Oil Pressure issues

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pdlrofdrms
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Location: Humboldt County Ca
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Oil Pressure issues

Post by pdlrofdrms » Wed Sep 05, 2018 1:49 pm

Description of set up:

I have a terrible memory but I feel I have owned my bus for about 6 years. Maybe a tad longer.

I have rebuilt the motor. Took me about 6 months because I had no idea what I was doing.
Heads are from Adrian in Southern California.
Balancing issue and resurfacing I had done locally on certain parts.
The bus came with so I rebuilt it with an external oil cooler. Never knowing how to remove it.

I have battled Fuel lines, vacuum leaks, and AFM issues.

This year I felt the bus was running pretty good.

Colin and I were lucky to focus on more nagging stresses like putting on a new slider door.

One issue that presented it self however this year was oil pressure.

We guessed maybe it was as simple as changing the oil and using the Napa gold filter instead of the Bosch filter.

I did this and took a long road trip and still the oil pressure issue is present.

So what it the issue.

When cold Oil Pressure shows 55 to 45

When warm oil pressure is 41-35

When warm and I shut off the bus and then restart oil presssure is 00 and the read light of death comes on for a few seconds.

I rev the motor and it starts building up again and red light of death disappears.

Bus runs great.
There seems to be a power issue in second gear or up hill.

I am using Valvoline 10/40 GTX

Head temp never got higher than 380 up hill in 90 degree weather.

Stayed pretty steady at 350.

Maybe this is the external oil cooler at work, I have no idea.

The only time I have ever hit 400-420 was when I had a vacuum leak.


Any thoughts on why the oil pressure take a minute to build when warm?

I should also say that it takes a minute to loose pressure too. It stays pretty steady after I shut the car off.

Thank you in advance...
Want to catch this if its something I need to address.
My uncle was saying maybe replacing the sending unit?

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asiab3
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Location: San Diego, CA
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Re: Oil Pressure issues

Post by asiab3 » Wed Sep 05, 2018 2:42 pm

Hi there! It seems you have a fuel-injected Type 4, correct? Can you trace the external oil cooler lines anywhere? Type 4's aren't commonly modified like Type 1s are, so I'm not sure of the possible ways to plumb the cooler flow. Do you have solid or hydraulic lifters?

Are you pressure numbers from an electronic VDO gauge? Or a mechanical/dial gauge?

Whenever giving us oil pressure readings, can you tell us at what RPM you are reading the pressure? Pressure should go up with engine speed, and down at idle. The stock oil pressure sending unit flickers between 2psi and 4psi, I believe. Some aftermarket switches flicker between 6psi and 9psi. So you could have three times the 'required' pressure at idle and still see a flickering idiot light…

EXACTLY how long does the oil light stay on when you restart the engine? You said "a few seconds" and "a minute" in two different parts of your post, and helpful responses will vary greatly, depending on which of these is actually the case. Does the light go out quicker if you blip the throttle slightly at startup?

Let us know! :)
Robbie
1969 bus, "Buddy."
100k miles with me.
279k miles on Earth.

pdlrofdrms
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Location: Humboldt County Ca
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Re: Oil Pressure issues

Post by pdlrofdrms » Wed Sep 05, 2018 3:23 pm

Yes Fuel injected.
Yes I can trace them because its mounted to the outside of the bus. UGLY! LOL
I have Hydraulic Lifters
I have Dakota Digital Gauges
Light stays on for seconds really just feels like minutes. I have not timed it but I would say if I give it three to five revs it disappears. once I start driving Digital gauge starts reading.
Red light of death and oil pressure gauge read 00 only when hot. Never warm or cold.
This is a new issue.
Never noticed this before this year

pdlrofdrms
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Location: Humboldt County Ca
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Re: Oil Pressure issues

Post by pdlrofdrms » Wed Sep 05, 2018 3:25 pm

First time it happened I freaked out. Ran to the back of the bus. Checked my oil levels.. All was fine.

This last oil change Required 2 top offs on the way down from
Eureka to Sacramento area.
Was taking about a half qt every fill up. Which was about every 200 miles.

However on the way home this was not the case.
Oil stayed level and slightly over filled the entire way home with out a top off.

pdlrofdrms
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Location: Humboldt County Ca
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Re: Oil Pressure issues

Post by pdlrofdrms » Wed Sep 05, 2018 3:47 pm

Whenever giving us oil pressure readings, can you tell us at what RPM you are reading the pressure? Pressure should go up with engine speed, and down at idle.
Sorry
Okay so
Idle:
Cold: about 18 is average
hot; 11-14

as I shift from N to 3rd or 4th
30-45

Acceleration:
Cold
45-55
Hot
41 to 35
actual RPMS I don't have a tachometer gauge for this.

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Amskeptic
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Re: Oil Pressure issues

Post by Amskeptic » Wed Sep 05, 2018 7:35 pm

pdlrofdrms wrote:
Wed Sep 05, 2018 3:47 pm
Light stays on for seconds really just feels like minutes. I have not timed it but I would say if I give it three to five revs it disappears. once I start driving Digital gauge starts reading.

Red light of death and oil pressure gauge read 00 only when hot. Never warm or cold.

Idle:
Cold: about 18 is average
hot; 11-14

as I shift from N to 3rd or 4th
30-45

Acceleration:
Cold
45-55
Hot
41 to 35
actual RPMS I don't have a tachometer gauge for this.

It's fine, Jennifer. Yes, it will take longer to build pressure when filling that monstrosity grafted onto the corner of the bus.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 93,996 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

pdlrofdrms
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Location: Humboldt County Ca
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Re: Oil Pressure issues

Post by pdlrofdrms » Fri Sep 07, 2018 9:17 am

Thanks!
It drives great so I have just been on an observation mode. That monstrosity is coming off this year!

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