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Lil Lulu Samba Member
Joined: December 08, 2007 Posts: 1745 Location: Mouth of the Columbia
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Posted: Fri Aug 11, 2017 11:10 am Post subject: Oil leak |
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I am going to attempt to put a stop to the persistent oil leak at the rear of my engine. I am sure there is no leak from the oil fillertube and dipstick boot. No leaks from the gallery plugs. Main seal is dry. New cooler seals. Crank seal and o-ring are dry. Oil pump cover is dry. Pressure tested the oil cooler, no leak. Gauge fitting is dry. I am using Ray's crankcase vent system that is adapted from a type 3 system. Still a small but annoying leak from just above the OPRV.
One thing I'm not sure about is the relief valve itself. At cold startup, the pressure pegs the VDO gauge. As it warms the pressure drops but is never less than 50# when running. Stays at about 16-20# at idle. As per Jake's requirement, I use only 20 - 50 oil. I remodeled the dipstick tube to the mod that wildthings suggested. (Best mod ever) Not leaking there.
Could it be that the oil pressure is just too high and I need to replace the relief valve? _________________ '65 Beetle "Lil' Lulu"- Ruby Red
1600 stock from '71 bus
'72 Deluxe - Niagara Blue w/pastelwiess Camper Special 2L dual 40 Webers 002
'74 Hightop Weekender "Dixie" 1800 34 Del singles |
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70Crew Samba Member
Joined: June 12, 2006 Posts: 776 Location: Grand Rapids, MI
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Posted: Fri Aug 11, 2017 12:02 pm Post subject: Re: Oil leak |
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OK, now you have me curious.... what is this dipstick tube mod of which you speak? Got a link to a thread? _________________ 1970 Crew Cab |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12686 Location: on a bike ride somewhere
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Posted: Fri Aug 11, 2017 12:34 pm Post subject: Re: Oil leak |
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How big of a restrictor are you using in the crankcase breather system?
70crew- were talking type 4 here, but Wildthings has a post on using rubber hose instead of the viton dipstick boot to stop leaks. Ray also has a few posts on his custom breather, to allow most consistent crankcase vacuum. I'll see if I can find them on my phone...
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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KentABQ Samba Member
Joined: September 11, 2016 Posts: 2406 Location: Albuquerque NM
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Posted: Fri Aug 11, 2017 1:14 pm Post subject: Re: Oil leak |
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Here 'tis...
https://www.thesamba.com/vw/forum/viewtopic.php?t=635809&highlight=dipstick+tube+mod%2A _________________ -Kent-
1976 Riviera, 1.8l FI chrome yellow VAN - "Chloe"
"I must say, how can you be in a bad mood driving this vehicle full of vibrant color.
Cars of today are so bland in comparison. It's like driving a celebration!" ---WildIdea
Bus ownership via emoticons:
---williamM |
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Lil Lulu Samba Member
Joined: December 08, 2007 Posts: 1745 Location: Mouth of the Columbia
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Posted: Sat Aug 12, 2017 8:36 am Post subject: Re: Oil leak |
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I'd really like to know how the oil pressure compares wth others. The oil pump is a Raby modified unit. I suspect it may be just blowing the oil past the seals. I thought about using the black light additive but the leak would still be hidden behind the shroud. _________________ '65 Beetle "Lil' Lulu"- Ruby Red
1600 stock from '71 bus
'72 Deluxe - Niagara Blue w/pastelwiess Camper Special 2L dual 40 Webers 002
'74 Hightop Weekender "Dixie" 1800 34 Del singles |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50254
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Posted: Sat Aug 12, 2017 9:02 am Post subject: Re: Oil leak |
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Oil pressure doesn't usually translate into oil leaks except for places like the oil pressure switch or galley plugs. Most oil leaks will however be somewhat sensitive to crankcase pressure. Not sure what you did to copy Ray's system, but remember Ray doesn't drive a bus and what works on his lightly loaded Type 4 car may not work on a heavy bus.
Do you have a diagram of your modified crankcase ventilation system? |
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KentABQ Samba Member
Joined: September 11, 2016 Posts: 2406 Location: Albuquerque NM
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Posted: Sat Aug 12, 2017 9:08 am Post subject: Re: Oil leak |
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Raby. Not Ray.
Looking for your glasses, wildthang? _________________ -Kent-
1976 Riviera, 1.8l FI chrome yellow VAN - "Chloe"
"I must say, how can you be in a bad mood driving this vehicle full of vibrant color.
Cars of today are so bland in comparison. It's like driving a celebration!" ---WildIdea
Bus ownership via emoticons:
---williamM |
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WhirledTraveller Samba Member
Joined: January 09, 2008 Posts: 1399 Location: Cambridge, MA
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Posted: Sat Aug 12, 2017 9:33 am Post subject: Re: Oil leak |
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KentPS wrote: |
Raby. Not Ray.
