ro*ta

Hi there,

Iv recently bought my Mazda Rx7 1993!
Have to say it looks awsome!
I was wondering if any of you could help me out here,
Once you turn the car on and let it worm up the fans dont come on.?
Then when you turn it off and put the ignition on the fans come on.
Can anyone help me out by telling me what the problem could be?
I really just want to jump in and drive it but don't want to cook the engine!

Thanks in advance,
Baz.

Sgtblue

iTrader: (16)

How long do you let it warm up? Do you have an after-market temperature gauge? Side-note...the stock gauge is worthless and should NOT be relied on.
There MAY be nothing wrong. There is a 'thermoswitch' for the fans. It senses the engine's coolant temperature, and activates the fans at a pre-set temperature. I believe on your car, at about 108 C. While your car may feel 'warmed-up', the temperature of the coolant may not yet have reached that 108 C. threshold...until you shut the engine off. With the engine off, the waterpump is no longer circulating coolant and the coolant heat-soaks. That actually causes it's temperature to rise, even though the engine is now shut off. And that rise in temperature is enough to activate the thermoswitch... and the fans come on if you switch the ignition switch on.

ro*ta

Hi mate,
I'v let it worm up for about 15 mins,
It has the standard temperature gauge,
Which only goes up to half way but the fan never kicks in.
Are you saying I need a thermoswitch then?
Thanks for your help!

Sgtblue

iTrader: (16)

No I'm saying you may not have let the engine run long enough, to get hot enough to activate the fans. And again do not rely on that factory temperature gauge. It is not linear. That means it will go to almost halfway as soon as the engine is even a little warm. But it does not mean it is at full operating temperature. What is even worse is that it will remain there until the engine is just slightly below overheating. And that typically means you will not have enough warning.

ro*ta

Ok I understand now lol,
Do how long do you think I should leave it on to pet the fans kick in?

misterstyx69

iTrader: (142)

OP: Please NOTE:
https://www.rx7club.com/new-member-r...ction-1049592/

This Forum is a self help based forum and the answers are given voluntarily.
If you need help ASAP then it is up to you to do research,not bury other people's threads by Bumping yours to the top.
That is Why we ask that you do not BUMP any threads especially in this section.
The 3rd gen section has plenty of info on the inferior fan setup and can be researched with a cup of coffee and Patience.I'd buy you one personally but the price of a plane ticket to meet you is outrageous!
So I kindly warn you that any further bumping of this thread will lead to a deletion of it as it is an inconvenience to others.
Thanks for your understanding.
STYX (MOD)

Sgtblue

iTrader: (16)

There is no 'pat' answer. Depends. What is your coolant to water ratio? State of tune? Ambient temperature? Idle speed? And do you have a stock thermostat? IIRC, they open at about 75 or 80 C. You can usually feel when the t-stat opens by touch...the radiator inlet hose gets hot.
But again, unless the Euro-versions are different than our S6 versions, the stock fan thermoswitch has a threshold of 108 C. It may take a while to get there at idle but I'm not going to give you a time. If you're concerned, install the aftermarket temperature gauge you need anyway...and then monitor it.

ro*ta

Sorry for the BUMP!
Thanks I will go and buy an aftermarket temp gauge and see what it reads!
I'll report back as soon as Iv done that, if that's ok to do??

misterstyx69

iTrader: (142)

I'd be looking into how others get the fans to kick on with aftermarket parts.
If you have an aftermarket ECU you can get the Ecu to operate the fans with one of the outputs.

ro*ta

I don't think its got an aftermarket ecu.
It's completely standard apart from a exhaust system.

ro*ta

Right so I went out for my first ride in the Rx7 today and after a while the fans decided to kick in which was great!
But when I got home I found out that my car has got a slight leak from the air seperation tank!
So Iv orded one which should be here next week hopefully!
Once that's fitted it should be 100% spot on!
Thanks for you help guys!

Sgtblue

iTrader: (16)

AST failure is typical. In fact sometimes they fail catastrophically and cause the engine to overheat...so it's good you caught it. Most owners choose to replace them with aftermarket all-metal versions. But since you've got OEM on the way you should be good for while. Know that the stock radiator also has end tanks that are made of the same plastic as that AST. And they tend to fail with age and heat in the same manner. The permanent fix is also similar...all metal (aluminum) radiators.
Still, don't delay getting a good aftermarket temperature gauge installed. Really. That stock gauge is worse than worthless.

ro*ta

Cool thanks for that!
Yea the gauge is also on its way!