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Running too hot

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Sugarloaf View Drop Down
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    Posted: 20 Dec. 2020 at 2:37am
Does anyone have a solution to connecting a pressure tester to the large neck on the old willys radiator?  I have a situation that’s driving me nuts. My Cj2A L134 is running at 200-210 when at 45 mph for about 2 miles. I don’t push it so I never got to boiling over. When I slow down to 25 or so (or stop and idle) it goes back down to about 170-175. 
I bought this Jeep a year ago with no previous knowledge of its owner. Seems he rebuilt the engine in 1990 as well as restored about 80% of of the it. It has all new gauges including speedo/odometer. There is 3400 miles on the ticker. And that is the story I got. Older gentleman “restores” Jeep. Drives in parades. After his passing family sells. I have all the receipts. Seems legit story. 

So for what I did. Removed t stat. Used Prestone flush twice. Ran for 50 miles on a few startups each time. Got a little gunk out of it. The heater didn’t work but now it does so I think I got a little help there. 
Replaced all hoses. And heater valve. Replaced t stat (160 deg) and the little riser it sits on. Replaced upper and lower hoses.  Replaced radiator. Used offshore unit from KW with shroud. Air deflectors are in place. New radiator cap. Not much change. Still gets over 200 at speed or slower uphill at higher loads. 
Checked head temp at sender with IR thermometer. Reads pretty much what the gauge reads. Used Fluke probe in the radiator (cap off) it hits 188-190 even when the gauge says 200. 
I guess my next step is remove the water pump. Check the impeller???  It was replaced with the engine work in 1990. No leaks or looseness. Belt is tight. 
Anybody got any other suggestions.?  
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otto View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec. 2020 at 3:10am
Seems you covered all the obvious bases, have you checked the ignition timing?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Michaeltru Quote  Post ReplyReply Direct Link To This Post Posted: 20 Dec. 2020 at 3:15am
And to go with timing, what do your spark plugs look like?  Color wise by the electrode?  Could be running lean
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RSR_MK Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2020 at 12:09am
From what you have checked my best guess would be that the radiator is plugged. You seem to be moving the heat from the engine to the radiator. 

Mike 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rus Curtis Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2020 at 3:54pm
Back in the day, there were adapters that went between the pressure pump and the radiator filler neck - to get the seal for a pressure check.  A good radiator shop should still be able to do that.

Beyond your first question, I was thinking radiator blockage too until you posted you had replaced the  radiator.  IF the old radiator was plugged, the new one should have "fixed" that.  

I wonder if you have checked the thermostat to see if it's opening fully at temp or is either sticking or only partially opening?  I had a new thermostat that stuck out of the box.

I also suspect the pump.  It would be easy to assume that if no leaks and belt tight, it should work.  But, other than potential block restrictions, there isn't much left.  If it inspects okay, then you're out sealant and possibly another gasket.   I'd be looking for a lot of build up or, as weird as it seems, a loose impeller.

Timing check is a good idea.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote RSR_MK Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2020 at 7:35pm
I agree with everything Russ said. Why I would suspect the radiator is it seems you dislodged some build up if your heater is working now. It’s hard to say how much was floating around and where it ended up. You seem to be getting heat from the engine to the radiator. 

When you check the pump I think I would back flush the radiator. 

Mike. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rawlo Quote  Post ReplyReply Direct Link To This Post Posted: 21 Dec. 2020 at 7:47pm
You say you, replaced the t stat and the little riser it sits on. It’s been 20 years since I removed a thermostat, doesn’t assembly go thermostat, retainer gasket and housing. Sounds like the thermostat is on top of retainer.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sugarloaf Quote  Post ReplyReply Direct Link To This Post Posted: 29 Dec. 2020 at 5:27am
Just an update- I pulled the water pump and t stat. The water pump looked fine but there wa about 3/16” (.187) between impeller and housing. I had read that gap wants to be smaller like around .010”. So I pressed the impeller on further to decrease the gap. It ended up at .011” BUT the bearings or something got really tight. Too tight to put back on. I had a brand new one from NAPA so I installed that one. BTW the gap on that one was .127”. 
I also drilled a 9/64” “bypass” hole in the stat body. To eliminate any chance for air bubble. It got up to about 171degrees running in the shop. I ran out of time to road test. Seems like there is no change. 
As for the adapter for the pressure testing at the radiator neck I have a snap on tester and it has several adapters but none fit. I’ve searched google and can’t 
Find anything that fits. Does someone know of a universal adapter that will fit the neck or is there something you could plug a tee into a heater hose or something?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rus Curtis Quote  Post ReplyReply Direct Link To This Post Posted: 29 Dec. 2020 at 7:44pm

Sugarloaf, 

I'm a bit surprised you're having difficulty finding an adapter.   If the cap is replaceable, and you still want to test, you can always make your own adapter with a spare cap (even to me this seems like a whole lot of extra work).  

On to what you're seeing now. 

