1989 Z24 Cavalier Overheating

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  #1  
Old 11-03-07, 02:17 PM
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1989 Z24 Cavalier Overheating

I bought a car for my daughter and I am having problems with it. It keeps overheating. I have replaced the thermostat and the water pump. I have made sure there is no air pockets in the system. It's just like it loses its prime and will not circulate. I am at my witts end. Can anyone help me??
 
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  #2  
Old 11-03-07, 03:18 PM
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First would be the coolant (which I'm sure you've checked). Secondly the cooling fans and their thermostat switch. Then check for air flow restrictions through the radiator. If the fans are activating properly and the air flow path is clear, the most likely problem will be the radiator itself.

I would pull it and see how the coolant flows through its inlet and outlet. If it isn't free flowing, you'll have to have it boiled out.

Hope this helps,

Bob
 
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Old 11-04-07, 08:25 AM
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Be careful with this test, but when the fan kicks on, feel behind it to see if the air is evenly warm. If it is cool and uneven with only warm areas, I concur the radiator is most likely plugged. After all, it is an 89. My one early 90's car's radiator was extremely plugged with lime. Years of coolant with regular water mixed in with the anti-freeze rather than a better method of using distilled water to mix in with it.
 
  #4  
Old 11-04-07, 08:50 AM
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1989 Z-24 Cavalier Overheating

Thanks very much for your input ...i failed to mention that the radiator is also brand new....i have unhooked all the hoses and made sure water flows through everywhere...thats whats getting me...i have never seen this problem before and have worked on several types of vehicles....it's like one time i'll drive the car and uit does fine....the next time it like loses it's prime and just won't circulate the water to cool it...im sure it's just something small that im overlooking but it's very frustrating.Thanks again!

Steve
 
  #5  
Old 11-04-07, 09:32 AM
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To make sure we're on the same page, you have replaced the water pump, thermostat, and radiator is brand new. Your fans for the radiator are turning on and running when the engine starts to heat up.

You feel the water just isn't circulating, which is the job of the water pump (which is new). I would check the belt drive on the pump for tightness.

If you know the fans are working or the overheating is occurring at highway speeds (55 +), I would pull out the thermostat altogether and see if the engine still overheats. If that stops it replace the thermostat.

There are some other things that can cause overheating, like an undiluted antifreeze coolant and timing issues. The latter brings a lot of other things to the table, though before you get to overheating.

Hope this helps,

Bob
 
  #6  
Old 11-04-07, 11:04 AM
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Do you even know that it indeed is overheating and not a faulty gauge? Does the motor smell hot and coolant smelling? And how much is it overheationg?: Where does the gauge point to and where did it used to point to? Does the oil pressure go down some? Do you know of anyone with an infrared thermometer they can shine at the thermostat housing?

And HAS anybody tried to feel the fan air to know that heat is being stripped away from circulating coolant?
 
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Old 11-04-07, 12:04 PM
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1989 Z-24 Cavalier Overheating

Ok ..back again....Bob...we are on the same page...all that is new....i checked the tension on the surpentine belt and it seems tight enough...i did take out the thermostat all together and it still got very hot which makes me think i have either an air pocket in the system or part of the water jackets in the block are stopped up.....


Ecman....i did check the fan and it is workin properly and pullin warm air pretty even across the radiator....the guage works fine because it smells hot and it spits water out the overflow....the oil pressure is about 35 or 40 at road speeds but idle it drops to about 15 or 20.....which should be ok since most older engines only require 7 to 10 lbs of pressure to sustain it...


im guessing i need to buy some kind of system flush and try that.....it still just seems like the water is not circulating even though everything to make it circulate is new....


Ya'll have helped me a great deal....thanks alot for your time and comments.

Steve
 
  #8  
Old 11-04-07, 12:48 PM
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The air pocket that always caused problems was usually at the thermostat. With air against the thermostat it wouldn't open. Most of those, anymore, have a bleed to take care of that problem.

