Ye Ol' Cherokee

so I've been meaning to do a cooling system flush; does this sound like a good way to do it in a 98 xj 4.0?

Disconnect lower rad hose, drain, refill with distilled water, run til hot with heat on, cool down, repeat two times, then refill with 50/50, and a little straight antifreeze in case some distilled water stayed in the system.

suggestions are welcome, but i will not be cutting my new heater hose for a T fitting, and i don't want to risk putting holes in anything with prestone flush.

also, when refilling at the rad, do i need to add any to the reservoir when the rad is full?

does everything typically come out when disconnecting lower hose or does some stay in there?

p.s. heater core has already been blown out recently

kgm

Most of it comes out via lower hose. I'd keep draining / flushing until it comes out clear. Then I added full strength antifreeze because the block still has distilled water in it.

Also detach and clean out your reservoir. I got about 1" of grit / grime / sand / rust out of that thing! Now she runs alot nicer. I still have to replace my components but it bought me atleast another season

djb383

Remove top rad and heater hoses from the t-stat cover. Remove bottom rad hose from the water pump. Stick garden hose in heater hose and flush. Stick garden hose in the heater hose nipple on the t-stat cover and flush. Stick the garden hose in the top rad hose and flush.

jpz

This is how I have done every cooling system flush. The way your descrbing I guess would work, but seems like a lot of extra work.

djb383

The recovery bottle should be about 1/3 full, motor COLD. Rad should be full to the top, motor COLD

About 1/2 gallon will be retained in the block.

Unless both the motor and rad were flushed at the same time the heater core was flushed, u can count on crud from the motor/rad finding it's way to the heater core. Flush all 3 (core, motor, rad) separately AND at the same time.

Ye Ol' Cherokee

i like what im hearing here, ill do this. just to clarify though, a few questions. 1.) im placing the garden hose on the heater hose nipple that the LARGER heater hose connects to, correct?
2.) when flushing the rad, and tstat housing, is all of that going to come out of the lower rad hose @ the water pump?

after this i will reconnect everything, fill with distilled, run, drain @ lower rad hose (to try and get the tap water out of the system) then refill with 50/50.. could you give me some advice for burping the system after the refill. i have heard horror stories about air in these systems

thanks for all your, and everyone elses help

djb383

Hope this helps.

tracyk

Sorry to butt in, but it's related...promise.
I changed WP, TStat, TStat housing and all hoses. I did NOT take rad out or flush it b/c I believe it to be new within last 7 months and I never had overheating issues since getting it (did a "gentle" flush on heater core though). At completion, filled it through radiator which took forever. It would get to the point of being full to top of radiator, so I ran it a little and squeezed upper rad hose to help it circulate/get air out. Had to do this several times.
Of course, I then found that despite my best efforts, new TStat housing was leaking pretty good at lower left (7 o'clock-ish). I had opted for the fel-pro gasket + RTV so I'm hoping that was the issue and I'm re-doing it now with the gasket the housing came with. Anyway...
My questions are also about re-fill....Is it supposed to take so long to re-fill through the radiator or is that a red flag? And, will coolant make it to reservoir on its own that way or should I fill through there as well? I noted the advice that the reservoir should be 1/3 full, but wondered if that meant to directly fill it through the reservoir to achieve that amount?
Thanks, this feels dumb, but I know I need to get it right. Ug.

djb383

Since the motor is cold after a flush and refill, fill the bottle about 1/3 full and fill the rad full to the top. Each time the hood is raised and the motor is COLD, the bottle should be about 1/3 full and the rad should be full to the top.

Always check coolant levels in the bottle and rad when the motor is COLD.

Fill the cooling system very slowly. Let the motor idle with the rad cap off keeping the rad full 'til the stat opens (it burps) and install a new rad cap.

Muddz

I often use a garden hose to clean out old sediments perhaps a half dozen or more times depending on the condition of the cooling system ... and sometimes run the engine with plain water for a while to loosen old sediment.

Rust and sediment gets trapped in the bottom of the radiator and in the heater core, flushing helps to remove sediment, but won't necessarily remove all the rust and sediment. I sometimes flush the heater core, radiator and the engine block separately. Back and forward flushing the heater core, radiator and engine block helps to remove additional rust and sediment.

Chemical flushing tries to loosens baked on rust, calcium and lime. Multiple rinses are usually required to remove flushing agents. Soda wash is sometimes used to neutralize chem flushing agents. One problem with chemicals flushes there often too weak and not in the cooling system long enough to remove baked on rust, calcium, lime, etc. Chemicals actually strong enough to remove baked on rust,calcium,lime,etc. can potentially damage a cooling system.

Our water is high in minerals. Perhaps filling the cooling system with only distilled water, running the engine for a while then empty. Would help to remove the mineralized tap water.

Flushing machines such as found in automobile service and repair shops normally use coolant and flushing agents in a closed system and are able to to apply forward and reverse pressure to cleanse the cooling system.