Coolant Leak?

Tiny
BLISSFULWISH
  • MEMBER
  • 1999 PONTIAC GRAND AM
Engine Cooling problem
1999 Pontiac Grand Am 4 cyl Automatic 126000 miles

I just drove across the country in this car about a week ago and every morning before hitting the road I checked all the fluids and I never had a problem. Everything appears to be fine. However, the other night I was driving home and about a mile from the house my low coolant light comes on. It was late and I was so close to home so I just watched the temperature gauge til' I got back to ensure it wasn't overheating on me. The gauge didn't move til' a stopped and put it in park. Then it started rising at a crazy rate so I shut it off fast. I could smell that burnt overheating smell and there was lots of steam and white smoke rolling out of the hood so it was obviously overheating. I let it cool down and checked the water levels. The reservoir was empty so I filled it up and started the car and watched for leaks. Coolant is obviously leaking out at a good rate but I can't quite tell where from. It isn't coming from anywhere near the radiator, nor the reservoir tank, nor the hoses going from the reservoir to the radiator, nor upper radiator hose, nor the lower radiator hose. However, I have pinned it down to a location but am not sure where it can be coming from. The lower radiator hose attaches to the coolant inlet pipe below the car's motor and the inlet pipe goes back up and connects to another pipe on the back right side of the motor (if you are standing in front of the car looking under the hood). This pipe appears to be of metal and then connects to another pipe that T's and goes into the motor on one side and somewhere else on the other side. It is around here that the leak appears to be coming from. But I can't get a hand or a good view on the area to see exactly where it would be faulty. So it is either a leak in a pipe in that area or it is leaking directly from that part of the motor. What do you think? What is the pipe(s) that the coolant inlet pipe connects to and does coolant actually enter the motor at this point? If my head is cracked or if I have a bad head gasket would coolant be leaking from this area of the motor? Note that there are no signs of oil in the coolant, nor coolant in the oil, nor milky residue on the oil cap, nor water drops coming from the exhaust (signs pointing to a bad head gasket) however, I haven't driven it since this has happened so maybe those sympotms haven't had time to show up yet? What do you think? Any advice would be greatly appreciated! Thank You!
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Thursday, December 3rd, 2009 AT 1:51 PM

58 Replies

Tiny
MMPRINCE4000
  • EXPERT
It is most likely coming from an external connection.

To be sure, first check oil for any coolant contamination (milky chocolate color), if present then head gasket is problem and heads will have to be removed.
Otherwise I would perform a compression test to test head gaskets, if compression is OK, then perform a cooling system pressure test to isolate leak.

This guide can help us fix it

https://www.2carpros.com/articles/car-is-leaking-coolant

VERY good idea to not drive car, eventually it will crack head, and what is hopefulley a $200 repair would move to $2000 or more.
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Friday, December 4th, 2009 AT 8:31 AM
Tiny
MARCOS_MBM
  • MEMBER
  • 1999 PONTIAC GRAND AM
Engine Cooling problem
1999 Pontiac Grand Am 6 cyl Automatic 145000 miles

Hello. My car keeps overheating and for some reason coolant keeps coming out of the coolant resevoir. The heater also blows cool air eventhough the temperature gauge reads over 200 degrees. I've noticed that when the heater does blow hot air, even though it's only for a brief moment, the temperature goes down, but then rises again as it blows cool air again. I've flushed the cooling system a couple of months ago after I replaced the head gaskets and the intake manifold gaskets and switched to the regular green coolant instead of using dex-cool. I flushed the heater core a few days ago hoping it would fix the problem that I have with the heater but it's still the same. I've also checked the two heater core hoses after running the engine for a while and noticed that one of the hoses is hot while the other one, eventhough it's not cool, is not even close to being as hot as the other one. The fans also do work as I took them out and connected power to them directly and they turn on when the temperature gets to about 215. What could be causing this? I'm getting tired of adding coolant every couple of days only to have it come back out.
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
MHPAUTOS
  • EXPERT
Hi there,

Get the radiator cleaned & flow tested. Make sure that the heater tap is working correctly and if a vacuum operated tap check that there are no vacuum leaks.

Start here.

