Vacuum pump oil inlet hose suddenly leaking badly

Hello all . The question being asked is

Does an oil inlet hose for an ancillary component on a diesel engine sometimes fail very suddenly and start leaking lots of oil immediately ?

Thanks in advance to any mechanics who might be able to help with this question .

I can and do most of my own mechanics on my vehicles but I'm certainly no expert .

Today I noticed a large oil leak under my 4x4 . It's old it drips a little bit normally , but no where near enough to worry about . I've taken it out and only done about 2-3 miles and back home . There was no large leaking when I left , nothing to mention on the floor where it was left before I took it out .

When I've come back however , I've had my dinner , then done 45 minutes work in the garden , and then I was looking for my keys to lock up and happened to see probably about 100ml or so of oil on the drive under the 4x4 . I've thought , oh crap that's not good , checked the fluids and had good look with a torch to see where it's coming from . I'm not happy to see theres oil on the exhaust downpipe , it's soaking all over the front transmission , and it's dripping down off the crossmember and the arm mounts on one side .

Theres me thinking owtf is this , and so I get a rag and get rid of the worst of it from various parts that are covered in oil . I couldnt see where it's coming from . Having cleaned it up a bit I thought , I'll put it in the garage so I can check the oil levels on the flat in the morning , stick some paper under it and try and see if I'll find it that way . But I get under and have another look before leaving it , and I see drips already dripping again off the lower arm mounts to the crossmember . It hasn't moved in the wind at all this time just to back it in to the garage , so I look directly above those drips ... and lo and behold its the oil inlet hose to the vacuum pump .

There's lots of oil around and coming from the inner crimped end of the high pressure braided rubber piping , which takes oil into the alternator mounted vacuum pump to lubricate the bearings .

Now , the question is , would that go as in fail as suddenly as all that ? I't's done a lot work that pipe , it's never been replaced yet , the oil is under high pressure inside so it's going to pish out if it's broken somehow . And it is doing , suddenly today .
But then again it's a high quality piece of kit for those reasons of needing to be . Why has it suddenly broken ? I'm expecting to pay maybe £80 quids for a new one from the manufacturers tomorrow , you can only buy them from main dealers parts dept . , or the uae off ebay . The UK Aftermarket people don't sell them . Maybe that's because they don;t often go . It's done about 210 000 miles , so I don't know . It still pulls well been serviced often especially oil changes , has hardly ever ever let me down so far .

So again the question is , is it quite normal for an oil inlet hose to suddenly fail ? And at the crimped connection to the hose - it's not the o rings inside the banjo connectors . It's lucky I saw that sneaky leaky on the ground before taking it very far because I've a feeling that when I start the 4by up tomorrow I'm going to see visible leakage from that pipe while it's running, probably it'll be worse while it's under load . That kind of problem could have quickly become a car killer if I hadn't seen it and luckily I've got some spare oil to keep filling should I have to drive it . Just reversing it downhill made quite a bit come out so I won;t be doing that until it's fixed .

I've heard of and seen hydraulic pipes exploding or leaking from crimped ends , so is this a similar thing , is the pressure involved in oil delivery to an ancillary enough to split the pipe ? Or could it possibly be down to blockage in that pipe , meaning I might to replace the oil return hose as well ?
Once again would appreciate any good mechanics advice thanks

a reply to: PrinceRegent

sounds like whatever was leaking a little finally let go, any rubber or plastic part can and likely will fail, hoses dry out, plastic gets brittle, what year is the vehicle?

a reply to: funbobby

It's getting on for 20 years old . Why it's suddenly decided to fail and make a lot of mess is what had me scratching my head

a reply to: PrinceRegent

It could be a lot of things. Get some engine cleaner and clean it top to bottom. Then run it and check for leaks. Check and add oil before running and check for water in the oil. It will look like chocolate milk if water is mixed in.

My GUESS is a blown headgasket.

a reply to: LookingAtMars

I ran those checks immediately , and there's no reason for the head gasket to go . Everything else is tickety boo . This is more about one pipe in particular ( taking oil at pumped pressure to the alternator ) which has been found as the cause of the leakage .

It has suddenly split or damaged itself , but it's probably down to old age - lasted 20years , bust in one day

a reply to: PrinceRegent

taking oil at pumped pressure to the alternator

A lot of times oil can fool you.

