Major Coolent Failure

[ChrisJ]

It is quite a common modification for our cars - gives you piece of mind that the fans have come on.

I haven't done this for mine, as I'm confident that Gerald (GST) is on top of things. There is only one time on 35 years of ownership when I wish that I'd had an override switch, and that is when my fan fail light came on whilst in the queue for the Duxford Sping Car Show. I watched the temps rise, and went and parked up to let them drop. Drove home and picked up my Excel and returned to the show. The earth connection had dropped - went though the washer bottle motor 

I'm seeing Gerald tomorrow, when I pick up my Excel, I'll ask him about it.

[GreenGoddess]

1 hour ago, snowrx said:

You've already done it by shorting the Otter switch leads.  Add a switch in parallel with the Otter and you'll have manual control of your fans. 

Thank you. I’m a bit of a numpty when it comes to electrics. When you say “in parallel” do you mean like this? (see photo of my dodgy diagram). 

[top-plumber]

My understanding is that the wiring for the fans on the esprit is not sufficient to run for long periods of time. Hence the “ thermal trip “ otter switch is to protect the wiring. It normally on the left hand inner wing on the Turbo Esprit. The fan switch is thermostatic and reads the water temperature directly as it’s normally in a coolant pipe. If you run the fans for too long you will get a “ trip “ of the otter switch which will need resetting. Normally the tell tail on the dash let’s you know “ fan fail” 

if the fans jam for some reason same result. Otter switch protects the wiring. 
let the fan switch do it’s job. If it’s overheating and the fans are running it’s not the stat. 
sitting in traffic with the fans running full tilt will cause issues else where. 
even the AC only runs 2 fans at half speed because the gauge of the wiring is on the small side. 
check the rad isn’t blocked. Not the cores, the fins. Road debris/ leafs etc can create problems. 
the crummy Ford fans have a habit of crud building and slowing them down making the motors work harder consequently heating up the wiring and allowing the coolant temp to rise. 

Edited August 27, 2022 by top-plumber

[GreenGoddess]

Thank you top-plumber!!! That makes a lot of sense! I vaguely remember reading something about not running the fans at max power for any length of time. 
 

My radiator looks brand new and there is no dirt or debris to be seen anywhere. 
 

I am completely new to the Esprit. Does the AC run the same fans (albeit at a slower speed)? If so, am I correct in thinking that I could theoretically use the AC on/off switch as a hillbilly way of cooling the engine if required?

[snowrx]

Your diagram looks fine. you are just closing the circuit as if the coolant had exceeded the Fan On temperature.

I have been interchanging "Otter" with "Fan" switch as the fan switch is commonly referred to as the "Otter".  I can't comment on the other Otter switch as my later car only has diodes feeding the fan fail switch.

[top-plumber]

2 hours ago, GreenGoddess said:

Thank you top-plumber!!! That makes a lot of sense! I vaguely remember reading something about not running the fans at max power for any length of time. 
 

My radiator looks brand new and there is no dirt or debris to be seen anywhere. 
 

I am completely new to the Esprit. Does the AC run the same fans (albeit at a slower speed)? If so, am I correct in thinking that I could theoretically use the AC on/off switch as a hillbilly way of cooling the engine if required?

I suppose in theory that would work. 
the most effective way if you get really worried is like @ChrisJsaid. Run the heater in the cockpit. 

56 minutes ago, snowrx said:

Your diagram looks fine. you are just closing the circuit as if the coolant had exceeded the Fan On temperature.

I have been interchanging "Otter" with "Fan" switch as the fan switch is commonly referred to as the "Otter".  I can't comment on the other Otter switch as my later car only has diodes feeding the fan fail switch.

You are correct of course the Fan switch is commonly know as “ otter” 

i differentiate because mine is a TE and has the otter switch under the bonnet. 

[top-plumber]

3 x 11” pull fans on modified frame with 3rows of copper cores on original end tanks. Lower power consumption, quiet and light with a slightly higher water content that still fits in the frame without mods.