Hello,

I recently replaced my thermostat (put in grey t-stat) and radiator (Nissens) in my '04 Disco. I believe I've bled air out properly and don't hear any waterfall sounds (I'll listen more closely). The issue I'm having is the heat coming from the vents is not as hot as it should be. I keep reading that the heater core might need flushing.

What I'd like help with is some clear instructions on what exactly I do. Some photos would be helpful. I'm not very clear on how exactly to do the flush. Help is appreciated!

Anything else I should check to try and solve this issue?

 

Since I have just done this in the last 60 days I think I can help.

Before you start...warm the truck up and check with your hand the temp on both hoses coming from the firewall on the passenger side. IF the hose closest to the drivers side is cool and the hose closest to the passenger side is hot, you may have a clogged heater core. If both are the same temp, your issue is somewhere else.

Tools
(2) hose clamps
(1) flat head screwdriver
(1) garden hose
(1) adjustable sprayer that will fit into metal pipe on the engine firewall side

1. Clamp both inlet and return rubber hoses as close to the metal firewall pipes
2. Disconnect both hoses from metal firewall pipes
3. tie off or get clamped hoses out of way
4. start on the inlet side (metal pipe closest to passenger side) and gently open the adjustable spray nozzle and allow coolant and water to dump out outlet side
5. after 5 minutes, repeat the process but, put nozzle on the outlet side (metal pipe closest to the drivers side)
6. watch for any debris coming out either side
7. the water flow coming out should be the same as the water flow going in
8. repeat a few more times on both metal pipes
9. you are going to have water in the heater core, you can either try to blow it out or realize that you will need to bleed it out of your system.
10. button things back up in reverse order
11. bleed system

I did this and in about (2) weeks I was having issues again and ended up having to replace the heater core (check Tricky Dick - No Hot Air thread)

 

Ok, so I after reading some threads here, I went to the truck and started her up. The hose that leads to the right side of the firewall is cooler than the hose that leads to the left side. I wouldn't say it's stone cold, but it's not as warm/hot as the left side hose, which is hot to the touch. Should it be like this?

 

I vote blocked heater core based off your description of hot and cold hoses

 

So FND, if the right hose is 'cooler' than the left one (which is HOT to the touch), does that mean that one is cold and one is hot?

 

The hose on the left is the inlet coming from the engine and will be hot. The hose on the left is the outlet and should be the same temp as the inlet. If it is much colder, it means the flow of coolant is blocked in the heater core.

 

Thanks FND. I think I'm going to take this job to my local LR mechanic to have him do. I just got done swapping out the radiator and t-stat and don't think I want to tackle another project right now. I also just ordered the Ultraguage.

Thanks!

 

Have you tried running the heat on full high for a few minutes while at operating temp?

Sometimes that will push a bubble out.

 

You probably just have air in the system. Happened to me yesterday. No heat after installing a heat exchanger. Keep the heat cranked up, and bleed the system every morning. 1 day later my heat is back

Bleeding is not an exactly science... I do a combination of squeezing hoses with the bleeder cracked, elevate the tank w/ cap off + crack bleeder + squeeze hoses, lower tank + fill coolant via bleed screw, + running engine high idle with cap off. Repeat every morning for 3 days to a week.