Oil leak on 3/4 side of 1.8L type IV

[Treehive]

Hello everyone. I have finally decided to take my problem to a couple of forums b/c I have exhausted my limited knowledge and experience. I have a 1974 Westy with a 1.8L run with a single weber progressive and 009 dizzy. I had a bargain rebuild done by a local mechanic (he rebuilds type IV's exclusively) about 6 months ago. I describe it as bargain b/c not all NEW parts were used. It has new solid lifters, cams, main bearings, re machined heads (they were already newish when I bought the bus), new seals and gaskets, new oil cooler (original had a hairline fracture)...ect. For the rest of the post I am going to cut and paste a communication i had with the mechanic....it describes all the work i did this weekend in pinpointing where the leak is located and some of the mechanics thoughts as well...the leak is on the 3/4 side..

Mechanic wrote:
"The only thing on that side would be "pushrod tubes" or a "valve cover" leaking, the oil sender shouldn't be leaking(new and checked) and the oil pump(no oil around it) is not leaking, the oil cooler & rear seal at the timing hub, is dry, so that don't leave much. I'm at a loss on it, whatever we find will make us look silly when we find it. One other place we could check is the bolt that holds the oil pick up tube in place, its between the push rod tubes on the 3/4 side, in the center of the engine, deep in a hole. I can send a picture if you don't know where it is."

I responded:
"This weekend a buddy and me pressure washed the belly of the beast to assist in discovering where the leak originates. I found the bolt you were talking about (between the pushrod tubes on the 3/4 side) and it was nice and snug. Also, just poking my finger around in there revealed it was clean of fresh oil.

A day after the pressure wash (to ensure it was nice and dry) we fired up the engine, and with my buddy underneath the bus, there was no leak UNTIL I revved the engine up to about 2000-3000 rpm. When the engine revs, the oil pukes out from the right side of cylinder #4 (driver's side cylinder closest to the rear of the bus). It is hard to see exactly where b/c there are many obstructions to our view, but it could also be just above the cylinder. There is NO oil coming from the top of the engine (dizzy is clean, oil pressure sender is clean, oil cooler is clean, dipstick is clean, oil filler tube is clean, fan housing is clean) Also, there is no oil coming from the pushrod tubes, valve cover, taco plate, oil filter, drain bolt, or from where the engine meets the tranny.

What do you think? The cylinder? Hairline fracture in the case just above the cylinder? It seems, at this point, the only way we can make a more accurate assessment is to remove the engine again, remove all the tin, remove the head and get a closer look at the cylinder?? I am perplexed yet again....Please, any advice or council will be greatly appreciated. Thanks"

As you can surmise from the two emails, I have pinpointed that the leak is coming from the right side of the #4 cylinder, and perhaps just a little above it. It is really hard to see, even after I have removed the tin that covers the pushrod tubes. I am really at a loss as to where it is exactly?? Could the #4 cylinder be leaking? The mechanic described that diagnosis as "impossible" and that he has rebuilt hundreds of T4's and has never had a leaking cylinder. The oil cooler is above that cylinder, but it is brand new and it was pressure tested b4 it was put in. Thanks in advance for any responses.

TEddy

[airkooledchris]

you could have a leaking jug. someone who knows more about these things will chime in eventually, but what you describe sounds a lot like the leak I had as well, but mine was more likely to happen at idle when warm/hot, and not specifically at higher RPM's.

[Treehive]

you could have a leaking jug. someone who knows more about these things will chime in eventually, but what you describe sounds a lot like the leak I had as well, but mine was more likely to happen at idle when warm/hot, and not specifically at higher RPM's.

Would you happen to know where in the Bentley I can find information about the "jug"? It's not ringing a bell...thanx for the response

teddy

[satchmo]

If the oil is really running out soon after start-up, about the only thing that can be leaking like that is the seals for the oil cooler. The seals slip sometimes as the cooler is put into position. I don't think the engine has to come out to check it, but you do need to get the upper tin off at the least.

I've never seen or heard of a cylinder crack. Leaking at the cylinder to case and the cylinder to head surfaces should be pretty easy to see with the lower tins off. If either of those are leaking, it should be a pretty slow one.

Good luck, Tim

[vwlover77]

My own personal experience: The oil breather gasket was not perfectly sealed, and when at operating RPM, a small oil leak flowed oil from this gasket down the block past the # 4 cylinder. I was convinced that the cylinder/jug mating surface was leaking untill I pulled the engine, removed the tin, and found the tell-tale trail of oil.

[vdubyah73]

look closely at the pushrod seals, at the case end. When things get whirling in there they tend to sling oil to the 3/4 side. sometimes all you have to do to stop it is to twist the pushrod tube, it kinda resets the seal. might have twist a couple times around. Has worked for me.

[Sluggo]

I also think it's probably the oil cooler seals. Saw this happen on a friends Bus.

[vwlover77]

Here's a photo of my leak:

[Treehive]

Thanks for the responses. I really don't think it is the oil cooler or the seals, but I will be dropping the engine in a couple of hours to get a better look. I have no way to bench test it, but I was thinking of removing all the tin that i can, putting the engine back in minus the tin, and running it (not driving it) that way to see if I can get an even better look.

@Don - I will check the oil breather gasket tonight

@vdubya - push rod tubes are super clean. the builder who worked on the engine painted them blue, so its real easy to see oil

Please keep any ideas coming....I'll keep everyone posted

thanks
teddy

[Amskeptic]

Thanks for the responses. I really don't think it is the oil cooler or the seals, but I will be dropping the engine in a couple of hours to get a better look. I have no way to bench test it, but I was thinking of removing all the tin that i can, putting the engine back in minus the tin, and running it (not driving it) that way to see if I can get an even better look.

@Don - I will check the oil breather gasket tonight

@vdubya - push rod tubes are super clean. the builder who worked on the engine painted them blue, so its real easy to see oil

Please keep any ideas coming....I'll keep everyone posted

thanks
teddy

You used the phrase "pukes out" which is a strong word. The only thing that could allows oil to puke, is a leak in a pressurised component, like the gallery plugs pressed in the drilling ends of passages adjacent to cylinder #4. Those passages include the main gallery/drilling from the filter/drilling to and from the cooler. The problem with gallery plug leaks, is you really need to have a running engine to definitively ascertain the diagnosis.

You CAN easily check the oil cooler seals from below. Merely sight up the leading edge of the oil cooler. Have a can of carb spray to rinse any oil away so you can track to the source . . . if the engine is not already out.
ColinNowI'mCurious

[Treehive]

My own personal experience: The oil breather gasket was not perfectly sealed, and when at operating RPM, a small oil leak flowed oil from this gasket down the block past the # 4 cylinder. I was convinced that the cylinder/jug mating surface was leaking untill I pulled the engine, removed the tin, and found the tell-tale trail of oil.

Well, a friend and i dropped the engine last night, stripped the tin, removed the fan shroud, and discovered the general area that the oil appears to be coming from. It is flowing down to the left of the oil pressure sending unit, but it is not the source. The oil cooler was clean and no oil is leaking from the seals. Also, it was mostly clean around the dizzy, but there was some residue....I think it flowed down there. The oil breather gasket was SATURATED with oil as well as the oil breather tube (i don't know if this is normal) however, it will be the next thing that I tackle after I pressure wash the top of the case to remove all oil residue. I really want it to be the oil breather gasket, but i expected, if that is the case, for there to me more oil residue. Could a oil saturated oil breather tube and oil breather gasket be the culprit? What would be the best way to seal the hell out of the oil breather? I will post some pics when I get home tonight. Thanks everyone!.....trouble shooting, trouble shooting, trouble shooting!


One quick question? Is is safe for me to put the engine back in the bus and run it without the tin? I have a feeling that will be the only way to solve this perplexing issue.

thansk

teddy

[Amskeptic]

What would be the best way to seal the hell out of the oil breather?
Is is safe for me to put the engine back in the bus and run it without the tin? I have a feeling that will be the only way to solve this perplexing issue.

Don't "seal the hell of the oil breather". Just because it was leaking (if it was leaking) does not mean you get to punish it. Let's say you find out the rebuilder didn't know that the gasket is actually a trapezoid, and he installed it backwards . . . just install it correctly, no hell needed.

You have about three minutes to run the run the engine cold. That is about your usual thermostat-closed runtime. If after it has warmed up, if you have to repeat run it, drop it down to no more than a minute.
Colin

[Treehive]

What would be the best way to seal the hell out of the oil breather?
Is is safe for me to put the engine back in the bus and run it without the tin? I have a feeling that will be the only way to solve this perplexing issue.

Don't "seal the hell of the oil breather". Just because it was leaking (if it was leaking) does not mean you get to punish it. Let's say you find out the rebuilder didn't know that the gasket is actually a trapezoid, and he installed it backwards . . . just install it correctly, no hell needed.

You have about three minutes to run the run the engine cold. That is about your usual thermostat-closed runtime. If after it has warmed up, if you have to repeat run it, drop it down to no more than a minute.
Colin

Thanks Colin. I won't "seal the hell" out of it, but if its not the culprit....I'm at a loss

[Treehive]

You used the phrase "pukes out" which is a strong word. The only thing that could allows oil to puke, is a leak in a pressurised component, like the gallery plugs pressed in the drilling ends of passages adjacent to cylinder #4. Those passages include the main gallery/drilling from the filter/drilling to and from the cooler. The problem with gallery plug leaks, is you really need to have a running engine to definitively ascertain the diagnosis.

You CAN easily check the oil cooler seals from below. Merely sight up the leading edge of the oil cooler. Have a can of carb spray to rinse any oil away so you can track to the source . . . if the engine is not already out.
ColinNowI'mCurious

Colin

I'm not familiar with the gallery plugs that you are describing, and you are the first to respond with such a diagnosis. I would really like to understand more of what you are describing. Could you elaborate a bit for this "semi" novice....Once this is over, I will know and have intimate knowledge of every place one of these suckers leak :)

[Sluggo]

If you look at the front & rear of your engine you will see little aluminum circles (plugs). Those seal the oil galleries in your engine. If one blows out it can dump a large amount of oil very quickly. When you say it "puked" oil that makes us think it was a very large dump of oil.