Expansion tank leaking + sender U/S

Hi All,

1994 DX 3L engine

Other half had an overheat while away in Daisy a few weeks back. Got trailered home, and she's been up to the mender's (Daisy, not the other half).

They say the head's fine, and the only reason they could see for losing coolant was that the incorrect pressure cap had been fitted - they found the correct original one in the bottom of the engine bay when they had the covers off looking for leaks, so I'm guessing someone dropped it, couldn't be bothered retrieving it and fitted another one they had laying around.

So - since we got it back, drove about 30 miles and the expansion tank was nearly empty. I re-filled it yesterday, as it may just have been an air bubble trapped in the system.

Checking it this morning, level had gone down about 5mm. Feeling underneath the expansion tank, there was evidence of either a leak, or it had been blowing coolant out of the overflow pipe.

So, questions:

What can leak on the expansion tank? Is it a one piece moulding, and how difficult is it to get it out for a quick shufty? Also, it seems that the low coolant sender is not working - the light on the dash is fine, but at no point did it come on while we were losing coolant. Same question really - is this difficult to replace? On TOYODIY, I can only find TANK ASSY, RADIATOR RESERVE - does this mean the tank and sender come as one unit?

Any advice gratefully received before I bite the bullet and try getting it out.

Cheers,

Rob

The level tends to settle between high and low....it will spit out the overflow above the middle mark....mine never settles at the full mark
I'd fill at the pressure cap...Squeeze the top hose to milk the air out while doing this. Make sure your front and rear heater valves are left open and just run it.
The 2.8 is cast iron block and head so should be OK..(empahasis on 'should' be though...other options are it may be sucking air in on cool down/vacuum cycle through a joint somewhere...or fine leak under pressure.....
Its a suck it and see situation....
The exp tank looks awkward to remove....you may check the plug at the bottom...see if it lights when you manually connect the wires...

Thanks Chris - I"m just going to keep an eye on the coolant levels then, and see if it settles.

I'll see if I can get to the bottom of the expansion tank and find the plug on the sender, but it's pretty tight for my size hands - may have to train a child.

Cheers,

Rob

The exp tank sensor is a float affair I think......cleaning out the tank a few times may help.
From below the exp tank is a couple of inches of wire.....then a connector. You could pull the connector and try to get the light going from there to see if its the bulb etc. or not. Easiest way to pull it is probably on your back from below.
Also be aware that the top hose does hold a bit of air as its the highest point...most of this can be massaged out. Check the seal of the pressure cap to thermostat housing.....then check the tube from the thermo housing to exp tank ....ensure its sound/well sealed and not sucking in air on cool down....then the pipe that is fitted under the exp tank cap that sucks back the coolant (I cut a small V on the end to rule out the slim possibility of it leeching on to anything on cooldown.

Looking at the pipe between the thermostat housing and the expansion tank, it looks like someone has tried to repair it with vulcanising solution, either that or it's had some brake or power steering fluid spilt on it.

Either way, I don't like the look of it, so I'm going to replace it and then keep an eye on the expansion tank and engine coolant levels. It's not using a lot, if any at all, so I'm guessing it's going to be a waiting game.

Low coolant sender is going to have to wait for a day when I've got time to get under the van.

Cheers,

Rob