Mark (mhpautos)
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
LILLIFLOWER
  • MEMBER
  • 1999 PONTIAC GRAND AM
Engine Cooling problem
1999 Pontiac Grand Am 4 cyl

Have a coolant leak and I replaced the themostat and it took down the level of making the car over heat, but still have a leak under the car, its dripping in 2 spots one in the center dripping from the transmission, the other is farther to the area where the fill tank is to put the antifreeze in. Could it be a hose thats under neath?
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
LEGITIMATE007
  • EXPERT
Yes it could, the lower radiator hose, or even the heater hose could be leaking and its just trickling down along a hose to the area of the drip. So you have to look really good
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
SAVEDBYGRACE0122
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 92,334 MILES
The coolant is leaking we think, but cannot find the leak. It heats up in less than 10 minutes to the third thick line the one right before the overheating stage. Can you give me any ideas where to start or what to do? Thank you
Jessica
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
2CEXPT
  • EXPERT
Start by replacing the thermostat see below info

Car Engine Over Heating - Troubleshooting

Inside your car's engine, thousands of controlled explosions called combustion events caused by igniting a fuel / air mixture inside the engine. Spark plugs are used to ignite the fuel / air mixture contained in the cylinders. These explosions are converted into power through the engine while producing a large amount of heat. These high temperatures are controlled with the help of the cooling system. A cooling system consists of a water pump, thermostat, radiator hose, hose clamps, radiator, radiator cap and coolant. Engine coolant is used to transfer heat from the engine to the radiator by the cooling system. The radiator removes heat from the coolant by forcing air through the radiator cooling fins. Without coolant your engine will over heat and if left unattended sever engine damage will occur. Engine coolant colors can vary from green, orange, blue and yellow each having their own unique protective and environmental properties. Coolant leaks are a common car problem that can lead to overheating; we have listed some of the most popular causes below. (Always inspect engine cold to avoid personal injury) (note: coolant and antifreeze refer to the same product, in below freezing, coolant lowers the freeze point hence the name anti-freeze and inn warm weather coolant help raise the boiling point, "coolant")
Troubleshooting Procedure

" Check Engine Coolant Level - Test For Leaks. Engine coolant is used to transfer heat from the engine to the radiator; if a coolant leak is present the engine will eventually overheat. Inspect the engine coolant level in the coolant reservoir tank; coolant level should be between the hot and cold marks. Always check the coolant level when the engine is cold, preferably over night. If the coolant level is not between the reservoir marks the cooling system may have a leak. - Engine Coolant Leaks

Radiator Cap and Coolant Reservoir

If engine over heating has occurred the coolant level will naturally be low due to expansion to the coolant from the extreme heat of the engine. This heat expansion forces coolant out of the radiator and coolant reservoir. To test for an engine coolant leak move the car to a dry smooth surface and allow the engine to cool. Remove the radiator cap and carefully (do not spill) add water until full, then re-install cap. Start engine and allow to run for about three to five minutes (do not allow to overheat) while the engine is running inspect the ground below the engine, if an engine coolant leak is present observe the location of the coolant drops, this will help determine where to start looking for the coolant leak (shut the engine off before inspecting).

Leaking Radiator and Radiator Hose

If no coolant is observed two additional checks are needed for a complete test. With the engine off remove the engine oil fill cap and turn it over, if a milky oil condensation is present the engine may have a failed cylinder head or intake manifold gasket allowing coolant to leak internally. To inspect engine gaskets disassembly is required. Next, the car heater core must be inspected; the quickest way to check the heater core condition without removal the heater core is to inspect the passenger's side foot well compartment carpet for the presents of coolant. If coolant is present the heater core has failed and must be replaced or repaired. After necessary repairs have been made refill the cooling system with manufacturers recommended engine coolant and recheck operation.

" Check Engine Thermostat. An engine thermostat is designed to stop the flow of coolant from the engine to the radiator. This temperature sensitive valve is designed to open when the engine has reached operating temperature (190 -198 F). The operating temperature of 190 -210 F is used to help facilitate fuel combustion. When a thermostat fails it will either stop the coolant flow at operating temperature "stick closed" or fail to stop the coolant flow causing the engine to run colder longer than necessary. If the thermostat fails "open" it will cause the coolant to continuously flow through the engine creating a diagnostic trouble code (check engine light) will be set. When a thermostat sticks closed it will cause the engine to overheat quickly, usually within 5 to 15 minutes of operation. To check for either of these conditions drain coolant and remove thermostat, (thermostat is located in the thermostat housing) if you are unsure of the location of the thermostat on your engine consult a car repair manual. Once you have removed the thermostat inspect the condition of the main body check for any cranks or broken pieces, also check the valve to make sure it is closed. If the valve is open the thermostat has failed and needs to be replaced. To check the operation of the thermostat prepare a pot of water on the stove top deep enough to cover the thermostat completely. Install the thermostat in the pot of water, turn the stove on a medium/high flame, the thermostat should open right before the water comes to a boil. If the water has boiled and the thermostat valve is still closed the thermostat has failed and needs to be placed.

