Is rust in the coolant OK?

[teenmal]

The most likely cause of "rusty" coolant is a previous "boil up".. this causes all the "rusty crud" to be disturbed from the depths of the system and colour the coolant....at the same time leaving a brown deposit in the header tank,

This guy knows his Stuff.

[mikeonb4c]

The most likely cause of "rusty" coolant is a previous "boil up".. this causes all the "rusty crud" to be disturbed from the depths of the system and colour the coolant....at the same time leaving a brown deposit in the header tank,

This guy knows his Stuff.

Quite right. And whilst we are travelling down that road, questions that need answering include:

* what caused there to be rust in the coolant in the first place (back to Bigdaddy's point)?

* Was the accumulation of rusty sludge in critical parts of the system what caused the boil up in the first place?

So to return to Julian's post, if components have become sludged up then a proper coolant system overhaul (with replacement parts really) would probably be the (expensive but) sensible solution.

[mikexgough]

Could just be a poorly maintained system with poor coolant % or incorrect type
Needs to be physically checked before we get ahead of ourselves with boil up scenarois as BDC says discover the reason for the brown/ rusty coolant first,Julian's initial diagnosis is probably spot on. I sometimes find brown/rusty coolant in recent GM vehicles,an Astra recently was the same,top hose leak no boil up - red coolant vehicle- clean water flush,new coolant, sorted - it could turn out to be result of a boil,but simple checks first before conclusions

[mikeonb4c]

Could just be a poorly maintained system with poor coolant % or incorrect type
Needs to be physically checked before we get ahead of ourselves with boil up scenarois as BDC says discover the reason for the brown/ rusty coolant first,Julian's initial diagnosis is probably spot on. I sometimes find brown/rusty coolant in recent GM vehicles,an Astra recently was the same,top hose leak no boil up - red coolant vehicle- clean water flush,new coolant, sorted - it could turn out to be result of a boil,but simple checks first before conclusions

I'm inclined to agree.

[bigdaddycain]

A lack of coolant in addition also can make the temperature control less stable, which i suppose could stir up any old crud in the system. Bottom line? There shouldn't be any "crud" in the system, not if maintained properly. I've never seen, nor extracted any of this so called crud from my system... All I've ever got out of my bongo is clear, clean, glistening coolant. Flushes (in my case) have been a waste of time, effort, and water.

If however a system has been topped up, and topped up, and topped up again with plain water (maybe due to a leak?) and the antifreeze/coolant has been so diluted to a stage where it's no longer effective, then yes, i do believe it could well be rusty... But you have to ask yourself why?... Yes, perhaps there has been an overheat, this could well exacerbate "rustiness", the core problem is however why that crud was there in the first place. I often smile to myself reading some comments on here, get this alarm, get that gizmo and so on and so forth... yet the fundamental, the core, the key reason to so many overheating woe's on here is plain and simple... if your coolant is correct, and healthy, the rest of the system will thank you for it... temps are stable, flows are stable,everything working within it's capacity as it's got the correct lifeblood flowing through it, yet so many times it's overlooked. It isn't rocket science when all said and done really is it? One might casually say "has it overheated"? It shouldn't overheat! And most don't!

[haydn callow]

The "so called" brown crud is probably not "rust" as such....Just a rusty coloured sludge, As you probably know you need oxygen present to get metal rusty.....as you say....a perfect system will be super clean...However how many 12 year old systems are clean unless many of the componants have been changed......Rad/hoses etc......Take any 12 year old rad and there will probably be a brown sludge in the bottom, this is extreamly difficult to dislodge by everyday use or "hosepipe" flushing.....BUT....get that temp up by leaving the cap off or getting up to boiling point and it soon shifts and circulates.
My system was flushed when I bought the Bongo....the coolant was then added and stayed clean for weeks....then I decided to treat it to a new header tank (sediment inside & stained) and a new rad......the exact same new rad weighed a Kilo less than the old one......this Kilo differance was the sediment in the bottom.

So I stand by my statement......Rusty coloured coolant is often caused by a previous boilup.

[Alacrity]

Crud build up in a rad where the tanks are on the top & bottom, & the gearbox oil cooler is in the bottom tank, is a common cause of transmission overheating as the (already poor) tubular cooler ends up buried in silt so it gets no water passing over/through it. This is less common than it used to be as most rads today have the tanks on the sides.

