[Shotimes] Overheat - Part II

[Shylo McKinsey]

IT sounds as if there is no air whatsoever going
through the radiator. More then likely clogged.
Something else seems amiss with your fan(s). But I
don't know enough about the electrical side to give ya
anything substantial...

Shylo McKinsey

'91 White MTx

--- Steve Tatro <stevetatro_shotimes@earthlink.net>
wrote:

> Thanks Rob.  Hope you don't mind me replying to this
> to the list, just so I can get maximum input!
> 
> I just did a bit more troubleshooting (at least as
> much as my peabrain will allow).  Engine cold,
> started it up, EATC "OFF".  Let it get warm,
> thermostat opened, allowing upper radiator hose to
> get hot.  EATC still "OFF".  The fans never kicked
> on.  Temp gauge needle up past "N" in NORMAL, still
> nothing.  Turned the EATC to "MAX A/C" and the fans
> (both of them) kicked on immediately.  Temp gauge
> needle continued to rise!  After a few minutes I
> turned the EATC "OFF" again, and the fans remained
> running for a few minutes, and the engine cooled
> down.  Once the needle got down to the "R" in
> NORMAL, the fans shut off.  EATC still off, the
> engine started to warm up again.  Got past the "N"
> again, and the fans never kicked on automatically. 
> Shut the car down.
> 
> So, here's what I *assume*.  The fans work properly,
> seem to be spinning freely (I was able to turn them
> both by hand), but something's not telling them to
> turn on when they need to.  Is this yet another bad
> ECT sensor (two-wire)?  Mine's only a few months
> old, although just a cheap plastic NAPA part.  Or is
> this a faulty IRCM?
> 
> Also, another question.  Even without the fans
> working, shouldn't the flow of air at highway speeds
> be enough to keep the car cool?  It's *better* on
> the highway and gets much worse as I cruise around
> town, but it just doesn't seem right.  Do the fans
> even run at highway speed?
> 
> It seems like something's still wrong with the
> radiator, since even with the a/c on and the fans
> running the car won't stay cool.
> 
> Thoughts?
> 
> Thanks to everyone for all the help.
> 
> If anyone has any more specific diagnostic tools for
> me to try I'd appreciate it.  I'm sorta guessing at
> this point!
> 
> Steve Tatro
> Red/Black '93 with 178k miles
> Monroe, Ohio
> 
> P.S.  List of recently replaced parts: ECT, gauge
> temp sender, thermostat, radiator cap, chemical
> coolant flush, door striker bolt bushing ;^)
>   
> -----Original Message-----
> From: Rob Pittman <email address removed>
> Sent: Jul 30, 2004 4:56 PM
> To: Steve Tatro <stevetatro_shotimes@earthlink.net>
> Subject: Re: RE: [Shotimes] Overheat - Part II
> 
> Steve, there are two sensors in the cooling system. 
> Since you've replaced them both, you should be in
> good shape.  The IRCM (Integrated Relay Control
> Module) is the "black box" on the driver's side up
> next to the radiator.  It's under the plastic panel
> that covers the top of the radiator.  If you trace
> the wires from the fan, you'll run right into it. 
> It should be putting out something like 12 volts. 
> I'm on my third or fourth one now.  My alternator
> was overcharging, and it was a while before I
> figured it out.  In the interim, I think I must've
> fried a couple of the things.  The two-wire sensor
> goes to the IRCM, and the one-wire to the temp gauge
> (or vice versa, hell, now I'm confused...)  You've
> replaced them both, and I've never heard of one
> going bad anyway.
> 
> Turn on the A/C while the car is cool.  Does the fan
> come on?  If not, then unplug the fan (the wiring
> harness leads right to the IRCM), and check the
> voltage at the IRCM end of the fan plug.  You should
> get a reading.  If not, then I'd suspect the IRCM
> has gone bad.  If you get a voltage reading, then
> suspect the fan motor is out.  Apply 12V to it and
> see if it runs.  
> 
> The only other thing I can think of is the
> thermostat.  But I recall you saying you changed it.
>  When it opens, you should be able to feel coolant
> flowing through the hoses.
> 
> All this is gen 1 stuff, with a single speed fan,
> but the two speed fans should operate in a similar
> fashion.
> 
> Are you in the D/FW area by any chance?
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> 



		
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