Oil going to the alternator? or air pump? Never seen that model

a reply to: PrinceRegent

"20 years old" that will do it every time! Rubber dry rots, I would guess that either whatever was leaking a little finally just let go. It will be interesting to see if changing the hose results in no leak at all or if the slow leak was coming from somewhere else. When you pull off the old hose bend it and see how stiff and cracked it is compared to the new one, take a look at other hoses nearby, they are probably in the same condition and also subject to fail at any time, sometimes you can buy them as a kit get a discount and replace them all at once.

a reply to: PrinceRegent

Yes hoses can blow without warning, even more chance if they are old. Find out what the normal operating oil pressure is and check what the hose is rated for (maximum pressure). Take the hose out and inspect it for cuts or holes, if there is none, pressure test the hose to about 10-20psi over normal operating pressure. If you can, fill the hose with water and remove any trapped air before you pressure it up, water can’t be compressed and you will not be storing any energy in the line should it blow under pressure. Most new pressure components are tested full of water (hydro test) to 1.5 x design pressure but NEVER go to that high of pressure with old components, it’s very dangerous. If the hose is bad the water will show you where the leak is. To save some money skip the dealer and take the hose to a hydraulic shop and they can make a new hose for you or they can sell you the fittings and hose to make it yourself.

Without knowing what you are working on, I’m guessing your “air pump” is a compressor which most diesels have, and they are supplied with engine oil pressure for lubrication. It could be that there is a bad gasket in the compressor and the oil is just following the hose making it look like a bad hose. Beyond that you could be looking at a blown head gasket. Pressure wash the motor and watch it when it’s running, any oil leak should be easy to spot.

originally posted by: PrinceRegent
Hello all . The question being asked is

Does an oil inlet hose for an ancillary component on a diesel engine sometimes fail very suddenly and start leaking lots of oil immediately ?

Thanks in advance to any mechanics who might be able to help with this question .

I can and do most of my own mechanics on my vehicles but I'm certainly no expert .

Today I noticed a large oil leak under my 4x4 . It's old it drips a little bit normally , but no where near enough to worry about . I've taken it out and only done about 2-3 miles and back home . There was no large leaking when I left , nothing to mention on the floor where it was left before I took it out .

When I've come back however , I've had my dinner , then done 45 minutes work in the garden , and then I was looking for my keys to lock up and happened to see probably about 100ml or so of oil on the drive under the 4x4 . I've thought , oh crap that's not good , checked the fluids and had good look with a torch to see where it's coming from . I'm not happy to see theres oil on the exhaust downpipe , it's soaking all over the front transmission , and it's dripping down off the crossmember and the arm mounts on one side .

Theres me thinking owtf is this , and so I get a rag and get rid of the worst of it from various parts that are covered in oil . I couldnt see where it's coming from . Having cleaned it up a bit I thought , I'll put it in the garage so I can check the oil levels on the flat in the morning , stick some paper under it and try and see if I'll find it that way . But I get under and have another look before leaving it , and I see drips already dripping again off the lower arm mounts to the crossmember . It hasn't moved in the wind at all this time just to back it in to the garage , so I look directly above those drips ... and lo and behold its the oil inlet hose to the vacuum pump .

There's lots of oil around and coming from the inner crimped end of the high pressure braided rubber piping , which takes oil into the alternator mounted vacuum pump to lubricate the bearings .

Now , the question is , would that go as in fail as suddenly as all that ? I't's done a lot work that pipe , it's never been replaced yet , the oil is under high pressure inside so it's going to pish out if it's broken somehow . And it is doing , suddenly today .
But then again it's a high quality piece of kit for those reasons of needing to be . Why has it suddenly broken ? I'm expecting to pay maybe £80 quids for a new one from the manufacturers tomorrow , you can only buy them from main dealers parts dept . , or the uae off ebay . The UK Aftermarket people don't sell them . Maybe that's because they don;t often go . It's done about 210 000 miles , so I don't know . It still pulls well been serviced often especially oil changes , has hardly ever ever let me down so far .

So again the question is , is it quite normal for an oil inlet hose to suddenly fail ? And at the crimped connection to the hose - it's not the o rings inside the banjo connectors . It's lucky I saw that sneaky leaky on the ground before taking it very far because I've a feeling that when I start the 4by up tomorrow I'm going to see visible leakage from that pipe while it's running, probably it'll be worse while it's under load . That kind of problem could have quickly become a car killer if I hadn't seen it and luckily I've got some spare oil to keep filling should I have to drive it . Just reversing it downhill made quite a bit come out so I won;t be doing that until it's fixed .

I've heard of and seen hydraulic pipes exploding or leaking from crimped ends , so is this a similar thing , is the pressure involved in oil delivery to an ancillary enough to split the pipe ? Or could it possibly be down to blockage in that pipe , meaning I might to replace the oil return hose as well ?
Once again would appreciate any good mechanics advice thanks

Could also be due to increased oil pressure or leakage related to a blown Head Gasket.

Oils clean, no milky look to it?
Any bubbles in your coolant when you take rad cap off and rev engine?
Coolant leaking outta exhaust? It'll smell sweet..

Hopefully just the hose gave up the ghost. If so, easy peasy.

Let us know how it turns out.

a reply to: PrinceRegent

Because it's parts are 20 yrs old. Duh...you can expect the rubber and plastics to stiffen, crack, and crumble...

a reply to: MykeNukem

Firstly thanks everybody for the helpful replies . I've had an interesting day seeing to fixing the component that feeds and returns oil to the vacuum pump , which is mounted on the front of the alternator .

