Thread: Overheating SIII

The thermostat should be checked as well, might be sticking shut....can cause the system to run hot.......put it in a bowl or bucket of boiling water and see if it opens to be sure, pressure will be noticable between the hoses when you squeeze them....

rich

Cheers for that. I took thermostat out, and is still overheating.....

Haven't been brave enough to cook it in one of SWMBO's pots yet :-)

Not sure what you mean re pipe pressure? Before and after thermostat opens?

you cannot expect the cooling to work properly without the thermostat so while youve got it out its rly worth chucking it in some water and using the IR gun to test when it opens. one way of thinking of it is that without the thermostat theres nothing to slow the water down so it can actually be cooled inside the radiator.

also about the temperature difference in top/bottom hose. ive seen my stage one with like approx 90C at top (roughly the thermostats temperature) and maybe 45 degrees or so @ bottom? its a pretty big radiator in comparison however...

it is worth establishing if the problem is like...overheating on a hot day working it hard type thing? or if you start it and it just keeps creeping up the gauge till the point where you presumably give up and turn it off

Thanks for that advice, I will test the termostat tonight and reinstal if it seems to be working. I think I have the temp ranges for the thermostat in the Haynes manual.

The temp increase is just gradual, after about 6kms it is starting to get towards the red on the guage, so I head for home. Fuel guage seems accurate so I am assuming voltage regulator/stabiliser is not causing mixed messages from the guage.

Originally Posted by RaggedJoe

I took thermostat out, and is still overheating.....

Use the thermometer on the radiator core; the top will be hot and the bottom cool if it is working properly. Check every vertical tube and make a note of any that appear to be too hot at the bottom.

If it overheats with no thermostat in it then the radiator is looking like the culprit.

Check that the ignition timing is correct, as this will also cause overheating,

Cheers Charlie

Chazza - i just had a similar problem with my stage 1 (different engine but similar issues). The things i did to solve were:

1. Fan
Check that your fan is thermo or viscous or whatever, is actually spinning in relation to the pulley. Mine was spinning at approx 1/2 and i over heated at idle.

2. Blocked Radiatior
Seems like you have this sorted. Check that there isnt any grass ect in the fins. I almost overheated a tractor once that way.

3. Replace Thermostat
I didnt even check the old one. Bought a newie and checked that in some hot water with an IR gun. Found that is was sticking as it was expanding, so returned to the manufacturer. New one hits 83 then opens like night 1 of honeymoon. Closed like night 2 below 83...

4. Water Flow
Have a look in the filler plug and see that the coolant is moving. Give a few revs and the water should move substantially faster. Could be an impellor in the water pump if not.

5. Oil
I have heard that a too viscous oil can over heat. i'll let someone else comment on that

6. Head Gasket
could be an issue here. Something for others to comment on also.

7. Expansion cap cover.
Mine was rooted - bought another for $8 that works well.

8. Air pockets
I first started with a massive air pocket behind the thermostate. Took a while to sort.

Good Luck!

8. Air pockets
I first started with a massive air pocket behind the thermostate. Took a while to sort.

How did you sort it? Am thinking I might get same when I reinstal mine...

Originally Posted by RaggedJoe

How did you sort it? Am thinking I might get same when I reinstal mine...

To get rid of air pockets. Start engine from cold, while leaving radiator cap off, this allows the air to escape. You will notice a water level drop as the air is expelled. And top up with more coolant, until proper level (That you can see it moving, and/or is above the fins). Put cap back on.. Done.

Wolf