Temperature differences

The Cub Club -- Questions and answers to all of your Cub related issues.

Moderator: Team Cub

Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
Mr_deco
Posts: 1
Joined: Thu Sep 23, 2021 8:47 pm
Zip Code: K7L4v1

Temperature differences

Postby Mr_deco » Thu Sep 23, 2021 9:09 pm

Hello to everyone new owner of a 1958 farmall cub. Bought it not running but now have it running. She runs beautifully. I’ve been reading about the pressurized and the non pressurized. My rad cap is missing parts. It doesn’t seal to the base of the neck only to the top. I’m treating this as no pressurized. After engine has been running for 5-10 minutes there is warm coolant coming to the top of the rad. ( normal) the return to the block has been abiant temperature with no temp change I can feel. Do these systems take a while to get moving within? I’ve let it run just a bit above idle for 20 min and the return still feels the same. If this is the normal way the system works then wow. The top on the rad is too hot to touch.

User avatar
Dale Finch
10+ Years
10+ Years
Posts: 5570
Joined: Tue Apr 27, 2010 11:34 am
Zip Code: 27517
Tractors Owned: '51 Cub "Bernie" with Fast Hitch
'55 Cub "Bruno" with Woods 59 mower
'55 Cub "Bertha" with Woods 42 mower
'55 Cub "Ben" with Woods 42 mower
'56 Cub "Boris" with Mott Flail mower
Circle of Safety: Y
Location: NC, Chapel Hill

Re: Temperature differences

Postby Dale Finch » Thu Sep 23, 2021 9:28 pm

Here is the Blue Ribbon Manual on the Cooling System. It describes how the system works, as well as servicing.
http://farmallcub.com/rudi_cub/www.cleancomputes.com/Cub/Blue%20Ribbon%20Service%20Manuals/GSS-1016%20Cooling%20System/GSS-1016%20Cooling%20System.htm

Most of the earlier cubs ARE non-pressurized systems. You may read discussions about antifreeze blowing out when the tractor heats up. They all have their own "normal" water level, and if filled too full, the excess will exit via the overflow tube.

WELCOME!! :hattip:

Note: This is the type cap used for the non-pressurized system, available from TM Tractors, a forum sponsor:
http://www.tmtractor.com/new/co/1642fp.htm
Some folks who find the previous owner (PO) of their cub put a pressurized cap on, simply cut off the spring-loaded lower seal.
Dale Finch
Image
Circle of Safety

Gary Dotson
Team Cub Mentor
Team Cub Mentor
Posts: 4558
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Re: Temperature differences

Postby Gary Dotson » Fri Sep 24, 2021 7:23 am

I think what you’re seeing sounds pretty normal. You’re not making a lot of heat at fast idle and the fan and radiator are cooling it back down. Put the tractor on hard labor, then see what it does. Your cap sounds correct.

Waif
5+ Years
5+ Years
Posts: 1011
Joined: Thu Aug 25, 2016 1:29 pm
Zip Code: 49343
Tractors Owned: 48 Farmall Cub "Seen Yore Dobbin"
53 F-Cub W/Loader.
Circle of Safety: Y
Location: Michigan

Re: Temperature differences

Postby Waif » Fri Sep 24, 2021 4:44 pm

No pump. "Thermosyphon".
Heat rises.(As heat will.) Your radiator top is evidence of where heat rises and builds in the design of the tractor.
Fan robs some heat from rising coolant.
Cooler coolant sinks. While getting fan air run through.

The expanding fluid (from heat) needs a place to go.
Your loose cap and overflow tube is where yours goes.
A snug cap would simply force the excess coolant out the overflow.

A tight/closed cooling system with no pump would be fussy trying not to damage it from pressure as heat expands fluid.
As mentioned your Cub will have a sweet spot in it's fluid level. The tendency is to run them too full.
But do be sure to have enough.
With hard work I'll usually see some coolant coughed out from where it runs (has a happy level) when not worked hard.

Gary Dotson
Team Cub Mentor
Team Cub Mentor
Posts: 4558
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Re: Temperature differences

Postby Gary Dotson » Sat Sep 25, 2021 7:39 am

Actually a pressure cap was an option and the Cub system will work fine with one, only about 4 psi, however. A pressure cap will raise the boiling point of the coolant and may help retain the coolant level in hot, hard working conditions. My oldest Kubota mowing tractor is thermo syphon with a pressure cap. It was losing a small amount of coolant each time we mowed with it. During routine maintenance, I replaced the coolant and the rad. cap and have added no coolant in the last 3 years. Very small leak but the cap was allowing coolant to be pushed out.


  • Similar Topics
    Replies
    Views
    Last post

Return to “Farmall Cub”

Who is online

Users browsing this forum: Nelson 634 and 2 guests