no heat at all

[handball]

Hi guys,<br />I have a 1986 mazda pick up that has decided not to put out any heat at all. Seems like both hoses that go to the heater core are not warm to the touch and also the guage shows warm up to take a very long time.My first thought is maybe the thermostat is stuck open or there is a blockage somewere in the system. the engine also races and will not come back to an idle. This racing happens every winter and goes away and becomes normal in the spring when the weather gets warmer. The water is also circulated thru the carb on this engine.<br />Anybody got ideas on this problem?<br /><br />Bill

 

[Mark42]

Re: no heat at all

Depending on year & model, Mazda used a valve in the hot water line to the heater core to control interior heat temperature. If the hoses going to and from the heater core are cold, then its a good bet the valve is stuck closed or the cable has become disconnected. Find the valve (if there is one) by tracing the temperature selector cable from the dash to the heater. If it has a valve, you might be able to work it back into service. <br /><br />If there is no valve, then the heater core or hoses are plugged up. <br /><br />Even if the thermostat is stuck open, there should be some warm water moving through those hoses, assuming there is no blockage.<br /><br />Good luck.<br /><br />Mark.

 

[fixin]

Re: no heat at all

It could have a vac. controlled valve-does the engine operate normal if you put the control on cold?

 

[ob]

Re: no heat at all

Souhds like it's time for a cooling system flush and maitenance on that near 20 year old puppy.Did you remove the heater hose from the block outlet nipple and see if it was restricted?<br /><br />My guess o the accellerator issue is maybe due to a sticky cable or linkage that gets stickier in cold weather.<br /><br />I don't think water runs through the carb on your engine but rather through the jackets of the intake manifold.

 

[Xcusme]

Re: no heat at all

Back flushing the heater core wouldn't be a bad idea either. As OB suggested, a cooling system flush, replace the thermostat (since you say it's slow to warm up). After doing the above suggestions, if it still has a high idle, check / replace the temp sensor. I have seen a lot of block nipple to heater hose restrictions too. Follow any factory refill procedures (if any) to eliminate any air in the system and go from there.

 

[dolluper]

Re: no heat at all

Termostatic control at the end of breather air horn ,flapper stuck or seized try to free up with penitrating oil or vacum hoses leaking will cause the high idle or term hose missing ,broken letting cold air in ,also check rad for same temperture in different spots by hand after running for awhile [shutdown first] should be consistant if not blockage try flushing

 

[handball]

Re: no heat at all

Hi fellows,<br />Thanks for taking the time to reply to my listing. The radiator has never been flushed since I bought the truck new back in nov. 1985 so I think that would be a good Idea to try. I will also try to trace whats attached to the heater control to see where that is going and if I can find some sort of valve. The fast idle happens every winter like clock work , it probably is racing about 2000 rpm's. A few years ago a mechanic changed an electric unit in the carb. and it was o.k. for some time after.He said he had to get the part used as otherwise I would have to buy a new carb at a very high prce.<br />Thanks ,<br /><br />Bill