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Heating up too much



 
 
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  #21  
Old July 21st 05, 09:03 PM
YouGoFirst
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>I go with Jerry. The pump is essentially dead weight until you get
> the thermostat open (Yeah, I know, it circulates in a closed loop,
> etc) and has little effect on closed cycle warmup time unless you're
> in the frozen North with the heater on. Slow warmup is almost a dead
> giveaway for a sticking thermostat.
>


I would agree with that if I hadn't had it gone through 2 of them getting it
replaced when it first started to overheat. Also, the warm up went really
close to its normal rate, except it didn't quite make it up to 190 until I
slowed down below 40 mph, then it went up above 190. I hope that I haven't
had 2 bad thermostats put in.


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  #22  
Old July 21st 05, 09:33 PM
Snow
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I would be looking at the t-stat again, take it out and place in a old pop
can (empty) then pour some boiling water into the can right out of the
kettle, if the t-stat opens fast and smooth then you can eliminate the
t-stat. You can try running without a t-stat to see if the vehicle over
heats, my money is on it won't. That will only help eliminate the t-stat
from your problem. You may have a collapsed hose that is reducing flow
through the rad.. or yes even a bad water pump. Water pumps are silly
things, some last only a couple years and then some (like on my 57 Pontiac
and 54 ford , both Canadian models) can last for over 50 years (the ford
water pumps leak if I let the system pressurize, shaft seals are weak and
failing).
For the few bucks it costs for another t-stat, I'd change it out and I would
even look at buying or having the work done at a different place, just in
case the place that the current one and previous one came from received a
bad batch, or to eliminate the same goon from possibly installing it
incorrectly.

Snow...



"YouGoFirst" > wrote in message
...
>I have a 1993 Grand Cherokee Laredo with the 5.2 L V8 engine. I recently
>had the thermostat and the fan clutch replaced, and 1 1/2 years ago the
>radiator was replaced.
>
> I live in Utah, and lately it has been getting up to 100 degrees, and I
> have found that if I am driving my car around and get stopped at a bunch
> of stop light my temperature goes over 210. I am not in rush hour trafic,
> and am able to go for a block or two before having to stop. Fortunately,
> if I can get going 40 mph or more for a few of minutes the temp goes down
> to about 190. My only thought would be that the fan clutch that I just
> had put in doesn't work right. Does anybody have an idea as to what is
> going on?
>



  #23  
Old July 21st 05, 11:29 PM
Will Honea
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Wouldn't be the first time I've heard of that. You can also install
the thermostat backwards or let it come out of the pocket as you
tighten it down (usually that leaks, but I've seen them warp things
enough to freeze the thing up).

On Thu, 21 Jul 2005 20:03:44 UTC "YouGoFirst" >
wrote:

> >I go with Jerry. The pump is essentially dead weight until you get
> > the thermostat open (Yeah, I know, it circulates in a closed loop,
> > etc) and has little effect on closed cycle warmup time unless you're
> > in the frozen North with the heater on. Slow warmup is almost a dead
> > giveaway for a sticking thermostat.
> >

>
> I would agree with that if I hadn't had it gone through 2 of them getting it
> replaced when it first started to overheat. Also, the warm up went really
> close to its normal rate, except it didn't quite make it up to 190 until I
> slowed down below 40 mph, then it went up above 190. I hope that I haven't
> had 2 bad thermostats put in.
>
>



--
Will Honea
  #24  
Old July 22nd 05, 12:14 AM
Billy Ray
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Okay, It will cool properly at road speed but not at idle would indicate fan
failure to move enough air as a primary concern. If you can send me an
e-mail address I'll forward you some Jeep Cooling System info.

