coolant overflowing (boiling)

[nda0602v6]

I know this is a Firebird forum but I'm working on a 98 Malibu with a 3.4L v6. I drained all the coolant and replaced the thermostat. There seems to be air trapped somewhere I'm thinking because after I filled it back up with coolant, the coolant in the over flow bottle starts to boil and comes out the drain hose. The car has a radiator however the radiator cap is located on the passenger side on a white plastic bottle. I don't have any leaks, the coolant isn't flowing right I don't think because of some air pockets. Anyone ever work on these motors with this kind of radiator setup? Perhaps there is a way to bleed the system somehow? ( I didn't see any bleed valves or anything) Any info would be helpful...thanks

[jola]

Re: coolant overflowing (boiling)

ok, so this started happening immediately after your flush? i'm not familiar with your engine, but could it be too high of a water content when you mixed the coolant?

[BLLDOGG]

Re: coolant overflowing (boiling)

Draining and Filling Cooling System
Caution: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously -- possibly with explosive force -- spewing the solution over the engine, fenders and the person removing the cap.

Notice: When adding coolant, it is important that you use GM Goodwrench DEX-COOL™ coolant. If coolant other than DEX-COOL™ is added to the system, the engine coolant will require change sooner: at 50 000 km (30,000 miles) or 24 months.

Before draining and recovering the cooling system, inspect the system. Perform any service needed to ensure that the system is clean, does not leak and is in proper working order.

Some coolant manufacturers are mixing other types of glycol in their coolant formulations; propylene glycol is the most common new ingredient. Propylene glycol is not recommended for use in GM vehicles that were manufactured with GM Goodwrench Dex-Cool. A hydrometer will not always provide a correct measurement of freeze protection when anything other than ethylene glycol and water is being tested. The degree of inaccuracy will vary depending on the proportion of other glycols present in the coolant. Hydrometers test the amount of glycol in a mixture by measuring the specific gravity of the mixture. The higher the concentration of ethylene glycol, the higher the float balls go in the hydrometer. This in turn indicates better freeze protection. Because ethylene glycol and propylene glycol do not have the same specific gravities, hydrometer readings of mixtures containing propylene glycol give incorrect values. It is recommended that a refractometer be used when testing coolant. Refractometers test for the amount of glycol in a coolant mixture by measuring the speed of light as it passes through the fluid and are not affected by the specific gravity of the glycol. For proper coolant testing refer to Coolant Concentration Testing .

Draining
Park the vehicle on a level surface.
When the engine is cool, remove the surge tank cap by following these steps:
Slowly rotate the surge tank cap counterclockwise about a ¼ turn and then stop.
Wait until any residual pressure is relieved. Residual pressure is indicated by a hissing sound.
After all hissing stops, continue to rotate the surge tank cap counterclockwise until the cap is removed.




Important: For procedures requiring the cooling system to be partially drained, opening the radiator drain valve should provide sufficient draining. No further actions should be necessary.


Open the radiator drain valve. The radiator drain valve is located at the bottom of the radiator tank.
Remove the engine block drain plug.
Allow the coolant to drain completely.
Inspect the drained coolant:
- Flush the cooling system if the coolant is discolored. Refer to Flushing .

- Continue with the filling procedure is the coolant appears normal.

Refilling
Notice: When adding coolant, it is important that you use GM Goodwrench DEX-COOL™ coolant. If coolant other than DEX-COOL™ is added to the system, the engine coolant will require change sooner: at 50 000 km (30,000 miles) or 24 months.

Close the radiator drain ****. Remove the drain hose.
If previously removed, install the engine block drain plugs. When installing the drain plugs, use pipe sealer GM P/N 12346004.
Important: On vehicles equipped with the 3.1 L engine, open the coolant air bleed valve. The coolant air bleed valve is located on the top of the thermostat bypass pipe/heater pipe assembly. Close the valve once a continuous stream of coolant is expelled from the valve.


Fill the surge tank to the base of the filler neck.
Start the engine with the pressure cap off. Let the engine run until the upper radiator hose starts to get hot.
If the coolant level in the surge tank is low, add the proper mix of coolant until the level reaches the full cold line.
Important: After servicing the cooling system, and if the vehicle is equipped with an intermittent low coolant light, an occasional low coolant light may be encountered during some extreme driving maneuvers. This complaint should be eliminated by removing the surge tank cap and adding coolant to a level just at or above the full cold line when the system is cold.


Install the cap onto the tank with hand tight pressure.



I wonder if your cap is faulty since it prematurly boiling.

[slow6]

Re: coolant overflowing (boiling)

ya, the cap acts as a pressure cooker
the higher pressure makes the boiling point of the coolant higher

[nda0602v6]

Re: coolant overflowing (boiling)

hmm, well the coolant doesn't boil instantly. With the engine cold, I filled it up with coolant then started the engine. I let the engine run for a few minutes till I saw the temp gauge start to move. The temp guage got to around to the half way point and stayed there. However, I could see coolant in that white plastic container on the passenger side bubbling/boiling then it started gushing out a small rubber hose (an over flow hose of some sort). The coolant I used was GM Dex Cool (the reddish/orangish stuff). I mixed a new jug of that with 50% water to make up two jugs. Was I supposed to use the Dex-Cool strait and not mix it with water at all?

[BLLDOGG]

Re: coolant overflowing (boiling)

no, you are suppose to use water also. Im thinking that you cap is faulty cause it shouldnt boil yet at the half way mark but it will if there isnt sufficient pressure supplied by the cap.

[nda0602v6]

Re: coolant overflowing (boiling)

just went out and checked....the cap seems ok but the part where it threads onto the white plastic containter is kinda funky looking (not smooth). I might go pick up another one at a wrecking yard tomorrow....they can't be all that much.

[Bass482]

Re: coolant overflowing (boiling)

Did you remember to purge the air from the system? Did you add the coolant to the radiator or to the overflow when refilling the system?

[BLLDOGG]

Re: coolant overflowing (boiling)

well on his malibu, i think that those cars dont have fill spots on the radiator, just the overflow tub. thats why it has the pressure cap.

[97burnout]

Re: coolant overflowing (boiling)

your supposed to replace the cap after those sort of things... typically new ones

[camaromalley]

Re: coolant overflowing (boiling)

My girlfriends Grand Am was doing the same sort of the thing it had the dreaded quad four engine in it and the head was warped really bad so the compression from the pistons was pushing the coolant out of the overflow container. Just a suggestion.

[BLLDOGG]

Re: coolant overflowing (boiling)

It never crossed my mind that the head gasket might be a problem. but your car is running fine other than the boiling coolant? if it was the head gasket, it would run like hell or not even run at all.

your supposed to replace the cap after those sort of things... typically new ones

no you dont

[camaromalley]

Re: coolant overflowing (boiling)

My girlfriends car ran fine until one day when she was on the highway it was really boggy and ran like crap, but she ran it with the head warped for at least 2-3 months. Should do a leak down test and just see if any cylinder loses pressure. Just to make sure it isn't the head or head gasket.

[slow6]

Re: coolant overflowing (boiling)

....or the piston rings

compression test could tell you the same thing