Engine Thermostat

" Inspect Engine Cooling Fan Clutch or Electric Fan Operation. The engine cooling fan system in your car is designed to move air through the radiator when the vehicle is at slower speeds or stopped. This air flow removes heat from the coolant created by the engine using the radiator as a conductor. Most radiator cooling fans are powered by the engine or by electricity. When a cooling fans fails it causes the coolant to retain heat, forcing the engine to run hot and eventually over heat. A cooling fan that is powered by the motor is engaged and disengages from operation by a temperature controlled fan clutch. This fan clutch is constructed using a silicon grease and temperature sensitive coil spring that expands and contracts with heat. As the spring absorbs heat it expands engaging the clutch fan utilizing engine power to drive the fan. A clutch fan can fail one of two ways, it can either locking the fan to the clutch causing poor mileage and a whirring sound, like an airplane is taking off next to you. Or the silicon grease can start to leak causing the fan clutch not to lock up allowing the fan to "freewheel", failing to pull air through the radiator. To check for this condition the engine must be off, inspect the fan clutch for leakage at the front or rear of the unit (input shaft and temperature controlled expansion spring). If leakage is observed the fan clutch has failed and needs replacing. Next, take the fan blade and turn it, the fan blade should free wheel, if you cannot turn the fan blade the clutch has locked up and needs to be replaced.

Engine Fan Clutch (fan blade not attached)

To inspect an electric motor cooling fan start with ignition key off, next spin the fan blade by hand, it should "freewheel" if the fan motor does not spin freely it has failed and needs to be replaced. If the fan motor "freewheels" the electrical system that operates the fan needs to be tested. Start the engine and turn the air conditioner to the coolest setting, if your car does not have an air conditioner skip this step. Within five minutes of the car air conditioner operating the cooling fan should activate, if not the fan motor fuse must be checked first; if the fuse condition is ok the remainder of the electrical system must be checked. To further troubleshoot this problem a wiring schematic is needed which is located in a car repair manual. Use the wiring schematic to trace the circuit through the fuse and relay components, if everything tests ok the fan motor has failed and needs to be replaced. The cooling fan motor failure is the most popular repair.

Radiator Cooling Fan

" Low Flow Through Radiator. A radiator is used to remove heat from the engine coolant through convection. Coolant is forced through the radiator hoses and into the radiator via the water pump. Inside the radiator many small tubes which are constructed with cooling fins transfer heat to the atmosphere. If the radiator becomes plugged it fails to transfer heat from the coolant causing the engine to overheat. This condition generally occurs gradually over time and will be more noticeable when climbing a grade or in warm climate. To check for this condition make sure the engine is cold, and then drain coolant to lower the level in the radiator. The coolant level is lowered to allow visual inspection of the cooler tubes in the radiator core. If the radiator cooler tubes are plugged drain the cooling system completely and replace the radiator with new, reassemble to refill with coolant and recheck system.

Plugged Radiator

Plugged Catalytic Converter. The catalytic converter or "cat" for short is one of your vehicles main emission control devices. The name was derived from the operation the catalytic converter performs; it utilizes a catalyst martial and converts unburned gasses into burned gases, "catalytic converter". The catalyst is heated to excite the chemical the catalyst is made of, this burns the unburned fuel making the catalyst even hotter furthering the effect (thermo reactor). Because of the extreme temperatures the catalytic converter produces the catalyst martial can crack and come apart clogging the outlet port of the converter causing low power and stalling.

