On 11/4/09 3:41 PM, in article hcsseu$bih$1@news.eternal-september.org,
"Seth" <seth_lermanNOSPAM@hotmail.com> wrote:

> "Gene Wagenbreth" <genewxxx@isi-OS4> wrote in message
> news:hcskr2$4ak@venera.isi.edu...
>> I doubt its the head gasket. It never gets too hot. Most of the time it
>> runs fine and doesnt get hot. Why would turning on the heater make the
>> temperature go down immediately if it were headgasket.
>>
>> Thermostat sounds interesting. Does the heater somehow bypass the the
>> thermostat ? How difficult is it to replace the thermostat ? How much
>> should it cost to have someone do it (ballpark) ?
>
>
> The heater doesn't bypass but redirects heat. Those coolant lines go
> through the heater core. With the heat on, a fan blows across it sending the
> heat into the cabin.
>
> For how to change it...
> http://wiki.answers.com/Q/How_do_you..._1990_Honda_Ac
> cord_LX
>
>
New radiator sounds like a clue. Check for air bubble in the system. I
believe a '90 has a "burp" screw.