Untraceable coolant leak

[corblimey]

Been on the phone to Allans this evening to book my van in for a service and coolant change and had an interesting chat re an ongoing coolant leak I've had for a couple of years.

Over the course of about a year my header tank coolant level drops from the Max to about half way (or just below). That sets off my LCA until I've driven a 50m or so down the road when it stops. I've had a look but I can see anything. So, occationally I top it up with a little distilled water.

Anyway, thought I'd share a little nugget that Allan mentioned, I'm sure the coolant system gurus will already know this but for those that don't....

Over time the rubber pipes can harden and the retaining clips are unable to apply the corrent preassure and don't seal properly so allowing a small amount of coolant to weep whilst the system is cold. Within a very short time the pipes warm up and reseal and the small amount of coolant that has leaked is given off as steam hence disgusing the problem area. Allan reckons it's quite a common problem and is most likely to be spotted in the pipework under the drivers side seat.

I shall be starting my van with the seat up tomorrow morning to see if that's what's been casuing my coolant loss.

[mister munkey]

Exactly the same problem I had but mine was due to (mostly) Jubilee Clips needing a tweak. As the hoses age, they compress after several hundred/thousand cycles of expanding then cooling hence the clips work just a teeny bit loose.

Not enough to detect a leak but enough to drop the coolant level after a short while..

[Northern Bongolow]

good point well made .the problem usually shows around now,with the onset of the colder weather,and lower coolant temps,the expansion is the same but the contraction can be greater,hense the slight weeps.
keep a sharp eye on your coolant level boys and girls,or better still,let an alarm do it for you.

[lpgimports]

Hi

There is a test for this that we do on unfathomable ones. Stick it on ramp last thing at night, pop bonnet in morning, pump up cooling system to just below cap venting pressure stick it up in air with under tray off and see if anything anywhere is moist.

Also worth checking is the white fur build up that sometimes occurs around aluminium housings, if this is between a hose and housing you may have a water tight seal but a tiny amount of coolant could wick up through the fur and evaporate before being noticed.

Paul

[haydn callow]

You could put some coolant leak detector fluid in the system......this will show up the smallest weep.

The reason the alarm stops sounding after 50 meters is the coolant expands as it warms up and touches the sensor screw.

Also worth checking the Radiator and header tank caps are sealing properly

[corblimey]

Interesting, I'll check for the furring and the caps

Unfortunately I don't have any way to do mechanical work on my van myself since it's parked on the street so getting on ramps is not an option for me.

I was in a rush this morning so didn't have time to check on start up. Hopefully I'll do it later when I leave work.

Hopefully Allan will cast his beady eye over it next Sat.

[waycar8]

or you could use a roll of bog roll, simply wrap it around the hoses, and tape it so it doesnt unwrap, leave or start up, see if you get a damp patch

[lpgimports]

Unorthodox approach, though we use baby powder to find leaks in minis so equally bizzare...

[T9sus4]

Just a thought: is there a safe fluorescent additive that could be added and the van examined under UV light? (Worth trying if coolant isn't fluorescent by nature anyway)?

[haydn callow]

You could put some coolant leak detector fluid in the system......this will show up the smallest weep.

The reason the alarm stops sounding after 50 meters is the coolant expands as it warms up and touches the sensor screw.

Also worth checking the Radiator and header tank caps are sealing properly

[T9sus4]

You could put some coolant leak detector fluid in the system

Ah, see, I didn't know how that worked.

Hey, I have another great invention: why don't we screw some round things to each corner of our Bongos, they could rotate and we could get from one place to another quite easily!

[Rob101]

Yup we are long term leakers too - about half a teacupful every year ! Have to have a gander at the clips on the weekend..