Final generation of the Pontiac Grand Am.

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Why dose my car keep overheating?

I have a 1999-2005 Pontiac Grand Am gt 3.4

let me tell u what i have done so far.

replaced:

water pump twice

thermostat twice

temp censer twice

intake gaskets / manifold gaskets

vale cover gasket

system been flushed countless times

resevoir and cap replaced

and still over heating radiator being replaced now! i know on these cars there was a problem with the dex coolant system and was a class action suit that ended in 08 and dose not help my only had it for 6months. but cant find what t do fix the problem. please help

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It's most likely the catalytic converter clogging 60 bucks cheap fix. I diagnosed my car at AutoZone for the check engine and that's what it was and it has fixed my overheating issue, also it you have a bad engine leak diagnose it before paying for an intake manifold gasket, right above and to the right of the oil filter on a 3.4 v6 grand am there's a oil pressure sensor and you have to buy a certain socket for it as well but if it is bad it will be pouring oil out like a small fountain so change it, ten dollar fix over a thirty dollar fix.

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Email me plz to fix my car problem .i hsve the same problrm after she cools off she ststts up again i changed two sensors landrade6635.la@gmail.com

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I have the same issue but i change thermostat twice i change my temp sensor once and my engine

Light not on but it's making a loud knocking

Sounds sometimes. Please help

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Fans on my 1999 Grand Am four-cylinder car will not come on car is overheating help please

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You have replaced a number of parts, most of the cooling system, some of them twice. The first thing that jumps out at me is the electric cooling fan(s). Either the fan(s) are bad or the sensor that controls them is. Usually those fans always have electric and the sensor acts as a ground when they engage. There should be a fuse to the fans. Have you checked it? Are you certain your fan(s) is working? The next thing is collapsed hoses if your hoses aren't firm, hard to compress they need replaced. More than likely it is the fan(s) or hoses. If those check out good the next thing to consider would be a clogged catalytic converter. Autozone should be able to test for this for free with their diagnostic scanner. After that is timing, again a diagnostic scan would confirm this _ free at autozone. I have given you some things to investigate but to really help you with an answer I must ask for a little more information with all the parts you say you have replaced in a 6 month period of time. Is it only the temperature gauge telling you it is over heating or are there other signs of it over heating, if so what are they? Does the car lack power? What kind of mileage is on the car? When you replaced the water pump did you replace the timing belt either time? Have you tried running it with out a thermostat? What is the temperature rating of thermostat? Was the thermostat professionally installed? There should be more than one temperature sensor on the car 1 for the gauge the other to control the electric radiator cooling fan, you mentioned only replacing 1, which one was it?

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I replaced all 3 fuses for the fan, as well as the water pump. All brand new parts and my 1999 pontiac grand am 6cyl still over heats bad. The overflow hose attached to my recovery tank spews out all the coolant or water I put in, in less than 10 minutes I'm stuck on the side of the road and the car is smoking. I've only had the car for maybe 6-8 months and it's getting to the point of having to fill it up any time I stop anywhere.

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Hi Clint,

With the engine hot but off (remove the ignition key) feel the radiator hoses. If the bottom hose feels 'cooler' than the top hose it may be that the coolant thermostat is not opening. A way to test this (without removing it) is when the engine is cold, remove the radiator cap, start the engine and let it warm up. After a while if the thermostat is working OK you will notice that the coolant is "flowing' in the neck of the radiator. Be careful the coolant expands as it gets hot and may overflow thru the open neck. If the coolant doesn't appear to flow the thermostat hasn't opened. If the flow appears sluggish it may be that the radiator core has blockages.

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after putting in the coolant i watch to see if it is leaking abd it overflows from the hose on top of the recovery tank, it rises and falls as it pumps into the radiator. After doing this my recovery tank is bone dry and I have to put more coolant in it.

