Coolant Tank Scum

[RHY 11S]

Yesterday I noticed in the coolant tank something which looks the scum you might see on a dirty river. Is this what is referrred to as Mayo? - it certainly doesn't look like anything I'd put in my ham sandwiches!

Had a look at the oil cap and the coolant cap and can't see anything that looks like Mayo.

The car recently struggled to get through its emmission test [although a failed lambda sensor seemed to be to blame] and has been hunting a bit on idle when cold.

Any ideas anyone? Thanks.

It's a Mk2 111S with a K-Series engine.

[NWTony]

It could be, IIRC if it looks like a pale brown foam then it could be an indicator of the dreaded HGF. If you head over to Seloc someone has put up pictures of a contaminated coolant reservoir for comparison. Might be worth asking a garage to do a sniffer test on the gases in the coolant tank to see if it picks up any CO2, although that isn't always definitive as it didn't pick up my recnt HGF.

[offshorematt2]

Nah, I ran an S1 with scummy coolant for 20k miles without an issue. Lack of knowledge meant I just held out for the bang but eventually realised that it wasn't as bad as that. Changed out the coolant and no further scum... Just a grubby system I think. Mayo is pretty obvious - if in doubt just get the fluid changed and monitor the situation. Sure you'll be fine, the K series HGF is exaggerated - no-one ever posts when it doesn't fail

Cheers

[SeanyD]

Could be left-over from a previous HGF. Had HGF with mine when I first got it, and despite getting the cooling system flushed etc, there's still some residue meaning coolant always looks a browny colour, but car is otherwise running spot on.

[JTBUSH]

I had head gasket failure before Christmas. Still got mayo in the header tank. The system has been flushed twice since and cant get rid of it. I needed to replace a hose last week and was very surprised when I removed the old hose. the thing was coated in really sticky mayo which was quite hard to get off even by scraping with my finger. You can imagine the rest of the coolant pipes and capillaries will be like this, so you will still get mayo deposits in the header tank for ages afterwards.

[RHY 11S]

Just had both the chemical test and a pressure test and both came back negative. Car seems to be driving fine, although it hasn't seen anything above 4000rpm!

Garage made a very good point which is that the coolant itself is perfectly clear. There are no signs of oil on the surface nor bits of residue in it. All I have in there is this scummy residue that looks like dirty river scum. This doesn't seem to be oil either - more like a clear liquid.

Can I relax now and just assume that something may have got into the system when I had some recent work done?

[JTBUSH]

Just keep an eye on coolant level, oil level and temp. If they stay ok, then carry on driving!

[R.P.M]

Agree with above, the scum or mould will be due to age and I assume bacteria growth. The most important thing is to keep an eye on the level.



Rpm

[Hag]

I wouldn't say that's it's bacteria, only the very hardy ones can withstand the heat and pressure. My Type 72 suffered HGF last week and I'm in the process of trying to get it sorted. I checked the service history last night and though I knew he'd had the head gasket done, I didn't know that he'd put the original gasket back in. Not common practice I would think. At least I caught it in time.

[JTBUSH]

Hag said:

I didn't know that he'd put the original gasket back in.

Why the fk would you do that?

[RHY 11S]

Well, she's driving like a beaut so I'm happy! Coolant level hasn't moved and temperature is steady as a rock?

I'll try and rinse the expansion bottle out this weekend and see if any scum returns.

Thanks for the input everyone.

[JTBUSH]

Dont bother rinsing the expansion bottle out. Did mine a few times, and everytime, the scum returns. Only worth doing if youre going to flush the whole system, and its a pig to get out!

[stinkysteve]

RHY 11S said:

Well, she's driving like a beaut so I'm happy! Coolant level hasn't moved and temperature is steady as a rock?

I'll try and rinse the expansion bottle out this weekend and see if any scum returns.

Thanks for the input everyone.

Hello there,

i've got the same problem on my 02 S2 at present. Temp seems high and fluctuates a bit and some scum in the header tank has me worried. I'll take a photo tonight as i was planning to clean mine out. ( i just want to see if it accumulates again) I've just got the car so don't know if it's had HGF failure before. I spoke to a garage yesteray and they said don't wory about HGF 'til it misfires, 'mayo' is a difficult description, but it should be obvious if there's oil in it. My mechanic says he's had cars in with a litre of oil in the header tank before!

I'll post a photo and would appreciate it if you could do the same.

Cheers,

steve

[JTBUSH]

stinkysteve said:

RHY 11S said:

Well, she's driving like a beaut so I'm happy! Coolant level hasn't moved and temperature is steady as a rock?

I'll try and rinse the expansion bottle out this weekend and see if any scum returns.

Thanks for the input everyone.

Hello there,

i've got the same problem on my 02 S2 at present. Temp seems high and fluctuates a bit and some scum in the header tank has me worried. I'll take a photo tonight as i was planning to clean mine out. ( i just want to see if it accumulates again) I've just got the car so don't know if it's had HGF failure before. I spoke to a garage yesteray and they said don't wory about HGF 'til it misfires, 'mayo' is a difficult description, but it should be obvious if there's oil in it. My mechanic says he's had cars in with a litre of oil in the header tank before!

I'll post a photo and would appreciate it if you could do the same.

Cheers,

steve

Just out of interest, here is mine prior to getting the head gasket done. I wasnt loosing much in the way of oil, or coolant, temps were ok, and the car was driving nicely, but obviously had this issue with scum in the header. The coolant was a bit brown, and there was obviously mayo as can be seen.

Edited by JTBUSH on Thursday 10th April 13:38

[stinkysteve]

Thanks JT.

That looks similar to mine but I'd say my coolant looks a bit cleaner than that and there's a bit less scum in mine.

You just get so paranoid reading all these threads about HGF! I'll wash it out and see if it re-appears.

Many thanks.

[JTBUSH]

Just noticed Steve, your in Durham. Where abouts? Im in Langley Park!

[stinkysteve]

Langley Moor!

I'm often seen at full throttle past the windmills, over the moor by Tow Law.

Let me know if you fancy a blat sometime!

[JTBUSH]

Ay, definately mate. My favourite road is over that way, the one through cornsay colliery to Quebec and then down to Esh Winning and back to Langley Park! Definately up for a run anytime you want. Dont need much of en excuse to get out in the Elise!

[stinkysteve]

Brilliant.

It sounds like we hunt in the same territory.

Next time there's a sunny evening and I'm heading out i'll drop you an email.

Feel free to mail me whenever you're heading out. As you said, the more excuses for hooning the better. I found a brilliant road recently from Cornsay to Tow Law.

The real fun starts when you head past Wolsingham and Stanhope into the proper hills. I did 28 miles last week and only followed one car for 1/2 a mile!

I'm looking forward to it.

[JTBUSH]

Theres a belter which goes from turn off on A68 to Derwent Reservoir (carterway heads), over to Stanhope! If Im not going to Donnington this weekend, we could have an informal meet up and convoy over the hills on Sunday!