AC 175 Diesel cracked block opinions
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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=155471
Printed Date: 06 Oct 2025 at 10:18pm
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Topic: AC 175 Diesel cracked block opinions
Posted By: bozrae
Subject: AC 175 Diesel cracked block opinions
Date Posted: 09 Nov 2018 at 2:16pm
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Bought a nice low hour original paint 175
diesel earlier this year that has a crack in the block. Previous owner had it
25 years and said the block cracked about 20 years ago. I didn't get a clear
answer on why it cracked, it seems it is a frost crack, but don't know for
sure. No water gets into the oil, previous owner put JB weld over block, but
the JB weld has since cracked. Owner said he could run it for an 8 hour day and
it would lose very little antifreeze. When I got it, I ran it for about 3 hours
and it lost almost no antifreeze so that story seems to be true. However, I
changed antifreeze with a heavy duty diesel antifreeze and ran it for about
another 3 hours and it seems to have deteriorated the JB weld some more and
started leaking more. I could JB weld it back up and continue
to run it, I don't really use it much, but would someday like to fix it right.
Replacing the block would probably be the best option, but it runs fantastic the
way it is right now. I've ruled out welding it. There is something call metal
stitching, but that looks costly and time consuming too and I don't know if
that would fix it 100%. I'm curious about other people's opinions
would be for fixing or not fixing the block. I'm 100% convinced this is truly a lower
hours tractor (2,400 hours), by the way it runs and drives and the overall
tightness of everything. Would anyone have a good correct block,
it's the 248ci.
------------- D15D, D17G, 170G, 175D, and two 5050FWA |
Replies:
Posted By: farmtoybuilder
Date Posted: 09 Nov 2018 at 2:37pm
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I would clean it off and "lightly" peen with air punch and fill with liquid steel or Cat 2 part steel Epoxy and continue running it. If you don't want to peen it you could still clean good and put the better epoxy's on it and continue running. We also had a small crack tig welded on block and it did well for many years.
------------- 5 different TT-10's,5 TT-18's Terra Tigers,B-10,2 B-207's,B-110,2 B-112's,HB-112,B-210,B-212,HB212,2 Scamp's & Homilite T-10. Still hunting NICE HB-112 & anything Terra Tiger & Trailers for them. |
Posted By: DrAllis
Date Posted: 09 Nov 2018 at 2:44pm
| It appears to be very close to a main engine oil galley, as evidenced by the oil pressure sender just below the crack, which leaks coolant. I have plated a couple of tractor pulling blocks years ago, but they were flatter and not as contoured as this one is from front to rear. As the engine works, that crack is trying to spread apart from the crankshaft pushing down and the cylinder head lifting up. If there was any way to get some good weld on it to keep it from spreading, then more epoxy/goop would last longer because the crack would stay shut. |
Posted By: darrel in ND
Date Posted: 09 Nov 2018 at 2:53pm
| There is a liquid metal product called belzona that puts JB weld to shame. It's a two part product that you mix together prior to use. I would try it. Not a fix that I'd be proud of, but I bet it will work, and if it doesn't, you really aren't out that much. Darrel |
Posted By: Gary Burnett
Date Posted: 09 Nov 2018 at 4:13pm
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Get a can of that spray on stuff they advertise on TV that they make a bottom for a boat out of a screen door,ought to do the trick. |
Posted By: Claus
Date Posted: 09 Nov 2018 at 4:22pm
| Nice looking tractor. |
Posted By: DougS
Date Posted: 09 Nov 2018 at 5:19pm
| There’s a 248 block on e-bay for $500. They want $175 for shipping, but it’s in Waukesha, WI, so picking it up might be an option. |
Posted By: AC720Man
Date Posted: 09 Nov 2018 at 6:23pm
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I agree with the good Dr, a good welder can fix that. My local machine shop has a welder that is unbelievable. When he is done you can barely see the repair. And it will be permanent. ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: bozrae
Date Posted: 09 Nov 2018 at 7:27pm
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Thanks for the comments, that gives me some more to think about. I did just check out the block on Ebay.......that is brand new still with the crate. That sounds tempting, but it's probably newer than the one I have, not sure what may have changed over the years. I wanted to stay away from welding, but if people have had good successes with it, then I'd still consider that too. Or maybe with a higher quality epoxy, it can take some stress flexing if the crack wants to open up a little under heavy load. ------------- D15D, D17G, 170G, 175D, and two 5050FWA |
Posted By: Roach
Date Posted: 09 Nov 2018 at 8:30pm
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I have welded several of the years with great success and is a much more permanent fix but as stated before, Belzona is a very good product and we have built up worn shafts, blocks and axels. It is tough as metal and machines very well. In the same token, a good spare block laying around for 500 may be a good deal if you plan on keeping the tractor. It does look like a good one. ------------- 1937 WC, 1948 G,1954 CA,1956 WD45, 1967 D17, 1937 M crawler, 1963 D-19, 1966 190XT, 1967 D-15, 1948 HG42 Cletrac, 1955 G456 Terra Trac, CAT 10 1928 and CAT 22 1938 |
Posted By: DiyDave
Date Posted: 09 Nov 2018 at 8:40pm
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What I would do is to have someone who has a magnaflux machine, and knows how to use it, use it to find the ends of the crack. Then talk with a good welder, he will be able to advise you better. Important thing is to stop the crack from spreading further. Once your welder advises you on what to do, take his advice... If it were a shorter crack, I would recommend an epoxy or belzona type epoxy, but that one is damn long... Also after welding, an antifreeze sealant containing sodium silicate, like Blue Devil block sealant, would be a good investment... I once had a JD 420I, that had a crack, about 3" long, from a rod hit, it was a vertical one, heafing up toward the water jacket. Found the ends with magnaflux kit, then drilled a hole, at each end, and threaded in a 3/8" fine threaded bolt, + 1 in the middle, then veed out the crack, and JB welded it shut. This was an oil only crack, snd that ole buvket of bolts lasted another 10 years, before I traded it off...
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