Overheating In Traffic (Stop and Go, Low Speed Driving)
Overheating in traffic and low speed driving has one common cause: the fan.
During stop and go, low speed "creeping" and low speed driving, there is not
sufficient flow of air through the radiator. Therefore, the engine has a fan
to draw air through the front of the car. This fan operates off of a viscous
fan clutch. Basically, the fan clutch is mounted between the fan and the
engine. As cold air flows over it, the clutch loosens up, allowing the fan
to freewheel on the shaft of the engine. The fan then hardly turns. As the
air flowing over the clutch heats up (as the engine transfers more heat to
the radiator) the clutch tightens up, spinning the fan faster and drawing
more air through the radiator. The cycle continues as long as the car is
running. Over time, this fan clutch can wear out, causing the fan to
freewheel whether it is hot or cold. This causes reduced airflow through the
radiator, and therefore high operating temperatures during low speed
driving. This theory is easy to test, because once you get on the highway
the car will cool right down.
Testing the fan clutch is pretty easy. Simply start the car and allow it to
warm up to normal operating temperature. Shut it off, then give the fan a
good flick with your hand. If it rotates more than about 1.5 turns, then
odds are the fan clutch is worn. However, I have found this test to be a
very bad indicator of the true condition of the clutch. A much better test
is to simply pick another one up and swap it on. If this solves your
problem, then the fan clutch was obviously the culprit.


"YouGoFirst" > wrote in message
...
>> The chances of everything failing at the same time is pretty small. That
>> being said it is possible that multiple components were in the process of
>> failing and it only took one additional event to provide the strain to
>> throw the rest over the edge (so to speak)
>>
>> PS
>> Do we know why the original cooling system failed a year and a half ago?

>
> Yes, it had developed some leaks and was leaking antifreeze.
>



  #25  
Old July 22nd 05, 06:10 AM
Stephen Cowell
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"YouGoFirst" > wrote in message =
...

....

>=20
> I am leaning more towards a bad impeller because I noticed thismorning =

as I
> was driving into work earlier than normal, that the temperature didn't =

get
> up to its normal 190 until I had slowed down below 35 mph. That would =

make
> me think that the coolant isn't moving through the radiator fast =

enough.

Your thermostat could be stuck partially open.... too much
cooling at first, then not enough later. Or it could have been
put in backwards... the sensing part should be toward the
block (spring out). Did the symptoms start after the
maintenance, or were they happening before?
__
Steve
..

  #26  
Old July 22nd 05, 03:10 PM
YouGoFirst
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> Overheating In Traffic (Stop and Go, Low Speed Driving)
> Overheating in traffic and low speed driving has one common cause: the
> fan. During stop and go, low speed "creeping" and low speed driving, there
> is not sufficient flow of air through the radiator. Therefore, the engine
> has a fan to draw air through the front of the car. This fan operates off
> of a viscous fan clutch. Basically, the fan clutch is mounted between the
> fan and the engine. As cold air flows over it, the clutch loosens up,
> allowing the fan to freewheel on the shaft of the engine. The fan then
> hardly turns. As the air flowing over the clutch heats up (as the engine
> transfers more heat to the radiator) the clutch tightens up, spinning the
> fan faster and drawing more air through the radiator. The cycle continues
> as long as the car is running. Over time, this fan clutch can wear out,
> causing the fan to freewheel whether it is hot or cold. This causes
> reduced airflow through the radiator, and therefore high operating
> temperatures during low speed driving. This theory is easy to test,
> because once you get on the highway the car will cool right down.
> Testing the fan clutch is pretty easy. Simply start the car and allow it
> to warm up to normal operating temperature. Shut it off, then give the fan
> a good flick with your hand. If it rotates more than about 1.5 turns, then
> odds are the fan clutch is worn. However, I have found this test to be a
> very bad indicator of the true condition of the clutch. A much better test
> is to simply pick another one up and swap it on. If this solves your
> problem, then the fan clutch was obviously the culprit.
>


I took it in to the place where I had the fan clutch replaced, and the owner
said that he has owned several Jeep Grand Cherokees, and that they all run
hot. He said that as long as I am not getting above the 235 mark I should
be ok. Is there anybody out there who has owned a 1993 V8 Jeep Grand
Cherokee that can confirm that it can get that hot when running the AC while
it is 100 degrees outside?


