URGENT HELP! Knocking sound in engine

[smileypete]

Hello all - back at w*rk so back on here, as per usual. Here's an update.Lovely engineer man came out to us on Saturday afternoon, tested every millimetre of the engine and was completely flummoxed by the knock-knock noise. He says it's out of synch with the engine itself. Sometimes the noise gets worse as you rev the engine, sometimes it disappears for a while. He suspects it's something to do with the alternator/fan belt system (he'd done some work on that a few weeks ago himself so he was a bit concerned) but he couldn't locate exactly where

Hi BSP,

 

Could be due to fuel quality and/or injector/pump problems:

 

http://www.google.com/search?hl=en&lr=...amp;btnG=Search

 

Also might possibly be the water pump bearings.

 

I'd get the next lot of fuel from a known good source (NOT 'gas oil') and keep an eye on the water pump for leaks.

 

cheers,

Pete.

[bottle]

Hi Blue

 

I am with John on this, just one thing you can try before running the engine without belts.

 

Check the alternator mountings, could be loose, also pull/push generally check he pulleys/bearings of the alternator/s and the water pump.

 

good luck

[BlueStringPudding]

Hi BSP,Could be due to fuel quality and/or injector/pump problems:http://www.google.com/search?hl=en&lr=...amp;btnG=Search

 

Also might possibly be the water pump bearings.I'd get the next lot of fuel from a known good source (NOT 'gas oil') and keep an eye on the water pump for leaks.cheers,Pete.

 

Thanks - although this engineer chap is very good. There's not one bit of the engine he didn't unscrew or look in, or sniff or rest his foot on (!). I am wondering about the water pump though. There's always been a lot of water in the oily bilge and the main bilge at the stern. We mopped it all out once only to have heavy rainfall that (we assumed) filled it up again very quickly.

 

I spent Saturday morning cleaning the bilges out again as I wanted to monitor some things. There's a known slight leak of diesel (seal on the diesel filter needs replacing) so I placed a small Woolworths loaf tin under it ( ) so I can montor exactly how much is leaking - usually any diesel just leaves a subtle colouring on the service of the water that swills around in there so it's hard to tell how much is leaking.

 

Also we've never been entirely sure how much to tighten the nuts at the stern gear, so how much drippage is okay drippage is also an unknown quantity (greaser handle gets frequently tightened though), so there's now a Wolworth's flan tray under that ( ). Plus, when mopping out the rather sludgy and disgusting oily bilge, I noticed a slight drip of water from a pipe above (central heating pipe I think) so there's another Woolworths loaf tin under there too ( ) as I wasn't able to tighten it to any affect. The idea is I can now isolate what's dripping from that pipe and if it smells of antifreeze, I know it's from the central heating!

 

But - what I will also check is whether any fluid appears under the engine now that bilge has been emptied and mopped out. If it does, then something could be leaking from the engine itself. To be monitored... (I wonder if Woolworths do any special bakeware for under engines...?)Incidentally, I've just booked my annual engine inspection and service with RCR (just waiting for them to confirm the date and time). The whole thing was only serviced in June but the company who did it were a bunch of f*ckwits...

 

Hi Blue

 

I am with John on this, just one thing you can try before running the engine without belts.Check the alternator mountings, could be loose, also pull/push generally check he pulleys/bearings of the alternator/s and the water pump.good luck

 

Again, our engineer attacked all that and found nowt wrong. He'd fixed the alternator mountings himself last month, when they compeltely went to pieces (missing nuts and incorrect fan belt size, apparently... fan belts having been put on there in June by the f*ckwit company mentioned above)

Edited October 22, 2007 by BlueStringPudding

[Sir Nibble]

I'd get the next lot of fuel from a known good source (NOT 'gas oil') and keep an eye on the water pump for leaks.

I've never found a canal side outlet that sells any fuel other than gas oil! (Apart from solid fuel).

