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Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 16035
Experience:  Have owned a repair shop for 25 yrs.
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Why is my antifreeze turning brown?

Customer Question

why is my antifreeze turning brown?
Submitted: 8 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 8 years ago.
HiCustomer Thank you for asking your question on JustAnswer. The other Experts and I are working on your answer. By the way, it would help us to know:

-What year is your Chevy?
-What model is your Chevy?
-How many miles are on your Chevy?
-What type of engine is in your Chevy?
-What have you already tried?

Thank you again for trusting us with your problem. Please reply as soon as possible so that we can finish answering your question.
Customer: replied 8 years ago.
1995 buick lasabre 3.8 98000 miles have tried nothing
Expert:  Tim's Auto Repair replied 8 years ago.


do you ever need to add coolent?or did you just notice this?


Customer: replied 8 years ago.
no don't have to add coolant   yes just noticed could iy just be dirty had car for 5 yrs and never changed coolant
Expert:  Tim's Auto Repair replied 8 years ago.


yes,you need to flush the coolling system and add new clean ati-freeze,,use a name brand like peak or prestone,these have a lube added for the water pump


please ACCEPT my answer so I can get credit for my work.i don't receive commission unless you do ..i'm not always going to be giving you good news,so please dont let this stand in the way of you accepting my does not cost you more money.we will still be able to communicate.. Bonuses and positive feedback are appreciated!if you are not satisfied with my answer,please do not leave bad feed back,i will gladly opt out and let another expert handle the question.PLEASE ASK IF YOU NEED MORE HELP

Service and Repair


Note: Ethylene glycol/Water fill ratios have been established to ensure a minimum of 50 percent Ethylene Glycol in the coolant mixture following the recommended coolant flush, and drain procedure, and that all engine block drains and air bleeds were utilized.

The cooling system capacity is 10.9 liters (11.6 quarts) . The coolant recovery reservoir capacity is 0.75 liters (0.8 quarts) to the "COLD" mark on the reservoir. The quantities listed in the filling procedure include the additional quantity to displace the air remaining in the coolant system after a static refill,

Using the correct fill ratio and the following procedures will ensure a minimum concentration of 50 percent Ethylene Glycol in the coolant system and simplify the customer fill task. Refer to Figure for static fill radiator capacities. Every five years or 166,000 km (100,000 miles) whichever first occurs, the cooling system should be drained, and filled using the following recommended procedures.

NOTICE: When adding coolant, it is important that you use DEX - COOL (orange-colored, silicate-free) coolant meeting GM Specification 6277M. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner at 50,000km (30,000 miles) or 24 months.


Important: This procedure significantly increases the amount of used coolant and diluted hazardous waste.

CAUTION: As long as there is pressure in the coaling system, the temperature can be considerably higher than the boiling temperature of the solution In radiator without causing the solution to boil. Removal of the radiator cap while engine Is hot and pressure is high will cause the solution to boll instantaneously- possibly with explosive force - spewing the solution over engine, fenders and person removing cap. Under same conditions, the ethylene glycol in engine coolant is combustible.

  1. Park the vehicle on a level surface.
  2. Remove and clean coolant recovery reservoir.
  3. Remove the radiator cap when the engine is cool, by:
    1. Slowly rotating the cap counterclockwise to detent. Do not press down while rotating pressure cap.
    2. Wait until any residual pressure (indicated by a hissing sound) is relieved.
    3. After all hissing stops, continue to rotate counterclockwise until the cap is removed.

Important: Recover coolant and store in a used coolant holding tank and submit the used coolant for recycling on a regular basis. This procedure significantly increases the amount of used coolant and diluted hazardous waste.

  1. Place drain pan under vehicle to collect all drained coolant.
  2. Open the radiator drain valve located at the bottom of the radiator tank.
    • For procedures requiring the cooling system to be partially drained, opening the radiator drain valve should provide sufficient draining and no further actions should be necessary.



  1. Remove the thermostat housing cap and thermostat or open the air bleed vents. Open the air bleed vents on the thermostat housing and above coolant pump. The air bleed vents should be opened two to three turns.



  1. Remove the engine block drains. Remove both engine block drains. The front engine block drain is located between the starter and the engine oil filter. The rear engine block drain is located by the engine crank sensor.
  2. Allow the coolant to drain completely.

Important: Dispose of used coolant in a proper fashion, i.e., in a used coolant holding tank. NEVER POUR USED COOLANT DOWN THE DRAIN! Ethylene glycol antifreeze is a very toxic chemical; disposing of it into the sewer system or ground water is both illegal and ecologically unsound!


  1. Close the radiator drain valve. Reinstall all engine block drains (knock sensors on 3S00). Reconnect the inlet hose to the engine oil cooler.
  2. Install the coolant recovery reservoir and empty. Flush the reservoir with clean water, drain and reinstall.



  1. Slowly fill the cooling systems through the radiator neck using the following procedure:
    • If the coolant system has been flushed, first add 100 percent ethylene glycol in the amount listed in figure for the appropriate engine application. Then slowly add clean water to the system until the level of the coolant mixture has reached the base of the radiator neck.


  • When refilling the engine cooling system, add two engine coolant supplement sealant pellets, GM P/N(NNN) NNN-NNNNor equivalent and GM approved new Ethylene Glycol coolant antifreeze GM P/N(NNN) NNN-NNNN
  • If the cooling system is being refilled ONLY (no flush), a 50 percent ethylene glycol and 50 percent clean water mixture should be used to fill the system. Fill the system until the level of the 50/50 mixture has reached the base of the radiator neck. Wait two minutes and recheck the level of the coolant mixture, add a 50/50 ethylene glycol/water mixture as necessary to restore the coolant mixture level to the base of the radiator neck.
  1. Install the radiator cap making certain the arrows line up with the overflow tube.
  2. Close all air bleeds. DO NOT over-torque the air bleed valve. The air bleed valve is made out of brass.
  3. Fill the coolant reservoir with a 50 percent ethylene glycol and a 50 percent clean water coolant mixture. The proper amount of this mixture to be installed into the coolant reservoir is listed below:
    • All engines Add 1.7 liters (1.8 quarts) of a 50/50 mixture of ethylene glycol and clean water to the coolant recover reservoir.

NOTICE: The low coolant indicator lamp may come on after this procedure. After operating the vehicle so that the engine heats up and cools down three times, if the low coolant indicator lamp does NOT go out, or fails to come on at ignition check and coolant is at the level indicated in step 3 go to Testing and Inspection. If at any time the "TEMP" warning indicator comes on, immediate action is required.

Inspect: The freeze protection of the engine coolant after the engine heats up and cools down three times using a refractometer or a thermohydrometer to ensure proper freeze -37°C (-34°F) protection. Obtain the coolant mixture for the inspection from the base of the radiator neck, NOT from the coolant recovery reservoir.