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aksyta Samba Member
Joined: March 16, 2017 Posts: 35 Location: Texas
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Posted: Tue Feb 20, 2018 12:40 pm Post subject: Oil pressure loss on hills |
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I've been driving my bug on some trips through mildly hilly areas and sometimes on uphills I'll lose up to 20 psi indicated by the VDO pressure gauge which usually reads around 40-50 psi on the freeway at about 55-65 mph. The dipstick reads as full right after shutting off the engine on flat ground.
I have a 1500 single port motor, with a large deep sump that brings total oil capacity up to about 6.5 quarts, a high flow pump, and a filter bracket attached to the pump.
I replaced the oil sump plate with a nice billet one since the one I had leaked. When I did this and got the old sump off, I noticed the pickup tube was extended with a piece of copper plumbing pipe which fell out when I pulled the sump off, and there is no strainer. The tube was cut at an angle on one end, I assume so it could rest on the sump plate and stay connected to the stock pickup tube. I did have to push it a little to make it stick on the stock pickup tube so I could fit the new sump on without it falling off. My concern with this is either I loosened the stock pickup tube somehow or the copper tube fell off, and either or both of these things is letting air get into the oil pickup when the oil moves around on uphills.
What I'm here to ask is are there any other causes for a sudden (takes about 5 seconds) drop in pressure on a mild hill, and how should I go about fixing this? I might eliminate the deep sump or get another, smaller compete deep sump kit with proper pickup extension, and either way get a strainer.
Also, if the stock pickup tube inside the engine is loose or broken, how would I go about fixing it?
Last edited by aksyta on Tue Feb 20, 2018 12:58 pm; edited 1 time in total |
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ROCKOROD71 Samba Member
Joined: January 18, 2012 Posts: 2770 Location: Boston, MA
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Posted: Tue Feb 20, 2018 12:43 pm Post subject: Re: Oil pressure loss on hills |
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downshift dude _________________ 1971 STD BEETLE- DD-1st car, 1st love. keepin' it stock! 1600DP, Solex 34-3 Mexi Bosch SVDA Dist NOW w/POINTS
1977 WESTY "KrustyKamper" 2L FI
79SuperVert wrote: |
30 years from now, the next guy may not want your girlfriend, but he may want your classic car, depending on how nice you were to it. |
asiab3 wrote: |
Careful guys, a petulant child can grow up to be president these days. |
**winter drivers: no survivors!**rust warrior**#keepbodyshopsbusy** |
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aksyta Samba Member
Joined: March 16, 2017 Posts: 35 Location: Texas
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Posted: Tue Feb 20, 2018 12:50 pm Post subject: Re: Oil pressure loss on hills |
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I'm not climbing mountains, these are maybe 20%/10 degree grades at most. The engine isn't shouldn't lose that much pressure that quickly from heat, especially with the amount of oil in it and how quickly it recovers pressure on flat ground. |
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Max Welton Samba Member
Joined: May 19, 2003 Posts: 10697 Location: Black Forest, CO
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aksyta Samba Member
Joined: March 16, 2017 Posts: 35 Location: Texas
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Posted: Tue Feb 20, 2018 4:09 pm Post subject: Re: Oil pressure loss on hills |
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Max Welton wrote: |
...where the stock pickup press-fits into the case up by the oil pump. |
If that's loose I'm screwed and need to split the case open to fix it, correct? Although that's at the oil pump end of the engine where the oil would be sloshing to on a hill.
I think the copper pipe may have slid down or something, opening a gap higher than the lowest point on the stock pickup that lets air in.
Is overfilling the oil by any amount safe for the engine until I can pull the sump off to check the pickup tube and replace the extension? |
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Max Welton Samba Member
Joined: May 19, 2003 Posts: 10697 Location: Black Forest, CO
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Posted: Tue Feb 20, 2018 4:33 pm Post subject: Re: Oil pressure loss on hills |
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aksyta wrote: |
If that's loose I'm screwed and need to split the case open to fix it, correct? |
Nope. There's a plug ( looks a lot like a freeze plug) in the case you can pull to expose the end of the pickup. Then you reach inside that with an expander tool (most people just make one) to swedge the tube into the surrounding case material. Then replace the plug.
Here's another picture from the galley. This guy put his oil temp sender in that spot as a plug.
However, from your description it seems more likely the extension isn't sealing on the stock pickup. I like to weld those on but some use a clamp. Never ever rely on just a snug fit there.
Max _________________ 1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836 |
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Max Welton Samba Member
Joined: May 19, 2003 Posts: 10697 Location: Black Forest, CO
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12721 Location: on a bike ride somewhere
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Posted: Tue Feb 20, 2018 4:49 pm Post subject: Re: Oil pressure loss on hills |
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If the pickup tube was loose in the case, it would be sucking oil on the downhills, not the uphills.
Gravity, dudes......
Robbie _________________ Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
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Max Welton Samba Member
Joined: May 19, 2003 Posts: 10697 Location: Black Forest, CO
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Danwvw Samba Member
Joined: July 31, 2012 Posts: 8892 Location: Oregon Coast
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Posted: Tue Feb 20, 2018 6:34 pm Post subject: Re: Oil pressure loss on hills |
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Let me guess, it's got a big oil pump on it right? A 30mm or something? I went through some of this on a single port motor. I think it was an F case maybe H case?
I think the problem is the choice of parts.
I would start by removing the sump all together, What oil filter does it have? What oil weight?
Think about this: As the car goes uphill the oil runs to the back of the engine and I don't know but the scenario may be that through the longer pickup tube it is farther down to the oil level so the big pump is causing cavitation in the small original tube or even somewhere where it goes to the pump or in the pump.
Lighter weight oil should solve this problem too if this is what is happening.
