I have a 245 with an unusual overheating problem. About 4 years ago, while driving out to Yosimite on a hot summer day, and going up a steap grade, I looked down to see the tempurature almost in the red. by the time that I found a spot to pull over, less than a minute later, the temp had gone into the red.

I have never had problems like this before so this was very shocking to me. After letting it cool down, everything was fine.

Within the next few months I noticed that the coolant levels slowly when down, white smoke out the tail pipe, and a milky residue in the oil. Then, I failed a SMOG test. So, I decided it was do or die and took on the largest project I had taken on a car. I changed out the head gasket, and put in a new cat. She started right up and passed the next SMOG with flying colors.

Ever since then she overheats every now and then, but since I am now trained to look at the temp guage more than the road, it never comes close to critical levels. All I have to do is blast the heater for a minute and she drops back down.

In my feeble, by brute force methods to fix the problem I have done the following:

Changed the coolant every few months, replaced the heater with a heavy duty one from IPD, 3 row. Put in a new fan clutch. Recently I changed out the heater hoses that goes to the back firewall, and I put in a new engine wiring harness. Also, I have replaced the thermostat.

I have checked the mixture, and watched the O2 sensor to make sure than she wasn't running extremely lean. And the timing is on. I have run out of ideas. Does anyone have any ideas?

She doesn't do it all of the time, maybe 5% of the time. And when she does act up, it will often happen a few minutes after she reaches operating temp. But I have seen it when I had 4 people in and going up a hill on a warm day.

The only thing I haven't done is to actually flush the system. But I have changed the coolant so often within the past couple years that I sort of feel like there is something else going on than a little restricted flow in the engine. I am wrong about this, and this could be the source of all my problems?

Any responces are apprieciated.

Thanks,

Mike