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2CV engine oil leak

My little old motor is running like clockwork however it continues to be incontinent and insists on leaving oil spraints on my garage floor and when it visits other places which is rather embarassing. The leaks seem to come from the dip stick of all places and despite securing it with a reusable zip tie, it continues to insist on preserving my engine with a liberal coating of oil spray. The original breather has been retained - the cap does seal properly - together with the return feed to the distick and a 2cv Specials club Foo foo valve has been fitted on the breather outlet and it is the right way round and after that there is a small vented catch tank for residual vapours. A nappy has been suggested but that is just a tad over the top, it may be old but........
I am considering removing the diptstick and replacing it with a plug (removable) but would prefer not to go that route; I understood that with a correctly operating foo foo valve the crank runs in a vacuum and should not pump out anything save oil mist in the re-circulating system. It has never made the Foo Foo noise that Callum Beveridges (Burton) one does! I don't think it is the front crank oil seal as most of the oil is above that. I am at a loss on how to cure this and would appreciate any help. I am also posting this on the Pembelton forum in the hope of finding a cure.

Tom

Membership No. 1859

Re: 2CV engine oil leak

Tom,
is the dipstick being pushed out of its tube?
If that's the case, the crankcase is being pressurised, most probably because the pistons and rings aren't sealing adequately.

Have you carried out a vacuum test? All that's needed is about 1.5 metres of clear windscreen washer tubing and some LHM to make a manometer.
The tubing needs to be about 8mm OD, then the end is wrapped with some insulation tape to make a good seal into the dipstick tube.
The difference in level between the 'legs' of the manometer should be around 50mm at idle, with the 'high' side towards the engine.

However, it's much more important that it shouldn't show positive pressure at higher rpm, so you need to raise the engine speed to over 5,000 rpm for that part of the test.
Don't forget that matters would be even worse on the road, with the throttle wide open and the engine under load...

Ken

Membership No. 724

Re: 2CV engine oil leak

Thanks Ken, did a compressions test early on and all was well with that, I can't remember what the readings actually were but a knowledgable friend reckoned they were fine. However the problem does occur after prolonged high speed runs (everything is relative) I will carry out your check and report back though ;-)

Cheers

Tom

PS Might be a good time/excuse to do a barrell/piston upgrade methinks

Membership No. 1859

Re: 2CV engine oil leak

Ken, just re-read your post and yes, the dipstick has been pushed out - twice and both on motorway runs. Sounds as if rings are required, is it one size fits all?

Tom

Membership No. 1859

Re: 2CV engine oil leak

Tom,
a compression test, with engine hot and throttle wide open, should give 150 psi for 8.5:1 pistons and 175 psi for the 9.0:1 variety.

Bore is always 74mm, but some older engines had slightly different depths of rings.

If the engine's overheated and nipped up, it's possible that a ring may be broken or stuck in its groove, but that would have a noticeable effect on the compression readings, maybe even on the running.

Maybe a Winter job to have the heads off and a peep inside? ;o)

Ken

Membership No. 724

Re: 2CV engine oil leak

Cheers Ken, really helpful as always. I will indeed remove the heads and have a look, just as soon as they salt the roads!

Tom

Membership No. 1859

Re: 2CV engine oil leak

I have just acquired a Dart "Snake Scope" (endoscope)


http://www.dartsystems.co.uk/shop/index.php?main_page=product_info&cPath=58_117_123&products_id=781

which will look inside a cylinder without taking the head off. It plugs into the USB port on a laptop and shows a picture on the screen.

You can get one from Maplin for £79 but the exact same product is available from DART (see link above) for £35.

I bought it to check some domestic wiring in the void between ceiling and upstairs flooring but I expect to use it for mechanical inspections when necessary.

Membership No. 1159

Re: 2CV engine oil leak

David, much as I like gadgets, the heads and barrels seem easy to remove so I will pass on that one.

I note there are two types of 9:1 high compression barrels and pistons available, one is about £150 and the other, (Perfect Circle) about £195. Given that it is going on a less than new engine is there any sensible reason not to buy the cheaper one?

Tom

Membership No. 1859

Re: 2CV engine oil leak

Hi

I have just found the 'Dart Snake Scope' on ebay for £22.99 Buy It Now or Make Offer + £6.99 p&p.

