426 oil cooler oil leak
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=204711
Printed Date: 07 May 2025 at 1:49am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 426 oil cooler oil leak
Posted By: automaticdave
Subject: 426 oil cooler oil leak
Date Posted: 26 Dec 2024 at 12:03pm
| I have a 426 that was in a 7045 that has a slow oil leak between the bottom of the housing and the rear elbow, can l remove the six bolts and slide the elbow back and out to replace the gasket with out disturbing the cooler o-rings or I'm asking for trouble ? Thanks Dave |
Replies:
Posted By: tbran
Date Posted: 26 Dec 2024 at 3:59pm
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Is this a leak at the block - water - at the bottom of the elbow or the bottom of the cooler on the rear elbow. IF you pull off the rear elbow you have to replace 2 gaskets anyway - might as well take a day and do the whole thing unless it has been done lately, and check the relief valve. We have more trouble with the elbow to block gasket that anything. We use the old tech trick of gluing a circle of 6 # test fishing nylon line to the gasket on both sides of gasket with Indian head stuff the day before installing to the block. It is very frustrating to do the job then see a trickle of antifreeze the next day...like I have... 74028823 is the block gasket at rear and cooler gasket is 74028822 and there are 2 separate holes at the bottom - not joined as the early ones -70933325 are the lube contact orings-70923637 are the water side and 74028820 and 70923621 are the tube orings. ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: tbran
Date Posted: 26 Dec 2024 at 4:00pm
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can get the other pn's if you need them ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: ekjdm14
Date Posted: 26 Dec 2024 at 4:08pm
This is the kind of knowledge that's in danger of being lost if not passed down.  (I'm 43 & never heard of it before)I'm guessing the fishing line is a "double whammy" in that it squishes out and creates an extra sealing layer as well as giving you more squeeze on the gasket paper? One to commit to the memory banks anyhow, be plenty fishing line left years after the last of the RTV has gone bad.
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tbran wrote:Posted By: automaticdave
Date Posted: 26 Dec 2024 at 4:29pm
| Yes tbran its the #74028822 gasket that is leaking engine oil at the bottom between the cooler housing and the elbow, Thanks Dave |
Posted By: tbran
Date Posted: 26 Dec 2024 at 4:30pm
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we do that on the left rear and back of the head gaskets on 426's but don't glue them - almost every engine seeps there... saw that 'trick' in a 1972 AC service school... also there is a correct position of the brass cooler in the housing as well - just like the cooler cores in intercoolers...
------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: SteveM C/IL
Date Posted: 26 Dec 2024 at 9:29pm
| How do you keep fishing line in place on a head gasket without gluing it? |
Posted By: tbran
Date Posted: 27 Dec 2024 at 7:57am
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You just lay it on the block, lay on the head gasket, put the string around the back corner and side top of the gasket and put on the head. The string has a natural curve. It only takes about a foot. This just mimics some gaskets that have a slight ridge of material in certain areas prone to seepage. IF the string doesn't want to lay right a slight coating of sticky Indian head on the thin nylon string is so small it will not be a factor. ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: tbran
Date Posted: 27 Dec 2024 at 7:58am
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Since it is oil leaking - do the whole thing... ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |