Mx5 getting hot

shirtz · Postby **shirtz** » Tue Oct 31, 2017 10:58 am

manga - where do you get those fancy rad fillers?

does it have a screen filter at the bottom? I tend to get crud in mine when I empty the rad.

but yeah agree with everyone. burp properly (squeeze the bottm rad pipe a lot) and put the undertray on

redchicken · Postby **redchicken** » Tue Oct 31, 2017 5:41 pm

Hi everyone
So took the car back today we’re i got the radiator installed. They think there are two problems one is the radiator fans don’t mount flush with the radiator as the radiator doesn’t allow this and two my number plate sits right in front of the radiator reducing air flow. I took the front number plate off and went for run and the temperature needle didn’t move mind you the weather was much cooler today. I have ordered a new front number plate bracket so the plate sits in front of the bumber thus not restricting air flow to the radiator.

project.r.racing · Postby **project.r.racing** » Tue Oct 31, 2017 5:51 pm

But wasn't the number plate installed in the same place before new rad?

And rad fans do nothing when moving. Especially at 120kph in 4th gear.

So both their possibilities don't make sense.

redchicken · Postby **redchicken** » Tue Oct 31, 2017 6:49 pm

Thanks for the reply mate what would you suggest could be causing it ?

1600Dave · Postby **1600Dave** » Tue Oct 31, 2017 7:19 pm

davekmoore wrote:Properly burped?

This.

ManiacLachy · Postby **ManiacLachy** » Tue Oct 31, 2017 7:26 pm

Also, you haven't answered if you have an undertray in place, this is important. The undertray is a plastic tray that mounts directly under the engine and ensures air doesn't duck out under the radiator.

If you can look in your engine bay and see the ground in front of the motor, you don't have one, and you need to get one ASAP.

Magpie · Postby **Magpie** » Tue Oct 31, 2017 7:34 pm

project.r.racing wrote:And rad fans do nothing when moving. Especially at 120kph in 4th gear.

ManiacLachy wrote:If you can look in your engine bay and see the ground in front of the motor, you don't have one.

redchicken · Postby **redchicken** » Tue Oct 31, 2017 7:43 pm

Yep undertry in place

redchicken · Postby **redchicken** » Tue Oct 31, 2017 7:49 pm

I questioned the mechanic if there was any air in the system and he replied the car would be getting hot straight away not just under load.

Mr Morlock · Postby **Mr Morlock** » Tue Oct 31, 2017 8:35 pm

The best approach is a logical one- like a formal problem solving exercise like an 8D or similiar. All possible causes need to be listed.
Look at what the situation was before making the change- i.e. was the car overheating - and what has been changed since.
I dont think anyone can tell you what the problem is but only identify what items can cause overheating.
The temp gauge should normally sit in the middle position. If the car boils its pretty obvious but the MX-5 does get very hot under the bonnet- it does not mean its a big problem. By all means change the number plate position but my guess is thats its not a root cause.
Look at PRR's comments.
PS I see the under tray was in place - i.e. what has changed- on that point nothing - rule it out.

Roadrunner · Postby **Roadrunner** » Thu Nov 02, 2017 9:53 pm

Have you tried simply letting the car idle from cold up to operating temp.
Once it gets to “thermostat temp” the fans should kick in, coolant flows through the now open thermostat and temps drop.
Best viewed with an OBD scanner for numerical temps not just based on the needle moving.
If the fans kick in but the temp just keeps rising, your thermostat is rooted not allowing coolant to flow.

Though I’d have thought that would have been obvious when the mechanic burbed the system.

Process of elimination - start with the easy things first.