mx5cartalk.com

Hey all,

So I own a turbo NB running a T28, PWC radiator and FMIC.

I decided to take the mx5 to uni today up in Randwick (car rarely sees crappy traffic) and on the way home I realised something a bit odd. I realised that my oil temperature was reading ~115-120C opposed to the usual 100C when fully warm. Thermostat reading on the cluster was also a quarter past 12.

Given I was crawling in the congested M5 tunnel at no more than 15kmh with the AC on during a quite warm day I was still pretty surprised.

Exiting the tunnel, temperature gradually returned to normal and when I got home I checked that both the fans were working as intended and fluids were intact.

Kinda scared me a little, I'm sure this isnt normal?

Not sure where you have your cooler but having the AC isn't helping the car when it's stationary/low speed.
There isn't enough air flow to remove the heat from the radiator/oil cooler/AC condenser with just your fans. Try some beefier fans or ducting or just turn off the AC

A.Chen89 wrote:or just turn off the AC

Yeah it was pretty much the first thing I did when I noticed. I gathered airflow may have been restrictive crawling in a tunnel and all but was just a bit surprised given the car wasn't in boost or being dríven hard.

Fans don't pull as much air through the radiator as driving at normal speeds does but usually they do work well enough in stop/start traffic. It's worth checking that there are no bugs or debris impeding that airflow enough to make the fans ineffective. Otherwise is it possible that your ignition is too retarded or your mixture too lean under those conditions?

Do you have the OEM undertray installed? Also have added an vents to the bonnet or raised it? Notwithstanding that oil temp would not be too concerning as oil will handle higher sustained temps than the coolant.

A quick solution, albeit an uncomfortable one is to turn your heater on full as this helps draw off some of the heat.

If you are running factory fans still I'm not surprised. They are ok for OEM radiators but you've added a heap of core thickness but upping the radiator and then putting a inter cooler in front of that.


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sailaholic wrote:If you are running factory fans still I'm not surprised. They are ok for OEM radiators but you've added a heap of core thickness but upping the radiator and then putting a inter cooler in front of that.


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True
I'd missed that. Thicker radiators can in fact impede cooling at lower speeds.

Mine will also have a thicker radiator and IC in front of it.

What fans do people recommend to improve airflow?

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I have no issues with a single eBay slim fan. I've never seen above 90deg water temps.
That's with a big mother eBay rad and coolant reroute.

Two eBay slim fans would probably be ideal.

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I'm still running the OEM shroud and undertray. I suppose giving the radiator and cooler a light pressure clean on the weekend to rid of flying bugs and what not wouldn't hurt too.

best answer is to run a cross flow radiator and either the evans coolant or redline water wetter or equivalent. Also a couple of oil coolers are not a bad idea

I drive down Victoria Road to work and the traffic there can get quite bad, and I seeing 110degC oil temp was not unusual. I have an OEM replacement radiator for the auto model which has a slightly thicker core but not as thick as an alloy radiator.

I recently had Mania install a Derale Typhoon fan and so far, have not seen oil temps pass 100degC. You might want to try that.

smy0003 wrote:I have no issues with a single eBay slim fan. I've never seen above 90deg water temps.
That's with a big mother eBay rad and coolant reroute.

Two eBay slim fans would probably be ideal.

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Thank you. Will have to get one (or two).

Staaahp wrote:I'm still running the OEM shroud and undertray. I suppose giving the radiator and cooler a light pressure clean on the weekend to rid of flying bugs and what not wouldn't hurt too.

I'm looking forward to seeing your beastie at the dodgy day



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speed wrote:

smy0003 wrote:I'm looking forward to seeing your beastie at the dodgy day

When and where...

There's a great comprehensive cooling thread on miataturbo.net, definitely worth a read: http://www.miataturbo.net/race-prep-75/miata-cooling-system-thread-79930/