Oil pressure drop after start up

[oprn]

[paul356A]

Hi folks

I have been busy with other stuff but here are some pics of my system, the filter is plumbed the correct way round and it does have a drain back valve, it's a Meyle 100 115 0001

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1956 RHD PGSG bus
1959 RHD 356A

[Clatter]

Here’s an idea..

Maybe it’s like this..

Racers run a deep sump not for cooling but because revs can suck the sump dry before the oil drains back.

Maybe you’re the same with the filter and cooler?
Perhaps the oil (or some of the oil) drains out of your filter and cooler before you check your oil level.
Then when you start up the filter and cooler get pressurized but the pickup goes dry before the oil gets back to the pickup tube.
Once the oil gets some heat in it, it thins out and flows well enough to make it back to the pickup..

Maybe something like this is happening?
Try stopping right when it’s happening and run back there and check the dipstick real quick.

Noticed your filter being sideways and thought it could drain mounted like that,
Even though it probably doesn’t..

Something like this happened to me,
And it was the sender wire coming loose.
Maybe you have an intermittent loose connection and the timing of how it happens is coincidence?
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Bus Motor Build

What’s That Noise?!?

[74 Thing]

I would try to mount the filter vertically maybe using a few zip ties temporarily to test like Clatter suggested.

[VW_Jimbo]

I went through a couple oil pressure issues and learned way too much about the oil system. I learned to overfill my engine by a 1/2 quart, because at 6300rpms the standard oil level gets sucked dry, causing a lack of lubrication. But overfilling the case worked. Down side has been on high rpm deceleration, when I get to a complete stop, I can smell burned oil. Oil that has been sucked into the carbs more easily with the higher level. But that does not happen often enough to make me worry! I much prefer knowing the engine is ALWAYS LUBRICATED!
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[paul356A]

Ok so I’ll try vertical filter and a bit more oil

👍
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1956 RHD PGSG bus
1959 RHD 356A

[Kafer_Mike]

If all else checks out, remove the sump plate and check the pickup tube. I had one that came loose (nut backed off and was loose in the case inlet). It would suck air after startup and during hard acceleration when the oil was lower in the case. Also, the oil temp would go up.
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Kafer_Mike
Build 'em fast...or let 'em sit.

[evanfrucht]

Could it simply be an issue with the sender or gauge?

Maybe try a new filter?
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1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[oprn]

With everything mounted that low I can hardly believe it is drain back no matter what position the oil filter is at! You shouldn't even need a filter with a drain back valve.
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We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[74 Thing]

Well these are the suggestions:
1. Mount the oil filter vertical and see if that makes a difference and it is easy to do.

2. Check the sender. Either replace with a mechanical sender not an electrical one or use a new sender. Also, depending on what you used if anything to sea the sender it could have prevented it from grounding to the case. I solder a ground wire to the body of those VDO pressure senders and run the other end to a good ground.

3. Your pickup tube can be loose and sucking air. Drain oil and see it you can wiggle the pick up tube back and forth. If so you are going to need to swedge the end in the case.

4. Clean the oil pressure and relief valves. Not sure that this is a problem, but if you drain the oil this is easy to do as well. They should just drop out with the springs.

5. Oil pump may not be a tight fit causing it to suck air. Berg and Jaycee offer an o-ring pump to help with that issue.

Keep us posted and good luck.

[paul356A]

Today I measured the oil level just after switching off the engine. It was on the lower mark. Should I add more oil?
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1956 RHD PGSG bus
1959 RHD 356A

[madmike]

If your running a deep sump? No
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'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[Wreck]

Yes and report back if it fixes your problem .
Alway look for the KISS solution first . I don't know how many times Ive heard of people adding extra oil lines , filters and coolers and not allowing for the extra oil capacity when everything is full and the engine is throwing oil up to the heads .

[paul356A]

Ok so I put a litre of oil in yesterday and I didn’t get the dreaded green light but this morning as I was getting it out of the garage to go to a local car meet it blew the oil filter seal! What a mess!
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1956 RHD PGSG bus
1959 RHD 356A

[oprn]

Are you running a 30mm oil pump?
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[paul356A]

No 26mm

straight 30 grade running in oil
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1956 RHD PGSG bus
1959 RHD 356A

[madmike]

I too have blown oil filters up, even the High pressure ones,,I run a System One filter now , no more blown seals/filters

_________________
'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[Wreck]

I worked out the messy way that you need to let the oil temp get to a temperature that will allow the oil to flow well enough for the pressure regulator valve to be able to bleed off excessive pressure before revving the engine over a certain rpm .

[oprn]

I have never had that happen on anything in all the years and all the vehicles I have driven. The closest is a couple have seeped a bit around the oil filter gasket at - 35 or so until they warm up!

My TDI and the wife's Lupo both do that in extreme cold but it's never more than a few drops.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[paul356A]

I have ordered a Golf (Rabbit??) diesel filter - Mahle OC 51 which has been recommended many times on here. I’ll try again with extra oil and make sure I keep the revs down when it’s cold.
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1956 RHD PGSG bus
1959 RHD 356A