primary fan

Question on the primary fan. 1990 Miata. Primary fan sometimes does
not come on when engine temp reaches midrange on gauge like it should.
almost overheats if I don't turn on the ac, when turn on the ac both
fans come on like they are suppose too. just wanted to see if anyone
has had this happen before so I don't have to spend hours under a very
hot hood trying to trace down a problem. thanks.

Mac > wrote:

> Question on the primary fan. 1990 Miata. Primary fan sometimes
> does not come on when engine temp reaches midrange on gauge like
> it should. almost overheats if I don't turn on the ac, when turn
> on the ac both fans come on like they are suppose too. just
> wanted to see if anyone has had this happen before so I don't have
> to spend hours under a very hot hood trying to trace down a
> problem. thanks.

Takd a guess and replace the temp sensor for the fan, that's probably
the most likely suspect.

--
XS11E, Killing all posts from Google Groups
The Usenet Improvement Project:
http://twovoyagers.com/improve-usenet.org/

Mac wrote:
> Question on the primary fan. 1990 Miata. Primary fan sometimes does
> not come on when engine temp reaches midrange on gauge like it should.
> almost overheats if I don't turn on the ac, when turn on the ac both
> fans come on like they are suppose too. just wanted to see if anyone
> has had this happen before so I don't have to spend hours under a very
> hot hood trying to trace down a problem. thanks.
>

good troubleshooting information found here...
http://www.miata.net/garage/CoolingSystemProblems.html

Thanks for the info. Found the same stuff today and am going to try
and see if that is the problem. little bit of a pain since that
sensor is on the back side of the engine.
thanks again


On Wed, 12 May 2010 18:19:32 -0400, Mac > wrote:

>Question on the primary fan. 1990 Miata. Primary fan sometimes does
>not come on when engine temp reaches midrange on gauge like it should.
>almost overheats if I don't turn on the ac, when turn on the ac both
>fans come on like they are suppose too. just wanted to see if anyone
>has had this happen before so I don't have to spend hours under a very
>hot hood trying to trace down a problem. thanks.

Mac wrote:
> Thanks for the info. Found the same stuff today and am going to try
> and see if that is the problem. little bit of a pain since that
> sensor is on the back side of the engine.
> thanks again
>
>
> On Wed, 12 May 2010 18:19:32 -0400, Mac > wrote:
>
>> Question on the primary fan. 1990 Miata. Primary fan sometimes does
>> not come on when engine temp reaches midrange on gauge like it should.
>> almost overheats if I don't turn on the ac, when turn on the ac both
>> fans come on like they are suppose too. just wanted to see if anyone
>> has had this happen before so I don't have to spend hours under a very
>> hot hood trying to trace down a problem. thanks.
>

could be just the fuse. read the section about 'fans and relay' closely
as well as the section called 'a/c condenser fan circuit'. since both
fans run when the ac is on we know that nothing is wrong with the
radiator cooling find itself. this leaves the the 30 amp cooling fan
fuse (found in the main relay box under the hood - not the fuse panel by
the drivers feet) is suspect as well as the cooling fan relay or the
main relay.

30A fuse ok, TFA to gnd test works. Looks like the thermoswitch is
bad. not sure of replacing it since I can't easily see it or get to
get. how does putting the jumper in all the time sound? Fan would
just stay on when the ignition is on. any issues.


On Wed, 12 May 2010 18:19:32 -0400, Mac > wrote:

>Question on the primary fan. 1990 Miata. Primary fan sometimes does
>not come on when engine temp reaches midrange on gauge like it should.
>almost overheats if I don't turn on the ac, when turn on the ac both
>fans come on like they are suppose too. just wanted to see if anyone
>has had this happen before so I don't have to spend hours under a very
>hot hood trying to trace down a problem. thanks.