Rootes1725cc

Hi,
my newly aquired Gazelle V1 has over heating problems, not boiling but red needling ! the thermostat has been removed the water temp climbs slowly but goes into the red in traffic but a clear run 30/40mph drops the needle as does putting on the car interior heater.
fan and fanbelt seem ok and there appears to be quite a drop of temp top to bottom of rad.where do i go from here to check if i have enough flow?,the rad fluid is clean and not getting any loss of fluid.
if the car gets really hot in traffic it is prone to stall and not want to start untill it cools a bit.
thanks for reading
Jon

First thing I would do is get a hold of an infra red temperature reader, and use that to determine the temps of water coming in and out of the rad. Quite often, the temp gauge and sender can be mis matched, hence giving poor readings.

Other things to consider is the radiator blocked? Maybe when you are putting the engine under load and it is heating up, it's usually because the radiator is not letting as much water flow as it could. This means that when idleing, the radiator can cope, but when more water needs cooling as the engine speeds up, it cannot, and so the temp starts creeping up. This will usually result in a complete overheat. Other factors can be an inefficent water pump. Thermostats don't usually make much of a difference and only aid warming the engine up and will only give problems when faulty. In your case, removing it has made little or no difference?

Sounds to me either the rad needs replacing or the water pump. I'd back flush the system first to see if that makes any difference before shelling out for new parts.

A

Hi A,
thanks for your reply, have got one of those infrared thermometers,a great litle gadget,seems to me that i am getting a large temp drop top to bottom of rad so i assume not enough flow.
had to leave that and look into a charging problem as it appears i've been running on the battery charge,a bit of cleaning inside the regulator box has sorted out the problem but i will not travel too far until the fix is permanent.
cheers
Jon

My money is still on the rad.

Your thermo outlet, with thermostat fitted should have a temperature around the thermostat - typically 80 something degrees. Usually I'd expect a 40 degree drop at the bottom of the rad. If it's only overheating under load, my first suspect would be the rad flow. Take it off and give it a good clean, reverse flushing it (putting hose in bottom outlet) and then seeing if that makes a difference.

A

as soon as i get a chance the rad can come out for a bit of flushing, seems the regulator is ok now.
cheers
jon

new thermostat fitted,it seems that the gauge goes into the red before the thermostat opens so difficult to guess where the gauge might end up during operation.
i suppose the sender is incorrect for the gauge ,a suitable potentiometer might help set the gauge so that i can see how hot the rad fluid does get.
no loss of fluid or evidence of boiling ,hopefully that means the system is OK. i obtain all sorts of temp readings with the IR thermometer but nothing that appears too high.
Jon