Low Cooling Temperature Problem

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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carl51
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Low Cooling Temperature Problem

Post by carl51 » Thu Nov 16, 2017 4:47 pm

My 1943 GPW had been running great, but lately I am beset with several problems. One problem is addressed in another post regarding the failure of the charging system. However, I just recently escorted several veterans in our Veterans Day parade and experienced a cooling system temperature problem. At idle speed for over an hour in the parade, the temperature gauge never moved past 130 - 140 degrees on a cool day 70 degrees outside. Previously, the engine ran well and had pegged at 180 degrees on a moderate day and 200 degrees on a hot summer day. The only maintenance procedure I recently made was re-torqueing the head stud nuts after an engine rebuild about 150 miles ago. The radiator now is only just warm to the touch and the inlet and outlet radiator hoses are not bulging with pressure. Could my thermostat be stuck in the open position? When I rebuilt the motor, I had the radiator reconditioned with 3 rows of tubes in the core. Did I over-engineer this reconditioned radiator and create a problem? Thank you one and all for your excellent advice.
Carl
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GPW #117302 DOD 5/21/43 Louisville, KY
MB #210593 DOD 2/11/43 matching frame & body under restoration


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Re: Low Cooling Temperature Problem

Post by dinof » Thu Nov 16, 2017 5:34 pm

The fact that it ran 180 degrees before would make me suspect the thermostat is stuck open. Radiators for these jeeps is usually a three core unit so I doubt that it's causing your too cool problem. When the jeep is cold, take off the radiator cap and start the motor and see if the coolant is moving briskly by. If so, it's the thermostat. Normally it should not move when first started. The coolant will travel from the top hose part of the radiator tank, to the left.
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carl51
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Re: Low Cooling Temperature Problem

Post by carl51 » Thu Nov 16, 2017 5:39 pm

Thanks, Dino. That test makes real sense.
Carl
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Re: Low Cooling Temperature Problem

Post by artificer » Thu Nov 16, 2017 5:52 pm

Don't get these inter-related coolant system components & what they do confused.

1. Radiator capacity will not cause/alter lower temperature unless there is no [or a stuck open] thermostat.
2. The thermostat is there to restrict the flow, after startup, until the correct coolant temperature is achieved then the thermostat opens & closes continually to maintain that reasonably constant temperature.
3. If the thermostat is stuck/broken & fully open then the engine will take much longer to reach temperature, especially with a high capacity radiator.
4. If the hoses are not getting pressurized, the radiator cap is faulty or there is an air leak in the cooling system letting pressure out, but these things will not cause overcooling.

Check the gauge first, then the thermostat & test the radiator cap operation.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Low Cooling Temperature Problem

Post by tsmgguy » Fri Nov 17, 2017 10:12 am

Others will know better than I, but if I might add from personal experience:

Yes, your thermostat is either missing or it's failed completely open.

You want an original brass bellows 180 degree thermostat. The repros sold today are of a different design from India or Pakistan and are complete junk. I managed to find three originals, new in the boxes and wrap, made by Harrison, part 3122285, dated 1953. One went on to the MB, and possessing the other two means that the first one will probably never fail. :D

180 degrees seems to be the correct heat range. I'm seeing no corrosion on my MB's oil dip stick, so I know that somewhere in the cooling system it's getting hot enough to boil off moisture in the engine oil, which is hydrophilic. Perfect.
Willys MB 236426, Hood 20336549, DOD 5-20-43
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Re: Low Cooling Temperature Problem