First of all the OEM part new costs £150 from the manufacturer ! It's a short piece of braided rubber containing both an inlet and return feed within . Both ends have metal banjo joints , with crimps to the hose in between .
The two bolts that go through the banjo holes both have a hole in the end and in the side allowing the oil in and out .

Second of all I found out that you can either take the hose and fittings to a hydraulic specialist to overhaul them . So I thought , rather than pay the 150 I'd try that . I also discovered there's a firm which comes to you to do this too .
Thinking of the cheaper option , what I did was call the AA , explained the problem and they were happy to come and pick me and the 4by up , take me to the specialists and have it repaired, on which the plan was to refit the offending article at the local hydraulic specialist's site , and drive away .

It didn;t quite work out that way ; on getting there they went "oh dear , that's a one of them and it's a difficult fix . The AA man and myself were thinking "problemo" , but then the nice man who runs the place said , "hang on let me try something" , after realising why the thing was leaking . What had happened it seems was that at one end where the crimp goes into a short metal offset angled pipe . He found that it was spinning loosely on the metal union when it shouldn;t have been :

SO in fact it wasn;t the rubber braided pipe that was perished and had split ,

but actually the metal union which allows the component to fit the vehicle had worked itself loose somehow .

He took it and made it firm very quickly , didn;t charge me but wasn;t sure if would now work . He said it was a temporary fix but to try it and see .

So the AA man (who was sound as a pound too ) let me fit the pipe back while it was on the lorry , run it up and see the leak was still dripping - it was visibly dripping while running yesterday at about 2 drips a second , fast enough to worry , but after the fix , only a couple of drips came out and then it pretty much stopped leaking , down to about a drip every 10 seconds , and by now it appears less than that too .

So the fix , temporary so I'm told , cost me a day's faffing about instead of the day's planned work , and a grand total of £0 - result . A little extra oil to top up and that's it , done , for now . I'm happy with that .
As to what's the actual cause of the non-tamper unthreaded metal union becoming loose by itself I'm still not sure , could be the oil pressure itself was high , but both the oil and the coolant seem in good condition , both were changed recently enough too . It went up to a bit higher speeds than it is generally used to recently but not by much . The fix seems to have improved the drive it gives very slightly too , perhaps now giving slightly more oil pressure to where it's supposed to be .

Thanks again all posters I've enjoyed writing out this technical discussion actually , and it's helped to share it .

a reply to: Grayarea

All the hoses throughout are still in serviceable condition as it was built to last, and it has been looked after all over generally . The actual leak was very easy to spot , dropping from the flexible part . At first , the rubber / braiding therelooked damaged but actually what has properly stopped it is having the metal union adjusted back to where it's supposed to be - in a fixed position and not spinning on the housing which also forms the crimp .

The oil goes through the holes in the bolts , down a short angled metal pipe , into anarrowing funnel shape which is meant to be fused / fixed to the metal union which is of the rounded crimped type - pressure crimped . The pipe had come away at the rounded join between the metal fixing so the oil was not in fact flowing out not from the rubber parts . How the system allows pressure to feed both in and out I'm not actually sure but I beleive there's two pipes within the flexible rubber, or else the system only serves to provide oil at pressure to the actual bearing within the vacuum pump , being spun off the belt of course . When the oil is changed the oil must at some point change there too and that'd be how it comes out again - and just having thought about that one , maybe it's that the' provided' oil has become degraded inside the chambers leading to the bearing , perhaps allowing pressure variables and fluctuation enough to break a seal . An expensive one at that . That's getting in depth probably too far for me , I'm not a scientist I know I took the alternator assemblys apart because I was simply annoyed with some minor enough leakage around there last year , though it's hardly worried me until now whether it's formed some spots . Never had to replace the alternator yet either , though it might be a bit dirty . So maybe it's that that pipe was damaged sometime and never came across that because to remove the alternator you only have to take the one union off , and that's obviously the vacuum pump end , not the other end which was leaking , although pretty badly all of a sudden yesterday .

I'll try and not analyse it into the ground any more Who gives a one now it's fixed . If it was the head gasket I'd know , although putting it another way if it is that starting , then it's had a more than fair run on the last one and it'll be time to break out the new as that's the plan with that vehicle . It's not going to be allowed to just die is it unless I can help it , but it's doing the clutch I'm really not looking forward to which has also had a fair innings by now . But , when it's time it'll be time for it . Most of the people I dealt with todaywere all really nice and that was great the manufacturers not so much but it s all good

a reply to: PrinceRegent

Good to hear

Was hoping for your sake it was the hose. Head Gasket issues can sometimes cause issues such as this, as well as other weird symptoms that seem unrelated.

Without pics or video, we're all just walking you through the general issues/troubleshooting that is pretty standard from our experience.

If you're unable to definitively troubleshoot a problem, always start with the cheapest part and work your way up, lol.

Anyways glad to hear you got 'er.