1993 4.0 124K

The coolant is dark and disgusting. The jeep heats up during slow movement or uphill travel. It can be kept from overheating by running the heater. I see no leaks anywhere and the oil is fine.

I know that the radiator was replaced about ten years ago and that the jeep was garaged for several years between then and when I bought it a few months ago.

I'd prefer to avoid the "just replace everything" approach if I can. Any suggestions on what I should do?

 

If it were me it would get an overhaul. New thermostat, new water pump, ANY hoses that look even slightly bad replaced. New fan clutch (pretty important). A thorough flush and fill. Oh new radiator cap too.


Also make sure you have a fan shroud and check to make sure electric fan functions if you have one. (If you don't have one get one)

Now if you don't want to do that, you could start by flushing out the system until you get clear fluid through it.

 

I'd think a good flush and some new coolant would suffice for a while. A 50/50 mix of new coolant to distilled water and make sure the fan clutch is working properly.

 

Very likely that's all you need!

 

He should also clean out the fins in the radiator and a/c condensor.

Thing is though a GOOD flush means doing the radiator,engine,and heater core seperately. So before putting it back together and refilling it (50-50 mix) he needs to decide if he wants to take the chance that the radiator,thermostat,water pump,and all the hoses are in good working order.

 

All of the cooling system components are a ticking time bomb, under the conditions described. Sure, u can replace components one at a time BUT, replacing components one at a time is kinda like "kicking the can down the road" AND each time u replace just one component, u gotta drain/re-fill coolant. $250 buys all new components and the water pump, t-stat and fan clutch can almost be changed blindfolded, when the old rad is out of the way.

 

^^^^These Are the answers that really want to consider on doing. Personally I would just replace everything since you say that it does start to get hot and that the coolant is already nasty. Who knows what all of the internals looks like. You would be best off taking care of everything all at once.

 

Where are you in Pa? I am near Pottsville, in Minersville.

The best thing to do IMO is what I've been doing. I have drained and refilled my coolant system about 25 times, I finally have perfectly clean water coming out every time. I removed my grill (I drive without it currently because I continue to flush it every 3-5 days) to get easy access to the drain on the passenger side of the radiator .



Rockauto.com

GATES Part # 21615 Lower Hose
GATES Part # 21616 Upper Hose
GATES Part # 33509 Thermostat
GATES Part # 42004 Water pump & gasket
GATES Part # 28411 Heater hose 20'' X10
DORMAN Part # 902306 Thermostat housing & gasket
HAYDEN Part # 2625 Fan clutch
DORMAN Part # 56398 Water pump tube


$103.99 with 5% discount code& shipped from 2 locations (it was only 1 when I last ordered the same thing). If you do order from there be careful on things like the heater hose which comes as 50' roll that you have to click the (1) to get 1 20'' section then in the checkout add "10" to the quantity. For the price you can't beat $104 for everything but the radiator shipped to your door.

Also remove this and run heater hoses from the heater core to the water pump inlet tube/ thermostat housing. These heater valves are junk.



If your a/c works you can turn that on to verify your electric fan is working, the temperature sensor that the ecu uses to turn on the fan is in the thermostat housing. It should come on between 210-215, but the dash gauge may be inaccurate like mine (it comes on at 220-225 for the gauge). There's a thread somewhere on here to ohm the sensor , best replacement is this http://www.ebay.com/itm/NEW-HERKO-TEMPERATURE-SENSOR-TXH43-FOR-VARIOUS-VEHICLES-1984-1997-/360904451318?pt=Motors_Car_Truck_Parts_Accessories&hash=item540794e4f6&vxp=mtr

 

Definitely consider the hoses as they tend to disintegrate from the inside out. Black chunks of old hose can be floating around your cooling system.

Definitely check the radiator and condenser for airflow. Sand, dirt, etc. can collect blocking airflow which increases running temperatures.

Definitely check the fan clutch. Hot or cold it should not free wheel when spun with the engine off.

Definitely check and/or change the thermostat. I prefer dealer thermostats.

Definitely check and/or change the water pump. If a vehicle sits for a few months its not a big deal, but after YEARS the water pump can start leaking/die shortly after the vehicle is put back into service. At least be aware of this.

Flushing will likely take many gallons of water. At first you probably just want to use tap water or garden hose. If there are heavy deposits, as you drive they can be freed up and dirty your fresh coolant so don't expect miracles overnight. This problem will be worse if your radiator is deteriorating. Do NOT use Dexcool. Use Conventional Green and distilled water (or Zerex G-05 if you wish).

 

If I'm reading between the lines correctly, it possibly sounds like the OP would not be to sure what a bad/good water pump looks like, or what a bad/good t-stat looks like, or a bad/good fan clutch or even bad/good hoses, for that matter. Again, a ticking time bomb going by the scenario described by the OP.

No way one can tell how plugged a XJ radiator is.....u can't see in it. Just because garden hose water flows freely thru it doesn't mean that all of the tubes are free flowing. If the bottom half is plugged internally and the top half flows freely, u only have half a radiator dissipating heat. Only a rad shop can tell how clean/crudded up the XJ rad is after they have separated the tanks from the core......but if one starts with all new parts, including the rad, even a newbie will most likely understand that overheating and ticking time bombs can be eliminated from the get go.

 

If budget is an issue, I would recommend replacing all components but the radiator personally. You may be replacing a party that doesn't necessarily need it now, but it's peace if mind knowing exactly when those parts were put in. Flush the crap out of the radiator and heater core. If it still over heats, then stay saving for a new radiator. But at least you will know everything else is good also

 

I have to once again agree with you. Why not just replace everything before you do have that ticking time bomb go off.
If you had to drain your system 25 time you have more problems then you think. Also I would never suggest draining the cooling system with the petcock on the radiator especially on an older rad since more then likely it will start leaking or worse it will break. It is so much easier to just remove the lower rad hose and drain it from there.
You may save a few buck by ordering everything on line from several different places or you can pick everything up at just about any parts store. Plus if you have any problems with any of the new parts you don't have to wait when you have to return them and wait for them to ship everything back to you. I have not had any problems getting all of my cooling system parts from Auto Zone with the exception of the t-stat. That I would recommend getting an OEM one from the dealer set at 195deg. which is recommend for the 4.0. This is just my opinion and experiences with the 4 XJ's that I have owned.

 

Could not have put it any better for your problem and the year.

 

Thanks for the responses. I find the "ticking time bomb" argument compelling, so I think I'll just go ahead and replace everything after all. Please check my shopping list:

Water pump
195 thermostat
Air water outlet (tstat housing?)
Water pump gasket
Water outlet gasket
Curved radiator hoses upper and lower
Water pump inlet tube
90 degree coolant hose
Fan clutch 6"
Radiator
Peak 50/50 coolant
Permatex water pump and thermostat RTV

Am I missing anything?

Comanche1987--I'm between Harrisburg and Hershey.

 

Don't forget to flush, flush, flush then rinse, rinse, rinse till you see only clean clear water coming out. Make sure the heater is on and the temp on high to clean/flush to get it clean and the block before you install the new items.