Sprinter Heater Problems

[PSC]

Sorry if this has already been asked but i have searched the forum and cannot find the answer.
The problem i have is that my heater blows hot air constantly even when set in the cold position.
The vehicle concerned is a sprinter 312 on a P reg.
Thanks in advance for any helpfull suggestions.

Regards

Bal

 

[mister_cee333]

I'm pretty sure (but not 100%) that they have a traditional cable type set up. If I'm correct then probable culprits are a broken cable, a faulty valve, or the cable has come loose from behind the control knob.

Look under the bonnet at the heater hoses which go through the bulkhead. There should be a valve somewhere on them with a cable connected. Have an assistant move the heater knob while you observe whether the valve operates or not. If it operates then it's probably a faulty valve, or not operating far enough.

If it doesn't operate then dismantle the dash to gain access to the rear of the heater controls and verify that the cable is connected properly and moves with the knob. If it does then there's every chance the cable has snapped.

In the meantime you could adjust the valve on the heater hose under the bonnet by hand to a more suitable mid point.

 

[PSC]

Thanks for the quick reply mister_cee333 and you are right that it is a traditional cable type set up.

I have already checked that the cable is attached both ends and it is and also the valve on the heater matrix seems to shut and open correctly.

Also excuse my ignorance but when you say you can adjust the valve on the heater hose under the bonnet are you referring to the one on the heater matrix or is there another valve.

Regards

Bal

 

[mister_cee333]

I'm not sure of the exact set up but it should work in the following manner:

There should be 2 hoses going through the bulkhead - one for hot coolant flow to the heater, and one for cooler coolant to return to the engine/radiator etc. There should be a valve somewhere on one of the hoses which regulates the amount of hot coolant flow and therefore the heater temperature. The cable should be attatched to this valve, and should operate the valve closed/open when turning the temperature knob. If the valve is stuck "open", or is faulty, then the heater will be on max flow and therefore always hot. If you disconnect the cable and operate the valve by hand the heater temp should vary. If the temp varies when manually operated then the cable isn't operating the valve correctly. It's this valve which you could set at whatever point you want and therefore have a "permanently tepid" heater.

 

[brownja]

Hi,

I also have the same fault with my 312d. Did you manage to solve the problem? I have found the two pipes but there is not a valve on either on the engine side of the bulkhead.

Any sugestions would be appriciated.