Is that thermostat you drilled the hole through the same one from before?  I would be testing that in a container of hot water to observe it opening and closing (use a thermometer in the water to verify temp as it opens and closes).   Does it fully open or just partially?  Is there a hesitation and then a full open? 

I had a brand new thermostat that stuck the first time it was used and I replaced it not because I couldn't get that one to open and close (exercised in a bowl of hot water, multiple times - it took a while to get consistent) but because I would not trust it.   

While running, if the water doesn't shoot out of the uncapped radiator (indicating no circulation, i.e. a stuck thermostat) I observe a rise in temp on the upper hose (indicating circulation) and I watch to see if the coolant moves across the cores inside the neck but not rising (confirming circulation). 

And as Mike has pointed out, there may still be deposits that are affecting your flow.  Back flushing should fix that.    

When you do get a drive on it - to see if it rises like before, have your IR thermometer with you to compare.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 29 Dec. 2020 at 8:16pm
All good advice, including the two mentions of timing which I see no response on. Timing can certainly cause an engine to run hot.

If timing is right at idle, another thing to check, which can impact timing at higher RPM, is the mechanical spark advance in the distributor. The weights can get stuck, the springs can break or weaken, and that is something often neglected in maintenance. Some people never inspect these things, and we are running vehicles that are older than I am. Anything that moves is subject to wearing out, just like my knees did. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote OnlyOneDR Quote  Post ReplyReply Direct Link To This Post Posted: 29 Dec. 2020 at 8:37pm
Crack the temp sender loose to see if any air comes out of the head.  It shouldn't but you never know.  I also agree on the timing; the advance will push that ahead under load/speed and if it goes to far it will run hot.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sugarloaf Quote  Post ReplyReply Direct Link To This Post Posted: 10 Jan. 2021 at 4:37am
During  road test it Got up to 205 degrees and lost power. Idled fit 2 minutes and temp came back to 180. Drive for 10-12 miles and temp stayed 180 ish. No more loss of power. 
Came back pulled the t stat and tested It starts to open at 172 and is fully open at 184. (160 degree stat)
So I bought another one  tested it. It starts opening at 170 and fully opens at 180.  It was my understanding that a 160 t stat should be fully or close to fully open at 160 degrees. Is this wrong?

Anyway while I wait for another t stat to test I will be working on timing tomorrow.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 10 Jan. 2021 at 5:33am
Originally posted by Sugarloaf Sugarloaf wrote:

During  road test it Got up to 205 degrees and lost power. Idled fit 2 minutes and temp came back to 180. Drive for 10-12 miles and temp stayed 180 ish. No more loss of power. 
Came back pulled the t stat and tested It starts to open at 172 and is fully open at 184. (160 degree stat)
So I bought another one  tested it. It starts opening at 170 and fully opens at 180.  It was my understanding that a 160 t stat should be fully or close to fully open at 160 degrees. Is this wrong?

Anyway while I wait for another t stat to test I will be working on timing tomorrow.

Please let us know what you find timing wise- where you found the initial and total settings.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sugarloaf Quote  Post ReplyReply Direct Link To This Post Posted: 10 Jan. 2021 at 7:08pm
Well friends it seems timing was the culprit. Although the cooling system DID need some maintenance I could have probably saved the radiator and water pump cost. But I feel good about pulling it out and replacing it any way since I bought the Jeep with the “assurance” that the motor was good. 
So initial timing was about 15 deg BTDC. Advance took it 20 more. 
So now I have it set at 6 deg BTDC mech. advance puts it at 26 at 3000 rpm. 
Water temp never got over 185. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan. 2021 at 4:11am
Interesting, thanks for posting your findings.

I set my jeep at 8* initial and get 30* total where it makes noticeably more power than when it was only reaching 24* total. My jeep always runs on the cool side though.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote smfulle Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan. 2021 at 2:48pm
Originally posted by Sugarloaf Sugarloaf wrote:

Well friends it seems timing was the culprit. Although the cooling system DID need some maintenance I could have probably saved the radiator and water pump cost. But I feel good about pulling it out and replacing it any way since I bought the Jeep with the “assurance” that the motor was good. 
So initial timing was about 15 deg BTDC. Advance took it 20 more. 
So now I have it set at 6 deg BTDC mech. advance puts it at 26 at 3000 rpm. 
Water temp never got over 185. 

Probably should have  a little more advance at higher RPMs. I suspect your counterweight springs are weak or the posts that hold them are bent. This causes the the base plate to move some advance at idle. You then set your idle timing to the standard idle advance and there is not enough advance left in the counterweight system to get all the way to the max advance. 
Just something to check sometime.
Stan
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sugarloaf Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan. 2021 at 8:22pm
I was wondering how much advance the counterweights add. It’s a replacement electronic distributor. Don’t know what brand. It was there when I bought the Jeep. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan. 2021 at 10:52pm
According to the service manual, the mechanical advance is good for 22 degrees. I too have a no-name distributor- it's a points unit and had to go through it last year because the springs were slack. Had to bend the anchor points outward, but fixed it up.
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