Home » Forums » Tech Help Forum » Veg Oil Fuel Conversions

Heater circulation issues

Submitted by guttermonk on 30 March 2008 - 2:55pm.

In one of my 82 300DTs the heater isn't working. I have replaced the brushes on the blower, the climate control unit, the monovalve, thermostat, radiator, and water pump all to no avail. Where should I turn next? The a/c works but the heat doesn't. I haven't noticed any leaks from the heater core nor am I loosing a discernible amount of coolant. When the a/c comes on we don't smell anything weird but when we switch it over to heat, the heater never comes on. Something else I have noticed (that might or might not be related) is that the coolant doesn't seem to cycle as thoroughly as it should. I know this because I tapped into the cooling system on both of my 123's (right at the oil filter in order to heat veggie oil) and this one's hoses don't seem to get as warm as the other one. This is causing veggie burning issues and possibly has led to coked injectors.

Any suggestions or advice would be of great service.

Thanks,
Julius


‹ Fuel Pump WVO and Biodiesel Exempted in WA State ›

Couple things to narrow it down

31 March 2008 - 11:24pm
Kent Bergsma

Hi Julius, have you changed the fuse (not just looked at it)? Have you unplugged the blower motor and powered it directly with 12 volts?


changed the fuse and directly powered fan

1 April 2008 - 8:25am
guttermonk

Hey Kent,

I just changed the fuse and tested the heater (through the control panel) to no avail. Then I disconnected the blower motor and powered it directly. It works when powered directly. While under there I saw that the green wire had been spliced into previously but was now reconnected. I actually new this but forgot about it. When we bought the car the previous owner's mechanic had installed a switch in the glove box that would flip the a/c and possibly the heater on high. While tinkering one day I came across this strange addition and removed it. I can't remember if my problems began at that moment... Could this switch have bypassed the problem?

Thanks for the expert advice,
Julius