Expansion tank question

[bradders89]

Should my van have a expansion tank as it only has the header tank. Its a 1988 one and was a 1.9dg (now a scooby ) There wasnt one fitted when i bought it so has it been removed for some strange reason and do i need to fit one??

[kevtherev]

did subarus have two tanks?

[DentedDevon]

I think the original vw set up with 2 tanks is purely for the users convenience.
You can check and top up the water level Via the numberplate hatch (same as the oil).
I am not convinced by comments about needing 2 tanks due to the volume of the system and the quantity of rubber pipe used etc .
I am using a Golf fishbowl headertank with my rover v8 and have no problems , so you should be ok with a similar setup on your subaru. I just have to remove the engine cover to check the level/top up. The water level sensor in it is connected and working as well.

I think if you just use the original T25 headertank you should not fill it full to allow space for expansion, which in turn could bring on the warning for low water.

[ghost123uk]

strictly IMHO, I think the low water level sensor built into the main header tank is something I would not want to live without. For this reason I would recommend the two tank system. It's not as if it is expensive or hard to fit plus, as mentioned above, you get the convenience of checking levels via the flap.

@ bradders89 - does your tank have the normal "Dalek" shaped cap fitted ?
If so, where does the thin vent pipe go ?

Note = if the cap is working correctly, when the system is fully up to max temp and pressure it should vent some coolant into the top up tank, then suck it back again as the system cools.

Also see topic on the low coolant sensor at = https://club8090.co.uk/forum/viewtopic.php?f=37&t=99463" onclick="window.open(this.href);return false;

[bradders89]

@ bradders89 - does your tank have the normal "Dalek" shaped cap fitted ?
If so, where does the thin vent pipe go ?

Yes it does have a "Dalek" cap. I bought the van with a dg engine and converted it to a scoobaru a few weeks ago myself. When i bought the van it never had the expansion tank just the header with a pipe from the "Delak" floating about going nowere. Was wondering if i sould fit a expansion tank.

[DentedDevon]

If you have room to fit the expansion tank in its original position then that is probably the best way to go.
Regardles of whether you go for a 1 or 2 tank set up, as ghost123 says , make sure you have a working coolant level sensor , it could save you engine .

[tinman]

Mines a subaru and I've retained the vw 2 tank system with no problems.

[AdrianC]

strictly IMHO, I think the low water level sensor built into the main header tank is something I would not want to live without. For this reason I would recommend the two tank system.

There's no reason why a single-tank system can't have a low-level sensor - I've had 'em on a couple of cars, but this is the first I've had with two header tanks.

[DentedDevon]

I think the problem is that if you use the original T25 header tank on its own it will have an air space for expansion, Whether you like it or not it will push out and loose a small amount of coolant when hot then suck in air to replace it as it cools.
As the tank should normally be full this could mean the probes are not in the water so the LED would flash.
JK quote the probes as being 68mm long which may allow enough space for expansion and keep the probes in the coolant ?
Tanks like my golf one are intended to have air space at the top and have probes of a length to suit this.