Oily Coolant...

[LoneWolf]

Try draining some gearbox oil out too. It won't hurt to do a change anyway and doesn't take a lot of oil. Have a look and see if you get oil or an emulsion

 

Richard

I guess it's possible the gear oil in the cooler is at a higher pressure than the coolant and you only pass oil into water, not the other way around.

 

That's what the mechanic said

 

 

But check/change the O-rings 1st (thats what i meant by 'seals')

[Bobbybass]

Without flushing first you may get existing oil floating to the top - even after the fault is fixed

I used to work as a motor mechanic, whenever there had been this sort of problem, after repair it was usual to fill up with clean water and automatic washing powder, then after a good run, drain and flush before the final fill, it prevented customers returning with the same symtoms even tho the fault was fixed.

 

Well...knock me down...and call me sudsy !!.

 

I understand what you mean...and sounds like a good idea....

 

Bob

 

That's what the mechanic said

 

 

But check/change the O-rings 1st (thats what i meant by 'seals')

 

I changed the gearbox oil when I did the engine oil...so I have no indication of this new fault....the oil was clean....

According to my book...the PRM150 gearbox cooling feed is at nearly 350 PSI....!

Plenty of scope for a seal failure...

I'm putting my money on that...and hoping it will cure it..

Will let you all know how it goes..

 

Bob

[RLWP]

Do be careful with the engine though, just in case this hypothesis is wrong.

 

Richard

[Radio-Ga-Ga]

Well...knock me down...and call me sudsy !!.

 

I understand what you mean...and sounds like a good idea....

 

Bob

 

They will if you use non automatic or wash up liquid!

[dor]

Was the antifreeze you used to top up compatible with what was already in there? I understand that some newer types of antifreeze (red?) will react or curdle if mixed with the old type.

[leolady too]

I've had this problem, and for ages. Mine's a Beta Marine BD3 tug and the coolant has a small amount of grey/black oil floating on the top. It doesn't seem to be emulsified, it's as if it had been poured on to the coolant in the expansion tank. It doesn't seem to get any worse, it happened after the last oil change, it's too dark to be gear box oil, it could be sludge from mixed antifreeze and there's no sign of coolant in the oil. My next step is to drain and flush the coolant and refill and see what happens. It may have been the result of mixing incompatible antifreeze but I suspect oil because it's pretty black. That said, the total is no more than a table spoon and it's never got any worse. It is a puzzle because I don't see how, if it was a gasket, it could happen one and then stop happening, or fail to get worse. Equally, I don't see what else it could be. If anyone has any more bright ideas I'd be very interested. It isn't possible that anything in the pumping out of old oil, replacing filters, refilling with new oil could be responsible, is it? I have an additional "kleenoil" filter fitted but can't see how that could be involved.

Edited April 26, 2010 by leolady too

[RLWP]

I've had this problem, and for ages. Mine's a Beta Marine BD3 tug and the coolant has a small amount of grey/black oil floating on the top. It doesn't seem to be emulsified, it's as if it had been poured on to the coolant in the expansion tank. It doesn't seem to get any worse, it happened after the last oil change, it's too dark to be gear box oil, it could be sludge from mixed antifreeze and there's no sign of coolant in the oil. My next step is to drain and flush the coolant and refill and see what happens. It may have been the result of mixing incompatible antifreeze but I suspect oil because it's pretty black. That said, the total is no more than a table spoon and it's never got any worse. It is a puzzle because I don't see how, if it was a gasket, it could happen one and then stop happening, or fail to get worse. Equally, I don't see what else it could be. If anyone has any more bright ideas I'd be very interested. It isn't possible that anything in the pumping out of old oil, replacing filters, refilling with new oil could be responsible, is it? I have an additional "kleenoil" filter fitted but can't see how that could be involved.

 

Can you "mop" it out with some kitchen towel to see if more comes back?

 

Richard

[leolady too]

I've tried that but the amounts involved are small and so I can't tell if more is being let into the cooling system or what's already in there (distributed around everywhere) is finding its way to the surface in the header tank.

Edited April 26, 2010 by leolady too

[RLWP]

If there is a fixed quantity of oil in your cooling system and you mop your header tank out, as you say some more may settle out there again. If you keep repeating this it should take longer and longer to get the same quantity of oil in the tank. You'll have less oil in the cooling system too!

 

If oil is getting in somewhere, there will be the same quantity of oil in the tank every day. I wonder if diligent mopping will help you to understand what's going on.

 

Richard

[Richard T]

We have recently had both engine and gearbox oil coolers fail - the pressures in them are such that oil goes into the coolant but not the reverse. It does make a mess of the cooling system and I guess we have to flush it out several times and mop oil out of the header tank for some time to come. The downside is that this may mask a more serious problem like the head gasket failing. The coolers are usually made out of brass and brazed together with the vibrations on an engine eventually the thin brass can crack or a brazed joint fail.

