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| Stubborn Thermostats? | |
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| Tweet Topic Started: Sep 28 2009, 12:00 PM (669 Views) | |
| ParadigmCrime | Sep 28 2009, 12:00 PM Post #1 |
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Ive tried TWO new thermostats now, and they just seem to be stubborn on opening. Its like they wont START opening I watch the temp climb and climb and no opening. Usually what I find is best is to warm up the jeep, let it get to 210, then wait for a minute and eventually the thermostat will open and Ill see the temp drop quickly. Sometimes I need to stop the jeep, wait a few, start it again and that will get it to go. If I go about my morning routine though of starting the jeep. Going back inside, drinking coffee etc. Ill come back outside and see the temp has climbed all the way to 230! It does open every time, but its like it is being stubborn. Sometimes if I squeeze the hose from the radiator to the top of the thermostat, I can get it to open. I did a short stint with the thermostat removed, but then the jeep drives like crap cuz it never gets above 160 operating temp (which is after driving it for a long time.. short drives it will be less than that). Plus its so freakin cold here sometimes I REALLY need a thermostat. I have tried two different brands, both 180 degree thermostats. I dont want to go with a lower temp tstat, because it gets so cold here. When the thermostat is OPEN it keeps the jeep at a nice even 180-190 and it runs great. Do thermostats require 'break in'? is it maybe just because it gets so cold at night that its sticking? I notice its worse on mornings where it gets really cold at night. Its very frustrating, because once the thermostat does open it does a good job, its just getting it to open that seems to be the problem. |
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| bob east texas | Sep 28 2009, 12:40 PM Post #2 |
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It might be in upside down. bob |
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| ParadigmCrime | Sep 28 2009, 12:48 PM Post #3 |
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I thought about that.. I assume the side with the spring goes DOWN, so that its touching the hot coolant. The box pictures it in this orientation, and I believe the old one I pulled out during the rebuild was also in that position (the old one was stuck open). |
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| gearwrencher | Sep 28 2009, 02:24 PM Post #4 |
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I have a friend with a Ford F150, he now has gone thru two Temp valves in one one year ,same kind of problem. I think its poorly made parts from China .Bad parts out of the box!! |
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| 1954cj3b | Sep 28 2009, 02:24 PM Post #5 |
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I would try another brand thermo or go to a 185 |
3b'ers do it on all 4's
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| jeeper50 | Sep 28 2009, 04:35 PM Post #6 |
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ol' skool jeeper jeff
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The original ones had a small vent that bleed air out of the system so the head would be completely fully of water. I'd suggest you drill a 1/16" hole in the new stat to dplicate this feature(in flat area next to spring). I'd also "borrow" a thermometer outa the kitchen to double check your temp gauge if reading correctly. |
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In the land of the blind... the one eyed man is king Texan at heart, Georgian by paycheck '53 CJ3B, F134, 12v alternator, lockrights, Hot-Spark electronic module,11"self energizing brakes, Belleview winch, Beachwood summertop, OD color, built to honor all Veterans of this great country Kayaks- Hobie Revo 13, Hobie Outback 12' both ready for the salt... | |
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| ParadigmCrime | Sep 28 2009, 06:07 PM Post #7 |
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Temp guage is most likely correct, its brand new. Also I did try two different brands. One has a little hole on it, the other doesnt, they both produce the same problem. Im positive its the thermostat, because I notice when it finally does open, the tempature drops quickly. Also with no thermostat in, it takes a long time, and some driving to even get it up to 160. The old thermostat was stuck open I believe, and the temp almost never got above 140. The jeep purs at 180-190 and runs great, I notice its always in the mornings getting it to open the problem. I drive it to work every morning, and usually when I come back after 8 hours of work the thermostat opens normally, unless it was particularly cold during the day (like during the last snow storm we had a week ago). Today I took it out for a drive, I had to fiddle with it to get the thermostat to open. Later in the day (4-5 hours later) I went for another drive and the thermostat opened normally. without fiddling. I guess it could be TWO crappy thermostats out of the box, which is very frustrating. There is no auto parts store up here in the mountains, I gotta go all the way to the flat lands to find ANOTHER one. Can anyone recomend a brand I can buy online? |
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| HOGHEAD | Sep 29 2009, 06:26 AM Post #8 |
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Old Jeep Fart
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We used to drill a few more holes (4or 5) in our thermostats in our race jeeps as the AMCs like to run cold... Did you check all the hose's sometime times they collapse & stop the flow of the fluid ,,Ive seen the inside of the hose come lose & clog the system & then the fluid cant get past it ,,, I take a new thermostat and put it in a pan of water to make sure it opens at 160 in the summer & 185 in the winter,, 160 in the summer cause they like to run cold & 185 cause I like to stay warm :rolleyes: ,,, Wait!!! I just had a brain fart,, Have you bleed the system of air ,, That can cause that ,, Preston (anti-freeze people) makes a real nice flushing kit for the stystem that has a garden hose conection in it ,, put it at highest hose youve got & just break it lose & run it till all the air is out,,, Bet you got a air pocket in there,,, |
