Overheating problem - has me stumped - HELP!

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
User avatar
YLG80
G-Lieutenant General
G-Lieutenant General
Posts: 4095
Joined: Fri Aug 05, 2011 9:45 am
Location: near Namur, Belgium
Contact:

Re: Overheating problem - has me stumped - HELP!

Post by YLG80 » Mon Nov 22, 2021 4:52 am

reusablem.com wrote:
Mon Nov 22, 2021 2:25 am
hi, I am doing a little article in the classic military vehicle mag re keeping things cool on jeeps , I have had dozens of jeeps pass through my hands with overheating problems, generally the main cause has been the channels in the radiator internally blocked or partially blocked with rust that has set and very difficult to clean out, the outside of the radiator sometimes blocks with chaff and dust so a good blow through with compressed air will soon reveal if it is chocked up , I have also had a couple of jeeps with the fan fitted the wrong way round so pushing air the wrong way, several jeeps had thermostats with to high a temperature and no air bleed hole in the thermostat, ( I use 71degree thermostats ) joes motorpool do a fast flow thermostat but make sure its a 71 degree , if they don't say the temp on the thermostat I don't use them, air vent hole in the thermostat is vital or you will get an air lock at the top of the engine and the thermostat wont open if it has no water around it, this causes a build up of heat in the engine block until the coolant boils and has to push out the bottom of the engine and come up through the radiator causing a sudden eruption of coolant to force out , If you choose a nice cool thermostat 71 degree or 160 f and drill 1 or even 2x 4.8mm holes in the outer part to let out any trapped air , also a small amount of water will be able to constantly flow past the thermostat spring so as soon as the water is hot enough the spring will respond and open quicker , I have also had jeeps with no radiator felt fitted so hot air form the engine bay can be sucked back into the radiator, also the tin shroud around the fan is sometimes missing , the shroud is hugely important and helps stop recirculation of hot air from engine bay, generally the worst i have had to do is have the radiator re cored, constricted radiator is usually the problem 90% of the time and one a re core has been done it usually does the trick, If the radiator wont fill up as fast as the hose or watering can can feed it , that shows a restriction in the channels, specially if you get lots of gurgling and noises on fill up, nice strong antifreeze will stop rust buildup in the future , I know worst cause would be a blown head gasket or an internal crack in the head or the engine but this is far less likely the cause , even the fan blade angles do get changed to stop the wurr noise , the blades should have a good curve with the leading edge at right angle to the radiator, small adjustable is ideal for re shaping the blades, Hope this is helpful
Waooh, that's a good summary of the question ! Thanks
And do not forget :
Often 'NEW' radiators have 2 core & not 3.
Cheaper is not always better.
JEEP has 3 or extreme 4 core radiators.

Yves
Ford GPW 1943 - Louisville - DoD 12-7-43
serial 164794


Kings
G-Master Sergeant
G-Master Sergeant
Posts: 109
Joined: Mon Jan 20, 2003 7:10 am
Location: Newbury, Berkshire. UK

Re: Overheating problem - has me stumped - HELP!

Post by Kings » Fri Jun 24, 2022 12:04 pm

Hello everyone,
Whilst in Normandy a few weeks ago my 1944 MB fan 'threw a blade'. Luckily no damage done and only a 3-4 mile drive back to where we were staying. The following morning I cut off the opposite blade to stop the vibration. No overheating issues whatsoever and drove the 60 ish miles from the uk port to our house all good. New fan (NOS one) received. Now it would appear my jeeps fan has been fitted the wrong way for 20+ years with no heating issues, or it's a gennerator one.
The centre mounting boss is sort of dished and, once bolted onto the pulley, will be either 1. Sort of be further forward (twds rad) or 2. Sort of wrap around the pulley (a small amount) thus the blades more rearwards.
I know the air should be drawn through rad into engine area.
Does anyone have a definite picture of how THE BLADES should be please. Currently I've seen about 50/50 of each.
Thanks all
Kingsley

User avatar
YLG80
G-Lieutenant General
G-Lieutenant General
Posts: 4095
Joined: Fri Aug 05, 2011 9:45 am
Location: near Namur, Belgium
Contact:

Re: Overheating problem - has me stumped - HELP!

Post by YLG80 » Fri Jun 24, 2022 12:45 pm

Kings wrote:
Fri Jun 24, 2022 12:04 pm
Hello everyone,
Whilst in Normandy a few weeks ago my 1944 MB fan 'threw a blade'. Luckily no damage done and only a 3-4 mile drive back to where we were staying. The following morning I cut off the opposite blade to stop the vibration. No overheating issues whatsoever and drove the 60 ish miles from the uk port to our house all good. New fan (NOS one) received. Now it would appear my jeeps fan has been fitted the wrong way for 20+ years with no heating issues, or it's a gennerator one.
The centre mounting boss is sort of dished and, once bolted onto the pulley, will be either 1. Sort of be further forward (twds rad) or 2. Sort of wrap around the pulley (a small amount) thus the blades more rearwards.
I know the air should be drawn through rad into engine area.
Does anyone have a definite picture of how THE BLADES should be please. Currently I've seen about 50/50 of each.
Thanks all
Kingsley

Hi Kingsley,
Here is a photo of the engine bay taken in the Ford factory in 1943.It show the fan blades orientation.

Engine-Ford-original-LATE.jpg
Engine-Ford-original-LATE-magnifier.png

And another one from a motorpool

56E0DE49-E2E4-4D78-8AEB-20EE79AADFC7.jpeg

and from my GPW engine bay.

fan blades orientation.jpg

Yves
Ford GPW 1943 - Louisville - DoD 12-7-43
serial 164794

Kings
G-Master Sergeant
G-Master Sergeant
Posts: 109
Joined: Mon Jan 20, 2003 7:10 am
Location: Newbury, Berkshire. UK

Re: Overheating problem - has me stumped - HELP!

Post by Kings » Fri Jun 24, 2022 1:10 pm

Many thanks.


Post Reply

Return to “MB GPW Technical Knowledge Base”

Who is online

Users browsing this forum: Bruce W, Majestic-12 [Bot], maurywhurt, Vic ALLAN and 26 guests