Item no. 290472798982

Best regards

Ray

Membership No. 1606

Re: 2CV engine oil leak

This one certainly looks the same although it doesn't say "DART" With postage it comes to £29.98 BUT note that it is despatched from "outside UK". I actually paid £33.50 with free postage from the UK from Ebay "buy-it-now". Thought it was worth the extra. Either way it is a useful tool to have around.

Membership No. 1159

Re: 2CV engine oil leak

Ken Hanna
....
The difference in level between the 'legs' of the manometer should be around 50mm at idle, with the 'high' side towards the engine.

Ken


Ken I have done the low speed test using a vacuum guage and registered 2" of vacuum (it's an old guage) so this should be okay n'est ce pas? I have then revved it hard and the reading was maintained, indeed it was greater at very high revs so am I right in assuming the breather/foo foo is doing its job? The dipstick is a very loose fit and the rubber seal has gone hard and is ineffective and it has been suggested that this may be the culprit. I propose to try it using a rubber bung and see if it helps.

Tom

Membership No. 1859

Re: 2CV engine oil leak

Tom have you done a crankcase test take a tube frome the dipstick and make a big "u " on a length of wood say 3 foot draw a line at 1 foot the at 1 inch incriments fill u with water up to the start line add food colouring for a better visual effect start engine and read the vacum at tick over mine is 8 inches and i have no leaks any questions give me a call also check the return from the breather to the dip stick this gets blocked with crud when the valve breaks down. this stops the oil draining back to the engine and ends up in the carb if standard carb used even if there is a fu fu valve with twin carbs it will just blow out the breathere pipe. Don

Membership No. 1667

Re: 2CV engine oil leak

Tom,
out of interest, was that gauge graduated in inches Hg?

If so, I'd be more than a little sceptical about the accuracy of its reading, as 2" mercury gauge is equivalent to 27" water gauge... ;o)

Bear in mind that the 50 to 60mm water gauge vacuum specified by Citroen is equivalent to only 0.07 psi vacuum, so the _only_ way to measure to the required degree of accuracy is with a manometer.

1.5 metres of 8mm OD windscreen washer tubing, plus some insulating tape to wrap round the end that's going into the dipstick tube and you're in business.

I use LHM instead of water, not just because it's easy to see, but also because if some did get sucked into the engine, it won't cause any problems...

ken



Tom Rae


Ken I have done the low speed test using a vacuum guage and registered 2" of vacuum (it's an old guage) so this should be okay n'est ce pas? I have then revved it hard and the reading was maintained, indeed it was greater at very high revs so am I right in assuming the breather/foo foo is doing its job? The dipstick is a very loose fit and the rubber seal has gone hard and is ineffective and it has been suggested that this may be the culprit. I propose to try it using a rubber bung and see if it helps.

Tom

Membership No. 724

Re: 2CV engine oil leak

Don, I have done the equivalent of your test but registered a vacuum of about 3" which does seem to be slightly above the norm of 2" found by other folk, mine is constant throughout the rev range so it is at least a vacuum if nothing like as stong as yours! I am going to experiment blocking off the dipstick tube and see if that helps stem the leaks or at least reduce them.

Tom

Membership No. 1859

Re: 2CV engine oil leak

Ken Hanna
Tom,
out of interest, was that gauge graduated in inches Hg?

If so, I'd be more than a little sceptical about the accuracy of its reading, as 2" mercury gauge is equivalent to 27" water gauge... ;o)

Bear in mind that the 50 to 60mm water gauge vacuum specified by Citroen is equivalent to only 0.07 psi vacuum, so the _only_ way to measure to the required degree of accuracy is with a manometer.

1.5 metres of 8mm OD windscreen washer tubing, plus some insulating tape to wrap round the end that's going into the dipstick tube and you're in business.

I use LHM instead of water, not just because it's easy to see, but also because if some did get sucked into the engine, it won't cause any problems...

ken



Ah, thanks Ken, back to earth now, yes, the gauge is calibrated in inches HG. I'll just have to get some tubing and rig up a manometer, hopefully I can do it this weekend, I should be able to get some tubing at Partco. Life never seems to be straightforward...........

Membership No. 1859

Re: 2CV engine oil leak

Tom,
although, like a road, it wouldn't be half as entertaining without a good few twists and turns along the way. ;o)

Ken


Tom Rae

Life never seems to be straightforward...........

Membership No. 724

Re: 2CV engine oil leak

Ken, made a Manometer and lo and behold, about 1/2" vacuum on tickover and then positive pressure right up to 3" which is not a good thing. As the engine is running well with no sign of burning any oil, either on acceleration or on the overrun then my suspicion is that the Reniflard is not operating properly despite the inclusion of a Steve Parrish Foo foo after it and it is the right way round!

