Expansion tank empty after fair bit of use this week?

[Jimbob738]

Hello people been a while since me last post hope everyone enjoying the snow!

i have an N reg bongo changed head gasket last september as it blew luckily no damage to the head (got it tested) all has been well since, same time did the cambelt and tensioner new head bolts.

last few months i have been keeping an eye on the expansion tank last time i checked was about a week and a half ago was just below full about in the middle full and low so i left it, did my checks tonight on both my cars oils and coolent the tanks empty?

for me its pointing to a small leak either a pipe or the water pump it doesnt seem to be consistently dropping coolent just seems after heavy use for a week or so it emptys the expansion tank it is worrying me in the back of my mind but until next month i cant afford to replace all hoses and water pump as i want to but i cant see a physical leak does that make sense?

advice please folks

[haydn callow]

If the tank is empty (no coolant in at all) DO NOT DRIVE IT AT ALL.
Find the leak and get it fixed...then bleed it properly according to the you tube vidio's and the instructions which you can download........fail to do this and you could crack the head...
As you overheated last Sept I would still be worried about possible head damage which was not evident at the time.

[Jimbob738]

I feared you'd say that, i need to find where its going better leave it where it is then and get it all check over the waters got to be going somewhere.

just made a decision to take her off the road and wait for it to warm up a bit and over haul the cooling system and study for leaks something just doesnt feel right.

[Jimbob738]

I am going to try and identify the leak first off if i can whats the best method of trying to pin point it on such a tricky system like the bongo 2.5TD ?

[mikeonb4c]

I am going to try and identify the leak first off if i can whats the best method of trying to pin point it on such a tricky system like the bongo 2.5TD ?

Get some u/v dye to put in the coolant, and a u/v torch to disclose where a pinhole leak may be occurring. Also, have you checked oil for emulsification and/or ate you getting a lot of steam/white cloud from the exhaust?

[Jimbob738]

the engine is running sweat as a nut right now no indication of any water combustion what so ever i have been checking and no build up of gunk anywhere either i fitted new K&N and fuel filter last weak and cleaned under there all clean, checked oil tonight not moved a drop since i did the head in september?

i personally think i made school boy error not changing the water pump and the hoses and rad as these i think are where my issues lie?

just got dye off ebay and getting a torch too.

[Jimbob738]

or maybe i bought the wrong stuff the one i got was for diesel and oil not coolent leaks thats 50 pounds i aint doing that i asked for refund.

[Northern Bongolow]

most leaks show up with a pressure test. make a pressure tester that inflates the system to NO MORE THAN 1 BAR then look for leaks. connect a bike/car foot pump with a gauge on it to the overflow pipe on the expansion tank.
the water pump has 2 holes which leak when it fails, one is easy to see from the passy side, if you imagine the clock face viewing from the front of the bongo one hole is at 10 mins past, and the other is at 6 oclock. the 6 oclock one is really hard to spot leaking because of the crank pulley and belts, i use a dentist mirror and look for telltale water marks on the casting, you wont see it drip because it only leaks when the pressure builds up as it warms up, but the leak evaporates away as it runs behind the crank pulley.

generally if its been loosing coolant for a while and it hasnt boiled its either the head, or a hose that is high up on the system, like the top of the rad, cracks under the expansion tank, or the water pump. most other leaks usually result in an overheat and boil .

[Jimbob738]

Thanks for advice, my bongo's expansion tank has been fluctuating in the last month or two one week looks fine when i check it (generally weeks where its not been used much) and other where its empty like this week coz i been using her to get about as the snows bad round here.
i have bought a uv leak testing solution and a uv light but also borrowing my mates pressure tester to try and find out whats leaking i have a feeling its the water pump not once has it boiled over since last september and im not getting any emulsified oil build up any where which is a sign of the head or white smoke.

thanks guys all fantastic help as always.

[steveyd]

Hi,

There's been concerns voiced in the past about the integrity of the header tanks themselves - some seem to crack along the bottom. If the tank is already empty it might be easy to actually disconnect the tank and take a look at its base. I have VERY slight trickle under there, but I also have a nasty old non-well known LCA with a separate reservoir with plenty of jubilee clips which could also account for the dribble. Not using it at the moment but will pull it apart when it warms up.

cheers,

Steve

[Simon Jones]

It is worth mentioning that I've never (yet) come across anyone with head gasket failure who has had any symptoms of coolant in the oil.

In an ideal world, the level in the tank should always be at the same level under identical conditions (i.e. always checked cold). It does go up & down by a few mm between cold & hot - someone posted details recently.

Water is generally pretty incompressible, so if the level is going up & down significantly it would indicate either air in the system or there is something else which is expanding & contracting such as a weakened rubber hose which is ballooning under pressure & then contracting as it cools & the pressure is reduced.