20W50 started leak
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From: Longview, TX
20W50 started leak
I think I'll try Mobil Clean High Milage 10w30. My '94 5.8 Bronco had Mobil 10w30 dino. oil for the first 160K and did not leak a drop. I tried to improve pressure reading on the factory guage reading so went to Castroil 20w50 and I have had a messy garage for a year now with 169K. Could thicker oil be squirting from the mains through the seal? Of course the junky factory guage moved up very little. Motor oil is leaking from the rear of the engine. Yesterday I installed a mechanical guage and read 56 psi at cold startup, 52 psi highway 32 psi at traffic light idle with A/C on and 700 rpm after twenty mile drive. How about some thoughts on going to Mobil Clean High Milage and these current pressure readings please? I hear no motor noises. What is too low pressure...when lifters rattlle at startup?
Last edited by b4hntn; Jun 1, 2005 at 05:31 AM. Reason: typo
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From: Centerville, Iowa
The stock guage is a dummy guage, you know that already it seems.
I'd say change back. Stop the damage the motor oil is doing/has done and get back to bearing-friendly oil.
A 10W40 would be much nicer to use....or even 15W40. You don't need thickness on the bottomend, its the top end you should worry about.
I'd say change back. Stop the damage the motor oil is doing/has done and get back to bearing-friendly oil.
A 10W40 would be much nicer to use....or even 15W40. You don't need thickness on the bottomend, its the top end you should worry about.
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From: Longview, TX
Thanks for the help. I don't have but 2,000 miles on the 20w50 but think I'll go ahead now and try 10w30 again since I can really watch it with my new mechanical oil pressure guage. Here is something I just found saying good flow and low pressure is better than high pressure and low flow.
http://lubricants.s5.com/oil_pressure.htm
New question....after a really good warm up in summer in the South what should be the lowest pressure at idle? 5? 10? 15? 20? 25?
If you know that, what about at highway speed?
http://lubricants.s5.com/oil_pressure.htm
New question....after a really good warm up in summer in the South what should be the lowest pressure at idle? 5? 10? 15? 20? 25?
If you know that, what about at highway speed?
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Joined: Oct 2001
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From: Cypress, CA
Your problem could be no more than changing brands of engine oil. Had a similar situation several years ago with a Chevrolet 2.8 v-6. We had been using Mobil 10/30 oil in it from day one and while on a trip had the oil changed and Valvoline 10/30 was poured in. That oil went right past everything and out the tailpipe in short order. Went back to Mobil and it never used any more oil.
In consulting a chemical engineer from Ashland Chemical at the time their explanation was that all motor oils are manufactured to the same standard for viscosity however the additive packages differ greatly and can cause oil consumption.
That said and from past experience, go back young man.
Russ
In consulting a chemical engineer from Ashland Chemical at the time their explanation was that all motor oils are manufactured to the same standard for viscosity however the additive packages differ greatly and can cause oil consumption.
That said and from past experience, go back young man.
Russ
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From: Longview, TX
I used to have a Chevrolet 2.8 v-6 in a Jeep Cherokee. I was the last carburated one and a vacuum hose hell. Previous owner used Castroil 20w50 and I stayed with it and it leaked at the rear of the engine like my Bronco is but both are/were very high milage so I am not blaming Castroil. After reading that low pressure and high flow rate are better it could be the 20w50 high pressure at the rear main is creating the leak. I saw a mechanic yesterday and asked him how low is too low oil pressure. He suggested with oil warmed up 15 idle and 30 psi highway is when I need to be thinking about doing something. With 20w50 I have 32 and 52 so will go with 10w30 and use the high milage formulation to see if it will soften the seals as advertised. Oil is cheap compared to the alternatives and undercoats nicely. I am just tired of the garage puddle.
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From: Running Springs CA
In a street engine you only need about 10psi for each 1000rpm as a general rule. So, at 700rpm idle, 7psi would be the minumum, about where idiot light oil pressure switches are set. That also means that going down the highway at 2000rpm, 20psi is the minumum. So, 15psi hot idle and 30psi at highway speeds is fine. What you dont want to due is "lug" the engine, because low oil flow and pressure in heavily loaded bearings is not good.
Jim
Jim
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From: Longview, TX
Thank you Jim. I have learned more about oil guages in the last five days than in the last fifty years of driving. That "10psi for each 1000rpm as a general rule" is what I have been looking for. I have had the "more pressure is better" idea forever and now that I think about it 20w50 builds the pressure but if it does not flow well then perhaps bearing heat builds and oil pressure against the seals is also higher which generates leaks. I'm changing back to 10w30 dino but making it High Mileage option this time. I'll check my readings again so we can have a before and after pressure comparison if anyone is interested.