Tom

Membership No. 1859

Re: 2CV engine oil leak

Have run again without the Reniflard but with the Foo foo valve fitted and I am now getting good negative vacuum so it would appear I have a part blocked faulty Reniflard!

Tom

Membership No. 1859

Re: 2CV engine oil leak

What is the Reniflard, do I have one!!! are we talk ing about the oil filling/vent unit, in which case I can sit back as mine is there!
Maybe some day I'll check the vaccuum but its wet at the moment and the forecast is poor for the next week

Membership No. 1832

Re: 2CV engine oil leak

Bill, it is indeed the oil filler/vent however having one is not the issue, it is whether it works or not as the purpose of it is to a) maintain a vacuum in the crankcase reducing oil leaks and b)to trap oil that is breathed out in the fumes and return it to the sump. Within the Reniflard, there are some cunning goings on but an old Reniflard is quite likely to have hardened rubber valves which no longer perform properly and this can be tested using a manometer connected to the dipstick tube as mentioned above. In my limited experience, if the engine has been lying unused for a long time then the valves could have hardened in a position which will restrict the breathing which will not be improved if an after market foo foo valve is fitted. I think the only way to properly tell what is going on is to use the manometer.

Tom

Membership No. 1859

Re: 2CV engine oil leak

Tom,totally off subject but Don tipped me off to look at the video of your Oban trip absolutely magic!
Regards
Chris

Membership No. 1488

Re: 2CV engine oil leak

Chris, if I have lasted this long without having to become sane I reckon I am home and dry........

Tom

Membership No. 1859

Re: 2CV engine oil leak

Ken Hanna

Have you carried out a vacuum test? All that's needed is about 1.5 metres of clear windscreen washer tubing and some LHM to make a manometer.
The tubing needs to be about 8mm OD, then the end is wrapped with some insulation tape to make a good seal into the dipstick tube.
The difference in level between the 'legs' of the manometer should be around 50mm at idle, with the 'high' side towards the engine.

However, it's much more important that it shouldn't show positive pressure at higher rpm, so you need to raise the engine speed to over 5,000 rpm for that part of the test.
Don't forget that matters would be even worse on the road, with the throttle wide open and the engine under load...

Ken


Ken, I have now set up my new home made Reniflard using hermetically sealed catch tank, return oil feed and vent to Foo Foo valve. Vacuum on tickover is about 3" to 4" as revs build this reduces to about 1/2" positive pressure at full revs as measured on my home made Manometer. I realise positive crankcase pressure is not desirable however it is a used engine with the usual wear and it isn't much pressure. It seems to have stopped the oil leaks so far though I have yet to do a trial blast. Before my tinkering, there was considerable positive pressure but this amount shouldn't push out the dipstick again. Am I right in thinking that Citroen would design in a small negative vacuum at max revs when new?

Tom

Membership No. 1859

Re: 2CV engine oil leak

Tom,
certainly an improvement compared to the situation with the original breather, which presumably had failed with its valves in the 'closed' position...

Not quite sure what you mean by 'negative vacuum', but assuming that it's negative pressure/vacuum of only 1/2" water gauge, that's less than 0.01 psi, so shouldn't cause any problems.

Tbh, all 3 Dyanes which I've got on the road show 'slight' positive pressure at high rpm, but because the pushrod seals and front crankshaft seals aren't old and hardened, there's no problem with oil leakage on any of them.
One of those engines has well over 200,000 miles racked up, so although it still pulls like a train, the bottom end is showing signs of age and is rarely taken much above 5,500 rpm.

I'd guess that for your engine 'The proof of the pudding' will be if the dipstick stays put, rather than launch itself out of the dipstick tube. ;o)

Ken.


Tom Rae

Ken, I have now set up my new home made Reniflard using hermetically sealed catch tank, return oil feed and vent to Foo Foo valve. Vacuum on tickover is about 3" to 4" as revs build this reduces to about 1/2" positive pressure at full revs as measured on my home made Manometer. I realise positive crankcase pressure is not desirable however it is a used engine with the usual wear and it isn't much pressure. It seems to have stopped the oil leaks so far though I have yet to do a trial blast. Before my tinkering, there was considerable positive pressure but this amount shouldn't push out the dipstick again. Am I right in thinking that Citroen would design in a small negative vacuum at max revs when new?

