Questions...

Think i've done this diagram before but here you go, this should help you get your head round it....

So you have 2 wires going to the fan motor and two to the switch in the rad. If you take the wires off the switch and join them together (or use something metal to connect them if they're in a connector) with the ignition on, the fan should run. You won't have power at the fan motor until the switch passes on the current.

If that doesn't make the fan run, either the motor is dead or it's the wiring, but as you have power to the switch it seems the wiring should be OK. The switch and motor are wired in series (as HJ's diagram shows).

Ok, so if I just put the fan wires into the switch connector and turn the ignition on, I should have life, so I should be able to connect the fan wires to the switch wires and have it all working, provided the fan switch works. Is this right?

Little Black Van wrote:the wires going to the rad fan switch have power going to them when the ignition is on, but they disappear up behind the dashboard

Well when you say that, I'd assume that one of the wires has "power" as in a 12v live feed, while the other is a ground. E.g. you can put a fan or bulb across the two wires and they work.

What you need to put together is this:-

HighlyJetted wrote:I'd risk the cam belt personally - as long as it hasn't done about 80k miles or lived in a very warm climate they go on forever.

I've stripped down engines with 140k miles on the clock, 20 years old, and the original belt is still pretty ok'ish.

I think totally the opposite of you.
After an engine repair for a "good looking" cam belt ("funny" story, in year 2000 I have a Seat Ibiza 1.2i,I gone to the mechanic, a friday after work, he take a look on the belt, and said "it's OK, but is old, I suggest you to change it !", i say "ok", then I take appointment for tuesday, monday belt breaks off and I had eight bent valves.

Now I change cam belts every five years or 60'000km...I don't care if it seems new.

Breaking the belt cause big damage to the engine.
Valves bents, but even pistons, cams, rocker arms and cylinder head takes a big whack.

I see some engines with broken belt, about 50% of that had problem of oil consumption after the damage, because the piston rings seat can be deformed by the blow, then piston rings can't follow the cylinder properly, causing blow-by, then engine suffers of oil and fuel consumption, and it lasts less.

In pratical, I prefer spending one hour and 150€ to change a belt every 5 years or 60'000km rather spending 5-600€ of parts and about 20hours to take off and control an engine after a belt breaking.

Thanks HJ, that makes things a lot clearer. Thanks for taking the time to draw up a diagram and everything, you're great.

I worked around the fan in june, I add a manual switch to run the fan when I run in offroad or in hard slope street.

From what I'm remember, the system is a basical one.

The fuse is OK?

What kind of connection you have on the manual switch?
Any work different than a simple bypass of the original switch can be a problem.

Fan starts if you give it power with two free wires from a battery?

The fan is fine, and the wires going to the switch form a circuit and give me a reading on the multimeter. I've just run my engine until the pipes were hot and the rad was warm, and I couldn't get any continuity on the switch. Unless I wasn't waiting long enough, can I assume the switch is dead, or should I run it hotter? If it is dead, will the switch listed on ebay fit my van?

Rad needs to get hot before switch will operate, on mine it's at least 20 mins when idling from cold. Not sure why they put it at the bottom, as the top of the rad should always be the hottest (so the theory goes).

PFM wrote:Rad needs to get hot before switch will operate, on mine it's at least 20 mins when idling from cold. Not sure why they put it at the bottom, as the top of the rad should always be the hottest (so the theory goes).

On mine is about impossible to make the fan starting in this period running the engine at idle from cold.
It stops heating at about 80°.
Probabily my radiator is very clean.

The sensor will be placed at the exit of the radiator, to turn on the fan when the water returning to the engine is overheated.
Putting the sensor at the inlet makes the system unstable, because it sense the temperature coming from the engine.
In that case, it happen the fan start after just a little engine load, or a few minutes stop at idle.
Maybe the engine was only a little over the the right temperature, but the fan starts, and from the radiator enter to the engine a too cool fluid, then thermostat starts to close, fan stops, engine reach the right temperature, thermostat opens, sending hot water to the radiator and so on...

Ok, just left it for 20 mins, came back and found coolant boiling out of the header tank and an awful lot of steam, so promptly turned the engine off and tested the switch, and still nothing. If that didn't trigger it, I don't know what would.

Little Black Van wrote:Ok, just left it for 20 mins, came back and found coolant boiling out of the header tank and an awful lot of steam, so promptly turned the engine off and tested the switch, and still nothing. If that didn't trigger it, I don't know what would.

Change it...

At which point, does anyone know of one online for the 1.0? The only one on ebay appears to be for the 1.3.

Can't help you there. I bet it would kick in at about 95 degrees.

Take it off, hook your multimeter up to it and get it hot.... maybe water, maybe be very gentle with a blow lamp if its metal.

Both of mine kick in when the water temp gauge gets to about 2/3 up the scale, just past the half way mark.

Was your bottom hose hot when it was boiling over?

Anyway, the one on ebay says its a M16 thread with a 1.5 pitch. Measure yours and you'll probably find its the same part as daihatsu are pretty easy going like that. No point manufacturing something else when there's a standard part on the shelf already.

