On a cold Saturday in the new fallen snow, I once again realized that my heater with the new motor wasn't any where near as hot at the old 285 motor. I decided to wait out the -20 degree day and tackle the job on a nice warm Monday in the future. Isn't it always the coldest day of the year that any thermostat decides not to work? It's like the battery dieing on a smoke alarm. It never dies and BEEPS at 3:00 in the afternoon, it only Beeps at 2:00 in the morning.... but I digress.

The easiest check for a bad thermostat is to pop the radiator cap and start the engine cold. If the fluid is moving right away, you can tell that the thermostat is stuck open. I did, and it was. We had replaced everything on that "new" motor I could think of during the swap; seals, plugs, wires, fluids etc, but I guess I never thought to replace the thermostat while the engine was on the stand :-\

So. Minute 0 to minute 4, I unscrewed the drain plug on the radiator (yes, no matter how hard I tried to keep a hold of it, I didn't.....I dropped it in the bucket. Is that a shock? :-P )

Still. Minute 4-6 I grabbed a ratchet and 13mm socket and took out the bolts and popped off the Thermostat housing. That is when I noticed all the "form-a-gasket" from the previous owner's repair was almost completely clogging the heater core inlet. That may have been another issue with the heat, eh?

A quick scrape and grind and it was shiny as new again. I light coating of gasket treatment on the new gasket, and just enough to hold the new thermostat in place and minute 12 was coming to a close.

One of the bolts looked a little stripped, but since I still had a coffee can full of spare parts from the motor swap, I just located another 5/16 bolt and all was good.

With the housing carefully placed over the new gasket and thermostat, I finger threaded the bolts and grabbed the ratchet again. (Minute 12-14 if you are still counting) Top bolt started to snug, so I switched to the bottom bolt. Even though the bottom bolt is only 3/4 inches long, it seemed to take a lot of time to snug up.... long time....quite a long time....really, quite a long time....... something was wrong.

I reversed the ratchet and removed the bolt and it too was stripped. Odd, since there was never any real tension on it, but I grabbed another (new) bolt and made sure to not cross thread it or anything. It too went in easily, but never tightened! So I took it all apart to have a look. Hmmm. Not a good thing to see during this particular "look". What you are looking at, as was I, is the bolt hole on the bottom part where the thermostat housing bolt goes into the engine block seemed to have a 25% Discount in the circumference department. Yes, about a quarter of the hole was broken off. Broken off! There I was with 3/4 of a hole. Not very helpful. 

Well, it was looking like the 30 minute estimate would not hold, and sitting there staring at it, hoping it would heal it's self, or elves would jump out and fix it for me wasn't coming to fruition, so I decided I should just drill it out and tap it. It might take an extra hour, but I have the tools and the know how, so I told myself to quit whining and just do it. Well, first I had to go to bowling league, then a nice dinner and some girlfriend time, and at 10:00 PM I was back out there again.

Now, even with a small right angle drill, I was not going to have enough room to get a nice 90 degree hole drilled into an engine block with the fan and radiator there. And of course, to tip the radiator and grill forward, the big winch had to come off first, but since it was all off just a couple months ago, I knew I wouldn't have any frozen or suck bolts. So off came the winch and the top bolts holding the grill and radiator. With the Grill tipped forward a few inches, the drill with a 17/64 bit could easily drill a deeper hole. How deep before I broke through the block was unknown. It's not something you can find on the web, either... I checked :-) But I figured I was safe for 1/4 or so. Now, for those literate folks out there who know all about "foreshadowing", I will ruin the suspense and let you know that this is not foreshadowing, and I did not drill all the way through the block and create more problems.

I drilled about 1/4" out of the existing hole, tapped it with a 5/16th tap and test threaded a new, longer bolt. All seemed fine, and when I took it out, it wasn't stripped! All is good (So why is there so much more writing on this page????? Maybe this is the foreshadowing part)

With some very meticulous scientific measurements, (I stuck a nail in the hole and marked it with my fingernail) I realized that a 1" bolt was too long to fit in that hole and still make the housing sung enough to stop and fluid leaking, so I threaded on a nut on the bolt and went to the grinder to remove a few threads. That too went smoothly, and removing the nut smoothed out the rough ends from the grinder and the bolt threaded into the new hole just like it should have.