Tom

Membership No. 724

Re: 2CV engine oil leak

Thanks Ken, thats what I thought. After a run today there was no traditional spraint on the drive so I think, with your help, I have licked it as they say.

Tom

PS I meant just a small vacuum at max revs.

Membership No. 1859

Re: 2CV engine oil leak

out of interest have tested 3 of cris day's cars and 2 of mine with the following results
+ indicates pressure 7" 1ndicates vacume

tick over 6000rpm
cris's 3 wheeler pembleton 7" 7"
brooklands 3" +2"
2cv 5" 3"
my 2cv 1/2" 1/2"
fitted fo fo valve 7" 4"
rocket 7" 5 1/2"

the brooklands was also given a compression test which was well down so barrels and pistons and a top end overall will be done. will retest and let the results be known.
just one point the 3wheeler pembleton has our own designed filler/condenser used with a fo fo valve

hope this is helpfull crankcase vacume/pressure will indicate if the citreon breather is working effecently or not after establising that it will give a good indication to the state of the engines bores barrells and rings




Membership No. 1667

Re: 2CV engine oil leak

Cheers Don, quite a stable you have there! Useful though, it seems that I will need to do a barrel/piston upgrade at some point soon but as Ken pointed out, my positive pressure is still very small at high revs. The leaks seem to have more or less gone but the thread has been really helpful to me and, I hope others. The manometer seems to be the best way of checking breather and engine health.

Tom

Membership No. 1859

Re: 2CV engine oil leak

Okay I have fudged the issue and put off replacing the pistons and barrels as it seems to be running so well but after a run today with prolonged cruising at 75 to 80mph for two hours the engine was an oily mess so I will need to do this now. I have the required pistons, rings and barrels and will replace the front crankshaft seal as well as all the gaskets, anything else I should attend to at the same time to help cure the oil leaks once and for all? I do plan to check the valve seats, decoke and regrind the valves and replace the stem seals at the same time.

Tom

Membership No. 1858

Re: 2CV engine oil leak

Tom,
Might be worth doing the rear crankshaft seal - remember to buy new flywheel bolts first!

Rgrds
Callum

Re: 2CV engine oil leak

Callum, not taking the engine out, doing it in situ, in fact nearly half done now.

Tom

Membership No. 1858

Re: 2CV engine oil leak

is there a way of testing for a breather failed in the closed position? E.g. by sucking or blowing through the pipe connecting the breather to the airbox?

i have a bad oil leak which looks like it's from the spectacle seals on one side. the engine is from car which had been unused for 10+ years. i've fitted a foo foo to no avail. keen to do as much diagnosis as possible before resorting to removing heads & replacing the spectacle seals.

i will of course now go off and check hot compression and the manometer dipstick measurement, but how do i test the original citroen breather?

any advice gratefully received.

Membership No. 1611

Re: 2CV engine oil leak

In the 2cv service manuel it is changed every so many thousand miles..as they do wear out and the rubber inside goes hard..
maybe just get another one.and a foo foo.then you know where you are..

Membership No. 1336

Re: 2CV engine oil leak

David, if the Reniflard is being replaced, is there still a need for the additional foo foo valve?

Tom

Membership No. 1859

Re: 2CV engine oil leak

thanks for the advice.

is the Reniflard the whole oil filler unit or is there as removable part? or can a suspect reniflard be removed or bypassed in any way?

thanks

Membership No. 1611

Re: 2CV engine oil leak

Hi Tom, belt and braces and forget about it then as necessaire the foo foo will do it .
Cye, yes it is the whole unit, sorry, bits of french stick in there.. yes its the whole filler breather unit
which if cut open is quite complex.. but the foo foo will be a very good back up..-it may even work if you just have a similar volume canister-with all the pipes in and out with the foo foo valve doing the important vacuum bit.
rather like an accordian squeeze box as the pistons move in and out...
I think halifax 2cv people do a new version that is cleanable-but its like a foo foo..and works ok..

Membership No. 1336

Re: 2CV engine oil leak

iirc, there is a kit to rebuild a Reniflard, cutting it open at the waisted bit but I would advise you to replace the whole unit, ECAS do a replacement one which is smaller and looks quite neat. I would caution against trying to replicate its functions with a foo foo and catch tank etc unless you really understand the functions, for example, the oil return to the dipstick must be before the foo foo valve. I tried that and failed, all I did was highlight my ignorance whilst still mopping up oil from the garage floor after a run!

Tom

Membership No. 1859