is 180-220 degrees. That's HOT.

Bwad · #26 12-09-2011, 07:46 PM

I've got a question for you, Matt:

My heat didn't work at the start of the season, I ran it anyway. After a week or two now I have somewhat warm heat.

HOWEVER: I used your guide when I found out my heat wouldn't work and the hoses to the 4-way valve and from the valve to the firewall were both hot (with the heat blowing). So that led me to believe that it was the blend door actuator.

....but the heat works now...? And the air is still not THAT hot. Could it be a clogged heater core?

My truck is a 97 2.3L.

FireRanger · #27 12-09-2011, 07:50 PM

I would think it is the actuator if it's just been seemingly working at random.

Bwad · #28 12-09-2011, 08:31 PM

Well it works all the time now, just not really that hot.

mrwolff · #29 12-12-2011, 01:28 PM

I double checked the hoses on a 4 cyl 2.3 going to the hot water valve. The one coming up is Very hot, the other is hot but not as hot. The 2 going through the firewall are only slightly warm. I took off the vacuum hose, there is suction when control is set to AC/MAX and none on any other setting. Still blowing cold air and the firewall hoses never heated. I am thinking the valve needs to be replaced?

FireRanger · #30 12-12-2011, 02:09 PM

Quote:

Originally Posted by Bwad

Well it works all the time now, just not really that hot.

Well it should be blazing hot. If the hoses are HOT, then it is probably not opening the blend door all the way.

Quote:

Originally Posted by mrwolff

I double checked the hoses on a 4 cyl 2.3 going to the hot water valve. The one coming up is Very hot, the other is hot but not as hot. The 2 going through the firewall are only slightly warm. I took off the vacuum hose, there is suction when control is set to AC/MAX and none on any other setting. Still blowing cold air and the firewall hoses never heated. I am thinking the valve needs to be replaced?

When you set it for off or max ac, do you see the valve operating? If the valve is jammed shut, you will never get heat. If it isn't moving, you can try moving the lever by hand to un -jam it. If it is working properly, then there's a good chance it is a clogged heater core then.