Took the car in for her biannual compulsory check (or else she stops being road-legal on the 19th), and discussed the issues I've noted here earlier with him. Based on this photo, he suspects there might be oil in the coolant. Does this look like oil in the coolant? It doesn't look like any photos I've seen of oil in coolant, being more of a sludge than a milkshake. The coolant itself is still green and clear, albeit with small specks of crud visible.


Is this oil in the coolant?

Crud in the reserve tank neck

Also, they're going to pressure-check the rad to precisely locate the leak is that I mentioned sort of in passing in the What Did You Do For Your XJS Today thread, but if it is a leak, it seems aluminium rads aren't easy to repair, and a new one would be a better idea. The current one is a Wizard one, and Wizard is supposed to be good and if it's leaking after less than four full years I will not be a happy camper.
(The mechanic did suggest that if that gunge in the coolant is oil, it might not be the head gasket but the oil cooler in the rad, and, given that if there's one leak, there might be more, that could be the culprit. I really don't want the head gaskets replaced. I gather you might as well buy a new car for that amount of money....)

As usual, any suggestions and advice will be gratefully received.

 

Could it be the transmission fluid cooler has a small leak ?

 

Oil in water/coolant can do that.

The Milkshake is generally teh other way round, as in, water in teh oil.

The trans cooler, and on some, the steer cooler, is in the radiator, and YES, they can leak. Scariest part of that scenario is coolant getting INTO the trans or steer system, as that is FATAL.

I remember you talking about this "gunk" he was adding for leaks, and that can also do that in overdose situations.

I would suggest the leak test for sure.

FLUSH the system, get all HIS gunk out, and then fresh coolant, and see what gives in a week or so. That flush MUST be thorough, no 2nd guess with it.

Side note:
I remove the trans and steer (if applicable) plumbing from any of my cars radiator. Fitting a suitable cooler out the front, thus preventing this situation 100%.

 

My last post was a boo-boo, so I amended it ! Oil in coolant is never a good thing and I think Grant has his finger on it. Either way some investigation is needed, or at least keep an eye on it.

 

Very interesting you said that--while I do try to take her for a hoon at least weekly, a lot of the time it is just to the university and back, which is about 20 minutes one way. Not sure if that's a "short" journey or not--I don't drive her five minutes to the shops or anything.

When I bought the car, there was a coolant leak into the transmission oil, which was fixed.

This was what it was like before the car was delivered. The seller fixed this issue.

I've told the mechanic clearly that I definitely don't want any leak-stop added this time. He said they're going to do a high-pressure flush, check where the leak is, then get back to me. There's some parts on their way, stuck in Oz at the moment probably due to a shipping backlog due to a lack of flights between Melbourne and Japan at the moment, so we're going to hold off on major work until they arrive which will give time to check the way Grant said.

 

Damn - I was hoping it was something as simple as not letting her stretch her legs often enough.....
Certainly will keep an eye on it, however.

 

OK, that Pre delivery issue may be the root cause.

IF and I mean IF, that cooling system was not flushed 100%, and then again, any residual oil in there will do that over time.

It may be that simple, but step 1. 2. 3 is the only way now.

Good luck.

 

Hmm. I have been noticing that gunk from time to time, but never in quite such generous amounts. While the rad and the hoses have been changed, there's doubtless plenty of other places for muck to hide in the system. I'll get onto the mechanic and tell him about this original issue (this was four years ago) and make sure that the system is really well flushed.
On the bright side, if it is just residual muck from the contaminated transmission oil, the more gunk I scrape off the expansion tank neck, the less in the system....

 

Another thought, but not seeing it in the flesh so to speak.

Mixing coolants, can cause this Goop sludge also, seen that many times at work.

It can be as simple as changing brands, and that is scary, but fact.

He is clearly adding coolant, plus his stop leak, and if these "addings" are a different brand/spec to whats in there, this can happen.

They are easier to fix, FULL flush, refill and go, and REMEMBER whats in it for next time.

 

Hmm. Well, I certainly do top up the coolant whenever I notice it's low, using a green pre-mix. I have no idea what brand the garage uses--I thought the main thing was to get the right colour.
This is what I use to top up. It's a 50-50 premix you just pour right in.


(I hope that stays small and doesn't expand to huge when posted... EDIT: Nope. Bugger.)

Anyway, it'll be interesting to see what happens when the system's been flushed.

 

This coolant is a mine field.

Colour is really just cosmetic, mix Red and Green, and you get a rusty looking liquid, NOT good for sales etc HA>

We now have Blue, as in VW, Toyo, Merc, some Honda, so that gets interesting.

MOST coolants down here come as you have, then the makers also have a "one that fits all if you dont remember" product, and its clear,and compatible with all Aussie spec coolants.

That coolant goop is not as common now as it was, but I remember mixing 2 different brands (not saying names on here) , in the work Hi-ace van, and a week later had goop almost the same as you have.