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I got 1999 pontiac grand am se fuses were good for fans but they never kicked in so I had a friend of mine show me how I hook it up direct to battery it can be a pain in the ass unless u install a relay switch inside car. I should have installed the switch also at least I knew it was wrking. Later on u found out my thermostat went out an sensor changed sensor one fan kicked in the other just clicked an did not turn

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These cars just have terrible cooling systems and I've found that they don't make a thermostat that keeps them cool enough. I ended up taking my thermostat all the way off and it worked great. Never overheated again.

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Have you had the head gasket checked out? I have seen numerous vehicles overheat because of a blown head gasket, or other gaskets in the engine for that matter.

Are you constantly having to fill the car with coolant? Is there any white residue in the oil or on the oil cap? Do you notice any leaking coolant?

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None of the above

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It has none of the above, i bled the system it then spit antifreeze out the reservoir hose, then the heat goes cold then warm

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Hi @talia ,

As per the answer above, loss of coolant, signs of coolant on the oil dipstick or on the oil filler cap. Also white smoke out of the exhaust is another sign.

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This is not an awnser but i have had 7 chevys with the same problem. (that includes pontiac) the 3.4 and 3.1 have a disconnect from the temp switch to pcm or pcm to the relay. If you turn on the AC yhe fans will run and if you unplug the temp switch the fans will run but you will have hard shifting in the trans because it gets info from the temp switch. I belive the problem is in the pcm not the harness as so many cars have that same issue. PS never change anything with out diag your waisting time and money and why would you ever change it twice really think about that.

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Hi, I have a Pontiac Grand AM GT 2000, I have exactly the same over heating trouble, fans not running until I turn on AC, do you think if I change the relay or PCM the issue will fix?; thanks a lot.

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Head gaskets do it. Just got done doing them on my 2005. Cylinders 1 and 2 were bad. Replaced a bunch of other parts as well. No more over heating. Head gaskets were what took care of the problem.

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I had a similar problem after changing a water pump, that I could not figure out. In the end I fixed it with a gallon of water. I refilled the radiator with straight antifreeze rather than a 50/50 mix, not knowing that glycol does not transfer heat as well as water. Using straight antifreeze caused the car to run hot and overheat at low speeds. Using the correct 50/50 mix solved the overheating issue. Unfortunately, I didn't figure it out until after going through the time and expense of changing head gaskets.

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I gotta 1999 pontiac grand am se 3.4 it ran ok when I first got it then seripeteen belt broke overheated a lil had problems since.got belt fixed then had problems with the fans not wrking also so hooked them up direct an found out outta 2 fans one wrked. Then this is why u never ever ever let ur woman drive ur car cause she overheated it for God only knows how long an I found out a sensor went out an thermostat fixed that problem an everything seemed alright till i seen resivoir start filling up with oil it started using more an more oil then an now my reservoir is filling up with antifreeze an leaking slowly just started doing that today 12-27-2016 oh their's more top of spring broke on drivers side drives ok but leans a bit lol window broke on drivers door friend owns pontiac grand am also he said his broke an he fixed his but had to use glue so I decided not to fix.oh yeah power steering pump leaked then went out 60 sum miles away from home I pulled over an the plastic pulley was off but still moving lol it got caught between the motor mount an the middle bar the pulley ran on so I got lucky drove it bk home.pulley had no middle to it anymore an wasn't turning but belt kept on a moving thank God now I'm thinking should I keep the car an fix heads or actually put another motor in it someone said probably just drop another motor in it if I keep it with all the problems these grand ama have I'm not sure loved it when I first got it brought used with only 112000 now 131000 if I can find a cheap motor 3.4 I probably will fix it

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My wifes car runs when its cold and when it gets hot and i shut the car down and try to start it again it wont start back up. What could be the problem with it. Heres my cell number text me and let me know what u think.... 989-721-7494

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I have a 2003 Pontiac Grandam, last week all of a sudden it started overheating. Temperature gauge maxed out within a 5 minute drive.

I let it cool down ran it a couple of miles at night with no problems. Tried it again the following morning still no problems. At noon it started overheating again. These time even when car is cold and I add coolant it disappears.

No apparent leaks

I fill it up to max capacity and within seconds it's gone.

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