Sportrak overheating



I'm having trouble of an overheating kind. Around town the temp stays fine, but steady speeds on the motorway causes the beast to overheat. I've had the viscous coupling on the fan changed and the thermostat seems like its opening as the pipes both sides of the engine get warm.

If she gets hot on a run the only way to cool her back down is to take your foot off the throttle for a couple of seconds at a time - so its accelerate, foot off, engine braking, accelerate - not much fun for anybody following.

Any ideas much appreciated.


Water pump.

Is the radiator blocked? Tried flushing it out?
You have not mentioned the water pump ..... check the belts tension. Then check if the pump has seized.


I had a similar problem with my fourtrak, new cylinder head, fan, thermostat and water pump, still overheated. Turned out the rad wasn't working even though it looked well.

1985 Fourtrak 2.8, Intercooler, 4"Lift, on 31,10.5,15 Grizzly Claws.

1985 Fourtrak 2.8turbo, Spring over axel, on 35,12.5,15s

Try flushing the fins from th

Try flushing the fins from the outside with a hosepipe. The previous keeper to me had taken mine off road, and not washed the rad proberly. I put a hosepipe on the rad from the outside and a ton of mud and sand fell out. Problem solved, cheap and easy!!!

Andy G

Andy G

I have a '91 and am having th

I have a '91 and am having the EXACT same problem. I've tried a new thermostat, new fan clutch (I went with one off of a Toyota, since the correct part is very expensive and hard to find), radiator flush, adjusted the timing (service manual said timing could cause this), new radiator cap, everything so far but tear it down to the water I'm curious too, have you checked the radiator fluid for oil, or the oil for radiator fluid? Somebody told me that this could be caused by a blown head gasket. The funny part is, with mine is seems to get worse in the winter. I'm going to check the cylinders with a compression gause tomorrow to see if it is the head gasket, and then it's into the water pump. My radiator doesn't look dirty or anything, but I should probably clean it out just to be safe. Please let me know if you find anything out on your's that might help me, and I'll certainly do likewise.


I just figured out the fix...

I just figured out the fix.......put a piece of cardboard in front of your radiator, covering 75-85% of it. I know that sounds completely backwards, but here's what I figured out.....this car is designed to run in tropical climate, so the radiator is a little larger than it really needs to be. That combined with the fact that the thermostat is on the bottom of the engine rather than the top, means that the cold coolant going into the engine will keep the thermstat from opening, causing the engine to overheat. I was remembering that the guy who owned the car before me told me that it is critical to put something in front of the radiator during colder weather, but he didn't tell me why. So I just tried it as a last resort and it worked. Even after replacing the water pump and radiator. I do notice that the temp will rise sometimes when I first start driving on the highway, but it will not reach critical temp and then goes back down once the warmer coolant works its way through the radiator and reaches the thermostat. Not sure if you figured it out yourself yet or not, but hopefully this will help if you haven't. Cheers.