Looking for your glasses, wildthang? |
Irony alert, KentPS! Ray's system of crankcase ventilation is what is being discussed, and the pump is Raby modified. So, both, and Wildthing's post is spot on. I doubt oil pressure is the culprit although it sound *very high* and I would be running a much thinner oil despite Raby's "requirement". Every rebuild is different and pegging the pressure gauge is never a good thing. You are aiming for 45 psi or so on the highway at full temp, more than that is counterproductive.
I'm about to tackle the blacklight/dye procedure myself. My gut feeling is that even behind the shroud, if you get the bus up on jackstands, remove the lower tin, and get under there on a creeper with a blacklight you should be able to see where it is coming from. _________________ 1977 Westy, Automatic. Big Valve heads, CS Cam. |
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hazetguy Samba Member
Joined: April 06, 2001 Posts: 10773 Location: iT StiNgeD iTseLf tO dEAd
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Posted: Sat Aug 12, 2017 10:15 am Post subject: Re: Oil leak |
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with such high gauge readings, have you tried hooking up a different/manual oil pressure gauge? it would, at least, confirm or disprove your vdo gauge readings. perhaps your sender is bad. _________________ thebucket: I invested in hoodride, now DBD won't return my call?
hazetguy: invested?
thebucket: Yeah Haze, its where people put money into a company in hopes of a return on their money |
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KentABQ Samba Member
Joined: September 11, 2016 Posts: 2406 Location: Albuquerque NM
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Posted: Sat Aug 12, 2017 10:41 am Post subject: Re: Oil leak |
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WhirledTraveller wrote: |
Irony alert, KentPS! Ray's system of crankcase ventilation is what is being discussed, and the pump is Raby modified. So, both, and Wildthing's post is spot on. |
Now I know I left those speck-tackles around here someplace... _________________ -Kent-
1976 Riviera, 1.8l FI chrome yellow VAN - "Chloe"
"I must say, how can you be in a bad mood driving this vehicle full of vibrant color.
Cars of today are so bland in comparison. It's like driving a celebration!" ---WildIdea
Bus ownership via emoticons:
---williamM |
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Lil Lulu Samba Member
Joined: December 08, 2007 Posts: 1745 Location: Mouth of the Columbia
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Posted: Sat Aug 12, 2017 11:30 am Post subject: Re: Oil leak |
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Sender is new. Does not leak. I have the light and gauge plumbed with a good split. Gauge is an older one that I had before the CS was installed. Pressures were not nearly as high with the old pump. I have another gauge so will try to test that.
Photo of breather system coming. _________________ '65 Beetle "Lil' Lulu"- Ruby Red
1600 stock from '71 bus
'72 Deluxe - Niagara Blue w/pastelwiess Camper Special 2L dual 40 Webers 002
'74 Hightop Weekender "Dixie" 1800 34 Del singles |
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WhirledTraveller Samba Member
Joined: January 09, 2008 Posts: 1399 Location: Cambridge, MA
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Posted: Tue Aug 15, 2017 3:51 pm Post subject: Re: Oil leak |
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BTW did the dye test on my bus today. Had been putting it off because I suspected that it was my front main seal and I didn't really want to know that for sure, because then I'd have to fix it. Turns out both main seals are fine and my primary leak is the oil pump to case seal, secondary leak from a pushrod tube. Both relatively easy fixes.
My recommendation for the dye test, since you know its from the rear of the engine, is go ahead and remove the fan since the fan gets in the way of seeing what's going on and also blows the oil everywhere. Just take it right off, and run the engine for 2 minutes which isn't enough time to overheat. Then get in there with your UV flashlight and all shall be revealed. _________________ 1977 Westy, Automatic. Big Valve heads, CS Cam. |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16922 Location: San Diego, California
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Posted: Tue Aug 15, 2017 5:05 pm Post subject: Re: Oil leak |
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From personal experience I can tell you that VDO makes a 0-80 gauge with matching sender. They also make a 0-150 gauge with matching sender. Get them crossed and you'll have an abnormally high gauge reading.
