D12 series 3 oil pressure
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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=185007
Printed Date: 13 Aug 2025 at 2:07am
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Topic: D12 series 3 oil pressure
Posted By: bozrae
Subject: D12 series 3 oil pressure
Date Posted: 08 Dec 2021 at 7:19am
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What should the average oil pressure be for a D12 series 3 at higher rpm's? I bought the tractor this past summer and don't know the history on it, the oil gauge looks to have been replaced, but the gauge needle goes all the way to the end. The gauge is an AC type gauge with the word NORMAL. I assumed it to be the wrong gauge so I connected a numbered gauge and it reads about 45psi when cold and drops slightly when warm. Most AC type gauges I see for sale for a D12 read from 0 to 30psi, however one vender had a gauge from 0 to 45psi. ------------- D15D, D17G, 170G, 175D, and two 5050FWA |
Replies:
Posted By: Charlie175
Date Posted: 08 Dec 2021 at 12:37pm
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Mine goes to the R on Normal They don't push a lot of PSI, 45 seems high ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: PaulB
Date Posted: 08 Dec 2021 at 1:24pm
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The small D series will have higher oil pressure than the low pressure typical of the B,C, RC & CA models. What weight oil are you running? Nothing to be concerned about. I have a D10 that I brought with the knowledge of a known recent overhaul, It will maintain the needle far to the right at all times with 15W40. ------------- If it was fun to pull in LOW gear, I could have a John Deere. Real pullers don't have speed limits. If you can't make it GO... make it SHINY |
Posted By: bozrae
Date Posted: 08 Dec 2021 at 1:51pm
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I'm running a 30wt oil in it. A concern I had is the the pressure release spring may be stuck. But if 45psi is not to far out of the norm I'll just leave it and find a different gauge. ------------- D15D, D17G, 170G, 175D, and two 5050FWA |
Posted By: DiyDave
Date Posted: 08 Dec 2021 at 5:54pm
As long as the needle is in O R or M, you're OK. Now if the needle bounces a lot, you might have a problem... ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: bozrae
Date Posted: 09 Dec 2021 at 6:59am
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On the AC gauge with the word 'Normal' the needle is buried to the right of gauge and no bounce in needle. The gauge with numbers on it the needle does bounce around at 45psi. I'll see if I have another gauge around to test and see if that needle bounces also. Is a bouncing needle the sign of a relive valve or spring problem? ------------- D15D, D17G, 170G, 175D, and two 5050FWA |
Posted By: PaulB
Date Posted: 09 Dec 2021 at 12:03pm
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A bouncing needle is the result of an undampened gauge with a 2 vane oil pump. The correct AC gauges has a restriction with a very small orifice to smooth out the pulses from the pump. Be happy with good oil pressure and don't worry about it. ------------- If it was fun to pull in LOW gear, I could have a John Deere. Real pullers don't have speed limits. If you can't make it GO... make it SHINY |
Posted By: bozrae
Date Posted: 10 Dec 2021 at 5:44am
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Thanks for the responses everyone. I did try another gauge and the needle did not bounce on that one and the pressure read about 40psi when cold. I'm still curious to know what the oil pressure should be from the factory when it was new. The service manual I have does not say. ------------- D15D, D17G, 170G, 175D, and two 5050FWA |
Posted By: Ed (Ont)
Date Posted: 10 Dec 2021 at 7:30am
| That should be good. It will probably drop about 5 lbs when the oil is warm. |
Posted By: ShellJ
Date Posted: 18 Jan 2022 at 7:25pm
| I came here with basically the same question, so hopefully nobody will get mad for me popping in since this isn't an ancient post 😁. My D12 oil pressure gauge is rusty and hard to see (original gauge with just "normal" no psi markings) but I can see the needle stays far right even after warmed up. I don't see a warning zone for too high on the original "normal" gauges. So does it sound like my pressure is OK or should I investigate further? |
Posted By: DiyDave
Date Posted: 18 Jan 2022 at 7:53pm
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You could try hooking up a 45 psi max gauge to it, but the originals are pretty accurate unless leaking or missing the needle... ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |