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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
I have a 2015 Jeep JK with 25K Miles .. which during a Coolant Flush , Brown Sludge was found inside components. Currently under Warranty. What causes this ? We all know it contaminated . but vehicle was always exclusively serviced with Dodge Dealership.... Why is it Brown sludge besides corrosion?
I have done this on 4 cherokees and it has worked great every time.
1 .Drop lower hose off block and remove thermostat housing.
2. Run water hose water through the radiator until the water is clear.
3.Run water through the block until it is clear.
4. Backflush the heater core from both directions until water is clear and flows freely.
5. Mix a half a box of Cascade dishwashing detergent in a half gallon of water until it is dissolved.
6. Put the jeep back together with NO thermostat.
7. Pour the detergent mixture in the radiator and top off with the hose. Burp it and drive it for week.
8. Drain and flush twice with distilled water.
9. Put a new 195deg thermostat in, and fill with a 50/50 mix of distilled water and antifreeze.
Everyone I have done this do comes out shiny as a new penny inside. If it's nasty again 6 months after you do this you have a head gasket or head issue.
My coolant has been rusty sludge for years, flushes helped for about a day, then rusty again.
I finally realized the Prestone flush n fill kit was pretty much worthless due to the two TINY holes they use in the inlet piece to restrict the water pressure from the garden hose. (The black and yellow piece on the far left in the pic)
They do that evidently for liability purposes because they don't want to be responsible for blowing the innards out of your heater core.
So anyway, I took the heater hoses off where they enter at the firewall and blasted out the core with the garden hose, I couldn't believe the amount of gunk that came out. I blasted it out from both the inlet and outlet hose, ever since then my coolant has been rust/sludge free.
As a bonus my heater is now a blast furnace.
Be careful pulling the hoses off at the firewall because you don't want to break the metal fittings that the heater hoses attach to.