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rad fans are not cutting on, where to start?


Callaway

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Hey guys,

I noticed today while letting the car idle in my driveway that the temp gauge had climbed up to 100 degrees and the fans had not kicked in! I quickly engaged the A/C and they came on and cooled her back down.

I did manage to get all of the relays in the bulkhead box wet last week while flushing the chargecooler, however I dried all of it out with a fan, and dried the relays by hand. I am not getting a check engine light or any other tell tales. I am going to start with the fuses but wanted to get some opinions. Thanks!

-Callaway

1994 Esprit S4

Edited by Callaway
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According to the service notes, the fans are energised by the ECM at c 90 degrees temp' as sensed by the coolant temp' switch in the inlet manifold water jacket.

It also states that the fans will not operate if the battery voltage is sensed as being to low. For fault diagnosis of the control circuits see sections EMG.4 or EMH.4 of the service notes. I do not have these sections in my notes as far as I can see with a quick look but if you don't have them, I'm sure someone here can provide a copy.

"If everything seems under control, you're just not going fast enough."

- Mario Andretti

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on mine there is a thermostat switch on the right hand side of the bay on the alloy pipe near the alternator. Mine started sticking a bit and a slight tap got it working ok. Might be it needs swapping or has jammed closed.

Cheers

Alan Croft

2000 V8 GT

87 Turbo Esprit HC

2000 Elise Sport 160

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Guest JimmyTheSaint
Hey guys,

I noticed today while letting the car idle in my driveway that the temp gauge had climbed up to 100 degrees and the fans had not kicked in! I quickly engaged the A/C and they came on and cooled her back down.

I did manage to get all of the relays in the bulkhead box wet last week while flushing the chargecooler, however I dried all of it out with a fan, and dried the relays by hand. I am not getting a check engine light or any other tell tales. I am going to start with the fuses but wanted to get some opinions. Thanks!

-Callaway

1994 Esprit S4

<{POST_SNAPBACK}>

I had the same problem once and it turned out to be the fan relay. The horn relay and the fan relay are the same one - so blow your horn, if it works, swap that relay out for the fan relay and see what happens.

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Hey guys,

I noticed today while letting the car idle in my driveway that the temp gauge had climbed up to 100 degrees and the fans had not kicked in! I quickly engaged the A/C and they came on and cooled her back down.

I did manage to get all of the relays in the bulkhead box wet last week while flushing the chargecooler, however I dried all of it out with a fan, and dried the relays by hand. I am not getting a check engine light or any other tell tales. I am going to start with the fuses but wanted to get some opinions. Thanks!

-Callaway

1994 Esprit S4

The temperature sender for the dash is different than the one to the ECU... Which would be the one that triggers the fans. You may have a defective temp sender under the intake manifold. Check it with freescan (watertemp) and see if it agrees with the dash temp gauge. If not replace the sender or check the wires to the sender.

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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  • 1 year later...
  • Gold FFM

sorry for digging up an old thread - this is exactly what is happening to me.

for the first time - I turned off my A/C - and the car started to overheat.

digging into it - the fans do not turn on based on temp - only when the A/C is on.

I FreeScan shows the coolant temp within a few degrees of the gauge.

I check fuse #13 and relay D - both are good.

Any ideas?

Lou Senko

Austin, TX

more, more, more....

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  • Gold FFM

more info:

- after reading more old posts - seems some people saw the fans kick in at 100+ and then turn off when it dropped to 90.

- I have not let my car get to 100 yet, it starts to expell coolant from the overflow above 90

- I do not see anything in the expansion tank - even when it's cold and I fill the header tank full

So I am wondering - if I let the car get to 100 will the fans kick in and everything is actually working normally - but there is something 'blocked' with the expansion tank - so the fluid gets dumped instead of overflowing into the tank...

is there normally fluid in your expansion tank? What temperature does your fans kick in?

Lou Senko

Austin, TX

more, more, more....

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Hi

I had the same problem a couple of years ago, It was a faulty quad driver in the ECM. Get a fresh one and transfer memcal. There a couple of alternate part numbers see dr Hess or esprit factfile websites. My fresh ecm cost $6.

Regards

Simon

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  • Gold FFM

so...

I found my issue - once the car warms up - and the thermostat opens - coolant begins to pour from somewhere behind the oil filter. so the car dumps it's coolant long before it gets normally up to 'hot' and the fans kick in.

I see a frost plug and the chargecooler pump - no obvious leaks from the limited view point I can get to. I'll pull the filter off tomorrow and see if I can't find the issue....

anyone had a coolant leak spring from something back there?

Edited by Quikr

Lou Senko

Austin, TX

more, more, more....

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so...

I found my issue - once the car warms up - and the thermostat opens - coolant begins to pour from somewhere behind the oil filter. so the car dumps it's coolant long before it gets normally up to 'hot' and the fans kick in.

I see a frost plug and the chargecooler pump - no obvious leaks from the limited view point I can get to. I'll pull the filter off tomorrow and see if I can't find the issue....

anyone had a coolant leak spring from something back there?

There is a short horizontal hose that goes from the water pump to the intake manifold, just above the chargecooler pump. I'll wager that's your leak...

Visit Sanj's Lotus Esprit Turbo SE pages

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  • Gold FFM
There is a short horizontal hose that goes from the water pump to the intake manifold, just above the chargecooler pump. I'll wager that's your leak...

THanks!

So do I have to take off the intake to get to it? (any tips on that?)

Is it just a standard piece of hose? (vs a Lotus special thing?)

you thinking it's this (circled in red)

Edited by Quikr

Lou Senko

Austin, TX

more, more, more....

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  • Gold FFM

Well - that was fun!!!

but - all is well now - thank you all for your help!

Turns out that the fans do kick in at the proper temp - just have to have coolant in the car.... :respect:

Those of you that have not done this yet...

- the first pic is the hose in the car - leaning over the engine looking down between the firewall and the front of the head. You can easily get to the end at the back of the water pump, but the other end is tucked up about 4" under the intake manifold - so getting to that clamp is a little tricky.

- the second pic is the removed hose with the hole

Edited by Quikr

Lou Senko

Austin, TX

more, more, more....

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I had that hose just plain explode last year... it sounded like a .22 being shot off behind my ear (roof was off)... Car started to overheat right away. As luck would have it, I was in the drive, so I shut the car off. Replaced the pipe in a hour or so... your right... "Thatwas fun"...

Drive topless!!!

Cameron

"If you feel that you are in total control of the car, well, your just not driving fast enough". Jimmy Clark

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