Club 80-90 Forums

so I've replaced the expansion tank, thermostat, radiator temperature sensor and the thermostat temperature sensor...

Its like a new van The stat opens/closes when it should and the coolant now goes through the radiator - the rad actually warms up, amazing! The new expansion tank holds pressure so now at last I can bleed it the system!

...or so I thought Yes, the system doesn't boil over anymore. And yes, I get air then lovely hot water coming out of the radiator bleed.... BUT... my brand new radiator temperature sensor switch NEVER switches the fan on, even when the temperature gauge is at max.

The fan does work BTW. I bridged the connectors to check it and left it running to see if it would cool the (running) engine... and no... it still overheated. Could it be that not enough coolant is flowing thru the rad for it to have an effect ???

This brings me to my main question - to help diagnose the problem I am wondering about the HEATER - for the windscreen / dash vents - I don't think mine works! Is it meant to have an electric fan? If so mine is bust. There is a rotary knob next to the sliders on the dash with a picture of a fan and 1/2/3 on it, which does nothing.

As the next course of action, should I get the heater working... to see if when the engine is hot the heater blows blows hot or cold? Hopefully this will shed some light about what is going on in there ???

Anyone know of anything else to check?

And yes maybe it is the head shims... I just want to rule out the things I can fix myself first!!!

Does the outlet pipe from the radiator (one that comes off the bottom of the rad) get hot with the temperature gauge on about 1/2 way? Another thing to check is the radiator temp switch. You can make up a pair of test leads to connect it to a multimeter then dip it in a pan of boiling water and see if the resistance goes to 0. Is it a single or double speed switch?

Dave

ambivert,
All you NEVER wanted to know about the heater fan motor is in this brilliant post by 'bilbo blue.' to whom many thanks.

http://archive.club8090.co.uk/viewtopic ... ht=#111489

The heater fan fuse for models up to 1985 is listed as number 10 (16 amp) and also does the wipers/washers.

Got a feeling that the heater control valve may be down in the spare wheel area, not sure never had any problems with it, (aint I the lucky one?)

Like irish.david says is the return hose from the bottom of the radiator back to the water pump warming up as the flow is established right around the system? Perhaps your new thermo switch for the radiator fan is not getting hot water past it. (I am just about past it by the way so make allowances for the aged among us )

P.S. Have you done a Mocki bleed look...HERE Hope I don't upset Laurie, who has a different approach to bleeding.

Mike

the heater will still blow hot air when moving wether the fan works or not..... first step to diagnosing the heater fan is the switch, assuming you have working wipers.........

as for the over heating, and the rad fan, as siad above check the switch in the rad, its the only thing that will be wrong if when you bridged it out the fan worked, just coz its new dont mean its good..........

as far as bleeding goes, are you REALLY getting all the air out, are the pipes to the heater getting hot?

[img:430:304]http://www.club80-90.co.uk/techhelp/radpipes.jpg[/img]
[img:680:480]http://www.club80-90.co.uk/techhelp/heaterbox.jpg[/img]

[img:551:578]http://www.club80-90.co.uk/techhelp/radpipes2.jpg[/img]

If you pull the heater switch out, you should be able to bridge it and get the fan running. If the heater is working, then I reckon the head seals are OK.

People get really paranoid about bellding the system but it should take about 5 minutes max.

When hot, can you feel the same heat across the whole of the rad?

irish.david wrote:Does the outlet pipe from the radiator (one that comes off the bottom of the rad) get hot with the temperature gauge on about 1/2 way?

Doesn't really feel warm until the gauge is at maximum. Then the whole rad gets hot, but only one of the pipes does. Haven't removed the spare wheel yet so I can't see if the pipe goes to the top or bottom of the rad. I can feel both pipes where they run next to each other just before they head into the rad (one is above the other) its the top pipe which is hot.

irish.david wrote:Another thing to check is the radiator temp switch. You can make up a pair of test leads to connect it to a multimeter then dip it in a pan of boiling water and see if the resistance goes to 0. Is it a single or double speed switch?Dave

Good idea! I will try this (single speed).

Grun wrote: http://archive.club8090.co.uk/viewtopic ... ht=#111489

thats really useful! Although not looking forward to removing the dash!!! Gonna have to book some time away from the missus to be able to do that (we have a 3 month old baby, my time is in short supply!)

Grun wrote: is the return hose from the bottom of the radiator back to the water pump warming up as the flow is established right around the system?

yeah this could be the problem... blocked rad or something... or maybe someone connected the pipes round the wrong way! I will have to get that spare off and have a proper look... Looks like thats the next job anyway if I am going to be playing with the heater...

Mocki wrote: check the switch in the rad, its the only thing that will be wrong if when you bridged it out the fan worked, just coz its new dont mean its good..........
as far as bleeding goes, are you REALLY getting all the air out, are the pipes to the heater getting hot?

I think I have all the air out, bled it again today and only ever water coming out the rad bleeder now. And now it takes an entire half hour of running before the red light comes on! Not like 10 minutes how it did before! YEE-HAW

And I don't know about the heater... Haven't found the pipes yet!!!

Laurie wrote:If you pull the heater switch out, you should be able to bridge it and get the fan running. If the heater is working, then I reckon the head seals are OK.

OK then that heater is next on my list! Hopefully I can do this without removing the dash?

Laurie wrote: When hot, can you feel the same heat across the whole of the rad?

Yeah, it seems to be the same all over (its not exactly HOT... not too hot to touch like the rad send where it leaves the engine). When the temp gauge is reading maximum (with red light on), the water that comes out of the bleed screw is only luke warm...

BTW note I am saying water not coolant as I don't want to be having to catch it all in order to reuse it. I am using water only until I know its all going to stay put... then I'll drain and put the G12 in... Unless you think this is wrong...? I am assuming that no corrosion will happen to the cylinder head bolts if it only has water for a couple of weeks???