2005 Grand Prix Overheeating

Hotsuma9

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2005 Pontiac Grand Prix GTP Sedan 4-Door - 3800 Series 3 (Grey)

The car began to overheat earlier today, so I added some anitfreeze and that didn't help at all. There are no leaks that we could see. The hose that goes to the thermostat is hot. The car begins to smoke and cut back erratically after driving it for 5-10 minutes. The smoke comes from the oil intake but the oil is full. What could be the problem?
 

melsg5

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Your thermostat make have failed. Remove it and put it in a pot of water and watch to see if it opens before the water boils.
Did you check your oil dip stick and oil filler cap for a brownish creamy substance?
 

Hotsuma9

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Your thermostat make have failed. Remove it and put it in a pot of water and watch to see if it opens before the water boils.
Did you check your oil dip stick and oil filler cap for a brownish creamy substance?
I checked the dip stick but not the oil filter cap. Will check that. No brownish substance on dipstick. Bought a new thermostat on a hunch.
 

Hotsuma9

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I found the problem. When I added water directly to the radiator, I saw that water was leaking from a short, black, 90° angle hose that's about 8 inches in total length. It's almost directly across from the radiator intake. I need to figure out what kind of hose this is. Here's a pic of the hose and its location:




Is this possibly the heater hose?
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Hotsuma9

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Yup. That's it. We took the car to our mechanic earlier today. Danny said that these cheap elbow connectors leak all the time and he fixes them all the time.
 
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Hotsuma9

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The mechanic replaced the two plastic elbow connectors that carry antifreeze and water to the engine with metal ones. We just got the car back on yesterday. I noticed that when the car is running idle, the temp hand would go just beyond the halfway point. But when I drive it, it'll go just past the halfway point but then go back down to it and run normally. It didn't use to do this before the overheating problems started, so why is it acting like that now?
 

Hotsuma9

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when the engine is completely cold is the engine coolant at the proper level?
Ok. The coolant in the reservoir is low as always. If i were to fill it up and crank up the car, it would drain until it's back to the low point. The radiator is filled up with antifreeze to the point where if I added a little bit of water, it would overflow.

I'm not sure if these are the proper levels.
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melsg5

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the radiator, if it has a separate cap, is supposed to be completely filled. The coolant recovery bottle should have a mark on it for cold level and you should add some distilled water to bring it the cold level. If there was air in the system from replacing the pipes it may take a few days of using the car to purge the air.
 

Hotsuma9

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the radiator, if it has a separate cap, is supposed to be completely filled. The coolant recovery bottle should have a mark on it for cold level and you should add some distilled water to bring it the cold level. If there was air in the system from replacing the pipes it may take a few days of using the car to purge the air.
Yes. The radiator has a separate cap and it's completely filled now; topped off with cold water. I checked the coolant reservoir tank for markings but can't see any due to it's position in the motor. I'll give the car a few days to purge the air. Thanks for the helpful information.
 

Hotsuma9

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The temp hand is now going up to but not into the red zone. This occurs after driving for about 30 minutes. A check of the radiator shows that it's full of antifreeze and there are no leaks in the engine. The mechanic mentioned that the radiator fan has two speeds and it's probably not kicking up the speed after driving for an extended amount of time. He also mentioned the head gasket but I'm not sure what he's referring to. Could these cause high temps even though there are no leaks?
 

melsg5

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Either problem can cause the engine to run hot.
I believe you have two cooling fans. When the engine is running very hot are both fans running?
You or your mechanic can perform a hydrocarbon coolant test, buy it at a auto parts store, or your mechanic can perform a compression test to check for a blown head gasket.
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Hotsuma9

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South Carolina
Either problem can cause the engine to run hot.
I believe you have two cooling fans. When the engine is running very hot are both fans running?
You or your mechanic can perform a hydrocarbon coolant test, buy it at a auto parts store, or your mechanic can perform a compression test to check for a blown head gasket.
Both fans come on when the engine is hot but it can't tell if it's low or high speed. I'll have to let him perform those tests and see what's going on.
 
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