Even just staying in a higher gear may solve the problem.
"aksyta"
One thing is for sure, It's real, you are running your engine without oil pressure when it happens. _________________ 1960 Beetle And 1679cc DP W-100 & Dual Zeniths! |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31360 Location: Hot Arizona
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Danwvw Samba Member
Joined: July 31, 2012 Posts: 8892 Location: Oregon Coast
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Posted: Tue Feb 20, 2018 7:35 pm Post subject: Re: Oil pressure loss on hills |
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More oil would help if this is what is happening. The thing about these engines, I just looked at a case and there is more room for oil in the back of the case than in front. So the oil level would go lower going uphill.
I found even 10W40 will cavitate in a single port with a 30mm oil pump. I would try 5W30 or 0W40 and I would not drive it up a hill cold.
Check out "TheEZGZ" here at 13:45 in this video he has opened up and angled his oil pump on the intake. TheEZGZ video. On a 1500 single port case the intake holes at the pump are quite small the main thing is how well does your pump hole match? It may be the wrong pump for a later case so there is a big offset where the holes meet up. I would start if doing a full flow get a 26mm small hole pump and perhaps modify it to supply the 1st gear better the way "TheEZGZ" did. _________________ 1960 Beetle And 1679cc DP W-100 & Dual Zeniths!
Last edited by Danwvw on Tue Feb 20, 2018 8:02 pm; edited 1 time in total |
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mascrappo Samba Member
Joined: January 11, 2012 Posts: 535 Location: New Mexico
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Posted: Tue Feb 20, 2018 7:57 pm Post subject: Re: Oil pressure loss on hills |
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Depending on what part of Texas, you may try Valvoline Racing 20W50 oil? Works well for me in hot New Mexico. No controversy needed about my oil choice, just giving my suggestion. |
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Danwvw Samba Member
Joined: July 31, 2012 Posts: 8892 Location: Oregon Coast
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Posted: Tue Feb 20, 2018 8:04 pm Post subject: Re: Oil pressure loss on hills |
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Yes, If it is cavitation then 20W50 should make the problem of the oil light coming on much worse. Remember it matters how thick the oil is when it's cold too. _________________ 1960 Beetle And 1679cc DP W-100 & Dual Zeniths! |
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mascrappo Samba Member
Joined: January 11, 2012 Posts: 535 Location: New Mexico
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Posted: Tue Feb 20, 2018 8:07 pm Post subject: Re: Oil pressure loss on hills |
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What works in beautiful Oregon may not work in Texas. I say it's only 2.5-3 quarts of oil, drop the plug and give both light/thick oil a whirl! |
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aksyta Samba Member
Joined: March 16, 2017 Posts: 35 Location: Texas
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Posted: Tue Feb 20, 2018 8:17 pm Post subject: Re: Oil pressure loss on hills |
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I run valvoline vr1 racing 10w30, it works well enough but maybe 5w or 0w would be better since the engine takes a while to warm up the large quantity of oil, especially in the winters even though they just barely reach freezing here. This is a recent issue as far as I've noticed, and I've always used 10w30 so the oil is probably fine.
This doesn't trip the oil light even though I use a dual sender with the higher threshold warning light, just a drop in indicated pressure on the gauge. |
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mascrappo Samba Member
Joined: January 11, 2012 Posts: 535 Location: New Mexico
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Posted: Tue Feb 20, 2018 8:25 pm Post subject: Re: Oil pressure loss on hills |
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I have discovered in my lifetime, try the simplest things first. If you barely freeze, you are well within VR1 20W50 range. VW's used to run straight 30W, so 20W cold is ok. What's it going to hurt? Try the thin Danwvw suggests, if still does it, try my suggestion. Oil changes are quick and inexpensive, engines are not. THEN, if you still have issues, more in-depth work is in order. |
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aksyta Samba Member
Joined: March 16, 2017 Posts: 35 Location: Texas
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Posted: Tue Feb 20, 2018 8:35 pm Post subject: Re: Oil pressure loss on hills |
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I've tried 15w40 shell rotella before, the pressure just goes way up. With 10w30 I get down to about 10 psi/1k RPM only on the hottest days while driving on the freeway. Cold start idle pressure on a freezing day is around 50 psi. I've had a pressure gauge on the car for as long as I've had it, and switched from a mechanical sunpro to electrical VDO after I rolled it. The readings have been fairly consistent between both, though they may not be entirely accurate. Since it has a high flow pump and the engine has fairly low miles(therefore bearings and parts aren't as worn out and loose), the pressure would be senselessly high with 20w50.
Last edited by aksyta on Tue Feb 20, 2018 8:38 pm; edited 1 time in total |
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Danwvw Samba Member
Joined: July 31, 2012 Posts: 8892 Location: Oregon Coast
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Posted: Tue Feb 20, 2018 8:36 pm Post subject: Re: Oil pressure loss on hills |
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It could just be the cold weather an all that oil has to warm up like you say. 10W30 seems reasonable to me. 20W50 would be ok in the summer in Texas on a stock single port engine, especially if it was a 6mm stud oil pump case. They had much smaller oil pumps?
Do you know what size of oil pump it has? Is it full flow? What filter do you use?
This loss of oil pressure problem for me was on a single port engine that I had put like a 32mm filter pump on it eventually lead to the engine seizing up a main bearing. _________________ 1960 Beetle And 1679cc DP W-100 & Dual Zeniths!
Last edited by Danwvw on Tue Feb 20, 2018 8:41 pm; edited 1 time in total |
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mascrappo Samba Member
Joined: January 11, 2012 Posts: 535 Location: New Mexico
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Posted: Tue Feb 20, 2018 8:41 pm Post subject: Re: Oil pressure loss on hills |
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Please let us know what you do and what remedies it. |
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