I had the fan run on issue for a couple of weeks, and finally replaced the thermostat. The problem went away. Then, without warning, a huge coolant leak at the rear of the engine emptied the radiator. When I look down on the drivers side I can see water running out of the valley area down the back of the engine when I add water. I would bet there is a rubber hose that travels through the valley that broke. Has anybody delt with this, and if so, what does it involve.

 

Yes, there is a small hose that runs to the throttle body down the center of the engine. On the 'R' it involves removing the compressor.

 

So, you are right, it did involve removing the compressor, and there are actually two hoses that run down the valley, and while one was ruptured, the other was swollen, causing me to replace both, and the water pump at the same time. I also broke a couple of bleeder hoses while I was at it, and got to replace them too. This was a big job, probably eight hours on wrenches to get it done. I do like that the book shows it at 3.5 hours. I supposed if I did twenty of these I could do it that fast. As for the hoses, they are called heater hoses at Autohausaz.com.

So when it all went back together, it still overheated. I went back to the fan wiring and found some abrasions on the wires, and maybe some loose connections. I rebuilt the harness again and put it back together. 110 degrees here in Tucson when I tested it, no overheating. What a hard way to diagnose the problem. I wonder if the heater hoses under the blower would have ruptured if I had fixed the fan in the first place.

So, even if the fan seems to be working ok, don't rule out an intermitant issue that is the result of bad connections or wiring. For those who have overheating issues, am I the only one who has noticed that when the cooling system is working properly the temp gauge needle never goes over half? Only when I have some undiagnosed problem does it barely creep to the high side of the halfway mark. Maybe I am imagining something....

 

Glad you got it all sorted out!


The cooling system like the transmission is not something to mess around -- At the first sign of any unusual opeation ---- have to be looked at.

Every car has weak components that show up with time -- often fixed while the car in in production -- but I don't understand the use of rubber hoses buried in the engine. I have had metal hoses rust out and leak -- so maybe the rubber ones are as reliable. You would have thought that they could have found a better way to route them.

 

I went through the process of cussing the engineers, and then thought that lasting 12 years and 120k miles in Arizona, I should not complain too much. Again, I bet I would not have had a problem if I checked the fan wiring first. Those rubber hoses could have been braided stainless for twenty bucks more...but I admit that when I replaced them with the stock rubber, I knew I was treating the next guy to the same issue in a decade....

 

Just had the other fan quit...another burnt connector.

 

I replaced those two heater hoses recently while I had the intake manifold off. There is a sort of rubber insulator pad in the valley between the cylinder banks that I guess is supposed to keep the hoses off of bare hot metal, but it does seem like an iffy arrangement. Pulling the intake wasn't as bad as I thought - on my N/A AJ27 - all the electrical connectors are the biggest pain.