General Catch can

[The Panda Nut]

First one arrived and is now installed. 30 miles later the top of the engine is free of mayo. About a tablespoon and a half of water in the can after 35 miles.

Second catch can arrived damaged so yet another job to sort out on ebay purchases. The cars original hose has been rotated and reclipped and is a perfect fit. The fixing bolt fits in a pre-existing hole and the out hose to the can from the cam cover is a bit of caravan water pipe for now using the spare hose connector from the can as a reducer. It took about an hour with fiddling and fettling and was simple.

It will be interesting to see if the whole system dries out over the next few hundred miles and settles down, or if it just runs wet. Judging from the amount of water in the exhaust this is just a wet engine.

Next job replace the clamps on the flexi as both are nearly rusted away altogether.

 

[The Panda Nut]

Well its still sludge free in the engine and throttle body, but its still producing a lot of water too. Next Panda is sitting ready for its can to be fitted after rather costly repairs. Another 30-50ml after another 60 miles.. I am going to have a look at the actual temperature the engine is reaching as I suspect the thermostat may be playing up. May be this is early signs of its demise.

 

[jrkitching]

I suspect the thermostat may be playing up

This is a well known issue, fortunately one with a cheap and easy fix.

No reason why this should hasten the car's demise if dealt with in a timely manner.

 

[koalar]

There's quite a few variants of the engine

I have had 3 Pandas and 2 have been well worn in. None so far have moisture in the oil. That incudes 2 that are only driven for sort miles ????


Mercedes A class does. But only because the oil filler tube is so long

 

[DaveMcT]

Every litre of petrol make a litre of water. Cold engines get more blow-by into the crankcase. Too many short runs lead to oily mayo in the cylinder head cover.

 

[Pugglt Auld Jock]

Every litre of petrol make a litre of water. Cold engines get more blow-by into the crankcase. Too many short runs lead to oily mayo in the cylinder head cover.

Yes, I remember, at college, being told about every gallon of petrol emitting slightly more than a gallon of water from the tailpipe - didn't believe it until I started repairing exhausts on the old bangers I bought in those days

 

[dac69er]

Worse at the moment with lockdown as only short journeys are allowed unless for work.

Exhaust manufacturers will be rubbing their hands together with All the rotten exhausts that will need replacing
.....

 

[DaveMcT]

Exhaust manufacturers will be rubbing their hands together with All the rotten exhausts that will need replacing
.....

I replaced mine last year with a cheap system. I mostly do long journeys yet its already looking pretty ragged**. I'm looking at going for bespoke stainless next time as it's less hassle overall. The potential issues are noise as most seem to use absorbent silencer boxes.

** Despite my copper grease treatment, the rear box inlet had a layer of flaking rust for about 10mm along the pipe and all over the weld. Ive scraped off the clag and recoated it. But suspect stress corrosion is part of the issue. Another year's life is about the best I can expect.

 

[A3jeroen]

Every litre of petrol make a litre of water. Cold engines get more blow-by into the crankcase. Too many short runs lead to oily mayo in the cylinder head cover.

Funny... Last year I stated the same on this forum after someone "lost" a liter of engine-oil after getting the oil hot.
I remember being called an idiot or something similar by some...

 

[DaveMcT]

Funny... Last year I stated the same on this forum after someone "lost" a liter of engine-oil after getting the oil hot.
I remember being called an idiot or something similar by some...

DuckDuckGo found this from Quora complete with arithmetic.
https://www.quora.com/How-much-water-is-formed-by-the-combustion-of-1-litre-of-petrol?share=1

 

[A3jeroen]

No need to convince me Dave. And you were not the one that called me an idiot.

gr J

 

[DaveMcT]

I would never do that, but others might need convincing. ;-)

 

[Cal2412]

i take it this is on a 1.2?

 

[koalar]

never had mayo in any of my Pandas three now 05 1.2L, 06 1.1L and 11 12L


I feel this is a sticking plaster masking the real problem.



I have had cars that have ad mayo due to the design. A Class for example has an oil filler tube that a couple of foot Long and the water condenses out to the top. But even the we are only talking about a teaspoon or so every 6 months.

 

[DaveMcT]

These things make some sense when you are thrashing around a race circuit. Otherwise there's no point as the engine is designed to recirculate any oil blow by into the combustion chambers. That solves the water issues and the catalyst deals with any pollutants it might create.

 

[The Panda Nut]

Well been running two cars with catch can fitted for some time.

The 2011 car is vastly better performance since fitted and a recent check of the inlet manifold shows its now bone dry and mayo free, It needs emptying every 300 to 450 miles and is 98% water with just a smidge of yellow oily ness. I am satisfied that it was worth the £20 cost on performance grounds alone.

2014 car also running dry takes half the volume of water. No noticeable effect other than no mayo anywhere as far as I can see, so I hope no more stuffed sensors.

If it ever stops raining and warms up it will be interesting to see how / if summer weather changes things.

 

[DaveMcT]

The catch can breather can be fed back to the intake tube ahead of throttle valve. That way water gets trapped but gases get burnt through the engine. Anything that risks an air leak behind the throttle valve will cause running issues.

The 100HP has a 20mm hose from top of engine to air intake after the air filter. There is also a small bore branch to the inlet manifold. Mine was beginning to split on the 20mm section. As a temporary fix, I've taped it up with self amalgamating tape. I can detect absolutely zero effect on engine performance.

A bike I had back in the 1990s was notorious for breather hose problems. Oil was supposed to drain back into the engine but often did not. Oil then collected in the base of air cleaner box until it leaked into the floor. Solution was a wider diameter hose from engine to air box.

 

[The Panda Nut]

It seems that the small bore pipe is responsible for allowing the water and oil to pool in the manifold as the larger pipe was mildly oily but no mayo in the air box. I suppose it has more vacuum as directly to the manifold rather than the larger pipe that goes direct to the airbox . Our 70HP 1.2 small pipe was broken off the air box end when we bought it and I fixed this back properly but it made little difference at the time. The can is piped as you say so the gas flow is largely unaffected by its presence, save for the rather low rate filter on it's top. I could plug this off but suspect it prevents fuel fumes accumulating if the car is parked up so have left it on. Blowing through it suggests its not doing a great deal as flow is very slow. I may try putting the blanking plug in and see if there are any changes.

 

[A3jeroen]

It's not the gasflow that gets affected by a vacuumleak. It's the air that gets sucked in without being monitored by the TPS. Then the O2sensor gives the signal to add more fuel. That will not improve performance nor consumption.

gr J

 

[DaveMcT]

An air leak behind the throttle valve will often cause the engine to rev at tickover. The idle control valve might try to compensate with stalling in town or clunky gearshifts.

The 1.4 100HP breather pipe looks much like this

This shows the 100HP engine with standard filter box removed. Ignore the pod filter which probably reduces power as the standard intake sucks cold air. You can see the breather hose (also taped up).