Post by carl51 » Sat Dec 16, 2017 3:08 pm

This is a follow up after following the excellent advice provided by G503 members. I purchased a Laser Infrared Thermometer (what a fun toy!) to check the accuracy of the temp gauge by measuring the temperature of the thermostat housing while the engine was running. The gauge is accurate measuring 140 degrees after warming up the engine. So, I pulled the thermostat housing to check the thermostat and discovered something surprising. The thermostat retainer had collapsed and moved somewhat allowing the thermostat to flip inside the housing to sit 90 degrees from a seated position. So, the thermostat was rendered completely useless. I checked this 170 degree thermostat in hot water on our stove and it opened at 170 degrees. This was a new retainer and thermostat purchased when the engine was rebuilt approximately 150 miles ago. Upon inspection, there was corrosion and pitting on the cylinder head where the retainer would normally sit after the housing was bolted on. As the retainer is split to expand to fit the inside of the housing, this split was apparently positioned right on top of the corroded area thus allowing the retainer to collapse and flip the thermostat in the housing. When I reinstalled the thermostat, I made sure that the split portion of the retainer was not centered over the corroded area of the head. Hopefully, this will prevent this problem in the future. The engine now runs great at 170 to 180 degrees. If the thermostat flips again, I may try to fill the corroded area with JB Weld so that the retainer always sits flush in the housing. Hope this helps someone else with this perplexing problem.
Carl
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GPW #117302 DOD 5/21/43 Louisville, KY
MB #210593 DOD 2/11/43 matching frame & body under restoration

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Re: Low Cooling Temperature Problem

Post by tamnalan » Sun Dec 17, 2017 5:42 am

Thank you Carl! For those of us in colder climates, the classic fix to a winter-time low cooling temperature problem is a piece of cardboard stuffed in front of the radiator.

I run a 170 thermostat also but it is a little too cool for wintertime Ohio temps. Covering about 1/3 of the radiator really helps.
Alan W. Johnson
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Re: Low Cooling Temperature Problem

Post by Wolfman » Sun Dec 17, 2017 6:33 am

Wolfman's trick of the day.
I have found thermostat retainers in really poor condition. Rusted. Corroded and falling apart.
The cure.
A piece of rubber stick hose. Like the radiator connector hoses that connect the radiator metal tubes to the radiator and engine.
This type hose comes in different sizes. Get a piece the proper size to fit snuggly inside the thermostat housing. Cut it squarely to length and use the hose instead of the metal retainer to keep the thermostat held securely in place.
The hose is thicker and does a better job of holding the thermostat in place but still allows proper thermostat function. And it is not effect by coolant. Won't rust or corrode.
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Re: Low Cooling Temperature Problem

Post by Joe Gopan » Sun Dec 17, 2017 6:49 am

639651 Thermostat Retainers are readily available from your favorite Jeep parts supplier. OEM were not plated thru the 60's all the replacements since then are plated. Thermostats stick in the open position. I use OEM bellows type 160F year round and my MB will maintain close to that in the hottest of 4th of July parades.
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Re: Low Cooling Temperature Problem

Post by Wolfman » Sun Dec 17, 2017 7:01 am

Necessity is the mother of invention and getting a job satisfactorily finished and out the door gets the job done and me paid by a satisfied customer. Money is motivational.
I could put the job on hold while waiting for a retainer to be shipped in or go to NAPA for a piece of stick hose. Let me think about that. .... Times up.
Suppose I could buy a case and set the unused ones on the shelf. Naa!
And honestly I like the stick hose better. Been doing this for a while and have not had a failure so far.
8)
Mike Wolford
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Re: Low Cooling Temperature Problem

Post by artificer » Sun Dec 17, 2017 7:47 am

It is good to get the feedback & a pity many others don't do the same.
The temperature Carl was running @ is indicative of what a Jeep, with a good radiator & cooling system, runs @ when a thermostat is removed. That clue was a pointer to look in that area.
That is not a reason to remove the thermostat, a component that plays a number of very important purposes.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Low Cooling Temperature Problem

Post by Chuck Lutz » Sun Dec 17, 2017 12:30 pm

From what I can piece together....
Harrison #3122283 is a 160F t-stat
Harrison #3122284 is a 170F t-stat
Harrison #3122285 is a 180F t-stat

Anyone with a Harrison manual able to confirm those numbers and their use on the L-134?
Chuck Lutz

GPW 17963 4/24/42 Chester, PA. USA 20113473 (USA est./Tom W.)
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Re: Low Cooling Temperature Problem

Post by fernando mendes » Mon Dec 25, 2017 3:31 pm

artificer wrote:
Thu Nov 16, 2017 5:52 pm
Don't get these inter-related coolant system components & what they do confused.