You can get excessive air entrainment in a system if the radiator cap isn't keeping the system pressurized. That would lower its cooling efficiency, but I can't see it affecting the circulation of the coolant.

You could have a blockage internally on the engine - at either the jackets or the head ports. I had a 440 Dodge that was plugged up with sand from the original sand casting of the block. At least that was the theory we came up with. It always ran hot from the time it was new. When we back flushed it we got the sand out.

You may be able to remove the thermostat and disconnect the radiator, but leave the water pump in place. Then use the upper radiator hose to feed a back flush through the engine block with pressure from a garden hose. If there is rust blocking something, though, there may not be a quick fix.

Hope this helps,

Bob
 
  #9  
Old 11-04-07, 12:58 PM
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Did you get the correct sized radiator?

The correct water pump whose blades are for the correct rotational direction? (Although this theory is doubtful if you got one that bolted up, unless it got pressed on backwards at the factory)

The fact you are drawing heat through the radiator means it is working to some degree at least. MINE did not hardly get warm at all, and yet would take quite a while for it to get hot. And mine never spit out the overflow like that.

Does it also heat up like this at highway speeds with no stopping?

If the jackets were clogged the radiator would not be emitting warm air through it, you wouldn't think. But the description of "warm" is subjective.

A blown head gasket would have to be a consideration. How soon after you start it up can you notice pressure in the overflow/bubbling?
 
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Old 11-04-07, 01:50 PM
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1989 Z-24 Cavalier Overheating

Thr radiator i got was just like the one i took out...the old one was bad off....i would hope the water pump wasn't made wrong at the factory but it did bolt right up....i have thought about that kind of thing happening too...seems if it's going to happen it'll happen to me....it won't get too hot just siiting at idle...maybe idle at 220 degrees.....but when u drive it....thats when it gets in the red and and it won't take maybe a halfmile down the road at 55....even with the thermostat taken completely out......thoughts of a blown head gasket has gone through my head but i don't see any signs of it as of yet....no water in the oil or vise versa...not to say that water couldn't be going out the tailpipe but i haven't seen any signs of that either....

I guess if a system cleaner/flush doesn't work....it's time to take it to a PRO....lol.....i have done about all i know to do.

thanks guys.
Steve
 
  #11  
Old 11-05-07, 07:10 AM
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I also should have said in my last correspondence that if you felt the air blowing from the radiator fan and it felt "warm", to compare this to some relative's or friend's car who would be willing to idle their car long enough to have their fan kick on, so you could tell better. If the air felt about the same, then I'd have to believe that your engine was generating more heat from somewhere, for some reason, other than what the radiator system is capable of carrying away. A weak pump or plugged jackets would slow the water flow and in theory the fan, spinning at the same rate would cause then the air to feel colder through the radiator fan. Hence some outside force at work like a blown head gasket which could add additional cylinder heat to the water, and/or sending air pocket into radiator displacing water and hence not enough water in radiator to get cooled.

Regarding the blown headgasket theory: Water does not always go into the oil. Many times water goes directly into the cylinder. If you have such a condition, not only can you experince bubbling in the reservoir prematurely (actually caused by engine cylinder air entering the coolant system under pressure, rather than bubbles from heat,) but you may notice coolant loss. Or at least your engine will lose the ability to expand coolant to the overflow reservoir and then suck it back into the radiator after the motor cools. That being said, is you coolant level to the very top under the RADIATOR cap, after you check it after the engine cools down? It should be, every time.

Do you have a/c? If so, have you made sure the a/c coil fins in front of the radiator are not plugged?

Make sure your lower radiator hose is not collapsing.

Keep us updated on this please.
 
  #12  
Old 11-05-07, 11:45 AM
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Dragging brake? Transmission going south (causing overheating because the tranny cooler is in the radiator)? Failing accessory causing more strain?

Can't wait until you figure this out; bit of a stumper.
 
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