  #27  
Old July 22nd 05, 08:50 PM
Paw
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I can confirm it though not a 1993 - I have the 1997 w/ v8 - was the next
notch up last week while driving in 90+ heat a little over 100 w/ heat index
in stop and go Philly driving for about 3 hours. I was worried for a bit,
since the all the xj(s) I've owned never went above 210 (unless you count
when the electric fan went)... but it never went above the next notch, just
stayed there all day...

Paul

> I took it in to the place where I had the fan clutch replaced, and the
> owner said that he has owned several Jeep Grand Cherokees, and that they
> all run hot. He said that as long as I am not getting above the 235 mark
> I should be ok. Is there anybody out there who has owned a 1993 V8 Jeep
> Grand Cherokee that can confirm that it can get that hot when running the
> AC while it is 100 degrees outside?
>



  #28  
Old July 22nd 05, 10:22 PM
Dick
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On Fri, 22 Jul 2005 14:10:34 GMT, "YouGoFirst"
> wrote:

>I took it in to the place where I had the fan clutch replaced, and the owner
>said that he has owned several Jeep Grand Cherokees, and that they all run
>hot. He said that as long as I am not getting above the 235 mark I should
>be ok. Is there anybody out there who has owned a 1993 V8 Jeep Grand
>Cherokee that can confirm that it can get that hot when running the AC while
>it is 100 degrees outside?
>


We have a '93 JGC Limited with 90,000 miles. With ambient running 100
to 105 lately, the Jeep runs at almost 210 degrees while moving at
least 40 mph. If I do a lot of stop and go driving, it will go over
the 210 mark. I let it sit and idle yesterday for about 10 minutes
with my wife in the car, and when I returned it was just below the red
line. As soon as I got the car moving above 40 mph, it came back down
to 210. My thermostat is less than 6-months old. Original water
pump. Seems like it has always run pretty hot. I have had to turn
the A/C off when in Phoenix at about 115F. The engine pinged so back
I thought it would blow up. Turning off the A/C stopped the pinging,
but darn near melted us.

Dick
  #29  
Old July 25th 05, 02:14 PM
YouGoFirst
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> We have a '93 JGC Limited with 90,000 miles. With ambient running 100
> to 105 lately, the Jeep runs at almost 210 degrees while moving at
> least 40 mph. If I do a lot of stop and go driving, it will go over
> the 210 mark. I let it sit and idle yesterday for about 10 minutes
> with my wife in the car, and when I returned it was just below the red
> line. As soon as I got the car moving above 40 mph, it came back down
> to 210. My thermostat is less than 6-months old. Original water
> pump. Seems like it has always run pretty hot. I have had to turn
> the A/C off when in Phoenix at about 115F. The engine pinged so back
> I thought it would blow up. Turning off the A/C stopped the pinging,
> but darn near melted us.
>


Thanks, I guess the mechanic wasn't full of crap.


  #30  
Old July 25th 05, 02:41 PM
Dick
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On Mon, 25 Jul 2005 13:14:52 GMT, "YouGoFirst"
> wrote:

>> We have a '93 JGC Limited with 90,000 miles. With ambient running 100
>> to 105 lately, the Jeep runs at almost 210 degrees while moving at
>> least 40 mph. If I do a lot of stop and go driving, it will go over
>> the 210 mark. 0

>
>Thanks, I guess the mechanic wasn't full of crap.
>


Some things to consider:

With the stock 190-degree thermostat, that's the minimum temperature
in the radiator. It can go higher and still be "normal."

Make sure your radiator cap is in good condition. The system depends
upon pressure in the radiator to increase the boiling point of the
liquid.

Make sure your lower radiator hose is not soft. This would allow it
to collapse from the water pump suction thereby reducing fluid flow.

Dick
 




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