Hi everyone
I just flushed my radiator out last week. The car hadn't been driven properly for years and it was filthy in there, brown fluid washing out for a few minutes.

I Put in new coolant and today just checked on it and saw the attached picture.

Any idea what it could be? The foam residue is quite stiff, and builds up reasonably fast.

I also changed the oil at the same time and it's sitting just on the max line, so not sure if I should drain a little of that out and discard.

Any thoughts would be really great.
Thanks

Oil in the water. Head gasket leaking, most likely.
Pull head, fit new gasket, get radiator cleaned.
Pull rad off, hose it out, pour in degreaser, slosh around, hose out again. If still grotty get a rad shop to service it. Or buy a new rad.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yep. Oil can do that

Argh. Thanks for the input.

Any chance it could just be the oil being a little overfilled causing the issue?

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Mini-less ... for now

No. The coolant system is a sealed system and a mechanical falure would had to have happened to allow oil into coolant or the other way around.

The most likely cause is the head gasket. Other causes are cracking or corrosion.

If you find it is the head gasket then make sure you do an oil and filter change after its all back together.

Thank you, I'll look into it and might even see if I can DIY it.
If so would be the biggest mechanical job I've done myself so fingers crossed.

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Mini-less ... for now

reasonably hard to stuff up - follow the workshop manual

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did I tell you that I won a trophy?

could it is also of got into the block behind the water pump,
and the welch plugs?

can you flush with degreaser

Personally I wouldn't fret at this stage. How good was that first flush. All that brown stuff most likely a build up over years of non servicing. I would flush again, go for a drive, flush again, another drive. This crap in the engine takes forever to clean out. Chemical wash maybe. Only then if the problem persists, you may need to dig deeper, remove head etc. If you have the radiator cleaned out by a radiator service before establishing what is wrong, you'll only clog it up again.

Thanks for the reassurance! I was looking at the water thinking gee I missed a bit.
It really was superbly filthy in there.

The oil actually looks very clean, doesn't appear to be any coolant in there.
The little car is headed for a tune up anyway, so I can ask them to do a test on the gasket too.

Any thoughts on either putting through a couple of litres of degreaser or a bottle of one of those radiator flush and clean things?

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Mini-less ... for now

I have used the radiator/coolant system flush stuff you can get from supercheap / repco, they worked great on my engine , simple enough to use and compared to starting pulling an engine apart (if you havent done it before) it's a pretty simple thing to do. worst case you still need to take the head off and replace gasket anyway, but the cooling system will definitely be clean.

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2015 Ducati 899 Panigale

What was the engine running like prior to flushing , what was the reason you decided to flush radiator in the first place ,was it because the coolant was something the same as the pic you show , if so there's a big chance that it has head / gasket issues .

I would be giving it a compression test first , that may give you an indication as to what the problem is, it will be a waste of time tuning it until you get that sorted .

I actually just picked the car up so don't know a huge amount about its history. I think it had sat in a shed for a good 3-4 years but was kept ticking over, but not registered. It hadn't been driven much more than on and off the tow truck. I figured the first thing it needed was new oil and filter plus a coolant flush, but unfortunately I just can't recall what it looked like before the flush!

It seemed to run ok for the minimal run around I gave it but was a little rough, though I'd definitely have the test done as a priority once it gets to the shop.

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Mini-less ... for now

Head gasket isn't rocket science. I'd look at that as that would be the only possible culprit. PM me and you can bring her over, we'll do it together if you buy the head gasket.

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Lillee - 1969 Morris Mini K

Now that you have said that you just picked it up there may be another thing it could be. Some radiator stop leak additives foam up and form a crust when exposed to air. A good flush should have cleared this stuff out but the original leak they were trying to fix may come back. Just something to keep in the back of your mind if the radìator or a welch plug starts to spring a leak.