[leolady too]

Just in case anyone else has this problem, the following may be useful. I thought about the oil in the coolant for ages and decided that the most likely source was the engine oil cooler. A blown head gasket was not likely, though possible and the gearbox oil cooler wouldn't have leaked black oil. I bought a new bowmans and drained the oil and coolant. I replaced the oil cooler and refilled with oil and water. I'd flushed the coolant and knew I'd have to do it again to get it clean befor knowing for sure anything that appeared was new and not just old stuff working its way out. At home I thought I'd pressure test the old cooler, which was a polar, as best I could by filling it with water with some green vegetable dye, blanking off one oil port and attaching a hose pipe to the other. Sure enough, green water dripped out when the hose was turned on. Not much but more than enough to notice. It turns out that the leak was in the seam at one end, just on the side where the end had been joined to the body. The reason the leak had been so slight was that the area leaking was under the part of the rubber end cap where the jubilee clip bites to seal the cap to the body so the leak had to seep under the rubber as well as through the gap. It's a relief to know that is all it was. £76 for a new Bowman's and a couple of hours and its done. I still need to fill and flush to make sure the coolant system is clean but I think its fixed and that's a load off my mind.

 

Incedentally, Bowmans are not doing the rass finish coolers any more. They now have an anodised finish. I got one from old stock but the "vintage" look old style will be more difficult to find in future.

[RLWP]

Thanks for coming back with what you did and discovered, it's nice to know what happens with some of these problems. I'm glad we managed to get to the source of your problem together. Brilliant stuff!

 

Richard

[Richard T]

RE my earlier post - having had both oil coolers fail what is the best way of flushing the oil out of the cooling system? We have got a small pump which is used to suck the crap off the top of the header tank, the amount of oil in the cooling system is reducing but I would like to get it all out before draining the cooling system and refilling with antifreeze/water mix.

[paulcatchpole]

RE my earlier post - having had both oil coolers fail what is the best way of flushing the oil out of the cooling system? We have got a small pump which is used to suck the crap off the top of the header tank, the amount of oil in the cooling system is reducing but I would like to get it all out before draining the cooling system and refilling with antifreeze/water mix.

 

Same as a car... Drain the cooling system, stick hosepipe in somewhere convenient, run until clear.

 

Time to think about a deckwash take-off! Where's Phyllis when you need her? (Sorry Phyllis, only joking!)

 

PC

[Bobbybass]

I'm the original poster...

 

It was the oil cooler stack that had sprung a leak after all.

Beta no longer make this 'in coolant' oil cooler...but they made one up for me using a raw water cooler and changing the end threads.

I was 'told' that there are problems as the cooler sits in the coolant...and instead of cooling the oil..the coolant can make it hotter....and so the latest units are external to the engine and cooled by the skin tank return water.

If I had this problem again...I would leave the 'in coolant unit' in place to block the holes in the header tank...but obtain and modify the external unit to make it fit. Doesn't look too difficult..its just improvising brackets.

 

By the way...I was also told that one of the problems with the 'in coolant ' type that causes failure..is that the water level in the header tank has an expansion gap...and hence the cooler stack isn't evenly immersed in the water...and this leaves a corrosion line on the brass stack. I will make a point of filling the coolant right to the top of the tank when I winterise.

 

Thanks to all who gave me advice.

 

Bob

Edited June 20, 2010 by Bobbybass

[leolady too]

Following on from the main issue, I've not got a problem with flushing out the oil from the cooling system. The problem is there's oil on the surface of the coolant in the skin tank. I've run the engine for hours with automatic washing powder and flushed it out and I've also used the Halfords radflush stuff (not at the same time). I've flushed through with a hose pipe until the water runs clear but if I take the plug out of the top of the skin tank, there's still oil coming out through the plug so the tank must have some oil left either on the surface of the water or the sides of the tank or both. The flushing with a hose was thorough and long but I suppose with a large system (it holds at least 5 gallons) it is difficult to get adequate movement/agitation everywhere. So, does it matter if there's oil in the surface of the skin tank water? Will it work its way round and damage the hoses? Is there another flushing chemical that actually works on oil? Any ideas?

 

I'm inclined to put the 50:50 antifreeze mix in and leave it for a year and then drain, flush and add washing powder and run it for a month or so and then drain flush and refill with antifreeze again.

 

Having got over the worry about a blown head gasket, I'm only really worried now about if the oil will damage hoses and if it will keep reappearing in the expansion tank. I know it's old oil working its way out but if I were a potential buyer seeing it, I wouldn't take the risk.

[Pretty Funked Up]

Holts do a heavy duty 2 stage rad flush, £7.99 I paid. There are others out there but the Holts one is easy to find. All the good ones will be 2 stage.

 

Cant you just let the water flush out the skin tank bleeders? get rid of the oily deposit and keep an eye out to see if it comes back.

 

I've just been through an outrageous flushing extravaganza and the hardest thing is to get the flushing to do the full circuit (block being the trickiest part as I had to pop a core plug out to get a good flush going). The skin tanks where easy: pop the thermostat out, put housing back together, send clean water in the calorifier return and let it flow out the return from the last skin tank, block off open pipes with a branch and a jubleeeee clip.

Edited July 12, 2010 by Pretty Funked Up