Apparently the diesel fan switch has a lower and longer kick in but you have to do a wiring mod but it was a fit for the rad.

Well, just held it in water with the multimeter on it, and it connected, so the switch is fine. I just needed two small spade connectors to provide a decent connection to the multimeter. So now I just need to hook it up, put the coolant back in and hope it works.

you may find the problem is somewhere else in the cooling system, when mine overheated the fan never kicked in

And now my choke is turning on and off, like someone's repeatedly touching the accelerator pedal...

I've already changed the thermostat, which was dead when I tested it, and is hopefully the only problem.

On the choke issue, when I rev it a bit, it works fine, it seems once the engine is warm enough, it's ok. Any ideas?

Little Black Van wrote:And now my choke is turning on and off, like someone's repeatedly touching the accelerator pedal...

I've already changed the thermostat, which was dead when I tested it, and is hopefully the only problem.

The auto chokes are controlled by water, when water of a certain temp passes through they close the fast idle valve, if there's no water in the valve assembly you get the hunting - as in reving up and down like on choke off choke on choke off choke.

I appear to have air in the system, judging by the fact that the radiator 'pulses' and I can hear bubbles passing through. So now for the fun of bleeding a hijet...

So, I have discovered the reason why the previous owner put the bodge in, the switch is fine, but still doesn't work probably because it is stuck in an air pocket. Judging by the fact that bleeding appears to be a pig of a job, I'm going to leave it on the bodge until I'm back from Spain, as the bodge has worked fine for over a year. Once I'm back, I will attempt to solve the problem properly.

Hmmm, bleeding isn't a pig if the cooling system is working fine, with no blockages ect, if you have time might be Worth flushing rad and blowing through the small pipes to allow air pockets to get moved out of the system better spending a Few mins now than breaking down while in Spain

Just take the head off it and have done with it.

Buy yourself a head gasket kit, a water pump, some coolant, belts, 2 rad caps etc. About £100 worth of parts.

By the time you've pissed about like both me and daisy you might as well do it properly. What do you say Daisy?

So if I bleed it, will it stop the hunting? If so, anything specific to the 993 I should know about?

Mine hunts when it's low on water, and I've never had any great problems bleeding either of my vans. Did you fill it slowly, through the rad, after you replaced the fan switch?

Yes, I did fill it slowly, is it possible for a little list of what you did to bleed yours? I assume you have the 993?

HighlyJetted wrote:Just take the head off it and have done with it.

Buy yourself a head gasket kit, a water pump, some coolant, belts, 2 rad caps etc. About £100 worth of parts.

By the time you've pissed about like both me and daisy you might as well do it properly. What do you say Daisy?

I do agree that first instinct is to say your hg needs doing, but I would say the rest of the system needs clearing out first, if had just left mine at a garage at the beginning they would no doubt have just done the hg and left me with a clogged cooling system which would have just caused the hg to go again, those little pipes are really important to keep clear (on mine the one going from the pipe where the fan switch is tothe expansion pipe, this alows air out preventing an air lock by the switch i believe and the one at the back of the engine)

Now I've been driving mine around a bit I would say on normal driving (up to 16 miles) there should be no water purged into exps tank, if there is you have a problem somewhere which will only get worse

I've taken my head off the red van today (and fitted my tyres and alloys to the other one and some other light pimping )

The head gasket is not as knackard as daisy's by a long way which is why mine never did the purging loads of water back and properly overheating, but it looks like its just started to blow past the compression ring on the two rear cylinders. It would drive fine, you could do a 30 mile journey, let it cool, go again the next day etc no problem. But when you take the cap off it there is air under there, and no amount of bleeding cured it, even being ultra (maybe overly) thorough. You could completely clear it of air perfectly, then let it tickover for an hour every day for a week and it would still be fine. But when you go and rag it around on the road that's when the head gasket would leak.

I agree with daisy, if you don't clear out all the scum from every pipe, and down the cylinder liners, before you know it you'll be going round in circles. Where if you do it right once, you'll have nice clean uncontaminated coolant which keeps the pump lubed up, keeps the thermostat clean, doesn't crud up the radiator and cools the engine properly.

Now I'm only speaking from a 1.3 engine point of view, but every coolant system works on the same basis.

My only extra comment to add to daisy is to say you should definitely carry out some kind of pressure test on the coolant system too. This will show you any small leaks you have from hose clips and other places which will cause coolant loss in the future - which after all may be the initial cause of the system failure.

On my red one, the head has not warped at all, I've checked it for straightness and its fine. What is bad on it is the valve adjustment, about 6 tappets have way too much play, were talking 1mm, while the rest are slack but not as bad. Taking the head off allows me to clean the piston crowns and combustion cups, rinse out the block, sort the valve adjustment, check the timing, change the oil, all all the other bits in between giving the whole engine a deep service probably doubling its life, giving it better performance and increasing fuel economy.

HJ rant over!!!

Oh yeah, forgot to mention doin the dry presure test to look for bubbles, I did that, nessecary job too

I must add that I'm really just passing on the great advice I got from these guys to help me fix mine along with any specific problems I found along the way!