[5speed]

OK now heres an odd one, an overheating problem. The radiator fan has stopped comming in, I have replaced the sender and if you bridge the terminals the fan comes in but it doesnt when running normally. The car runs normally apart from that. Its an 83 99GL [H engine]. Is there a relay on this because the workshop manual says there is but I really cant find it.

Ill just have to drive round with the windows open for a bit

Alex

 

[Tomarse]

I think that there is a relay for the fan on my 99 in the fuse box.

However - If when you manually bridge the terminals on the sender the fan is working, then it means that the relay is working, and your fault is definately the sender.

I had trouble with mine not kicking in until i replaced the radiator, and then it started working! - which was wierd as it was using the same sender! . I wondered if perhaps the radiator was blocked up round the sender or something before, or it was too dirty and swapping it across fixed it? The same happened on my 900.

If you want to fit a switch for your radiator fan to operate it from the cab, there is a single spare teminal in the wiring loom, just down at the front drivers side - near where the proper fan connector exits the loom.
If you earth this connector then your fan will turn on. This is very handy for just running a single wire up to the extra switch on your dash.

 

[Bawheid]

I had a similar problem in the 900, it was the thermostatic switch on the radiator that was causing the problem. It trips the fan when the radiator gets to a certain temperature think mine is 87deg C. Simple job to replace and i think the one from the 99 is the same as the 900 still redily available.

Do a search in the 900 workshop forum theres plenty of stuff in there about it

 

[5speed]

had a dig about inside but its a fairly new radiator put on by the last owner. I put on a new sender first as I thought that was the prob too so it should work... but doesnt. The new sender I put on says 200 on it, is there any way of knowing if thats the right one as I cant see any more marks [though the book in the shop said it was right and it fits] as I seem to have mislayed the old one.

Like the cabin switch idea though, think ill get meself some o that. Still cant find a relay for it either and the wires are very thick but surely it wouldnt put all the current through the switch? although there is a botch lock downt there on a random bit of wire that appears to have no purpose so maybe its been farmered in the past.

Will continue to hunt.

 

[Tomarse]

I'll have a look at my sender tommorrow if i remember and see if it has any numbers on. I can't look now as the car is elsewhere!
Mine definately works though and comes in at about half way up the gauge.

 

[nutcase]

I've skim read the thread and two things come to mind - bad sensor or clogged radiator. When you think the fan should be on, what does the area that the sensor is in feel like? If it's not particularly warm then I'd strongly suspect a blockage.

 

[heavy_t]

You could always hook up the fan to be permanently on as a temporary measure. My mate's old '82 model had this "modification"!

My '73 had a manual fan switch as well, so I think this is a *fairly* common issue. Mine actually works at the moment but I'm going to rig up one of my spare cabin switches to operate the fan anyway, in anticipation of it going wrong....

 

[Tomarse]

I dont think i'd want it on permenantly as they pull a lot of current.

In my 900 i can feel when the radiator fan comes on!

A switch is fairly sensible though, they always stop working on hot days when you are stuck in traffic!

 

[heavy_t]

Definitely. I only meant that as an emergency measure!


I think having a manual fan override switch is the way to go. I had it on my 73 and I loved it. Once you learn to watch the guage it just becones second nature to use it. When I left the car with a mechanic I used to worry about it though ;oops:

 

[5speed]

Well ive farmed a switch in and its all hunky dory for now. Ive come to the conclusion that the brand spanking new switch is either a dud or just works at the wrong temerature. Either way Ill get a new one asap. The switch does work well though and eliminates the fears of-will it come on its looking a bit hot.

So I fixed that up and yesterday the master cylinder went. Never rains but it pours, calipers sticking too so I think thats my three bits of bad luck and nothing else should ever go wrong.....

Cheers for the advice.

 

[sireid]

:lol: cant believe the coincidence................

thought id have a look on here as my 83 99 is overheating and the fan isnt working and what post is right at the top...

only problem is i am not up on the tech speak so if you dont mind what is a sender unit ??

also my car has over heated when i got stuck in traffic and there seemed to be a lot of brown gunk that blew out of the valve at the filler cap along with the coolant etc is this a symptom of the radiator being blocked ??

thanks in advance.............

 

[Tomarse]

the 'sender unit' is the little plug type thing with 2 spade contacts on that is screwed into the end of your radiator on the passenger side near the top.

It is just a temperature switch. It should close at a certain temp and turn the rad fan on.

Old cars often have cooling systems that are full of gunk! If yours is getting hot it could well be a blocked up radiator.
If i were you i would pull some of the hoses off and try to flush the whole thing out (do both the engine and radiator and in multiple different directions) with a hosepipe! Its impressive how many lumpy bits wil come out if you do this!

Refil it wisth clean water and fresh coolant and see if it still gets hot. If it does that start thinking about a new radiator! (about £80 or so)

 

[sireid]

cheers tomarse,

how can i rule out if the fan is working or not though, should this not be the first thing to do ??

i'll have a look at flushing the radiator as well though.

cheers

simon

 

[Bawheid]

Was thinking about flushing my rad at the weekend, have been driving the 99 recently and have noticed the heat creeping up. Anyone recommend some antifreeze? I use the comma xtreme green stuff in the 900 would this be ok for the 99?


Slighly off topic siried you wouldnt happen to own a beige coloured 99 would you? Was driving down to irvine one day and saw one.

 

[nutcase]

I use the comma xstream green too

 

[Rob Hill]

cheers tomarse,

how can i rule out if the fan is working or not though, should this not be the first thing to do ??

Go for a drive around to get everything up to normal tmperature, then park up and leave the engine to idle for a while.

Lift the bonnet so you can see the fan, it won't turn until the water temperature gets to a certain level, then it starts up for a few minutes until it is sufficiently cooled, when it goes off again.

On most 99s the fan kicks in with the temp gauge needle about halfway between the middle "normal" mark and the bottom of the red section. If the fan hasn't started up by the time the gauge is heading close to the red section then you have a problem with the fan or the sender - switch off and let everything cool down for a while (or go for a drive around, the air flow through the car will soon see the needle go down again as long as your radiator is in reasonable shape).

Don't leave it unattended whilst doing the above as serious overheating can damage the engine - it is easy to get distracted!

Rob

 

[sireid]

Thanks Rob

The fan isnt working my question was mopre how can i eliminate the fan as opposed to the temp sensor in the radiator not working ?? But i ithink i have a solution as i have an old fan that i will conect up and see if it comes on once up to temp.

Bawhied, nope mine is blue havent seen the biege one around.... yet.

cheers

simon

 

[Naranto]

Not sure if this has been suggested but could it simply be a stuck thermostat?

Asbestos underwear to the ready - preparing to be shot down in flames