1. Radiator capacity will not cause/alter lower temperature unless there is no [or a stuck open] thermostat.
2. The thermostat is there to restrict the flow, after startup, until the correct coolant temperature is achieved then the thermostat opens & closes continually to maintain that reasonably constant temperature.
3. If the thermostat is stuck/broken & fully open then the engine will take much longer to reach temperature, especially with a high capacity radiator.
4. If the hoses are not getting pressurized, the radiator cap is faulty or there is an air leak in the cooling system letting pressure out, but these things will not cause overcooling.

Check the gauge first, then the thermostat & test the radiator cap operation.
These days ago I ran my jeep with 93F or 34C weather temperature and the gauge marked 210F all travel.Yesterday I ran again with 75F or 24C weather temperature and the gauge marked 180F during all the travel.I do not use termostat.My radiator cap is not original and it allowed the cooling go out.Is it normal?
Jeep Willys MB DoD dec,16 1942 s/n:196275
Dodge B3-B 4x2 1952 s/n:90099559
CCKW 353 Banjo 1944 s/n:309623

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Re: Low Cooling Temperature Problem

Post by fernando mendes » Tue Dec 26, 2017 1:31 am

bantamj wrote:
Mon Dec 25, 2017 11:16 pm
Your radiator is on the top of it's tones.
Coolant spil is not good, it indicates boiling inside the head.
Another reason for coolant spil can be from overfilling.
A well sealing cap that build up pressure in the system can stretch the capacity from the cooling system.
But my take would be to remove the radiator and replace with a known to be good one just for trouble shooting sake.
Most likelly your radiator will need the bottom tank removed for serious cleaning and if still possible rod out the core.
In extreme case the core needs to be replaced.

Luc

033.jpg
I will send my radiator to a technique.I noticed the new under right side core was pouring this tone.Thanks Luc.
Jeep Willys MB DoD dec,16 1942 s/n:196275
Dodge B3-B 4x2 1952 s/n:90099559
CCKW 353 Banjo 1944 s/n:309623

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Re: Low Cooling Temperature Problem

Post by artificer » Tue Dec 26, 2017 9:27 pm

Fernandes wrote:These days ago I ran my jeep with 93F or 34C weather temperature and the gauge marked 210F all travel.Yesterday I ran again with 75F or 24C weather temperature and the gauge marked 180F during all the travel. I do not use termostat. My radiator cap is not original and it allowed the cooling go out.Is it normal?
These temperatures are too high when the thermostat is missing & indicates, as Luc has said, restricted or blocked cores in the radiator.
A good Jeep cooling system with the thermostat temporarily removed will run @ about 140*F or 60*C.
DO NOT RUN PERMANENTLY WITHOUT A THERMOSTAT.

If a cooling system is filled to the top
when the engine warms up that coolant will expand
the coolant expansion, whether there is a radiator cap on, it is working or not will expel air & excess coolant through the overflow
the more the coolant is heated/expanded the more coolant will be expelled
should the coolant boil huge amounts will be lost

After the coolant cools the missing coolant does not need to be replaced [unless boiling has taken place] as the coolant has found its correct level
Next time the vehicle is run the coolant will expand & again fill the top tank after air is expelled
no more coolant will be lost or expelled, unless the vehicle operating temperature is higher this time round

A pressure radiator cap doesn't alter the temperature of coolant, it raises the temperature @ which coolant boils
it also keeps more expanded coolant in the cooling system over a non pressure cap, a faulty cap or no cap @ all
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.


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