hi guys im going insane with my daughters mini.it overheats when going over 80kph.ive had the radiator stripped and cleaned,new thermostat,new hoses and a thermo fan fitted instead of the pulley driven one.at idle and all the way to 60-70kph its on normal,hit 80 plus and it overheats.there is no oil in water or water in engine oil,so i dont think its the head gasket.any help will be appreciated.cheers.

I guess you flushed the block out when you did the radiator, I always flush them in both directions - take the thermostat out and clamp the top rad hose onto your high pressure hose nozzle, then the same with the bottom hose, then the top again... untill it's all clean in both directions.

did you replace the water pump in all that lot? over time the impellers corrode away and don't do any pumping...

is the timing correct, if they're overly redarded they'll heat up too

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forgot to mention also replaced the water pump with a high volume one from karcraft

forgot to mention also replaced the water pump with a high volume one from karcraft

Hmmm - are those strips of rubber in place around the cowling between the rad and the cowl itself. Believe it or not they make a huge difference - probably not enough to overheat the car though. They stop the incoming air generated with forward motion slipping between the rad and cowling and straight out into the RH wheel arch - no cool air...

I bought a brass hydro fitting with an elbow in it that fits in the block drain hole at the back of the block. Lock the garden hose on and flush away - I had lumps of crud spew out the thermostat hole - mostly had the consistency of coarse sand. I find it all collects right behind number 4 bore and silts up really bad. I do that every 10000 km's and have never had another cooling issue(I did have before I replaced the rubber strips and the backflush...)

Good luck...

Hooroo

Rob Forsyth
Miniot!!

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Rob Forsyth
Miniot!!

generally it should get cooler once you go faster

so i think its the timing/dizzy
anyone else concur?

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Have you fitted a overflow bottle / surge tank yet?

ill try flushing the block on weekend.those rubber straps are no longer needed as the thermo fan is attatched to the radiator.

Try this-With new thermostat-drill 1/8th holes(about 6 or 7 holes) around the perimeter or edge of the thermostat,so the thermostat is still working,but you also get a better water flow going thru while the thermostat is making it's mind up what to do

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its not running to lean at that speed

could it be the wrong needle

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Is the fan pushing enough air through? myeslf and a friend have both had this problem with electric fans(cheep ones), they were fine in traffic, but at extended periods over 80kph or so they got hot, i put my standard fan back on and no more probs, the mechanical fan just pushes a huge ammount of air at 4000rpm, and if you compare the blades on a standard fan to an electric one you can see why. my mate just put a heater matrix in behind his grille (damm long clubby grilles) and he has no probs now, just needs a little more than his fan can push....

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speed costs....how fast do you want to go...

running lean was going to be my suggesttion...

try adjusting the jet...

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gadget thats the most logical answer!

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Inconspicuously Conspicuous
Appreciation without Depreciation
forever chasing clearer skies...

your real problen was probably that the fan was blocking the air from going through the radiator at high speed - race cars often do away with the fan altogether as air flow through the grille is all routed through the radiator... you need a nice open finned fan if you're going electric IMO

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that sounds abought right, my electric has LOTS of small blades, and the inner guard has been chopped out too, i now have the electric for busy trafic and the mechanical one does its job at high revs.

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speed costs....how fast do you want to go...