Jeep, Jeep Radiator Flush,, Jeep DIY, Jeep TJ

How to Flush Your Jeep’s Radiator

Jeep, Jeep Radiator Flush,, Jeep DIY, Jeep TJ

Your Jeep’s coolant system plays a vital role in health of your Jeep’s engine—it keeps it cool. The thing is, as time goes by your Jeep’s coolant gets filled with gunk (actually rust) from inside the engine and radiator. Eventually, it needs to be drained out and replaced with fresh coolant. Furthermore, the whole system needs to be flushed out. This article will explain how to flush your Jeep’s radiator and refill it when done.

You can easily service your Jeep’s cooling system and radiator yourself. The project requires no major special tools and can be performed in about two hours (mostly waiting for the engine to cool back down between steps) on a Saturday morning. The process starts the day before, with adding a cleaner into your Jeep radiator and driving the vehicle around. The following day you drain the radiator, flush the radiator, and then refill the radiator on your Jeep. It’s that simple.

How Often Should I Flush and Fill My Jeep’s Radiator?

Every two or three years you should consider draining, flushing, and refreshing the coolant in your radiator. It isn’t a complicated, but there are a defined series of steps and precautions to take. If your Jeep’s engine temperature gauge is running high (My Jeeps seem to run in the 190-205 degree range) or your Jeep is overheating you definitely want to perform a coolant change. Also, if your Jeep’s heating isn’t heating, it might be time for a change.

What is the Process to Flush and Fill My Jeep’s Radiator?

Let’s start with what we need to do this job. Here’s what you need:

Armed with the above listed items, you are ready to service your Jeep. Here’s what to do:

  • Put the radiator flush/ cleaner into the radiator the day before and drive the vehicle around. Word of caution: Only open the radiator cap when it and the Jeep is cool, or even better cold. The system is pressurized when hot, and you can be sprayed with antifreeze, and even worse scolded
  • Park the vehicle on a level surface
  • Let the vehicle cool (Touch the radiator cap– cool or cold is good. Remember, as I cautioned you above a hot radiator cap is “Old Faithful” in your face and possible burns)
  • Open the cool cap
  • Put the pets and kids in the house (Anti-freeze smells and tastes sweet, but is poisonous)
  • Check your Jeep’s owner’s manual for the drain cock location (on Jeeps, it is the lower passenger side) and the capacity for the radiator fluid (Jeeps with 4.0 liter in-line 6 cylinder engines take about 2 gallons)
  • Locate the drain cock (Small wing nut at the bottom of the radiator)
  • Place the drain catch pan under the drain cock location
  • Open the drain cock and let it drain down to the catch pan
  • Close the drain cock
  • Take the spent anti-freeze and use the funnel to pour it into the old containers
  • Now setup the flush kit hose and attachments and run cool water into the radiator (Fill with hose and run the engine- be sure the drain cock is closed)
  • Replace the catch pan under the drain cock and open it
  • When the flush is drained and flush completed close the drain cock
  • Repeat this process a few times until the liquid coming out is more clear than when you started—you will definitely see the difference. Also, the last time you do it don’t use the house, but rather the distilled water. House water from the hose has minerals, we want them out of the system—a last flush with distilled water removes that earlier water
  • Be sure to disconnect the two heater hoses that run along the valve cover back to the firewall. These go to your heater core, the system that provides heat to the cabin of your Jeep. Flush it both ways through each hose. This “back flushing” help unclog it and provide better heating in winter. Remember to use distilled water for the final flush
  • Remove the catch pan and pour the flush into old containers
  • Now you are ready to refill the anti-freeze with a 50/50 mix of coolant and distilled water (Remember: Tap water is no good– minerals rust radiators)
  • Be sure to fill your Jeep’s excess coolant reservoir if it needs to be topped off to the “Full” line
  • Now you can “burp” the system run the Jeep for a few minutes with the radiator cap off and watch the fluid. Also, squeeze the large radiator hose to help the process. You want to see bubbles appear, when to bubbles stop the system is burped. Don’t run the engine too long, since the fluid will rise and possibly over-flow
  • Top off the Jeep’s radiator using the funnel and close the cap, then run the engine for a minute
  • Open the radiator cap and check to see if you need to top off the fluid

Close the cap and you are good to go

Where are you going? To the recycling center or auto parts store with the spent fluids. In some states, the auto parts store will recycle spent fluids for you.

What Else Might I Replace While Flushing My Jeep’s Radiator?

When performing the radiator service on your Jeep, you may want to replace the upper and lower radiator hoses. This is a relatively simple job using the same tools as above, but you should also use some radiator hose grease to make putting the new hoses on easier, as well as getting them off in the future easier as well. If the radiator hoses on your Jeep are spongy when you squeeze them—they should be replaced. New radiator hoses are firm when squeezed. This will add about 15 minutes to the radiator flush and fill job.

Are There Any Other Things I Might Do When Servicing My Jeep’s Radiator?

Yes, you might want to change your Jeep’s thermostat and water pump. These are slightly more complicated jobs and I will cover removing and replacing Jeep thermostats and water pumps in another article.

Related Articles

How to Perform a Tune-Up on Your Jeep

How to Do an Oil Change on Your Jeep

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