coolant system flush

[DIYnewbie]

I've got a 94 Ranger, 2.3 liter engine, 5 speed manual trans, and I'm getting ready to do a coolant flush for the first time and I just wanna make sure I do it right. With a garden hose, I'm going to flush the radiator, flush through the upper radiator hose (with t-stat removed, later replace with new one), then back flushing the heater core. Along with the t-stat I'm also replacing the temp sender and see if that'll fix my temp gauge (reads cold). I also got a no-spill funnel to try and purge any air out of the system when refilling with antifreeze. Anything else I missed or any other tips? As I said, it's my first time doing a coolant flush and don't wanna screw it up.

 

[adsm08]

I am not sure if the 2.3 has a block drain or not, if it does you can pull that plug as well to get more stuff out.

When refilling the system you can avoid air pockets by filling the system through a heater hose. Unhook one of them at the heater core, stuff your funnel in it, and add coolant until it starts to come out of the heater core. Since you are filling and letting it exit through the highest point in the system it will push about 99% of the air out as it fills. You will need to top off the rad separately though.


Also, if your coolant is rust brown and really nasty adding some muriatic acid and water and letting it run for a while will help to scour some of the nasty out of the water passages. Just don't get it in your eyes, muriatic is a diluted version of battery acid used for cleaning concrete.

 

[Andy D]

I back flush with a tee on a heater if I do. Miraculously, the Rat's coolant level hasnt budged from the line in the tank. Something is gonna have to break to get fixed

 

[DIYnewbie]

Not sure there is a block drain in the 2.3 but i will double check to be sure. Also I didn't think to fill up through the heater core, not a bad idea, i'll give that a try. Gonna be doing the flush tomorrow morning, providing the weather holds up, I'll let you know how it goes.

 

[LearjetMinako]

Depending on how bad your coolant is now, may require extra steps. If the coolant system isn't too bad, a normal drain, flush, drain again, rinse, drain, and refill with coolant works pretty good. On something like the GM's dexcool, you might as well drain the system of the coolant and then keep the garden hose water going till the water turns clear from crud brown.

FYI, even though you will probably be using tap water for the rinse and flush. I suggest if you can, drain as much water out on the final and fill the coolant system with a pre-mix 50/50 coolant. Tap water contains minerals that can degrade the coolant system sooner than it needs to.

 

[kimcrwbr1]

You can confirm it is the temp sending unit by turn the key on and then short the wire to the sending unit to a good ground, the guage should read hot. A good way to flush the radiator and heater core is backflush both of them then plug the lower radiator hose and fil the radiator 1/2 and 1/2 bleach water and let sit overnight then flush both ways again. If the heater hoses are hard just replace them now also there is a good chance they will leak anyways.

 

[snake]

The way I flush is to remove the upper rad hose from the rad and let it hang loose. Crank the engine let it warm up. When the t-stat opens, water will begin to flow out of the rad hose, so keep a water hose in the rad to ensure the engine stays full. When the water flows clear, run 3 or 4 gallons of distilled through the rad so there is only dist water in the system. Shut the engine down, drain as much water as you can. Close everything, put upper hose back on, then put 1/2 of the cooling capacity of straight antifreeze into the system. If it holds it, fine, then add distilled to top it off. If it doesn't, dump the remaining antifreeze into the recovery tank. This way you'll have no calcium water in the system, and a perfect 50/50 mix when you're through.

 

[DIYnewbie]

So flush was going fine until i went to reinstall the t-stat, talk about PITA! I obviously didnt install it right because it's leaking now, not alot but still a leak. Is there an easier way to install it i don't know about? If it wasn't for that and the fact i ran out of sunlight i would have eventually got it. Any advice?

 

[97RangerXLT]

not sure about your engine, but the 4.0 the tstat has to be installed with a small part in it aligned with a notch in the intake housing. If you do not line this up, it will sit at an angle and not seal right, and you will damage the tstat as well when tightening the bolts.

Also for the 4.0 the gasket is basically an o-ring with a grove in it alll the way around the inside diameter that fits over the tstat's outer edge. make sure that the gasket is not nicked or cut, and make sure that all the mating surfaces on the intake and the tstat housing are absolutely clean and smooth with no burrs or nicks in either.

AJ

 

[tmcalavy]

Prestone makes/sells a flush kit for like $6 at any parts store, or StuffMart. Has everything you need, even a T-fitting, to plug into your heater hose and do it right.