Gunge in engine coolant

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Dull Spark

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I change the engine coolant and use OAT as per the previous owner, so no change of type or manufacturer of coolant. I still get deposits of gunge in the system, visible on the rubber seal around the pressure cap. No real issue, but last year the gunge blocked the overflow pipe and needed to be removed with a small cable tie. My concern is for any tight clearances in engine cooling channels. Am I worrying over nothing or should I install an in-line strainer on the line to the calorifier? The heat exchanger has copper-based alloys as, I'm sure has the calorifier. Is OAT the right stuff?
 
Dull Spark said:
I change the engine coolant and use OAT as per the previous owner, so no change of type or manufacturer of coolant. I still get deposits of gunge in the system, visible on the rubber seal around the pressure cap. No real issue, but last year the gunge blocked the overflow pipe and needed to be removed with a small cable tie. My concern is for any tight clearances in engine cooling channels. Am I worrying over nothing or should I install an in-line strainer on the line to the calorifier? The heat exchanger has copper-based alloys as, I'm sure has the calorifier. Is OAT the right stuff?
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What does the gunge look and feel like?

There is always a little build up of corrosion even in a perfectly treated system which normally looks like very fine grit so, unless present in much larger than usual amounts, would not cause any blockages and just tends to settle out in the lowest point of the system.

Richard
 
If on the other hand it looks like blobs of brown goo in the coolant, or brown slime coating the filler cap, then it is engine oil escaping into the coolant via ? head gasket /seal failure/ or worse case scenario cracked block or head.
 
Thanks, but no loss of water or oil over last season, so I don't think the head gasket has gone. The gunge is soft with no grit. It blocked the overflow pipe when it dried out, but no other problem noted. I think I may live with it until I can change to another type of coolant. Many thanks for your replies.
 
Dull Spark said:
I change the engine coolant and use OAT as per the previous owner, so no change of type or manufacturer of coolant. I still get deposits of gunge in the system, visible on the rubber seal around the pressure cap. No real issue, but last year the gunge blocked the overflow pipe and needed to be removed with a small cable tie. My concern is for any tight clearances in engine cooling channels. Am I worrying over nothing or should I install an in-line strainer on the line to the calorifier? The heat exchanger has copper-based alloys as, I'm sure has the calorifier. Is OAT the right stuff?
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Dull Spark said:
Thanks, but no loss of water or oil over last season, so I don't think the head gasket has gone. The gunge is soft with no grit. It blocked the overflow pipe when it dried out, but no other problem noted. I think I may live with it until I can change to another type of coolant. Many thanks for your replies.
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You dont say what engine you have but I believe it is a Beta 30 ?

As a general rule you should use the type of antifreeze recommended in the manual which if unspecified will be a conventional silicate type. Only use OAT when specified.

AFAICS there is no mention of antifreeze type in the owners manual therefore I think a conventional silicate type is the correct choice for the engine. I notice BS 6580 is referred to. I believe this standard is only applicable to the conventional type of antifreeze. You should see reference to BS 6580 ( the latest edition is 2010 ) on the label.

When changing from OAT to conventional antifreeze be sure to flush the system thoroughly to remove all traces of the OAT. (A chemical clean is usually recommended if changing the other way)
 
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I spoke to Granville when my Beta 13.5 was reasonably new, and suffered from gunged up drain pipe.

They advised that on their paperwork that engine was listed as requiring blue, though could not tell me what the consequences of putting OAT in was.

Since then I have cleared the drain (that was a story in itself), flushed it all though, and used blue, and no further gunge has appeared. Type of antifreeze might be nothing to do with the problem - could have been a 'new engine' thing. However on the principle of 'if it ain't broke...' I shall stick with blue unless good new information comes along!
 
