Cooling fluid cap leaking?

[OdinEidolon]

Hi all, I've been noticing in the last months that after the engine is off there's a noise coming from near the cooling fluid container.
It's like a "pffft" that lasts 2 seconds, then nothing for 10 seconds then again.

I thouhgt it was normal, but today giving some WD40 to my injectors I noticed some white stuff near the cap. Could be the cap leaking? The level's been fine for the last 4 months so if it's leaking it's not by much.

[FarmerPug]

is there pressure in the tank? If you open the cap does the water start to bubble, and is there any chance of oil contamination in the water, is the oil cap clean?

[OdinEidolon]

is there pressure in the tank? If you open the cap does the water start to bubble, and is there any chance of oil contamination in the water, is the oil cap clean?

Never tried opening the cap when the car's still hot, if I do I'm sure it shouldn't boil since water temp is always kept at 90°C by the fans, right?
Oil contamination? Maybe, never noticed.
Oil cap clean? Definitely it's dirty, probably the known small oil loss from the cap (see coupé forum)?

[FarmerPug]

is there any white mayonase stuff on the bottom of the oil cap.
As for the coolant cap being open, i mean have it open when the cars cold then start the car to see if it starts bubbling quickly.

[OdinEidolon]

My oil spill near the first injector - the watery stuff is probably all the WD40 I've been spraying in the last days, the oil was pretty much crystalized.



The white stuff coming out of the water cap - was more but the rain probably washed it away:

[FarmerPug]

that doesnt look too bad, some coolant may have been spilt when it was being put in and this is whats left.
Do you suspect head gasket problems?

[OdinEidolon]

that doesnt look too bad, some coolant may have been spilt when it was being put in and this is whats left.
Do you suspect head gasket problems?

Nah. If the oil's leaking then it's from the cap (see http://www.peugeot406coupe.com/phpBB3/v ... 45&t=37693) or maybe what I see is unburnt fuel coming from the first injector return hose that is missing the circlip (see first picture), dunno why.
The coolant was much more yesterday, rain washed it.

[mjb]

Don't worry about it - it's nothing. The cap's designed to give way at a certain pressure level, so when the engine's particularly hot (eg. up to temperature, hot day, stationary up the backside of a bus) it can spit a bit out. When I'm re-filling my coolant I'll typically fill it all the way to the top and just let the cap chuck out the excess when it's up to temperature, then wipe off the white stuff next time I'm under the bonnet.

DO NOT attempt to open the cap when the engine's up to temperature. 'tis very hot and very pressurised

[OdinEidolon]

Don't worry about it - it's nothing. The cap's designed to give way at a certain pressure level, so when the engine's particularly hot (eg. up to temperature, hot day, stationary up the backside of a bus) it can spit a bit out. When I'm re-filling my coolant I'll typically fill it all the way to the top and just let the cap chuck out the excess when it's up to temperature, then wipe off the white stuff next time I'm under the bonnet.

DO NOT attempt to open the cap when the engine's up to temperature. 'tis very hot and very pressurised

Thanks, good info. I know, never open the cap with hot water, bad things can happen

[teamster1975]

Yep it does sound as though the cap is venting excess pressure, the white staining is probably lime scale from the coolant.

[OdinEidolon]

Yeah just normal then. What worries me is the amount of black debris in the first injector. It may come from
- injector return hose (fuel), since it has no circlip
- oil from oil cap leaking
- an old oil accidental spillage
- head gasket

I tend for the second one, as it seems oil to me. I've done around 5500 miles snce the last oil change and the oil level has gone from full (checked with metal rod) to exactly mid of the metal rod measurer. (But the car at startup says the oil's almost finished, I guess the electronic gauge isn't very well calibrated?)

Is this a normal eating of oil by the engine or is it too much?

[FarmerPug]

dont trust the oil level thing it works better as a spirit level, the dipstick is the best measure of how much oil you have.

I cleaned the same area of my engine last week i was suprised by all the oil but they say its caused by road dirt and dust, so far none has come back yet, so i would advise you to put engine degreaser round the area, clean it off with a good brush, and see if you have any leaks.

[OdinEidolon]

dont trust the oil level thing it works better as a spirit level, the dipstick is the best measure of how much oil you have.

I cleaned the same area of my engine last week i was suprised by all the oil but they say its caused by road dirt and dust, so far none has come back yet, so i would advise you to put engine degreaser round the area, clean it off with a good brush, and see if you have any leaks.

It's not dirt by the road, it's only in the first injector pit, the other three are perfectly clean

[FarmerPug]

can you set cardboard under your car to see if any oils leaking out?
I dont know if they need replacing, is there a seal round the injectors?

[OdinEidolon]

can you set cardboard under your car to see if any oils leaking out?
I dont know if they need replacing, is there a seal round the injectors?

I park it every day in the same exact spot. There's no oil on the ground, so it's not leaking THAT much. Yep, there's a seal around the injectors but then it actually seems oil, not diesel. If it was injector 1 leaking it'd be diesel.