I may have missed it among all the replies, but I didn't
see any mention of core plugs (freeze plug/expansion plug
or whatever you choose to call them). I had a '96 that
would overheat all the time. I chased the problem for
almost a year. Replaced radiator, cap, had recently
replaced water pump. Nothing worked and I had given up. I
lost some coolant but never found a leak.
One day while doing some suspension work on the left side
of the car, I noticed a rusty streak on the side of the
block - under the exhaust manifold. I followed that up to
a hole in the block where a core plug used to live. It was
a hidden leak that must have burned off any trace of water
while driving, so I never saw any water on the ground. I
replaced it with one from Mazda (2 from NAPA wouldn't fit
for some reason) and problem solved.
On Sun, Apr 10, 2011 at 9:58 PM, bill zimmerman
<[email protected]<mailto:[email protected]>> wrote:
Now we're at the root of the problem, why did it
overheat, not because of
the heater core. It may have had a bad radiator,
leaking and you didn't
notice it, or it might be a bad water pump, also
leaking and you didn't
notice it, either way, low on coolant and overheating.
Very good chance you
have a warped head and leaking head gasket at this
point, check for water in
the oil, oil residue in the radiator, and do a
compression check. Go forward
from there, from the way you describe it I'm pretty
sure you are going to
find a head gasket problem. BZ
-----Original Message-----
From: [email protected]
<mailto:[email protected]>
[mailto:[email protected]
<mailto:[email protected]>] On Behalf
Of Bruce Labitt
Sent: Sunday, April 10, 2011 7:59 PM
To: [email protected]
<mailto:[email protected]>
Subject: Re: Diagnosing Bad Water Pump, or Heater Core or?
On 4/10/2011 7:42 PM, bill zimmerman wrote:
> Late coming in on this and have not read other posts
but if your problem
> came after any cooling system work, hose
replacement, etc, make sure you
> don't have an air lock in the system, which
frequently will result in no
> heat from the heater while everything else functions
normally. Would not
> suspect a water pump problem if the motor is not
overheating or signs of
> leakage around the pump. BZ
>
Original problem - overheat - radiator cap let go -
coolant
everywhere. Replaced cap, added water - trouble ever
since. Engine overheats.
Could be air lock. How do you get rid of it? I used a
coolant funnel attached to radiator cap. Attempted to
squeeze hoses... Car is not level right now. Front
end is
on jackstands. Problem?
> -----Original Message-----
> From: [email protected]
<mailto:[email protected]>
> [mailto:[email protected]
<mailto:[email protected]>] On Behalf
Of Bruce Labitt
> Sent: Sunday, April 10, 2011 7:22 PM
> To: [email protected]
<mailto:[email protected]>
> Subject: Re: Diagnosing Bad Water Pump, or Heater
Core or?
>
> On 4/10/2011 5:25 PM, Ross Kuhns wrote:
>> If the hoses are only a year old, they should come off;
>> take a pair of slotted type pliers/grips and you can
>> usually work them back and forth a touch as you pull -
>> tool is set perpendicular to the pipe/hose. Of course
>> don't squeeze too hard, those pipes are soft. If
you try
>> to confirm flow thru the core, make sure not to use too
>> much psi, system doesn't run under too much
pressure (what
>> 13psi?).
>>
>> Ross
>>
>>
>>
>> On Apr 10, 2011, at 4:34 PM, Ken Bogart wrote:
>>
>>> I would flush the heater core to verify flow. If its
>>> blocked and needs replacement, a temporary bypass will
>>> certainly work to keep you on the road.
>>>
>>>
>>> Ken Bogart
>>> -----------------------------------------------------
>>> 96 Montego Blue FFS Coldside (His)
>>> 97 Black& Tan (Hers)
>>> 90 Crystal White (sons)
>>> ------------------------------------------------------
>>> http://www.miatacare.com<http://www.miatacare.com/>
>>> http://www.cincimiata.com<http://www.cincimiata.com/>
>>>
http://www.bcchallenger.org<http://www.bcchallenger.org/>
>>> MiataMail.com<http://MiataMail.com> list owner
>>>
>>>
>>> On Sun, Apr 10, 2011 at 2:32 PM, Bruce Labitt
>>> <[email protected]
<mailto:[email protected]>
>>> <mailto:[email protected]
<mailto:[email protected]>>> wrote:
>>>
>>> I'm trying to diagnose if I have either a bad
water
>>> pump, or just a clogged heater core. The
hose at the
>>> output of the heater core has been spliced to
insert
>>> a GM temperature sensor in the line. [Other
than the
>>> temp sensor splice, the cooling system is stock.]
>>> The GM sensor is reading correctly - it
reads cold
>>> and the heater line *is* cold. However, at
the back
>>> of the head, the sensor which goes to the
dash reads
>>> very hot (after the engine has warmed up, of
course).
>>> It is as if there is no flow out the back of
the head.
>>>
>>> Things I've tried:
>>> 0. Removed thermostat, put housing back. Still
>>> overheats. Have new tstat, but have not
installed.
>>> 1. Remove GM sensor splice, and inspect the
inline
>>> housing. Can see daylight through the hose
>>> connections. Conclusion: temp sensor housing
is not
>>> clogged and not impeding coolant flow.
>>> 2. Added classic coolant flush tee in place
of the
>>> inline temp sensor. Flushed 12 gallons thru
system.
>>> Pretty ugly looking coolant, if I must say
so. It
>>> still does not quite look like clean water,
but it is
>>> far more water like than before.
>>> 3. Put back GM temp sensor.
>>> 4. Refilled with water. Installed a burp
bucket on
>>> radiator, ran engine. Filled bucket 1/3 way.
Bottom
>>> rad hose does not seem like it is full of
coolant.
>>> Feels like it is not uniformly hot. Tried
squeezing
>>> hoses, etc to burp. Not much happened with
respect
>>> to coolant level. Engine heated up - back of head
>>> sensor showed quite warm - heater core loop quite
>>> cool to the touch.
>>>
>>> What I'm going to do next:
>>> 1. Bypass heater core. Is there an 'easy'
way to
>>> get these hoses off? I cut them when I
replaced them
>>> last summer. Are they 'welded' on by now?
>>> 2. Maybe, flush core, if above works.
>>>
>>> Anything else?
>>>
>>> _______________________________________________
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>>> <mailto:[email protected]
<mailto:[email protected]>>
>>>
http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
>>>
>>>
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> Well, I didn't quite do things in order. I flushed the
> heater core. (Pulled heater hoses, attached garden hose
> with anti-backflow to one side, attached 6 foot hose to
> bucket on the other side.) Nasty, but eventually
ran sort
> of clear. So it is NOT the heater core. Loads of
water ran
> through it - it does not appear to be a restriction. No
> water in the cabin, either - thank goodness.
>
> Then I back flushed the head. In the water neck in
the back
> of the head - out the other pipe to the heater core.
>
> Hooked everything up again. Filled through burping
funnel.
> No apparent flow through the core. However, the
thermostat
> is NOT installed.
>
> Is the thermostat required for the heater core to
get water
> flow?
>
> I have a standard new Stant thermostat. Do I need
to drill
> out the 'jiggler'? Hole size? Hole is up, correct?
>
> Is there a good test for a water pump? Looks like I'm
> running out of ideas. Carried off 50 gallons of
'water'.
> What a fruitless day.
>
> Got insight?
>
> Thanks
> _______________________________________________
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>
>
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