Coolant running temperature

[MattPlaneCrank]

What temperature do 4.5s normally run at? Mine is between 85 and 95 degrees. The fans don’t come on until it reaches 95 which seems a bit hot. I’ve got an all aluminium radiator fitted.

[aide]

88 according to Al.

[Imran999]

They do run quite hot, 85-95 is exactly the operating range that I observe, with an increase up to 100 (and beyond) in 30 degree weather and traffic.

As far as I know, the ECU has its own temperature sensor/sender and the dash-gauge has it’s own. My dash gauge over-reads (compared the ECU sensor) by 3-4 degrees (and the needle can be erratic).

There are two radiator fans, the first comes on at 90 degrees and the second at 95 degrees (ECU temperature).

Joolz (Kits and classics) offers a reprogrammed ECU chip which brings the fan thresholds down by a few degrees. And some owners fit an override switch (under the dash) for the second fan, allowing at-will operation.

As long as the coolant mix is correct, the boiling-point will be 130degC or higher. Couple that with the fact that the dash gauge over-reads, and seeing 100 degrees shouldn’t cause too much alarm.

Of course, you could just turn off your AC, not all of us have (working) AC, you know…
;-)

Edited by Imran999 on Friday 28th May 00:06

[MattPlaneCrank]

Thanks Imran, I was going off the ECU temperature indicated on my MBE tool. The fans don’t appear to operate separately assuming this is displayed accurately. I’ll have to investigate further.

[Mr Cerbera]

Fitted Joolz's CoolChip (can't remember the reduction rate)
BUT
She has never exceeded 100 since
(...and, Yes, the ECU programming is designed to bring the two fans in at separate temps - separated by 5° iirc)

Ring Joolz he'll give you accurate info

[ukkid35]

If the car is moving fast enough and the ambient temps are cool enough, the coolant temp will never go significantly over the thermostat opening temp, say 85 deg

In the real word that means the coolant temps will easily exceeded 105 deg when the car is stuck in traffic on a hot day

I've watched that needle move erratically far more than most and it is truly disturbing

Especially when parts fail and you have to try to rescue the situation

If your rad or thermostat is old and misbehaving then good luck

[Mr Cerbera]

Just one little memory to amuse you....

When I first bought BlackBeauty©, I had no idea what was going on so I just drove her, as you do !
It didn't dawn on me that she never rose above 75° - I thought "Wow, this is one, cool Motor " - in every sense of the word

Then I took her to Joolz, he took her out for 10 mins, returned and said "Your Thermostat is jammed open !"
.... and that was after 3 years of official TVR servicing !!

He threw one in as part of the CoolChip upgrade - Wotta Man

[gruffalo]

ukkid35 said:

If the car is moving fast enough and the ambient temps are cool enough, the coolant temp will never go significantly over the thermostat opening temp, say 85 deg

In the real word that means the coolant temps will easily exceeded 105 deg when the car is stuck in traffic on a hot day

I've watched that needle move erratically far more than most and it is truly disturbing

Especially when parts fail and you have to try to rescue the situation

If your rad or thermostat is old and misbehaving then good luck

I have never seen mine get to 105, I have the digital temp gauge and I think the hottest it has got to is about 98 on a very hot day.

[pmessling]

What you have to remember is that the boiling point of water under pressure is greater than at atmospheric pressure, so even if the car reaches 100-110 it's still relatively safe, most coolant system will let pressure off around 20psi at the expansion bottle cap.

But we all know just drive faster so that the radiator gets more flow. Ha ha ha

[MattPlaneCrank]

I did some more checks and the first fan comes on at 91 and the second at 94 degrees which seems good. Diving faster works even better though