Many thanks. Engine is a Beta 30. The Engine is a Kubota D1105 and the Kubota manual refers to use of ethylene glycol, so looks like you are right VicS. I have had minor trouble clearing the drain in the engine block but used a coat hanger offcut to rod it out. I don't want to move to waterless coolant but will consider moving to ethylene glycol that meets the BS. Problem will be in flushing all of the existing stuff out. (A bit like trying to remove all traces of red diesel from the fuel tank?)

I gave the engine a one hour run at maximum power last autumn and there were no signs of overheating coolant. No idea about specific locations inside the block of course. But....given the lack of any real problem, I may just live with things as they are for another season. Thanks for your advice.
 
Dull Spark said:
Many thanks. Engine is a Beta 30. The Engine is a Kubota D1105 and the Kubota manual refers to use of ethylene glycol, so looks like you are right VicS. I have had minor trouble clearing the drain in the engine block but used a coat hanger offcut to rod it out. I don't want to move to waterless coolant but will consider moving to ethylene glycol that meets the BS. Problem will be in flushing all of the existing stuff out. (A bit like trying to remove all traces of red diesel from the fuel tank?)

I gave the engine a one hour run at maximum power last autumn and there were no signs of overheating coolant. No idea about specific locations inside the block of course. But....given the lack of any real problem, I may just live with things as they are for another season. Thanks for your advice.
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Both the conventional and the OAT are ethylene glycol based. The difference is in the corrosion inhibitors.

The low toxicity stuff is propylene glycol based but it is not in common use in the UK as an engine antifreeze. More common for winterising RV freshwater systems and as a heat transfer medium in the food industry. I believe though that when it is used as an a engine antifreeze a conventional silicate based inhibitor is used but that is something I would have to check on.
Its toxicity is low to mammals ie you, me, our children, cats and dogs and possibly one or two other forumites. As I understand it there is little benefit in using it from an environmental point of view.
 
I suspect that the "gunge" is not related to your current choice of antifreeze but is due to something which has been put into the cooling system at some point many years ago, the residue of which is still causing some issues. It could have been leak sealant or something similar, which might not even have been needed as the leak, or whatever, might well have been sorted by something else being replaced.

When the time comes, I would simply fill with water (soft ideally), run up to temperature, drain, refill, repeat until clear water is coming out. Then refill with the correct percentage of coolant. I would probably use OAT but use whatever the manufacturer type recommends if you are happier with that.

Forget about the colour as that won't help you .... you need to pin down whether it's an IAT or OAT formulation.

Richard
 
neil_s said:
I understand that OAT is not suitable for use with copper components. Had the same problem with my old Corsa!
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I understand the same, but I forget the reason!

RichardS said:
I would probably use OAT
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But you dont have a Beta engine

RichardS said:
Forget about the colour as that won't help you .... you need to pin down whether it's an IAT or OAT formulation.
Richard
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Agreed although I doubt if you will find an OAT type which is blue. Anyhow reading the label will tell either way
 
Removing all trace of the current coolant would take several flushes. Not easy when it's so difficult to drain down completely, but not impossible.

I have a concern that OAT may not be suitable for copper components, but if that were true, anyone with a calorifier would have the same problem. (I assume that all calorifiers have copper coils.). Did the change from OAT improve the Corsa?
 
Dull Spark said:
Removing all trace of the current coolant would take several flushes. Not easy when it's so difficult to drain down completely, but not impossible.

I have a concern that OAT may not be suitable for copper components, but if that were true, anyone with a calorifier would have the same problem. (I assume that all calorifiers have copper coils.). Did the change from OAT improve the Corsa?
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True ..... I had to flush one of my engines through about half a dozen times before I got all the old coolant out. Sometimes it's easier to just pull off the bottom hose. Although the two drain points in my engines are quite accessible, most of the coolant out of the cylinder block drain ended up in the bilges so I just let the auto bilge pump deal with it.

As you say, calorifiers are virtually always copper coiled ..... but modern OAT antifreezes are formulated to be copper-friendly so I use it in every engine without any problems. :)

Richard
 
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