Red diesel=gas oil, diesel fuel with red dye in is not available, it's gas oil, gas oil is also (erroneously) known as red diesel, but it's not diesel, it's gas oil, that red stuff that comes out of the boatyard pump, gas oil. You could always take a jerrcan to the garage and get some derv, but not the boatyard, that's gas oil.

[Supermalc]

Hi BSP - you're doing everything right. Noises in engines and machinery can be extrememly difficult to pinpoint sometimes.

 

Just a couple of examples with boating. When I bought the new outboard, which was in fact second hand, as it had been used once, I was always listening for noises. After a month or so it started rattling, and fearing the worst of course, I thought I had more serious problems (I'd spent a fortune for me to try not to have any).

 

In the end it was nothing more than the trim pin that it rests on. When it had been run a bit, this had just become slightly loose in the holes....it had just lost it's newness. I just removed it and put a little grease in the holes every so often, and it was quiet again.

 

With Wud I'm always hearing noises and vibrations. Partly due to the bodge of the whole setup, and partly due to an old engine that is managing to keep going. For instance this year it was running quite sweetly, well for the vibrating machine it is and I found I'd left a nut off one of the 'excuses' for engine mountings. I replaced it, only to find the boat shaking and vibrating as it it was on it's last. Took it off and it runs quieter again. Just one of those bodges that are found by accident, but seem to work.

 

If you want to listen to an engine, you can use a long stick, or piece of dowling as a stethascope. Many people just use a large screwdriver, but I say get a longish piece to keep your hair, hands and arms etc. away to prevent getting caught in belts etc. Just put the end of the stick on the engine in different places, and the other end on your ear. I'm sure you know to be careful. Even if you don't find what you're looking for, it's interesting to hear the different bits of the engine.

[Amicus]

If you have fuel leaking out of the filter housing, presumably with the engine stopped, this will leak air into the system when the engine is running. This is not "A Good Thing" and could cause yer knocking. Whatever, it should be sorted, IMHO of course

[badgerburger]

An 80K Peugeot 205 diesel I bought about 5 years ago ...

 

**** that's expensive for a Peugot 205 ! I'd let you have ours for less than half that. Engine doesn't knock either (well, not much ...)

[BlueStringPudding]

If you have fuel leaking out of the filter housing, presumably with the engine stopped, this will leak air into the system when the engine is running. This is not "A Good Thing" and could cause yer knocking. Whatever, it should be sorted, IMHO of course

 

Again the RCR enginner knows about it and has said the seal can be replaced when the engine's next serviced. As I mentioned above, the knock-knock is not in synch with the engine, apparently. (Perhaps there's a small vole under there, complaning about all the noise!?!?! )

 

Just been back to the boat in my lunchbreak to check on my lovely baking trays. I can confirm there is some fluid of some description under the engine. I dunno what it is, and there's not much of it - but there's definitely more than there was yesterday (as it was empty yesterday). It appears a yellowish colour and when I dunked a white tissue in it, it looked like vegeatble oil (but doesn't smell like oil).

 

Now the oil could be residue from the bilge, floating on top of whatever fluid is in there.

 

Any thoughts?

[Supermalc]

the knock-knock is not in synch with the engine, apparently.

 

Often, noises such as this are caused by something loose on, or near the engine. I know you, and your engineer have checked everything on and around the engine. I also assume this has been done thoroughly. This is what makes such problems hard to find. It could??? be something as simple as an engine mounting becoming a little soft, or allowing a bit more movement. This is allowing two solid surfaces to rub together.

 

I remember a tale often repeated by my friend and mentor I've mentioned before. In the late 50s or early 60s he had reconditioned the engine for a car he had. At that time he bought and sold a few I think. This engine had an annoying knock that they couldn't discover, despite taking the engine to pieces at least a couple of time. In the end it had cost him so much time and money he decided to stop it, by destroying the engine. He said he put the throttle flat out and left it screaming away. After about 10 minutes, when the noise was starting to annoy the others, someone suggested they stop it, as it was not going to go bang. When it was left ticking over the noise had gone. The car was later sold to a satisfied customer, who apparently drove it with no problems for several years.