I have no real opinion as to where the crud comes from, apart from the fact is was very common with radiators of this type & I can't believe they have all boiled at some point. Most cooling systems never get flushed unless they need work doing on them, that may not be correct but it is the reality of it.

[mikeonb4c]

Most cooling systems never get flushed unless they need work doing on them, that may not be correct but it is the reality of it.

Spot on Geoff, I reckon. Before I got a Bongo and we all became a*al about coolant issues, I don't think I gave changing the coolant on my other cars a second thought. I'm sure I'm typical, and my other cars all went on to a grand old age with no problems (they all had 50/50 in them of course).

[Dr.Jekyll]

I have no real opinion as to where the crud comes from, apart from the fact is was very common with radiators of this type & I can't believe they have all boiled at some point. Most cooling systems never get flushed unless they need work doing on them, that may not be correct but it is the reality of it.

+1 totally agree with you, the brown sludge does not = boil up in all cases.

[haydn callow]

I have no real opinion as to where the crud comes from, apart from the fact is was very common with radiators of this type & I can't believe they have all boiled at some point. Most cooling systems never get flushed unless they need work doing on them, that may not be correct but it is the reality of it.

I think you may misunderstand me.....I quite agree that the "crud" just builds up over the years....what I am saying is that...."rusty coloured" coolant can be a result of this crud in the bottom of the radiator being disturbed by a near "boil up".
I am not saying the engine has suffered a massive overheat.....although this would also stir it up even more.

The staining of the header tank I think is more "ageing" although it does look much worse after a layer of "crud" has been deposited in there.

[haydn callow]

I have no real opinion as to where the crud comes from, apart from the fact is was very common with radiators of this type & I can't believe they have all boiled at some point. Most cooling systems never get flushed unless they need work doing on them, that may not be correct but it is the reality of it.

+1 totally agree with you, the brown sludge does not = boil up in all cases.

Quite right....my bongo had a kilo of crud in the rad but was performing well within acceptable temp limits and had not boiled up.

[Dr.Jekyll]

I have no real opinion as to where the crud comes from, apart from the fact is was very common with radiators of this type & I can't believe they have all boiled at some point. Most cooling systems never get flushed unless they need work doing on them, that may not be correct but it is the reality of it.

+1 totally agree with you, the brown sludge does not = boil up in all cases.

Quite right....my bongo had a kilo of crud in the rad but was performing well within acceptable temp limits and had not boiled up.

Agreed, same here.

The problem is that it has now become a very common belief that if a header tank has "rust" in it, then it must of had an overheat episode at some stage in its life and should be avoided. This I feel is wrong and needs to be addressed.

[haydn callow]

You can normally tell if a Bongo has had a "boil up" by looking in the area around the Header Tank and the hoses that exit the tank (also underside of bonnet)....If there is evidance of brown stains it is a good indicator..
Also.. it must be remembered that not ALL Boil ups/overheating end in engine damage

I would say that if there is sediment in the header tank it could well have come from the bottom of the rad.....and getting well hot....would move it there at the same time as colouring the coolant...

[jaylee]

Yer all gonna slap me fer this.... But what the hey..!!

If anyone had Plasticine as a child brand new out of the packet with all the different primary colours.. After loads of use it got screwed up into a big multi coloured ball & packed away... Eventually the plasticine ball turned brown with more use & packing away...

Header tank discolouration tends to be brown... 16 years of staining with various coolant colour changes..??

Just a thought..

[Iwannabongo]

Thanks everyone for all your helpful info
I have been away the last 4 days in the bongo and just seen all the comments regarding my mucky sludge.
I have just used a halfords anti-freeze tester on the coolant and it states protection level is low on a scale of none, low, medium and high.
When I tested it the coolant was very clear with an orange tint, but when you touch the bottom of the tank it goes a very murky orange colour which I now know is not such good news.
I have checked around the header tank and there is no obvious sign of any previous leaks from boiling over.
Next task is to get it flushed out, which I am not over confident in doing myself so want to take it to a garage to get done properly.
I noticed Haydn that you are from Somerset. Do you know if Bell Hill Garage would do a good job of flushing and refilling coolant correctly or has anyone else used these before to do this?
It would be handy to know before I give them a ring, as I wouldn't want someone just to empty old coolant and refill it again(I don't have a lot of trust in garages anyway, let alone on my Bongo)
Thanks again for all your helpful comments,
Justin