Sprint running too hot or not?!

[sprintchris]

Hi,

Took the Sprint out for a short run the other day, the weather was pretty warm.
I’m trying to figure out if the engine is running too hot. Driving, the gauge goes up midway between half and the first mark after half. In slow moving traffic it goes to the first mark after half ( should have taken pics!! ).
Almost as soon as I stop the electric fan kicks in and runs constantly.
I have the alleged uprated aluminium radiator with built in fan switch on the passenger side.
It doesn’t appear as though the engine has overheated, it may just be the sender in the manifold ( Dellortos ) or the gauge are reading wrong.
Which direction does the coolant flow? I can only think if I put an aftermarket temperature gauge with adaptor into one of the radiator hoses I should get a pretty accurate reading of what’s going on - any thoughts on this would be greatly appreciated.

Many thanks,

Chris.

[soe8m]

Buy a 10 gbp aliexpress infrared tempgun and you will sleep again at night.

Jeroen

[cliftyhanger]

What temperature is the fan switch set to? that should give you a reasonable idea of what is going on. If early 90s, it all sounds well.

[dursley92]

Like has been suggested, I would check the fan switch setting and use an IR gun to measure the actual temperature of the engine.

[B8WLY]

Chris.

I had the same hang ups when I again got a Sprint.

I changed the radiator out, put an electric fan in, added some Evans waterless cooling but have since gone back to normal anti freeze, and got an infrared heat gun.

After about two weeks of checking the engine after every trip it only averaged 88 degrees.

The temperature gauge now sits bang on half way, the electric fan hardly ever comes on, and to be honest I hardly ever look at the temperature gauge now.

I think with a decent radiator and decent maintenance Sprints can run perfectly well without overheating headaches.

Richard.

[sprintchris]

Hi,

Thanks to everyone for the advice.
I do have an infrared temperature gun, some concerns over the accuracy.
I tested it with a boiling kettle, pointing it directly into the water it showed 97 degrees, however, pointing it at the kettle body ( stainless steel ) it only picked up late 40 degrees.
I would have thought it should show A temperature near to that of the water itself..

[ab1]

Hi

Probably just the shiny kettle confusing your thermometer. This website has some good info on using an IR thermometer.

A bit of black tape stuck over where you are measuring would help

https://www.fluke.com/en-gb/learn/blog/ ... hermometer

Hope this helps

Alan

[soe8m]

You did choose to use one of the least thermal conductive kettles you can use. A copper kettle would showed a higher temp on the outside.

Jeroen

[sprintchris]

Thanks for the comments, I’ll check out that link.

[TrustNo1]

is the fan running when the engine is running as you say it coms on after you've stopped?

[Carledo]

Ideally, an electric fan should not engage at all unless the car is running but stationary. (or crawling in traffic, if you want to be pedantic) If it deploys whilst you are driving normally, there is either a cooling problem or the fan sender switch is pulling the fan in too early.

BUT! A lot of people wire the fan relay and sender switch off a permanent live. Which means that when you switch off a warm engine, the water in the block stops circulating and the hot block warms the water inside locally to a temperature that sets the fan in action even though the engine isn't even running. This is quite normal and nothing to be concerned about.

I always wire my cars to ignition live for the fan so it won't do this. It's merely paranoia dating back to back to my early days of driving when batteries were expensive and less reliable than they are today, especially the batteries on my cheap old bangers! I can afford new batteries now and decent charging systems but I can't break the habits of a lifetime, so I never risk something coming on and leaving me with a flat battery! However I often find, after stopping for fuel for example, that on restarting and pulling away, the fan will deploy and the guage show a higher than normal reading till the water gets circulating again.

Steve

[sprintchris]

Hi,

Thanks for all the comments, all greatly appreciated.
The fan switch I can’t remember the temperature setting now, I did keep the box somewhere….I’ll try find it.
The fan switch is wired using an earth that then energises the relay. ( working on modern cars for a living switching is nearly always via an earth ).

Took car on a short run yesterday and left it idling for some time once hot, fan runs almost continuously, but this could be because I chose a switch with a low setting. No signs of the coolant boiling. Temperature gauge goes to 3/4 but this could be the sender on the manifold not suited to the gauge calibration.

Are the temperature gauges calibrated to a standard set resistance?

Chris.

[killysprint]

as others have said check the temp with a IR thermometer.

The gauge going to 3/4 on std running could be the voltage regulator being shot.
Try replacing that, I had a similar problem a couple of years ago, fannied on with checking and changing everything on the cooling system, rad, hoses, thermostat - and it was the voltage regulator causing the higher gauge reading.

Hope you get it sorted

[cliftyhanger]

Are the temperature gauges calibrated to a standard set resistance?

They should be, and all sensors should be the same.
However, I have played with sensors and gauges a bit, and you can get a fair variation. I had a friend who thought his car was overheating as it was always running at 3/4. I used a capillary gauge (checked in boiling water to 100degrees) and that confirmed it was 82 degrees when the gauge was at 3/4.
I had a few spare gauges and sensors, kept swapping until I got it bang in the middle. I could have returned it to him reading 1/4.....