[John Orentas]

Bluey.

 

A busted engine mount can make some alarming and sort of random noises.. As can a broken exhaust pipe or mounting.

Edited October 22, 2007 by John Orentas

[Speedwell]

I had irregular clattering sounds from the gearbox when some circlips, which should hold the gears in position on the shaft, broke. This let the gears fly back and forth especially at low loading.

Arthur

[BlueStringPudding]

We've still got the knocking sound. It's a bit alarming - especially as we'll be cruising over the weekend. Oh well, we'll see what happens...

 

Have booked my RCR engine inspection and service for next weekend. (I know the engine was only serviced in the summer, but there have been so many basic things that they didn't do - and so many things that they did do but did badly - that we're getting it serviced again)

 

Hopefully he'll find the source of the yellow goop that's leaking out of somewhere under the engine too.

 

Edited to say that by "they" I don't mean RCR but the previous company who serviced it.

Edited October 26, 2007 by BlueStringPudding

[carlt]

We've still got the knocking sound. It's a bit alarming - especially as we'll be cruising over the weekend. Oh well, we'll see what happens...

 

Have booked my RCR engine inspection and service for next weekend. (I know the engine was only serviced in the summer, but there have been so many basic things that they didn't do - and so many things that they did do but did badly - that we're getting it serviced again)

 

Hopefully he'll find the source of the yellow goop that's leaking out of somewhere under the engine too.

 

Edited to say that by "they" I don't mean RCR but the previous company who serviced it.

The yellow goop (you're really doing well with the technical terms, now) may well be water in the gearbox oil. Or you've spilt custard in the engine hole.

 

Edited because I thought I'd put the spot squeezing joke in, after all. But decided not to (again)

Edited October 26, 2007 by carlt

[BlueStringPudding]

The yellow goop (you're really doing well with the technical terms, now) may well be water in the gearbox oil. Or you've spilt custard in the engine hole.

 

Edited because I thought I'd put the spot squeezing joke in, after all. But decided not to (again)

 

Oh b*gger... yes, that's it. Kev warned me about heating the carton of Ambrosia custard on the engine.

[smileypete]

I am wondering about the water pump though.

Hi,

 

I'd just keep an eye on the level in the expansion bottle or header tank, if it's losing coolant the level will drop.

 

If the expansion bottle has a 'radiator cap', don't undo it before the engine has cooled down!

 

It appears a yellowish colour and when I dunked a white tissue in it, it looked like vegeatble oil (but doesn't smell like oil).

 

Now the oil could be residue from the bilge, floating on top of whatever fluid is in there.

 

Any thoughts?

That might be 'red diesel', it can have a fluorescent yellow dye. As others have said it's worth fixing fuel leaks, air in the fuel system can cause more problems.

 

When you get the engine serviced, ask them to show you what to check routinely and look out for.

 

cheers,

Pete.

Edited October 26, 2007 by smileypete

[BlueStringPudding]

Hi,

 

I'd just keep an eye on the level in the expansion bottle or header tank, if it's losing coolant the level will drop.

 

If the expansion bottle has a 'radiator cap', don't undo it before the engine has cooled down!

That might be 'red diesel', it can have a fluorescent yellow dye. As others have said it's worth fixing fuel leaks, air in the fuel system can cause more problems.

 

When you get the engine serviced, ask them to show you what to check and look out for.

 

cheers,

Pete.

cheers,

Pete.

 

Thanks, Pete. I will ask them as I don't know my expansion bottle from my Talisker bottle.

 

I don't think the fluid is red diesel, because the one thing I do have is a nose like a bloodhound, and it doesn't smell anything like diesel. The diesel leaking from the diesel filter thingy is defintely diesel and that's nowhere near this bit of the engine and cannot leak directly into the engine bilge.

