Loss of oil pressure under high speed conditions.

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I had a 1985 Ford E350 with a 6.9L diesel where the oil pressure dropped to zero after I slowed to get on an off ramp with a line of cars. I had added a Banks turbo.

I found two other oils that kept the pressure up under the same conditions.

Now I'm faced with a similar situation with a 2001 Chevrolet S10 Blazer (4.3L auto) where at higher heat loads the oil pressure drops.
Other than buy and try is there any way to know in advance which oils will withstand high speed operation? I'm currently using Mobil-1 10w30.
 

OVERKILL

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Oil pressure dropping to zero, is something not fixed with different oil. Either the dash gauge is wrong, or there is a mechanical problem.
Yeah, I wasn't going to touch that part, lol. His comment about pressure dropping (didn't say it went to zero) as the oil got hot in the S10, if it's an oil temperature issue, well, he could install an oil cooler. On the other hand, that could also just be a bad sender or gauge, could also be a pump problem, or the engine may have no rod bearings left in it, lol.
 

WVDarren

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change your oil filter any time you suspect oil flow problem.
I had just changed oil to the 10W30 and the filter because my mechanic changed the oil line to the cooler and put 5W30 in.
Oil pressure dropping to zero, is something not fixed with different oil. Either the dash gauge is wrong, or there is a mechanical problem.
That was on the Ford E350 back in the 1980s. I was running Valvolene. Both Wolfs Head and Delvac prevented the oil pressure drop. My take away is that there are differences in oils and some are better at resisting heat.
 

WVDarren

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Yeah, I wasn't going to touch that part, lol. His comment about pressure dropping (didn't say it went to zero) as the oil got hot in the S10, if it's an oil temperature issue, well, he could install an oil cooler. On the other hand, that could also just be a bad sender or gauge, could also be a pump problem, or the engine may have no rod bearings left in it, lol.
When I run normally at 60 to 70mph I don't see the oil pressure issue. I run as a pilot with oversize loads. Drivers can and will do 80 mph. That's when I have a problem.
 

WVDarren

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Oils thin as they get hot, that's how it works. If you want to reduce how much they drop by; how hot they get, just install an oil cooler.
The Blazers have a oil cooler that's on the right side of the radiator.
 
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It's not the oil. As has been suggested already you need to actually measure the oil pressure with a proper gauge. You have some sort of mechanical or indication problem. Whatever the problem actually is, it's not brand or winter rating.
 
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Is this oil cooler a factory item that came with the vehicle, or did you put on the Oil Cooler?
Factory.

My 6.9 in my truck scared me a few years ago. Oil pressure went to 0. Turned out to be a bad connection where all the engine control wires go through a plug. Bypassed the plug as well as installed a real guage and it's ok
 

ZeeOSix

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I had a 1985 Ford E350 with a 6.9L diesel where the oil pressure dropped to zero after I slowed to get on an off ramp with a line of cars.
When I run normally at 60 to 70mph I don't see the oil pressure issue. I run as a pilot with oversize loads. Drivers can and will do 80 mph. That's when I have a problem.
Are you saying the oil pressure goes to "zero" while stopped and at an idle after getting off the freeway? With that same oil, what's the oil pressure while cruising down the highway? Any idea what the oil temperature is?

What kind of oil pressure gauge does this truck have?
 

OVERKILL

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When I run normally at 60 to 70mph I don't see the oil pressure issue. I run as a pilot with oversize loads. Drivers can and will do 80 mph. That's when I have a problem.
What do you mean by "issue"? Like, you are just driving down the road and the pressure drops? If that was to really happen, I'd expect some noise (like somebody else mentioned). If you aren't hearing noise it's probably the sender.
 
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WVDarren

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Factory.

My 6.9 in my truck scared me a few years ago. Oil pressure went to 0. Turned out to be a bad connection where all the engine control wires go through a plug. Bypassed the plug as well as installed a real guage and it's ok
The truck was fairly new at that time. I tried out several oils and found I had no oil pressure drop with either Wolfs Head of Delvac. I never used Valvoline in that engine again.
 
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