301 compression in coolant
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=45250
Printed Date: 10 Sep 2025 at 4:15pm
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Topic: 301 compression in coolant
Posted By: heavy12d
Subject: 301 compression in coolant
Date Posted: 08 Feb 2012 at 11:26pm
I have a 190XT diesel that is getting compression in the coolant system, took head off and had it checked at a local head shop and he could find nothing wrong with it, no cracks, no warpage, etc. The head gasket looked good, no obvious leaks, pistons look ok, no sign of water inside sleeves, no water in oil and no oil in water but when you rev the motor the cap had better be loose or else. Any ideas? We can't see any sign of the sleeves leaking around the top either, guessing a busted sleeve? Maybe someone else has experienced this condition and can help. Thanks.
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Replies:
Posted By: MACK
Date Posted: 09 Feb 2012 at 6:22am
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Did they pressure check thr head or magnflux? MACK
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Posted By: DrAllis
Date Posted: 09 Feb 2012 at 6:50am
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No sign of coolant in the oil ?....if there was ANY shaving cream like material under the valve cover, or on the bottom side of the oil fill cap, you had coolant in the oil. I'm like Mack, it's probably the cylinder head and they can't see it or don't know where to look. Sometimes the floor of an exhaust port get cracked and they never look there.
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Posted By: bill2260
Date Posted: 09 Feb 2012 at 7:01am
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I am not nearly as qualified as most forum members on mechanical issues, but if it was me, I would try a new head gasket before I spent too much money. Bill
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Posted By: Amos
Date Posted: 09 Feb 2012 at 7:41am
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My 6060 did the same thing. A few tiny holes in the sleeves of two cylinders above the top of the piston rings in the compressions stroke. No oil in the water or water in the oil was noticeable but sure bubbled the rad cap over.
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Posted By: Dave in il
Date Posted: 09 Feb 2012 at 8:17am
I'd bet pinholes in a sleeve. Happened to me once, pulled the sleeve and had electralises (sp?) erosion.
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AGCO My Allis Gleaner Company
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Posted By: Hurst
Date Posted: 09 Feb 2012 at 1:24pm
I'll throw another vote for checking the sleeves for pin holes. Maybe you can find a plug from a plumbing supply store that will fit, drill a hole, put a fitting on it, and hook it up to an air pressure source at some pressure and recheck for bubbles on each cylinder with the piston at BDC. Just an idea. Not sure how well the rings will seal to hold the pressure, but it shouldn't cost too much to gather the parts to give it a try. That's assuming you can't see the hole and don't want to take the sleeves out. It may not be a bad idea to take all the sleeves out anyway to check for cavitation and possibly overhaul the engine, because if one sleeve has a problem with cavitation, it's likely the others are not far behind and the bottom bore where the o-rings seat has some good pitting. I would make sure the head was pressure checked before tearing the engine down. Did the head gasket have any signs of failure? Did you have any water in the oil? Even if it's not enough of a leak to collect in the bottom of the pan, it could still have done some damage to the bearings.
Hurst
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1979 Allis Chalmers 7000
5800 Hours
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Posted By: heavy12d
Date Posted: 14 Feb 2012 at 10:41pm
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Thanks for all your responses. I was told the head was magnafluxed. It sounds to me like the pinholes in the sleeves. Anyone know where a complete 301 or a resonable priced set of pistons and sleeves can be obtained? Again I appreciate all the good advice. I am glad my buddy told me about this website.
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Posted By: skipwelte
Date Posted: 14 Feb 2012 at 10:49pm
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Pin holes in the sleeves usually make for coolant in the oil, not so much compression in the coolant. A cracked cyl head makes compression in coolant more times than not. Ive had a good used magnafluxed head check bad with the pressure tester. Pressure testing is a pain in rear, but will tell the truth if correctly done. I fabricated the pressure testing parts using long bolts and heavy iron with cut inner tube seals. When the copper injector sleeves came about you just about had to pressure check them. Good luck
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