Catalytic Converter Starting to Fail

While the catalytic converter is failing it will partially plug the exhaust system, creating excessive back pressure in the engine exhaust. Excessive exhaust back pressure will cause the engine to have less power, to compensate for low power condition the user will add more throttle. When more throttle is applied the engine creates excessive heat overloading the cooling system causing the engine to run hot or over heat. This condition is always accompanied by low engine power.
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
RAINZ
  • MEMBER
Excellent write up on everything by razmataz. I would like add one more tid bit of advice. Before the thermostat needs to be changed it could be a simpler fix by replacing a $30 temp. Sensor. The sensor basically tells the computer to runs fans on high/los or not. The thermostat is more of a manual device telling to you your engine is hot. Also be sure to check your replays and fuses in the fuse panal under the hood, and just inside the side dash board at your door. If there is a faulty relay switch (looks like a big fat fuse) it could be telling your cars computer mixed messages. When you are replacing coolant, be sure to use the exact same coolant already in the car. Mixiing different coolants together such as regular prestone and dextcool together will basically change the life of the coolant by half and could also have a wearing out affect on any seals where coolant passes through. Good luck.
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
JTMUGS11
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 140,000 MILES
I just got a new coolant reservoir put it and my coolant is still leaking what could it be?
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
2CEXPT
  • EXPERT
From where is it leaking at?
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
CARADIODOC
  • EXPERT
Come on; you know we can't see it over a computer. The reservoir is the last thing I would think of if I were psychic. Many auto parts stores will rent or borrow tools. Ask for a cooling system pressure tester kit. Use that to pressurize the system, then watch where coolant is flowing from.

If the leak is very slow, you can add a small bottle of dye in the reservoir. After driving long enough for leakage to occur, you search with a black light. The dye will show up as a bright yellow stain that you can follow back to the source.
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Wednesday, July 29th, 2020 AT 10:13 AM (Merged)
Tiny
MLIFF
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
I was out of anti freeze this morning. I put in a new thermostat and more anti freeze. I drove it around. I checked under the car and no leaks on the ground. I checked around the head gaskets and no leaks and all the hoses and no leaks. I checked the oil and it was fine. I started the car and smelled the exhaust and it was fine also inside of the car with no smell.
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
WRENCHER1
  • MEMBER
If you had coolant leak out, replacing the thermostat didn't fix that. You need to pressure test the cooling system to determine where that coolant went. Bad head gaskets don't leak externally. The leak into the combustion chamber most of the time.
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
LETSGOHEELS
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 131,000 MILES
Its leaking oposite side of pullys. No water in oil. The coolant does not have any oil in it. But it leaks really really bad. Like 2 liter bottle of water gone in a block in a half. What could it be?
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
BMRFIXIT
  • EXPERT
Intake manifold gasket is no good
need to have it replaced


https://www.2carpros.com/forum/automotive_pictures/99387_Graphic1_232.jpg




https://www.2carpros.com/forum/automotive_pictures/99387_Graphic2_111.jpg

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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
MSTAV2011
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 139,600 MILES
I have a 1999 Pontiac Grandam GT. This car has what they call an "open" coolant system, I seem to be loosing coolant, I have to refill every month or so. I don't believe this should be, what pointers can you give me about where to look first?
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
SATURNTECH9
  • MEMBER
You could have a coolant cap not holding the correct pressure and venting the coolant off as steam or a leak somewhere without checking it can't say for sure. If you have never replaced the coolant cap I would. Also rent a coolant pressure tester its a pump with adapters that you use to pressurize your cooling system to find. Try auto zone they rent tools you can try other places too. Let me know what you find.
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
MSTAV2011
  • MEMBER
I should elaborate on what I've already done so far. I replaced the cap a couple years ago, maybe 3. I also noticed that my cooling fans were not working so the first thing I did was to check the fuses under the hood. The 2 fuses for the fans are still in working order. I did replace the relay for the fans after noticing that the fans would come on when I turn the air conditioning on, I also replaced the temperature sending unit. Now it seems like the fans don't come on at all wheather I turn the air conditioning on or not. When a person turns air on, should the fans come on instantly? Or after some amount of time?
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
MSTAV2011
  • MEMBER
Another couple questions. Is the best time to add coolant when the engine is running and at temperature? While the engine is running should there still be coolant in the fill tank? Up to the "coolant hot" line?
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)
Tiny
SATURNTECH9
  • MEMBER
If you replaced your cap 2 or 3 years a go you can't say its new and isn't bad.I would just change it there not that expensive and you have no way of testing it. It looks like the fans come on with the a/c and when the engine reaches a certain temp usually about 221 degrees.I posted a fan operation for you I would give the fan a little time to turn on with the a/c the fan comes on to keep the a/c pressure's down and to help turn the r134 from a gas to a liquid. As far as the coolant level I would check it or add it when cold so you don't burn yourself. Also yes there should be coolant in the bottle when its hot.
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Wednesday, July 29th, 2020 AT 10:14 AM (Merged)

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