SWMBO's DD problem - minivan content

Ok. her 2005 T&C has developed a problem heating the cabin.

Sometimes on the Highway we can get heat, but not usually and never at low speed/idle.

So, I disassembled the dash surround today to get to the heater core and controls.

Looks like all the motors are functioning, fans are working. but, after running the van for 10 minutes, only the lower input line was warm.

Now I've read check coolant (done, cold it's between the fill lines). Thermostat (nope haven't checked), then possibly heater core.

Oh great GRM what are your thoughts? She's complaining it's cold out

Sounds like Thermostat to me. No experience with T&C but replacing thermo is often a cheap place to start.

had the same problem the other day on my crx, thermostat and coolant and it's working fine now.

I had a similar issue with my wife's old '03 Golf when the plastic water pump impeller decided it was happier taking the form of glitter in the coolant overflow.

Best of luck!

Sounds like an air bubble at the core. Jack the front end up so the point you are filling from is higher than the core and let er run with the cap off and periodically fill it until it won't take anymore.

internetautomart wrote: Sounds like an air bubble at the core. Jack the front end up so the point you are filling from is higher than the core and let er run with the cap off and periodically fill it until it won't take anymore.

^^^ this!

Not relevant, but I remember years ago an old gf complained that her car had no heat. I checked it out. Radiator was about empty due to a pinhole leak. No coolant = no heat.

I still can't believe it wasn't running hot. Well, it probably was, just not hot enough to cook it. Car was a 2.2 Plymouth Reliant. Climate was north Jersey in the dead of winter. A new rad fixed the problem. Car was fine.

internetautomart wrote: Sounds like an air bubble at the core. Jack the front end up so the point you are filling from is higher than the core and let er run with the cap off and periodically fill it until it won't take anymore.

I'll give it a shot. gonna have to about stand this van on the tail for that though. inlet is at the top of the firewall, then drops almost to the floor.

Is it possibly to be clogged? We have about 70,000 miles on it. To me it's weird one hose of the heater core is hot after 20 minutes, and the other is cold as can be.

Sounds like the heater core is plugged. You could try reverse flushing it.

I would hazard to say the heater control valve in the hose to the heater core is stuck. Are you checking the hose temps before the valve or after. In heat mode the valve should open, but I have seen them get stuck. I don't think I have ever seen a heater core get blocked without other symptoms like the radiator also being blocked or serious sludge in the system.

If you have a good coolant level... And you are getting flow through the radiator....

Clogged heater core?!?

Pull the hoses and flush the core with a water hose. Then turn around and flush the block..remember to flush in both directions.

If you get good flow through the heater core then move on to the difficult stuff like thermostats and water pumps.

Check if you car has a heater hose cutoff valve. Might be malfunctioning!

Bruce

Here's an idea: drain some coolant ( a couple gallons) from the system, with the heat control for the core open, so you only lose what's in the hoses at the core connections. Pull both of the hoses and use a little bit of air pressure (not over cap pressure) directly on the heater core. Put the air to it from both directions. I'd bet the rent that you'll get a glob of goop out of one (maybe both!) of the core nipples. Then check the cool hose and see if there's anything physically blocking it, like goop that made it out of the core but not thru the hose. Clean as necessary and reinstall the lower hose.

Using a short length of heater hose on the upper core nipple, and a funnel, pour the drained coolant back into the system, thru the core. You might...should!...be able to get it all in and juuussstt barely get a dribble out of the (disconnected) upper hose. If the upper hose is left open and pointed up out of the engine compartment, you won't spill any (it'll be the highest point in the system) and you should be able to see the level come up. When all the drained coolant is back in the system, reconnect and start the engine. let it run awhile and get the t-stat open, and see if you have heat then. I'd again bet the rent you do. At that point you can decide of you want to have a shop flush your cooling system now, or wait for April and DIY at home. You will most likely need to get it done, though.

This morning I noticed a similar problem with my WRX. Sitting still I get no heat out of the vents. If I am moving the heat starts coming through. The temp gauge is normal, doesn't run cold or overheat or anything.

Thermostat, most likely. But...............................................

Did you get that van optioned with rear a/c and heat? If so, did or do you know if the recall for the a/c-heater lines has been done? Another possibility.

I have also seen where the water pump impeller flows at low temps, but then heats up and spins on the shaft. It turns just enough to kept the coolant flowing to avoid overheating, but nothing else. Check for a red/orange trail on the lower hose at the firewall. It maybe leaking and will be wet.

Brian

Guess I'll do the thermostat this weekend. No signs of leaks anywhere.