westy cooling poor

[chris-stockton]

Hi guys,

onto my next project with the westfield - look at its cooling system!

Ive noticed it sits quite high on the gauge - usually 90 if driving at 40+ mph, anything below 40 and it starts to rocket - the cooling fan is struggling to keep control of things when at low speeds or in traffic.

So where to start...

Rad looks reasonably new, but is small - something i cant do much about.
It has a single push fan instead of a pull.
If recently put a 74 deg stat in to try and help things, never done much good. The bonnet and sides of the body are very well vented to let hot air out.

What temp would you expect a tuned rv8 to sit at when driving at 40 mph?
Could be the temp gauge i suppose? check real reading with an infra red?
It also has one of the stat outlets that points up - so thats not great..

Any thoughts where to start first?

[kiwicar]

Hi
do you have any ducting directing the air through the Rad and preventing the ait that has passed through the Rad from returning to the front? Are you certain there is no t any air in the system? has the rad been back flushed recently?
Personally I would suspect the gauge before making any other changes. . a pan of water to put the sender in and a jam themomiter on the cooker are actually a better way of checking the calibration if you can get the gauge out.
Best regards
Mike

[ian.stewart]

I am a great believer in making sure all the air that hits the rad goes thru the rad, Air is like water, it will find the easiest route, all my rads are ducted, and any route where the air can flow past the rad are sealed, I have never had a problem with overheating once this procedure has been gone thru.

[richardpope50]

Does this help (Copy from a my radiator spec sheet)?

Aims of Efficient Cooling.
1 Maximum cooling is gained by slowing down the air supply in front of the radiator. To do this, add ducting from nose cone to the radiator surface. The reason is that the nose cone’s cross-sectional area is smaller than radiator surface area so by adding ducting to direct all air through the nose cone to radiator’s surface without gaps, air is slowed down. I.e. Fast air through cone is now slowed as the ducting increases cross-sectional area. (Same logic as a aeroplane wing.)

Slow air takes much more heat from core than fast flowing air as it has more time to heat up (unless too slow and does not move,I guess).

2 Fans should be sucking and not blowing because you do not want airflow turbulence*, you want smooth airflow at low speed. A blowing fan not only gets in the way of airflow but will blow air in all directions and what goes through the radiator core will go through with significant turbulence. A sucking fan will suck air through the core smoothly.

You should also have plenty of room for the hot air after the radiator (and sucking fan) to escape the engine area. Flared side panels are a good idea.

*Note that the Dax fan at an angle is even worse as it churns up the air through the nose cone.

3 Put your fan temp sensor on the output side of the radiator, not inlet as then the fan only comes on if the radiator cannot cool enough. If the radiator is cooling enough, the fan will not come on.

4 Within the radiator you need to force the water through furthest cooling distance. An inlet in the centre top and the outlet at centre bottom will mean that the water will take the shortest route and be cooled by a small section of the core. I had internal ducting put in the header and bottom tanks so the water took the furthest route. Some radiators have a barrier across the centre so the water has to spread throughout each radiator – if you like two radiators on top of each other with a connection opposite to the inlet / outlets.

5 A thick core allows air to take the maximum heat out as the flowing air stays in contact with core longer.

6 On a Rush, there is no point in having radiator lower than nose cone as air will not get there unless you add more ducting / holes to let in air. Thus you can have a smaller radiator height. The design of a short, thick dumpy radiator is best.