I suggest taking your container to him, empty, and getting him to fill it with whatever he is putting in the beast, that way there is NO doubt at all.

 

Hmm. I wonder if that would account for the tiny shiny green flakes I sometimes see.... You can make a couple out on my gloved finger in the top photo. The nearly empty bag's still in the boot. I'll definitely see if I can get them to try and mix coolants (in a cup, not my rad).

Wonder why they say not to mix colours then? Here, its red, green, blue, and yellow. Oh, and pink. In the Autobacs series at least, yellow is branded as for European cars (and is much more expensive that any of the others of course), blue and pink are long-life, and red and green are standard, I guess. I've also seen some where it's supposedly sorted by car maker, like you have I guess.

 

I have never worked the colour out, as it is really just a dye.

The formula differences causes the goop factor, and I reckon the 21st century has had them sort that out somewhat, but I still see it from time to time.

Here the Yellowish stuff is the same as the "Universal" stuff for those that forget.

All ours now is Long Life, as in 5 years and even 8 years.

 

Make sure the antifreeze is of the ethylene glycol type. That is the most important thing.

 

Looks like one of two things to me. On is stop leak gunk and it is simply collecting at a high point. Other is the cap is not sealing completely and there is a small leak. As antifreeze evaporates it leaves deposits similar to that. I just finished cleaning up something similar on an engine where the hose clamp had never been tightened after being built and there was a small weep and it had large deposits similar to that and massive corrosion of the aluminium hose nipple.

If it was a headgasket failure, I would expect coolant in the oil, not the other way around as the coolant is pressurized and oil generally is not where it passes through the head, it's just draining back to the sump under gravity.

 

With V12 I would rather check the system for CO/CO2. British 5.3 has a lot in common with MG in terms of head gasket reliability...
The rule is simple - check and don't touch if everything is ok.
1.Tranny won't operate correctly with even minor amount of water/glycol in it. Easiest way to check - invest £10 in ATF and drain 3.5l of oil from the tranny's sump pan.
2. Type of coolant is hellish IMPORTANT. Discard people saying ”it doesn't matter" or "it's just dye" (unless you're happy with head gasket change)
3. Any floating silver flakes in the coolant suggest "radiator seal" rubbish poured into the system. The most rubbish thing describing whole British automotive industry is the fact that due to over-engineered v12 engine and 100 ft of hoses involved - official repair manual states you should use "barrs seal" as normal additive...
4. There is a simple coolant test for contamination - not sure how your mechanic skipped it saying "it looks like..."

 

Thanks everyone for your wisdom and comments. I don't have the coolant bag with me to see if ingredients are listed on the back, but the Autobacs press release simply describes the colours thus:
So that says one the one hand that dyes mean nothing in terms of function, and on the other, there's a clear distinction between manufacturers. Not helpful.

Jagboi - What you say about a leak is interesting. I haven't found any notable signs of dribble around the neck of the expansion tank, but last time I took the cap off to check, the rubber gasket remained on the neck. I peeled it off and replaced it in the cap, but there could be a very gradual leak. Caps are easy to replace, and while the main one's new, this is an older one.

Banger - I'm afraid I have no idea about the head gasket reliability of the MG, but brief research online yesterday suggests the Jaguar V12 head gasket is not a common point of failure. The transmission seems fine in operation, and it's time for the transmission oil to be replaced anyway (I asked them to do it as part of the process). Last time I checked the oil, a month ago maybe, it was clear. But that was just from the dipstick. The mechanic only looked at the photo - the engine was still hot from the drive to the garage, so we didn't open the actual caps. This was just a preliminary discussion. The place I use was chosen carefully as a specialist in high-end European cars (especially Ferraris; there was one on the lift with the rear wheels off yesterday), and expertise in older models, and for the most part their work has been good quality. I just want to assure you that I didn't wheel her down to the nearest equivalent of Jiffy Lube or Walmart to save a few yen.
That bit about rad seal rubbish is also interesting. Based on what people have been saying, at this point I'm leaning towards rad seal + slight leak. At least I'm hoping it's just that....
Doing some more research on coolants, I find this:
And other threads on this forum also say use the green stuff. But the main warning I've found is basically "use the same colour that's in there."
Jaguar Car Club of Tasmania says which also tracks with what's in there.

 

I mentioned the leak theory, because this is what I recently came across, it's the lower radiator hose on an XJR. The hose was original, and hadn't been touched since it left Brown's Lane. There wasn't an obvious leak and it didn't seem to go through antifreeze, but there was slight weeping. Once I cleaned off all the corrosion products you can see how much it pitted the water pump outlet.

 

I have this as well after putting in a random elc coolant from the local walmart as opposed to the other stuff I get from the semi truck dealer. Grant might be spot on with the mixing different types even if they both meet same specs.

 

Wow. That is some corrosion.

I shall definitely ensure I know exactly what is being put in, and what I can use to top up.