ian_6301

I was called out to the car park this morning by one of the guys at work - there's a small puddle of fluid coming out from under the engine bay. It's about half a cupfull of blue liquid, the same colour as the coolant, but with an oily feel to it...

The radiator catch tank has been empty since I bought the car, but the coolant has been (and still is) right up to the top in the radiator. Bearing in mind that the only connection from the cooling system to the tank is from the pressure vent part of the rad cap, this means that unless the rad cap is either removed while the engine is hot, or the lifting pressure is exceeded, there should be no coolant flow along that pipe and into the tank.

The oil level is fine, oil looks a nice toasty golden brown colour, typical of mid-period between changes, IYKWIM.

Brake and Clutch fluid levels are fine, clutch fluid could do with changing, but not related to this issue.

There are no signs of leaks from anywhere in the engine bay, just a wet patch on the bottom of the crossmember at the rear of the engine bay and this small puddle.

we've run the car up, put the aircon on and watched it go through 2x cycles of fan coming on/going off and still no more fluid appearing.

What the hell is this fluid and where is it coming from? My best guess at the minute is that there's a coolant hose weeping somewhere at the back of the engine, which is collecting oil from either somewhere on its path to ground, or from the ground itself (manky old car park), hence the oily feel. Will top up the rad and coolant bottle to the max and await further updates.

Any thoughts?

BenRNBP

Windscreen wash ? I think either of the pumps can develop leaks/splits

richmc

If the only fluid in the car that is blue is the coolant, then you know what they say, "if it looks like sh1t, smells like sh1t, and feels like sh1t, then it's probably sh1t".
Seriously, the coolant can seem to feel oily as it's a little viscos and if its hot when it escapes tha water content will evaporate quickly and make it feel slippery, I;m not sure if this still works with modern coolant but in days gone by you could tell with a tiny lick of the stuff, if it tastes sweet it's coolant, thats the glycol.
You could spread an old sheet on the ground and park over it (ask the Doris first!) to see exactly where its dripping from, and go from there.
You said back of the engine bay, my bet would be the heater plumbing.

ian_6301

Thanks chaps - The screenwash is purple (nasty Halfords berry scented crap - don't ask...)

The only blue fluid that I'm aware of in the car is coolant. I did dip a finger in the radiator and the "feel" of the stuff in there is VERY different to the stuff on the ground - hence I suspect it's picked up a little oil en route.

Heater pipes/matrix is my best guess at the minute. I'm going to attempt to get it up on axle stands tonight to have a look, but it should be OK for the ~20 mile commute home.

I topped up the rad and it took around 0.8 Litres to bring it up to the top of the filler neck. I'd also like to revise my thoughts on the expansion tank - it has a "straw" in it, from the cap going down into the fluid, so it might actually function as an expansion tank / self bleeding valve...

richmc

As I said the stuff on the ground will be pure coolant as the water evaporates as soon as it escapes so it will feel different.
The expansion tank receves excess coolant as the diaphram in the rad cap gets pushed up under pressure and replaces it by suction as the rad cools. You are correct in how it works as a vent/valve.

RobAp1

Blue Glycol based coolant has a slippery, oil like feel. This is due to the Glycol content.

In all seriousness, do a little taste test, dab a finger and lick it. If it's initially sweet then horribly bitter, it's coolant.

unclefester

Either that or it's Smurf c**

That's what i'd do too though.

That expansion bottle has a min and max - if it isn't above the min and never has been you might want to investigate why - looks like now might be a good time

RobAp1

flanders

Yeah not good running with an empty expansion bottle, you are going to suck air in to the coolant system.
It's most certainly the coolant you saw on the ground if it was under the engine, otherwise I would check the diff for any leaks as well.
When I drained mine it had blue oil, not sure what the previous owner filled it with.

ian_6301

OK, so having added that Litre of water before lunch, I've done a round trip at lunchtime to see how things change and I seem to have lost nothing or next to nothing on the outward leg (heater set to cold) and an appreciable amount on the way back (heater set to hot).

To me, this sounds like a leak somewhere between the valve for the heater controls and the return on the other side of the system, which fits with the location (rear end of engine bay, roughly central).

Home I go with a top-up and the controls set for maximum frostiness, in search of some paving slabs, a jack, a pair of axle stands and a torch...