So.... Hoses go back on, fluid back in (Yes I did remember to fish out the drain plug and tighten it before refilling) and I think I should start it and check for leaks before I put everything back together. (Momma didn't raise no dummy) So I fire it up and wait.... about a minute..... then there is a strange, thunking, knocking kind of noise. Well, it seems that with the fan still off of the water pump, the bolts that hold on the pulley are no longer holding on the pulley! (momma raised a dummy) When I took off the fan originally, I tried to remove the pulley, but it didn't come off, so I thought it was there to stay. I guess a minute or so of a tight fan belt spinning around on it was enough to loosen it, make it slide forward a bit, slide off a bit and chew up the serpentine belt a bit. (and a bit more)

What joy.... A frayed and ripped belt at 10:45 at night isn't really what the Dr ordered, but since I just wanted to check for leaks, I figured I could make the old belt work. I took it off, Snipped off the stringy, dangly bits and put it back on and snugged it up and put the bolts back on the fan pulley :-)

I double checked everything... No tools in the way, belt run correctly, bolts all tight, turned the key and the jeep started right up... then died just as fast. Huh? Turned the key again..... Started right up, ran smoothly..... for 2 seconds and just quit. No sputter, no stall, just off. I did this again for about three more times just to disgust myself, it was really happening. Ran like a charm for two seconds and then quit. Now... all of you who read (and can still remember) the final chapter in the wiring fiasco might recognize the 2 second Run-Stop issue as a Grand Cherokee Security issue. Just like before, the computer seemed to be shutting down the engine after two seconds. or was it? I didn't do anything to the Computer, or Security Module, Or anything! I DIDN'T DO ANYTHING! Why won't it start?!?! Who is keeping time still? Not me, this was enough to make me just go to bed. I'll fix it tomorrow....... No I won't! I tried all the next day (a couple hours anyway) and couldn't find anything wrong with the Alarm, the fuses, the Auto Shutoff relay, or any electrical stuff. the only thing electrical I touched was the coolant temp sensor that I unplugged from the thermostat housing. That couldn't be it, could it????? No, it couldn't, but I took it off again and checked for anything odd, or coolant in it or bad connections or whatever I could think of. Then I left it unplugged and tried again. This time the motor would crank, but not start at all. Might be on to something... don't know what, but maybe something. I plugged it back in... Jeep ran for 2 seconds and quit. Unplugged it and and no start at all again.... plugged it back in and...... No start at all!!!! Again? No start at all.... Plugged in, un plugged, half plugged, fingers crossed, even stood on one foot facing East and hopped up and down and clucked like a chicken... nothing worked. Is wouldn't even run two seconds anymore. (well.... I think that eliminated the Security system as the culprit.)

If a motor wont start, you have to figure it's not getting one (or more) of three things. Gas, Air, or Spark. I thought I would start with gas. I could hear the pump working, the gauge said 1/4 tank, I pressed the relief valve on the fuel rail and a spit of air and then gas came out. Just for giggles I added a gallon and a half of gas and tried again. What do you think happened???? It started and ran for two seconds... three seconds.... four, and it just kept on running! Two days of messing with everything and it just need to be burped?

Well, now it is at the point where it should have been at 10:45 pm two days ago. The motor running to check for leaks :-P I'm sure I don't have to tell anyone that, Yes... it leaked! Slight dribble from the lower part of the housing, but I took out the bolt and filed it down another two threads and tightened it down again. A little tighter this time.... I hate that feeling of thinking the next twist is going to strip it out again, but it really did seem snug this time.

And, the Jeep actually started again, and it ran for a while and the thermostat opened and the fluid ran through the engine and the heater core and NOT out any place on the housing.. or anywhere else! it was fixed!!!! It only took another half hour or so to put the grill, radiator and winch back together, and to double/triple check all the belt tension, bolts, power, etc.

Just a simple little 30 minute thermostat change..... with a couple days of garbage in the middle!