Try installing a manual gauge to verify or check your VDO part numbers. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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WhirledTraveller Samba Member
Joined: January 09, 2008 Posts: 1399 Location: Cambridge, MA
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Posted: Wed Aug 16, 2017 7:50 am Post subject: Re: Oil leak |
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One thing that occured to me, is that if your homebrew crankcase vent system is clogged up or not working properly it is possible to pressurize the crankcase with combustion gasses which will lead to both high oil pressure readings and oil leaks. Typically pressurized crankcases leak from the main seals, though. _________________ 1977 Westy, Automatic. Big Valve heads, CS Cam. |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16922 Location: San Diego, California
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Posted: Wed Aug 16, 2017 7:57 am Post subject: Re: Oil leak |
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A broken ring, etc. can allow compression in the head to slip past the piston and pressurize the crankcase. This is known as "breather pressure". If it becomes excessive it can cause oil leaks. Breather pressure should not be noticed via the oil pressure gauge which reads the pressure in the oil galleries, not the case. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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WhirledTraveller Samba Member
Joined: January 09, 2008 Posts: 1399 Location: Cambridge, MA
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Posted: Wed Aug 16, 2017 8:03 am Post subject: Re: Oil leak |
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aeromech wrote: |
A broken ring, etc. can allow compression in the head to slip past the piston and pressurize the crankcase. This is known as "breather pressure". If it becomes excessive it can cause oil leaks. Breather pressure should not be noticed via the oil pressure gauge which reads the pressure in the oil galleries, not the case. |
The gauge reads the difference in pressure between the pressure in the galleries and ambient. Pressure in the crankcase is directly added to the oil pressure reading because the oil galleries are exposed to the crankcase. If you had the case at 10 psi, and the engine wasn't even turning, the oil pressure gauge would read 10psi. This doesn't mean oil is flowing, because the pressure is equal on both input and output sides of the galleries.
Some oil seals on the engine like the crankshaft seals are not normally exposed to pressure, and aren't designed to work against pressure, so when you have significant crankcase pressure they leak. _________________ 1977 Westy, Automatic. Big Valve heads, CS Cam. |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16922 Location: San Diego, California
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Posted: Wed Aug 16, 2017 8:18 am Post subject: Re: Oil leak |
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I'm no physicist so I'm not going to pretend to be one but I believe that if you had a crankcase (air) pressure of say 5 or 6 psi (which would be very high) pushing against oil pressure in a gallery of say 40 psi (fluid) a person couldn't tell on a oil pressure gauge. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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WhirledTraveller Samba Member
Joined: January 09, 2008 Posts: 1399 Location: Cambridge, MA
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Posted: Wed Aug 16, 2017 8:39 am Post subject: Re: Oil leak |
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aeromech wrote: |
I'm no physicist so I'm not going to pretend to be one but I believe that if you had a crankcase (air) pressure of say 5 or 6 psi (which would be very high) pushing against oil pressure in a gallery of say 40 psi (fluid) a person couldn't tell on a oil pressure gauge. |
Yeah I don't have a really good handle on how high crankcase pressure can get. I have heard stories (on other engines) of blowing the dipstick out of the engine which has to require pretty significant pressure. Anyway, this should be easy to test, vent the crankcase to the atmosphere and see if the problem goes away. _________________ 1977 Westy, Automatic. Big Valve heads, CS Cam. |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Wed Aug 16, 2017 9:02 am Post subject: Re: Oil leak |
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you would feel the breather pressure, and oil would seep many more places. The high oil pressure you are getting with 20w-50 is normal below about 80F. One thing is to check the length and spring pressure of the relief valve(s). The specs are in Bentley. Contrary to popular belief adding stronger springs does nothing except raise the top oil pressure meaning that if the engine used to see 12 psi at idle to 70 psi at 6000 RPM it will now see 12 psi at idle and 90 psi at 6000 RPM if the oil pump can deliver that. I can't tell Jake how to run his business but unless you are seeing constant days above 90F with lots of high speed freeway driving I would consider 10w-40. I've run 20w-50 for years but have to be really careful once we drop into the low 80's here because the pressure just gets too high on the engine. We don't drive a lot but if we did like on my 1971 I would drop to 10w-40 or 10w-30 in winter. Even a straight 40 weight is preferable to 20w-50 when temps are in the 70's and low 80's. I know 20w-50 is supposed to be thinner when cold than say 30 weight but how cold? My oil pressure on a 55 degree morning is higher on starting with 20w-50 than straight 30 weight. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin
Last edited by SGKent on Wed Aug 16, 2017 9:17 am; edited 2 times in total |
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lil-jinx Samba Member
Joined: August 14, 2013 Posts: 1109 Location: New Brunswick,Canada
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Posted: Wed Aug 16, 2017 9:11 am Post subject: Re: Oil leak |
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Crank case pressure can get very high,a loose engine with a lot of blow-by will produce more pressure quicker then a tight engine.if you feel the need to find out how high it gets.just block the vent system with your finger,that should give you a good idea.try not to blow out your valve cover gaskets.
I don't think high crank case pressure would effect oil pressure,I see where the oil pressure must overcome base pressure to exit the oil galleries.but at the same time the base pressure is also pushing the oil into the pump at the same pressure,equal pressure at both end so to speak. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy
1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes. |
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