dodge running hot

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  #1  
Old 07-30-02, 04:42 PM
coplin
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dodge running hot

I have 94 dodge sprit 3.0, I have replaced the radiator, thermostat, radiator cap and fluid. The electric fan seems to be working fine, always comes on when I turn on the a/c. The guage goes to hot and the a/c fades when I am sitting in traffic, then goes back down when I return to cruising speed. What should I check next ? I have owned the car since new, 91000 miles, and have never overheated to boil-over, or lost hose.
 
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  #2  
Old 07-30-02, 05:28 PM
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make sure it is full of coolant and then double check your cooling fan it sounds as if it is not getting much airflow at idle speed with the fan on it should have strong enough airflow to hold a shop towel to the a/c condensor without falling, could also be a waterpump causing poor circulation.
 
  #3  
Old 07-30-02, 06:14 PM
TECHMAN
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bejay has a good point. If you think it is the water pump, when it begains to overheat at ilde you dont have to drive the car just run the eng rpm up to about 3000rpm and see if it cools down if so you may have a water pump not circulating good, are water not flowing throw rady. well at low speeds.----good luck-Dave-
 
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Old 07-30-02, 06:56 PM
coplin
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Thanks for the replies. Raising the rpm does not help, maybe even heats more, but when I shut off a/c and move temp control to heater, temp starts to go down. Other than removing thermostat, is there a way to check pump circulation ?
 
  #5  
Old 07-30-02, 08:31 PM
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Check to make sure the fins on the a/c condenser are clear of debris and are not bent over. Seems as though the water pump is working fine if it cools off with the heater on acting as a radiator. If the condenser is slightly clogged with debris it will not be able to remove heat fast enough from the a/c system and raise the cooling system temperature. Best way to check is with radiator removed and look at a light through the condenser. Happy motoring!
 
  #6  
Old 07-30-02, 09:27 PM
coplin
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Thanks again guys. I checked the condensor fins for debris, all clear and easy to see light through it. Then tried the shop rag on the condensor, and seems to have very good flow. Any ideas ?
 
  #7  
Old 07-31-02, 10:15 AM
JackMaster
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Something to check.... back on 7/3 a poster had the EXACT same problem with a Dodge 3.3 engine in a Caravan. The problem was the new themostat! It was not opening all the way, causing a restriction in the system, which caused it to heat up at idle and with the A/C on but would cool at highway speeds.

Remove your "new" thermostat and reassemble without putting a thermostat in. Drive the vehicle without a thermostat and see if you still have the problem. If the temp stays normal, pitch the old "new" thermostat and replace with a "new" new thermostat.
 
  #8  
Old 07-31-02, 04:36 PM
coplin
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Well I pulled the thermostat, drove the car, it got hot at idle and ran cool at cruise speed. Same results as before removing it. Any ideas. Thanks in advance .
 
  #9  
Old 07-31-02, 04:42 PM
Joe_F
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Gauge fluctuation on Chrysler products is normal...there is a TSB on this.

I suggest you rent a scanner from Autozone and read the REAL temperature through the coolant sensor. Is it actually overheating? You may be pissing up a rpe for nothing
 
  #10  
Old 07-31-02, 04:49 PM
JackMaster
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Excellent! Now we are getting somewhere...slowly of course but progress is being made.

Put the thermostat back in. Check the water pump circulation by removing the radiator cap while engine is cold. Turn heater to HOT and fan on HIGH. Let the engine idle, watch the coolant in the radiator (use safety goggles). Once the coolant reaches a certain level 195 or whatever your thermostat rating is, it will open and allow coolant to flow from the engine through the radiator. You should be able to see the coolant flowing by watching through the radiator opening. If the coolant does not flow and bubbles out of the radiator, change your water pump....poor circulation. If it does circulate and the coolant level stays full (1" below the filler opening) let us know. If the coolant level drops as you are waiting for the thermostat to open, you just released a airlock in the system. top off the radiator and keep watching for the circulation. Be careful, the coolant can get very and burn you. BE CAREFUL!!!!
 
  #11  
Old 07-31-02, 05:19 PM
coplin
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Thanks alot guys. I will reinstall the thermostat, and test the circulation with engine cool and cap off. I am pretty sure it is actually overheating, because the a/c completly fades when guage reads hot, and a/c runs cold when I reach cruise speed and the temp guage goes back to normal. Will post the results.
 
  #12  
Old 07-31-02, 05:43 PM
TECHMAN
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Poss. lack of flow throw rady. May need a good flush are boiling out. Thats my .02----------Dave-----------
 
  #13  
Old 07-31-02, 06:48 PM
Joe_F
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My friend has a 1991 Dodge Shadow and that thing is forever gazorched with cooling system issues. He even got a defective thermostat from the Chrysler dealer (I think even they are farming out the parts to aftermarkets like Stant now ).