 

This yellow goop under the engine isn't diesel, but it looks a little like vegetable oil, and has almost no scent (but perhaps a feint sweet smell?) Don't know whether that's coolant or an oil...? I'll ask the servicing feller.

[Yoda]

Hopefully he'll find the source of the yellow goop that's leaking out of somewhere under the engine too.

 

Have you got antifreeze in the cooling system? This sometimes has yellow dye in it.

 

Another thought is, has there been a penitrant dye used for leak checking or crack checking as most are yellow.

[bottle]

Some anti-freeze has a 'sweet' smell.

[BlueStringPudding]

Some anti-freeze has a 'sweet' smell.

 

Hmmm... could be...

[onthecut]

Hi BSP.

 

Your description of the fluid fits that of bio diesel almost perfectly. Can you retrieve a drop or two from your tank to check, on the off chance your last fill up wasn't quite what you thought ? I am surprised your engineer has advised leaving a leaking diesel seal. If its on the suction side, it will draw air in; if it's on the pumped side it will leak, neither being very desirable. One thing you might get the engineer to try, if he hasn't already, is to slacken the injector pipes one at a time, while the engine is running and knocking and see if any particular one has an effect. You might get lucky and narrow it down to a particular cylinder or injector.

As I think others have suggested, it's also a good idea to run it up (briefly) with the belts off and see if that affects it. A minute or two without the water pump won't be too drastic. After that, (if you are able to, depending on the feet arrangement) it's off with the gearbox and run it up. That will take out all the drive train possibilities.

Mike.

[BlueStringPudding]

Hi BSP.

 

Your description of the fluid fits that of bio diesel almost perfectly. Can you retrieve a drop or two from your tank to check, on the off chance your last fill up wasn't quite what you thought ? I am surprised your engineer has advised leaving a leaking diesel seal. If its on the suction side, it will draw air in; if it's on the pumped side it will leak, neither being very desirable. One thing you might get the engineer to try, if he hasn't already, is to slacken the injector pipes one at a time, while the engine is running and knocking and see if any particular one has an effect. You might get lucky and narrow it down to a particular cylinder or injector.

As I think others have suggested, it's also a good idea to run it up (briefly) with the belts off and see if that affects it. A minute or two without the water pump won't be too drastic. After that, (if you are able to, depending on the feet arrangement) it's off with the gearbox and run it up. That will take out all the drive train possibilities.

Mike.

 

Thanks Mike.

 

The yellow splurgey stuff has been in there since we bought the boat. We've mopped it out twice since then - once partially, then we had loads of rain for days on end so put the build up down to rainwater. The second time (as described above) I cleaned it out completely. So whatever's coming out of it has been in the engine (and indeed leaking out of the engine) at least since the previous owner.

 

Last fuel top-up came from Kate Boats and looked and smelled the same as usual. Can't imagine they put biodiesel in their hire fleet, but you never know! I'm gonna let the mechanic talk me through the above as it's a bit daunting for someone with no engine knowledge. Thanks for your advice though, it's much appreciated!

[denboy]

the yellow splodgy stuff sounds to me like oil contaminated with water what colour is your oil on the dipstick if thats also yellow your head gaskets gone

[BlueStringPudding]

the yellow splodgy stuff sounds to me like oil contaminated with water what colour is your oil on the dipstick if thats also yellow your head gaskets gone

 

Dipstick oil is black.

[bottle]

Dipstick oil is black.

 

Nothing wrong with that but may need changing, which your imminent service will take care of.

 

Do not be surprised that the first time you check it after a run it is black again.

 

In an ideal world, when the oil is replaced, all of the old oil would be removed first but this is not always possible, some always get left behind.

[saltysplash]

the yellow splodgy stuff sounds to me like oil contaminated with water what colour is your oil on the dipstick if thats also yellow your head gaskets gone

 

 

Could the yellow splogy stuff be gearbox oil?