High oil pressure after oil change??

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dgibby

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I just did an oil change and now under high rpm the oil pressure is pegging at @ 100 psi at higher rpms. Ive been running valvoline racing 10-30 and with a wix 51085 filter. It would sit at 60-70 psi cruising and 40 at idle. This time I used valvoline advanced synthetic 10-30 and a wix 51085xp filter that is supposed to be for synthetic oils. It sits at 70-80 psi cruising and 50 at idle. Pegs at 100 psi if I get on it. Any ideas??
Engine is a 408 92 block with a standard volume oil pump. This is the fourth oil change I’ve done on it and had no problems before. Drove it to get the oil and filter and it was fine. Drove it after the oil change and it is too high. Thanks for the help.
 
I suggest two things. The filter may be defective. I have had a defective filter in the past. The other is to check your pressure with another gauge to be sure the gauge is not defective.

Is your gauge mechanical or electric?
 
I suggest two things. The filter may be defective. I have had a defective filter in the past. The other is to check your pressure with another gauge to be sure the gauge is not defective.

Is your gauge mechanical or electric?
It’s a mechanical gauge.
I was going to go back to the 51085 filter, not the XP version and see what happens.
 
I agree with post #2. Also, you may be finding out that different oils have different qualities. For instance, a long time ago, in my Omni, I used Quaker State oil. Changed to Pennzoil for some reason, anyway, started having oil pressure issues. Pennzoil had a higher cleaning/detergent capability, and it started loosening all of the crud up inside the engine . Now that took a week or two, not right away. Just be aware about switching oils down the road. I have also heard that going from synthetic to fossil oil is OK, but not the other way around.
 
I agree with post #2. Also, you may be finding out that different oils have different qualities. For instance, a long time ago, in my Omni, I used Quaker State oil. Changed to Pennzoil for some reason, anyway, started having oil pressure issues. Pennzoil had a higher cleaning/detergent capability, and it started loosening all of the crud up inside the engine . Now that took a week or two, not right away. Just be aware about switching oils down the road. I have also heard that going from synthetic to fossil oil is OK, but not the other way around.
Thanks for the info.
Ive always heard opposite about switching oil types. Break it in and let the rings seat for a few thousand miles with conventional oil before switching to synthetic.
I’ve also heard just run whatever you plan on using from the beginning (after break in oil) so who knows.
 
I would try a K&N oil filter first, but that’s just me. But defective pressure gauge could be a real possibility, too.
 
Could be the filter itself. Synthetic oil filters filter down to smaller microns and have different and more filter media. So, that could cause an increase in pressure simple from more resistance for the pump to pump oil through the filter.
 
Yep! The reason I said K&N filter. They used to have a tech article about micron filtration size vs flow. It’s worth reading, but all I can find on their site now is endless self promotion.
 
Could be the filter itself. Synthetic oil filters filter down to smaller microns and have different and more filter media. So, that could cause an increase in pressure simple from more resistance for the pump to pump oil through the filter.
Kind of what I was thinking but thought the oil pump would bypass at a certain psi?
Will get the standard filter on it and see what happens.
 
Kind of what I was thinking but thought the oil pump would bypass at a certain psi?
Will get the standard filter on it and see what happens.

Pump does have a relief. The filter has a bypass that could be opening due to filter media being too fine. When the filter bypasses all the oil isn’t being filtered. As stated I’d try a different filter or go back to what worked.
 
Pump relief valve sticking? All it takes is a little crud in there. Or maybe the gauge shat the bed on you.
The thing with the filter is....where's the oil pressure gauge sender? After the filter. So if the filter was plugged or restricted shouldn't that cause a LOSS of pressure at the sender? I think so...and a filter with that much restriction should open the pump bypass (70psi?)

Aw sheeat @spl440 you said it first....I didn't see your post:rolleyes:
 
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What is the theory behind a synthetic oil filter filtering smaller microns? It seems the engine is the determining factor, not the oil....
 
What is the theory behind a synthetic oil filter filtering smaller microns? It seems the engine is the determining factor, not the oil....
They seem to be marketing as better filteration since synthetic oil usually runs longer between oil changes.
 
OK but what is 'better' filtration?

I could see the filter being larger to hold more of the filtration element, so it last longer. But I don't think these filters are any larger.
 
If you are buying a K&N filter, check where it originated from as shown on the filter, not on the carton. Yes, maybe i'm being racist, but when i see the garbage that's going in our countries, so what?
 
What's racist about buying a product from a given country?

I'll make you a deal...between now and the year 4020 - that's 2000 years - you don't need to apologize for being a racist to me for anything you say or do, ever.

It's my effort to counter the stupidity surrounding racism, the most offensive of which is the elevation of racism to being a crime, and a crime worse than child molestation or murder at that.
 
If the filter was a restriction, wouldn't the gauge read lower since it is after the filter?


Yes, if the filter is a restriction you see LESS pressure on the gauge. That means the opposite is true. Maybe the pressure is up because the filter is LESS restrictive.

You can measure the restriction of the filter with 2 gauges. One before and one after the filter.

The greater the pressure difference the more restrictive the filter is.
 
How do you measure the pressure before the filter?

If you are just screwing the filter to the block it’s a bit harder than if you have a tight angle adapter.

There is a plug on the adapter that is on the outlet side of the filter. You just hook a gauge up to that and read the two gauges side by each.
 
Well I went the easy route first and tried the standard 51085 filter. It dropped the pressure 10psi at higher rpms. Kind of cold here now and could only get the engine temperature to 165 degrees. Still hitting 90 psi doing a burn out and about 80 psi if I get on it while cruising. Otherwise 50-60 psi cruising and 40 at idle.
 
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