oil viscosity and leaks

wilson ind · Jan 26, 2018

Some time ago there was a discussion on oil viscosity and leaking from seals. As I recall some brands and weights were much better than other as to seal leaking. Presently I am using Manufacturers advice of 30 st weight detergent oil. Thinking 10 w 20 might be better as tractor does no heavy work and has very high oil pressure even at idle. My thinking high pressure near worn main bearing would tend to push oil out. Seals are relative new and tractor is just not worth engine rebuild Advise is sought and appreciated.

grizz02 · Jan 26, 2018

My opinion don't over think it 30 weight is just fine a lighter oil will get buy the seals they were designed to run 30 w unless your in real cold climate

rustred · Jan 26, 2018

first of all what are you referring to? sounds like a rear main brg. seal? far as i am concerned once a seal is leaking it dont matter what viscosity oil is being used . from 20 weight to 30 weight i dont think the difference in leakage will even be noticed.if you have worn bearings 30 weight is better than 10 or 20 weight. myself i would use a 40 weight or 20-50 weight oil in worn engine to help keep the crank and cam suspended off the bearings.

Andy Martin · Jan 26, 2018

I've not seen an engine where the seal holds oil pressure. There is always a gap to let the oil back into the crankcase since the bearings require oil flow to keep the oil cool.

Cheap oil is best for a leaking old tractor.

Steve@Advance · Jan 26, 2018

Dropping to a lighter oil will likely not help, in fact it might be worse.

The very high oil pressure may be a contributor. What are you calling very high? Possibly the relief valve is stuck, assembled wrong, or was tampered with trying to get better pressure at idle. Do some research as to what it should be, be sure the gauge is right. If it is excessively high, that needs to be corrected. High pressure can wash out the bearing babbet, cause oil pump failure, or damage other components.

Other ways to slow a leaking crank seal is to be sure the crankcase vent is clean and working properly. Another trick is running the oil level a quart low. Many older engines will leak excessively if filled to the recommend level. Any doubt about the capacity, or it having the proper dip stick?

wilson ind · Jan 26, 2018

By high I mean to right of normal on gauge. High for most cockshutts dad and I ran in past. Matter of fach we had one new E 4 that always was low, verified with other guage, even after rebuild new check valve and rebuilt pump. So high to me in right on normal .

BJ · Jan 26, 2018

Might not hurt to check your oil pressure with another guage, yours could be bad.

Copperhead don't play · Jan 26, 2018

Steve and BJ gave you good advice. If you do not follow it, it is up to you.

jacks · Jan 26, 2018

High oil pressure is an asset on an old or tired engine. When I say high, I mean on the high end of the manufacturers specs. I do think you have gotten good advice on checking with a mechanical gauge. If you have worn bearings you probably would not have high oil pressure. Make sure that the oil pressure relief is clean and working properly. Most gasket and seal leaks are not too hard to fix on a tractor engine. Make sure that your valve cover and oil pan flanges are flat, and not dimpled from overtightening the bolts. If it has an old style felt seal for the front crankshaft, they can usually be retrofitted with a neoprene seal. If crank sealing surface is worn, install a speedi sleeve.

RBoots · Jan 26, 2018

I always run 15-40 in my Ford 7.3 Powerstroke. It has pretty high oil pressure, especially for having 300,000 miles on it. It leaks a little out of the rear main seal, but what can I expect? I switched Las winter to I think was either 5 or 10-40 diesel oil, but it sure sped my leak up, so I went back to the 15-40. Works great usually except when it's very cold. Forgot to plug it in a few weeks ago when it got down to -16F. Started right up but the oil was so cold and so thick it blew the o-rings on the oil cooler, so it was leaking oil all over, glad I saw the puddle under it before I left. The old, hard o-rings probably didn't help, but the thick oil didn't do it any favors either. The coolant heat goes through the oil cooler on a 7.3 so it will at least warm up the oil in the oil cooler and the oil in the injector galleys in the head are warmed by the coolant in the head. Helps anyways

Texasmark1 · Jan 27, 2018

I have a couple of old Fords, a '63 2000 and '65 3000. I changed fluids to trans/hyd from gear oil (134A) and didn't notice any increase in seal leaking....seals are all original and I had a few leaks to start with; nothing warranted tearing things all apart.

notjustair · Jan 27, 2018

I have some things I always used Rotella 15-40 on. There was a special on Delvac 15-40 so I bought a couple of buckets. It stopped the main seal leak on one pickup within 100 miles. I've switched over to all Delvac.

oil viscosity and leaks

wilson ind

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grizz02

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rustred

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Andy Martin

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Steve@Advance

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wilson ind

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BJ

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Copperhead don't play

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jacks

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RBoots

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Texasmark1

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notjustair

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