Question about 1986 Honda Prelude

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1986 honda prelude heater

The heater on my 1986 honda prelude hardly works, I had a rad flush done a couple of years back and it doesn't work properly anymore.
I'm looking for info on how to replace it myself. Diagrams would be helpful

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  • Adam
    Adam May 11, 2010

    What diagrams are you looking for?



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Radiator flushes can cause more problems than fix sometimes. Before you go removing the dash first replace the thermostat if you follow the lower radiator hose to the engine this is the thermostat housing.Remove the three 10mm bolts and the housing should come apart. Make sure you put the thermostat in the right way and not upside down. The larger end with the spring goes in first toward the engine and the little vent should be on top. When you fill it back up with a 60/40 mixture of coolant make sure you open the bleed hole on the thermostat housing to get out any air and tighten when coolant comes out with no air bubbles. Start the car and hopefully the heat is better. If not the heater core is the two coolant hoses on the firewall remove both hoses and check the flow with a water hose put the hose to both sides to get out any debris. If the flow is slow and does not improve you will have to pull out the heater core which means removing most of the lower dash pulling out the evaporator if you have A/C. Make sure you get a manual. Hope this helps.

Posted on Mar 23, 2009


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