If you plan on overhauling your cooling system on your Jeep Wrangler TJ, one of the steps you should always take is to flush your cooling system. This is something that far too many people neglect to do, when in reality it should be done every several years at most.
Before you read any further, this is a thread worth reading: Jeep Wrangler TJ Cooling System Overhaul FAQ
What kind of coolant should I use?
In my opinion you should be using HOAT coolant in your Jeep Wrangler TJ. Hybrid Organic Acid Technology (HOAT) is a combination of IAT and OAT. Several manufacturers are using HOAT for their vehicles. One version is dyed orange and contains 10% recycled antifreeze. Another version is dyed yellow and does not contain any recycled antifreeze. Both of these HOAT antifreezes use the marketing designator of GO-5. They are compatible with each other but mixing them with IAT or OAT is not recommended. The normal HOAT antifreeze service life is 5 years or 150,000 miles (250,000 km).
A perfect example of a good HOAT coolant for use in your Jeep Wrangler TJ is the OE Mopar coolant. It may be a little pricier, but it's generally going to last longer and be better for your cooling system.
How much coolant should I use?
See this thread for fluid capacities (it varies depending on which model TJ you have): Jeep Wrangler TJ Fluid Capacities.
Supplies
Drain Radiator
1. Make certain your engine is completely cool! Once it is cool, remove radiator cap.
2. Open radiator drain petcock and drain radiator into pan bucket or pan underneath vehicle.
3. Dump a gallon or so of distilled water through the radiator after is is done draining. Use enough so that you see nothing but clear fluid draining out.
View attachment 5111
View attachment 5112
Flush Heater Core
1. Found on the heater core inlet hose where I wanted the TEE fitting. Made 2 cuts removing a 3/4" section. This helps make up for the width of the TEE.
2. Use a funnel to put a gallon or less of distilled water through the hose.
3. Disconnected the heater core outlet hose and reverse flush the heater core.
Use the clear plastic tube to direct any coolant flushed from heater core hoses into drain pan.
Flush Engine Block
1. Look at the illustration below. Find your engine block coolant drain plug. Remove it and let the coolant drain into a bucket.
Finish With Heater Core Hoses
1. Install TEE in the already cut heater core inlet hose. Leave the cap off.
2. Reconnect the heater core outlet hose.
Clean Overfill Tank
1. Remove tank.
2. Clean tank.
3. Install tank.
Filling With Coolant
1. Added 5.25 quarts straight coolant to radiator. Topped off with distilled water.
2. Once coolant started coming out the TEE I screwed on its cap.
3. Filled coolant reservoir half way between Full and Add lines with premixed coolant/distilled water.
4. Started engine and let idle.
5. Squeezed the upper radiator hose a few times trying to expel any trapped air.
6. Made sure radiator was full of water and installed radiator cap. Instructions say to wait until you see water circulating before installing radiator cap. I didn't for some reason.
7. Ran engine for 20 minutes after it reached running temp.
8. Checked for leaks.
9. Stopped engine and let cool.
10. Checked coolant level and mixture ratio.
All Done!
Now wasn't that rewarding?
Before you read any further, this is a thread worth reading: Jeep Wrangler TJ Cooling System Overhaul FAQ
What kind of coolant should I use?
In my opinion you should be using HOAT coolant in your Jeep Wrangler TJ. Hybrid Organic Acid Technology (HOAT) is a combination of IAT and OAT. Several manufacturers are using HOAT for their vehicles. One version is dyed orange and contains 10% recycled antifreeze. Another version is dyed yellow and does not contain any recycled antifreeze. Both of these HOAT antifreezes use the marketing designator of GO-5. They are compatible with each other but mixing them with IAT or OAT is not recommended. The normal HOAT antifreeze service life is 5 years or 150,000 miles (250,000 km).
A perfect example of a good HOAT coolant for use in your Jeep Wrangler TJ is the OE Mopar coolant. It may be a little pricier, but it's generally going to last longer and be better for your cooling system.
How much coolant should I use?
See this thread for fluid capacities (it varies depending on which model TJ you have): Jeep Wrangler TJ Fluid Capacities.
Supplies
- 2 gallons OE Mopar coolant
- 3 gallons distilled water
- Large drain pan
- 3 feet of 1.5" ID clear plastic tube (I think it was 1.5")
Drain Radiator
1. Make certain your engine is completely cool! Once it is cool, remove radiator cap.
2. Open radiator drain petcock and drain radiator into pan bucket or pan underneath vehicle.
3. Dump a gallon or so of distilled water through the radiator after is is done draining. Use enough so that you see nothing but clear fluid draining out.
View attachment 5111
View attachment 5112
Flush Heater Core
1. Found on the heater core inlet hose where I wanted the TEE fitting. Made 2 cuts removing a 3/4" section. This helps make up for the width of the TEE.
2. Use a funnel to put a gallon or less of distilled water through the hose.
3. Disconnected the heater core outlet hose and reverse flush the heater core.
Use the clear plastic tube to direct any coolant flushed from heater core hoses into drain pan.
Flush Engine Block
1. Look at the illustration below. Find your engine block coolant drain plug. Remove it and let the coolant drain into a bucket.
Finish With Heater Core Hoses
1. Install TEE in the already cut heater core inlet hose. Leave the cap off.
2. Reconnect the heater core outlet hose.
Clean Overfill Tank
1. Remove tank.
2. Clean tank.
3. Install tank.
Filling With Coolant
1. Added 5.25 quarts straight coolant to radiator. Topped off with distilled water.
2. Once coolant started coming out the TEE I screwed on its cap.
3. Filled coolant reservoir half way between Full and Add lines with premixed coolant/distilled water.
4. Started engine and let idle.
5. Squeezed the upper radiator hose a few times trying to expel any trapped air.
6. Made sure radiator was full of water and installed radiator cap. Instructions say to wait until you see water circulating before installing radiator cap. I didn't for some reason.
7. Ran engine for 20 minutes after it reached running temp.
8. Checked for leaks.
9. Stopped engine and let cool.
10. Checked coolant level and mixture ratio.
All Done!
Now wasn't that rewarding?