No Cabin Heat

[TagHeuer]

My heat had been slowly diminishing over time. Now i get zero heat from the system. I've searched through the forum and read every post I could find. Seems like most situations involve overheating which I haven't experienced. Temp gauge stays right at the midpoint with no fluctuations. Also, despite a small leak at the throttle body heater plate, coolant level looks good in the expansion tank.

Not sure where to continue with diagnosis/repair?

As always thanks in advance for any suggestions or routing to a thread I might have missed.

 

[jeffro0502]

heater core plugged or air in system?

 

[TagHeuer]

Those were the 2 things I was looking at.

Just spent some time in the garage burping the system but doesn't seem to have helped. Nothing but cold air.

The heater core was the next aspect I was going to tackle. Currently reading all possible threads again to get a sense of the procedure/success involved in trying to flush it myself.

I was interested in any additional problem areas that I should also be looking at.

 

[sven]

Bad thermostat. Does the top hose ever warm up?

 

[fishEH]

I'd try the Thermostat first. It's a cheap and easy fix if its the problem. Thermostat and gasket can be had for $15 and takes a few minutes to change. Then at least you've ruled that out.

 

[TagHeuer]

Thanks for the suggestions. I am ordering a thermostat this morning. Since I can't remember when it was replaced, it certainly can't hurt to remove it from consideration.

Bad thermostat. Does the top hose ever warm up?

Sven - When you say Top Hose. Do you mean the Radiator Top Hose or the Heater Return Hose?

 

[landrovered]

I had to flush a D2 heater core with a mild water/sodium Hydroxide solution to get it flowing again because it was clogged. This would only be a last resort after you are 100% sure that you have gotten all the air out of the system and replaced the thermostat. In my experience you must raise the front of the truck up to burp it properly.

I had no choice but to replace the heater core when I thought I would give the acid flush a try. It worked thank goodness, all sorts of nasty crap came out but all is good now.

 

[sven]

Sven - When you say Top Hose. Do you mean the Radiator Top Hose or the Heater Return Hose?

Radiator. If it never gets hot, your t-stat is stuck open.

 

[TagHeuer]

thanks for the additional thoughts. As I indicated, I'm going to replace the TStat and "burp" again. If that's unsuccessful I'll attack the heater core.

Landrovered - 2 questions:
1. What did you do to verify the clog in the heater core?
2. Did you purchase the acid flush that you used? Or put something together on your own?

 

[landrovered]

Tag,

I disconnected the hoses at the rail above the passenger side valve cover and first put a water hose to it and then blew into it to see if it was clear. It was severely restricted.

I used a small amount of draino and water and mixed it myself in a coke bottle, got the recipe off the web, you don't want it too strong or it eats the core, tooo weak and it doesn't work, I used a funnel and poured it into the heater core. Left it for about fifteen minutes and then flushed it reall well with a garden hose.

Sure beat the hell out of a heater core replacement!

 

[TagHeuer]

Sven-I checked the Top Hose after getting home and it was nice and hot. Not surf if there is any chance that it's a contributing factor?

Landrovered- Thanks for the procedure. Once I burp the system a couple more times I'll have some direction to attack the heater matrix.

 

[xengineguy]

Tag, If your water temp is good, 195 or so your thermostat is most likely not the problem. Try warming the engine to operating temp, with the heater on high,feel the two heater hoses,both should be hot if you have good waterflow thru the heater core. If only one is hot,(the inlet to the heater) the heater is probably plugged !! Also make sure your presure cap is good,if your not holding pressure you will have a hard time keeping air out of your heater core. To flush the heater core,use water and air. At my shop I made a flush tool from two ball valves and a pipe tee. Connect the valves to two ports of the tee,(one for air in,one for water in) the other port connects to the heater core thru a section of 5/8 heater hose. Flush the heater backwards first !!! The line that was cooler first !! Start by using a small amount of water and a larger amount of air. Be gentle, watch the hose from the tee, it will buldge a little if you use too much water/air . Dont use hose clamps on the flush hose to the heater core connection. Better to get wet than blow your heater !!! The basic principal is to allow the heater to fill with water then use the air to move it out. over and over until clean.

 

[JMK]

You have probably checked but is the coolant level high enough? Sometimes its the simplest answer...

Good luck

 

[TagHeuer]

Hey guys,

Thanks for the continued suggestions.

Yep, coolant level is good. As I indicated, the radiator top hose gets nice and hot so I moved from the thermostat to the hoses going in/out of the heater matrix.

I checked the hoses after my commute home last night and the inlet (bottom) hose was hot (I could barely keep my hand on it) while the output (top) hose was justy barely warm. Seems as though the heater core being plugged is looking like the culprit.

Thanks xengineguy for the play-by-play solution.

One question. . .do you use any kind of a solution (eg radiator flush) along with the water as indicated by some posts?

 

[longball4]

Tag:
Just experienced the exact same symptoms on my 04 disco. Replaced t-stat no change. Ran a power flush through the heater core and out came this rusty black paste that was the culprit.

Now, I almost have too much heat and need to set the temperature to 64 degrees inside the cabin to stay comfortable. I thought about using the chemical method but wasn't sure of the after effects if you can't get all that crap flushed out!

Good luck......
btw....what tags do you own?
Lee