I know in his case, as Dave stated, the radiator is wiped. It's on the agenda along with new belts and hoses soon when he's ready .
 
  #14  
Old 07-31-02, 09:11 PM
coplin
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Thanks, Joe F, but the radiator was the first thing I replaced, 3 weeks ago. Hoses and belts were done at the same time. I am to the point that the only thing left is the water pump. Funny thing is I am not sure where it is. I know that sounds dumb, but my Chiltons does not identify where it is, no illustrations, it says it's on the timing belt, but all that is there is a/c, jack pully and harmonic balancer. On the serpentine belt, all that is visible from the top is alternator, power steering, belt tensioner, and 1 other pulley. I have not really dug into it yet. This is my wifes car, the only front wheel drive, traverse engine I have worked on. I drive rear wheel drive V-8'S, which I grew up on. Any help is appreciated.
 
  #15  
Old 07-31-02, 10:19 PM
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on the 3.0 dodge engine (actually a mitsubishi) the water pump is under the timing belt cover. The pump is driven by the timing belt and is a PAIN to change. If you change it, I cannot emphasise enough to change the timing belt at the same time.
 
  #16  
Old 07-31-02, 10:39 PM
coplin
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Thanks Cheese, that's what I thought. I'm sure that will be a PAIN. I will definitly change the belt. I think my Chilton covers that procedure. Will post results.

God Bless
 
  #17  
Old 08-07-02, 08:39 PM
buddybus
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Lightbulb overheating

did you bleed the system for air pocket you have a bleeder screw
on thermastat housing or a plug on head to blead the air out fill
radiator till the fluid comes out of screw
 
  #18  
Old 08-07-02, 10:08 PM
coplin
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Thanks Buddybus. there is not a bleeder screw on the thermostat. I took the the thermostat out. It stays cool until it sits in traffic, then heats up. From what they have told me on the forum, it must be the water pump, poor circulation. That is a bummer, since it is located inside the timing case. If the timing is off, can that cause the overheat problem ? Thanks for the reply.
 
  #19  
Old 08-08-02, 05:26 PM
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the timing being off would not cause it to overheat at idle only.
before you replace the pump i would suggest you check as joe stated if it is actually overheating or not, by using a scanner and reading the coolant temp sensor, it may not be overheating you can aslo let it idle whith the a/c off, the computer will turn on and off the fan as needed once the fan turns on it should turn back off in a very short amount of time usually around a minute, if it does cycle on and off it has to be indicating to the computer that the coolant temp is dropping, if the fan continues to run and does not cycle then obviosly there is a problem and likely is a waterpump since you have tried everything else.
 
  #20  
Old 08-08-02, 05:33 PM
coplin
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Thanks for the reply. I turned the a/c off, the fan does cycle, then goes off when temp lowers, within a minute. Removed the cap and there appears to be good circulation. I am really baffled. Any other ideas.
 
  #21  
Old 08-08-02, 05:52 PM
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well the engine is likely not overheating the only other thing that you can do is take it to a shop where they can scan the coolant temp and compare it to a reading taking by a laser thermometer to make sure your sensor is actually reading accurately, you have another sensor which is seperate from the computers coolant temp sensor which controls the guage it may be faulty or may have a guage problem causing it to read excessivly hot when it shouldnt be.
 
  #22  
Old 08-08-02, 06:55 PM
coplin
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OK, if it is not actualy heating up, why would the a/c stop blowing cold air only when the temp guage goes into the hot range, and blows cold again when the guage goes back to normal range ? I will have the shop check the coolant temp, although I am pretty sure it is getting hot. Thanks for any help you can give.
 
  #23  
Old 08-08-02, 07:21 PM
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if the shop checks it out and says that it is not overheating then i would suggest you have them check your a/c at the same time you may have problems there, you are dealing with two different systems and even if your engine was overheating i dont think it would make a noticable difference in a/c performance unless it was badly overheated and steam rolling out from under the hood.
after all your a/c condensor does set in front of the radiater and gets cooled down before your radiater does airflow moves from the outside in to the engine compartment.
 
  #24  
Old 08-08-02, 07:33 PM
coplin
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Thanks, do any of the sending units tell the a/c to shut off, in the event that they detect that the engine is overheating, because the sending unit is not functioning properly ?
 
  #25  
Old 08-08-02, 07:45 PM
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i suppose it is possible to be programmed in the pcm if it reaches a certain temp to kick off the a/c on some models but am unsure of this would be really easy to check just see if your compressor clutch plate is turning when its idling and showing hot and not blowing cold air, if its still turning the a/c is on.
 
  #26  
Old 08-08-02, 08:55 PM
coplin
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Thanks again. I will try what you suggest. I am really baffled by the fact that the a/c works fine when the temp is normal and does'nt when it reads hot. I will post what I find out.
 
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