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Dargan Md... Death Before 2 Wheel Drive... "On a Steel Horse I ride" AMC Rules. "Journey" not the Destination... 59 Cj3-b (married to a 74 Cj-5 frame & AMC running gear) Willys Overland,, My Build http://z4.invisionfree.com/CJ3B_Bulletin_B...?showtopic=2892 | |
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| ParadigmCrime | Oct 1 2009, 08:14 AM Post #9 |
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air pocket sounds the most plausable... but wouldnt it eventually work itself out? Also wouldnt it keep it running hot? As I said, once the thermostat gets going it works fine. I find it usually doesnt open until the temp hits 210-220! once open it runs at 180 Also my experience this week has been after work the thermostat opens fine, even if it sat for 8 hours. Its just these cold mountain mornings. When I get back from a vacation in a month, Im installing a new water pump, Ill dick with getting the air out then. I think my water pump is working fine, but it makes an aweful squeaking noise sometimes, and Im sure its going on its way out. A new water pump was cheap. (Couldnt find any rebuild kits!?) |
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| HOGHEAD | Oct 1 2009, 09:51 AM Post #10 |
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Old Jeep Fart
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You have to find the highest water hose make a break in the line & let the air find its way out,, Thats were the Kit from Preston comes in handy I just crack mine & sit over night,, And you can use it to flush the system when you change out the anti-freeze too.. air can be trapped in a highier place than the radiater cap ,, I turn on my heater also i have a valve on my heater hose ..so it lets fluid go throw the heater |
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Dargan Md... Death Before 2 Wheel Drive... "On a Steel Horse I ride" AMC Rules. "Journey" not the Destination... 59 Cj3-b (married to a 74 Cj-5 frame & AMC running gear) Willys Overland,, My Build http://z4.invisionfree.com/CJ3B_Bulletin_B...?showtopic=2892 | |
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| elawson | Oct 1 2009, 07:19 PM Post #11 |
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Would adding the bypass hose between the front of the cylinder head and the top of the water pump help? My CJ3A does not have the bypass hose, and the engine temp goes up to around 210F before the 160F thermostat opens. Fro mtehre the temperature cycles up and down for about 5 minutes until it finally settles down to the 160F temperature. My CJ5 has the bypass hose, and its engine temperature gets up to around 180F before the 160F thermostat opens. One time I jumped into the cold CJ5 and had to immediately drive fast and the engine temp went up to around 200F before the thermostat opened. My guess is that the back of the block (where the temperature sensor is located) gets hotter than the front of the block (where the thermostat is located) and the slow water flow through the bypass hose helps keep the block temperature more equal until the thermostat can get open. Eric |
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| yjcanibul | Oct 1 2009, 07:46 PM Post #12 |
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mine overheats , it also weeps from the overflow tube on side of rad trying to diagnose it after shutting off several minutes I could hear it start to boil in the rad not saying its a solution "yet" but I read the rad cap may be bad , something todo with the coolant turning trying to turn to steam or something if the system isnt kept closed properly I have a new cap now but the jeeps in storage, they should get introduced within the month and I can see if it works ... |
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57 3B : big speedo / Hurricane / YF 938 SD / IAY-4012 / T90 / D18 / 5.375 final drive / open diffs / Firestone 6ply Military NDCC / 12v Delco SI alt / Kayline Top / venting windshield / tub patched / "still fixing leaks one at a time" 89 wrangler : h/duty axles + 5spd / 200+hp 4.2L / arb locked / multiport fuel inj / warn hubs+winch / 1/4 mil km / fishing+trail riding / gets me to work | |
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| HOGHEAD | Oct 2 2009, 06:48 AM Post #13 |
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Old Jeep Fart
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Wow I'm glad more people having brain farts,, (it hurts when I have them) Ive seen the impellers slip on the shaft of a brand new water pump,, Ive seen the cap not releise the presure & that caused it to over heat.. Ive seen hose brake lose on the inside & clog the system,,, Clogged radiaters ... Even str-8 anti freeze will affect the cooling system,, once I bought a old motor to get me by & it had a mouse inside the block that stopped the flow... God I love Jeeps... |
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Dargan Md... Death Before 2 Wheel Drive... "On a Steel Horse I ride" AMC Rules. "Journey" not the Destination... 59 Cj3-b (married to a 74 Cj-5 frame & AMC running gear) Willys Overland,, My Build http://z4.invisionfree.com/CJ3B_Bulletin_B...?showtopic=2892 | |
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| jyotin | Oct 2 2009, 09:10 AM Post #14 |
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The trapped air solution makes sense. I've rebuilt several F heads that overheated initially. It usually took a couple of days or so for the problem to go away. Why not try putting the jeep in an attitude where the left front wheel is lower than the rest of the jeep. What you are trying to do is to generate a position where the right rear of the engine is as high as possible, since any trapped air in the head will 'want' to migrate out of the aft cooling port. Once any trapped air in the head has passed through the hoses to the return you should be OK. I don't think that this an altogether unusual problem -- I have seen other threads on F heads overheating and then cooling down and sometimes continuing the overheating-cooling process. |
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It's just my luck that something good is going to happen to me today. 54 - 3B - down on the farm 67 - cj6 - former state of Alabama vehicle ?? - cj5 T98a - made from spare parts - Ford tractor blue ?? - cj5 T98a - made from spare parts - Jeep green | |
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