salinity

Hi - 95 Cherokee 2.5L RWD no A/C - I noticed a bit of a coolant leak yesterday - it seems to leak 4-6oz when parked. I looked as close as I could last night and noted coolant on the bottom half of the water pump and it's running down the lower hose (water pump to radiator). I plan to look into possibly replacing the water pump this weekend, but as I have to baby it to/from work until then I have a few questions:

After driving for over an hour, I noticed the lower hose (water pump to radiator) was not hot - is this unusual, or could it mean the radiator is doing it's job?

I also noticed the upper large hose from the radiator to the engine was not "firm" - does this indicate a lack of pressure and / or coolant not getting to the engine? I have plenty of coolant in the reservoir and have been running with the heat on just in case. Note: I don't have a temp gauge - just a dummy light.

Given where the leak is occurring, is there anything else I should look at in terms of where the leak / issues may be stemming from?

I'm also in need of any info and advice on replacing the water pump / thermostat as I'm in the process of moving and my Haynes manual is in storage 200mi away.

I have a general sense of how to go about replacing the water pump (drain system, remove fan, loosen (remove?) belt, remove bolts, look for bolt behind P/S pump), but if there is any advice or a good write up you know of, I'd be very appreciative. I've read some info about saving the bolts for the water pump, as new pumps don't come with them typically - is this usually the case (and are the bolts easily removed or obtained?

Also, where is the thermostat located? I assume it's a pretty easy swap out, and I'll probably be looking to do that as well.

Finally, I noted some new pumps come with a recommendation to replace the fan clutch. My fan seems to run constantly (is this indication of an issue?) - how important would this be in your opinion?

Wow - sorry for the long post, but thanks for looking and any advice!

djb383

Hope this helps.

Roler

When doing the waterpump and planning on replacing the thermostat and maybe the viscous fan clutch as well, you might as well go ahead and renew the hoses and be done with it. Flush your radiator (which like djb stated seems to be doing its job, the lower hose should actually be significantly cooler to touch than the upper hose). This way, you only have to drain your coolant once.
With winter coming up for you guys , flush your heater hoses as well, in preparation of colder temps.

And indeed don't overtighten the bolts (no, they ususally dont come with the new waterpump), especially the thermostat housing is prone to crack if you do.

Wish I could copy/paste from the FSM pdf I have for the step-by-step procedure, but there are several write-ups available, IIRC.

salinity

Sure does - thanks. The "fan constantly running" is in reference to the belt-driven fan, which makes sense to be constantly spinning - I suppose I don't completely understand the purpose of the fan clutch. That might be the next project after I get the water pump and thermostat in.

Corroded bolts are definitely a concern - I have a few days to work on it (true Labor Days), so overnight soaks with PB blaster are not out of the question.

salinity

Thanks for the info - are there any "tricks" to getting the bolts off the old pump to install on the new one? I ran across a couple of mentions of that being an issue. I did run across one decent writeup, but I think it was for a wrangler or 4.0 - but I think it outlined the general idea of what I'm looking at.

djb383

Most of the time the fan clutch is "free wheeling".....virtually no load on the motor for better engine performance, better mpg's and less fan noise. When the fan clutch senses high enough air temp from the rad, the clutch begins to "engage/grab" more, thus pulling more air thru the rad for increased cooling. The sound/roar is very noticeable when fully engaged. The fan clutch is a very important component in the cooling system, especially during summer heat and slow speed driving.

As previously stated, fan clutch performance degrades with time/miles.....+/-$35 spent on a new one will be money well spent.

Roler

What, other than remove them and put them back on with the new pump? No, nil tricks. I had no issues whatsoever. I guess you could spray them with a bit of PB blaster or the likes, if you;re concerned they might be rusted in there....but other than that, just use common sense and don't use an impact on them

Fred/N0AZZ

Might be a good idea to replace the thermostat housing (they corrode up) as well they are cheap <$20 for the 4.0 should be about the same for yours.

salinity

Thanks for all the info - going to dig in this weekend. I'll let you all know how it goes (and if I run into any inevitable issues).

djb383

How old is the radiator, or did I miss that? Water pump, t-stat and fan clutch can almost be replaced blindfolded when the rad is out of the way. Don't use the drain plug in the rad to drain coolant.....they're plastic, brittle and break easily. Remove the bottom rad hose from the water pump to drain both the rad and motor. Removing the plastic air filter box 1st makes for easy access to the rad hose at the water pump.

PocketsEmpty

Yep...best way. Just be prepared for a mess, LOL. Also, while you're going to be doing all this nice maintenance to the cooling system, don't forget to replace the radiator cap. Often overlooked, cheap insurance. Also, if you were just changing the pump, there's no need to remove the T-stat housing or fan (except the electric fan) to get the pump out. But you're replacing all that anyways, right?

Another thing you should do at this time--replace those annoying plier clamps with normal clamps, like these:

djgrayxj

Note from DJ
Make sure that the counter person where you by the replacement water pump understand that it is for a 2.5 engine not a 4.0. The rotation is different.
NAPA Numbers and Rotation:
TFW 42005 by Tru-Flow Water Pump
Water Pump Rotation: Reverse for a 2.5 L 150 CID L4 AMC Design
Note Reverse Rotation

TFW 42004 by Tru-Flow Water Pump
Water Pump Rotation: Standard for a 4.0 L 242 CID L6
Note Standard Rotation

salinity

Good advice - thanks. I plan on bringing the old pump in to ensure it matches up. I do plan on replacing the t-stat along with the pump - may have to wait til the next paycheck for the fan clutch (could probably spring for a new cap too). The radiator is about 5 years old, but seems to still be working well, so that's one for another day.

Totally agree about the clamps - I replaced a few when I did the radiator - I'll replace any I pull off for sure.

salinity

Update: Put in the new pump, thermostat and thermostat housing yesterday. I learned a few things. First - somewhere along the line I noted a procedure for removing the "double threaded" bolts that are threaded into the water pump that ultimately bolt the fan on. The procedure is to reverse thread on a nut, then put another nut on top of it the standard way effectively locking them together ("nutting them"?). I did it with a couple wing nuts I had that happened to fit (see pictures). This allowed me to backt he bolt out of the old pump and install on to the new one.





The next lesson: seat the thermostat BEFORE installing the gasket. I let it sit overnight (to allow the RTV to set - very thin coat on both sides of gaskets) then went to fill with water to do a couple flushes of the system (there was definitely come crud in the upper part of the block where the thermostat housing attaches). Just filling the radiator resulted in water squirting out of a compromised part of the thermostat housing gasket. I drained it, pulled it off, and realized my error - I put the gasket on first then the thermostat, then the housing. The result was a torn gasket when the thermostat was pressed into it's seating on the block. I'm actually pretty anxious about the seal (both on the thermostat housing and the water pump) - tomorrow will tell...

salinity

Update II: Filled her up today and noted what I thought were a couple small weeps - one where what I'm assuming is the temperature dummy light sensor threads in and another on the lower part of the housing. I put a bit of teflon tape on the threads of the assumed sensor and decided to fill it up again and start her up - I let it run for 10min or so with NO APPAREN/T LEAKS! The upper radaitor hose is nice and firm too - which I assume means decent pressure in the system. I'm currently monitoring for leaks as she cools down.

I'm going to flush a couple mroe times. How can I tell when the thermostat opens up (I don't have a temperature gauge)?