Gurgling expansion bottle.

Hi all,

So I got myself a Daihatsu Hijet 1.3 16v efi project.  I’m a complete novice to mechanics but always wanted to have a go!

On driving it about I noticed the temp gauge would go high.  I’ve drained the cooling system, filled the system.  Did this a few times as per the manual with not much luck of purging the air until I saw the watering can on a step ladder trick.  Did that earlier (I used my bike cleaning stand) and I got the water coming out the heater pipe.  All good.

I left it to idle on the driveway first until the fan kicked in (30mins ish) it was dead centre on the temp gauge then took off.  The gauge more or less dropped to the lowest point.  I’m thinking the thermostat is probably stuck open as the coolant in the engine wouldn’t be staying in there long enough to scavenge the heat but after about another 30mins it started to climb and still went high.  It would however drop back from about 4/5ths on the gauge but then hover above the halfway point before starting to climb again.  I figured this drop could be down to the fan kicking in and then stopping or the sensor being a bit dodgy.

I’ve pressure tested the cylinders and got 175psi across all 4.  It runs lovely and smooth, quiet, no signs of smoke, steam or gank in the oil cap so I wasn’t thinking head gasket.  

Once back on the drive I let it idle and the temp started to return more to the middle; still right of mid point but definitely lowering.  

On switching off the engine I heard lots of gurgling and on lifting the passenger seat I could see bubbles of air popping in the expansion bottle.  The expansion was also more or less full of water.  

I’ve got a new thermostat to put in as well as a new temp sensor which I’ll hopefully do this weekend but I assume air is getting in somewhere?

I’ve got a radiator pressure test kit to see if there’s any obvious hissing coming from a hose - I’m obviously
expecting it not to hold pressure but it should give me an idea as to where the leak is.  

If it’s the hose(s) I figured I’d get some jubilee clips and put these on alongside the squeeze clips that are already in situ to double up in case it’s down to old hoses that have gone a bit brittle. Are hide kits easy to source??  

Could it be that I simply didn’t get all the air out?  Can anyone suggest anything else that I might try in order to resolve it?  I did put a new radiator cap on under the seat but the main cap is different so I need to source a another (the sprung part is like a flat disk with a rubber washer on it and it’s bigger in diameter than the one under the seat).  

Amy ideas, suggestions or advice greatly appreciated!

After bleeding the system, does it hold the water with an open radiator cap in the front or does it drip out somewhere or flow into the expansion bottle?

Second post from Raggy in this thread contains a lot of useful info

https://hijet.forumotion.com/t3207-gurgling-noise