1989 - 2.1 petrol panel van - Overheating without heating!

[Moss-Turpin-T25]

Thanks for all your help T25convert!

I'll update with progress!

[hightop ratty]

Maybe committing to the Brickwerks one is best then in the long run!

Would it be worth testing the current radiator to ensure that's the issue before replacing completely or do all signs lead to that almost certainly being the problem?

Cheers!

Brickwerks - absolutely
Great service & knowledge - they specialise in T25's & only supply the best - buy right = buy once

[Moss-Turpin-T25]

Small update is that the previous owner has now let me know that the old thermostat was removed as it had rusted solid.

New thermostat will be going in this weekend and if that solves nothing then the radiator next weekend. Is it necessary to do a full bleed when replacing the thermostat? I haven't managed to find a comprehensive set of directions for replacing this... if anyone knows of one that would be a great help.

Thanks!

[937carrera]

Here you go

http://www.brick-yard.co.uk/forum/bleed ... 29710.html

[Moss-Turpin-T25]

Ahh I meant for changing thermostat. Thanks though!

[Syncronorth]

Just remove the four screws № 17 in the illustration then you are there!

[Moss-Turpin-T25]

Thanks snyncronorth!

[T25Convert]

You don't need to when changing thermostat, but I would bleed it anyway - you'll need to get good at this if you are going through the cooling system! Plus air locks might still be at least partly behind the issues you are having.

Two methods - Brickwerks link above shows a good method by a professional who works on these vans.

I found that the popular method from the Americans worked well for me - the so called 'libby bong' method. Bit more Heath Robinson, but for me effective. Get length of white plastic waste pipe, wrap a couple of turns of gaffa tape round the end so its a snug fit in the header tank filler hole. Fill pipe with water and open radiator bleed valve - bubbly water and air comes out, leave it, occasionally topping up your white plastic pipe until no more air is coming out the bleed valve. Shut valve. Remove pipe. Run up to hot, then crack radiator bleed valve to let any last tiny bits of air out. Done.

More details here https://www.thesamba.com/vw/forum/viewt ... e28264e61b

[Moss-Turpin-T25]

Thanks for the reply! Is there an easy ay to drain/flush the whole cooling system so I can replace with all new coolant whilst I'm there? Thanks!

[Moss-Turpin-T25]

Thermostat has just been changed and we have drained as much from the cooling system as possible replaced liquids until header tank is full. Although I'm sure there cannot be 16 litres of coolant and water through. Any idea how to get more in? When we run the engine to temperature the heaters will now not turn on or blow any air. Hot or cold.

The engine still overheats but I don't think we've managed to fully bleed. It seems as thouhh liquid isn't circulating fully. The fans also aren't turning on as the engine heats up.

Any help greatly appreciated!

[T25Convert]

Right, heater not running hot is airlock - you need to keep bleeding the system with the heater set to hot. Getting the air out will also let more water in. You probably haven't got all the water out, so don't worry too much about not getting 'enough' water in.

If the fan is not coming on there a couple of potential causes:

1) Hot water not reaching radiator (the fan switch is in the rad)

2) Fan or switch knackered.

Some hose groping at the radiator will tell you if hot water is getting to the radiator - both feed and return should be toasty hot.

You can test the fan by bridging the switch (located on the right hand side of the radiator) - fan should spring to life.

However, putting together sluggish circulation and lack of radiator fan, plus overheating when heater switched off I would suggest that your radiator or one of your front to back pipes is blocked.

[Moss-Turpin-T25]

After going for a drive and getting everything circulating the heater began to work. We drove for an hour with heater turned off and there was so sign of overheating throughout the journey, motoroways and town driving. This was impossible prior to the changes, so already a huge improvement.

However at the end of the journey as I was pulling up I got stuck at a traffic light and here is when the temp gauge rose and began to flash although I had stopped throughout the journey with no issue. What I have noticed is that the fan isn't kicking in. Previously it would only start up once the engine was turned off. However now even after that journey it didn't turn on. Could this be due to not bleeding properly and air still being within the system? Or more likely to be the switch or resistor (read this bit online)? The radiator was heating up once running, I presume this means the water is circulating?

I shall bridge the switch and see if the fan is still working however like I said it was working yesterday. Could I have knocked anything when putting the grilles back on?

Thanks!

[jas915]

Think its unlikely you knocked anything todo with the fab switch because I sure its either on the side or at the back face of the rad.i would test the fan and check to connection to it and the switch. I would also not expect the fan to come on with just a brief traffic light stop. Have you checked the pump as I have heard that the impellers can rust and fall to bits this making the less effective at moving water.

[Moss-Turpin-T25]

Think its unlikely you knocked anything todo with the fab switch because I sure its either on the side or at the back face of the rad.i would test the fan and check to connection to it and the switch. I would also not expect the fan to come on with just a brief traffic light stop. Have you checked the pump as I have heard that the impellers can rust and fall to bits this making the less effective at moving water.

Hi Jas,

It's more that it didn't come on at all after a one hour journey and when the gauge showed it was beginning to overheat.

Pump looks okay to me.

cheers

[937carrera]

Check the levels in the header tank and top up tank, if air has circulated it will be in the header tank.

Top up the water into the top up tank (behind the flap) and see what happens when it has cooled down. You may then need to directly add water to the header tank.