I have a 98 ITR motor with I/H/E horseshoed into a CRX. On the track when in Vtec for long periods of time, the temperature starts to climb. I have a double core rad and run 75% distilled water, 25% honda coolant and water wetter. I thought the thermostat isn't opening all the way and is blocking the flow of coolant to my block so I put in a new one from the dealer and then the same thing. Then I pulled the thermostat altogether and still the same thing.

Took the cap off another car and ran it today at an autocross. Started the course at 150 degrees (because of no thermostat) and finished it at 210 degrees 52 seconds later. Don't think it's the cap.

Going to get a sending unit so I can run the stock temp gauge and the aftermarket one at the same time. Though I don't think it's the gauge, it was also overheating on the stock gauge before I bought the aftermarket one.

I'd like to check the rad, - either the hose method or find a shop that can test it somehow - but my guess is it's not the rad. It overheated the same with the double core rad as it did with the single core. They're both full sized rads and should be adequate to run my motor. Odds of both being duds is small, but still possible.

My next thought was head gasket. The car was blowing white smoke a while back but that stopped when I went to the 15W50 syn oil. Now occasionally it blows smoke on startup. My mechanic said the head gasket is bad but not bad enough that it needs to be replaced right away. But maybe he's wrong - he never saw the car run on the thinner oil. Could a head gasket cause overheating?

Only other thought is a failing water pump. Might not be able to keep up with the demands of racing. What happens when a water pump starts to fail? Does it just dye or pump less?

Anyone else who has experienced this?

 

It does sound like it could be the pump. I don't have experiance with racing and over heating issues, but I've had a water pump go on me before. Except my pump froze alltogether.
As far as the hose test, don't do it. Take it to a shop, some places will do it for free. The hose can actually create way more pressure in the rad than it was designed to handle, and unless you had some way to monitor/regulate the pressure, I'd take it to a shop. I've seen ppl think they have a leaky radiator when doing the hose test, when in fact they were pushing close to 50 psi through the radiator.

 

Thanks for the tip.