Just finished reading all the other threads that I could find about overheating 850's and none of them gave me a clear direction to go with mine.

So here is the issue in a nutshell:

The car runs strong and will stay in normal temp range so long as I keep it moving, but if I drive in rush hour traffic the temp will climb into the red and the car will overheat. Once I get some airflow over the radiator the temp goes right back to normal.

Some troubleshooting has revealed that the radiator fan is not comming on at the appropriate time when the coolant is heating up so I replaced the relay that is located above the fan on the passenger side of the car, but this did not remedy the issue.

I have taken and jumped power directly to the fan(positive only), and it runs and spins freely with no odd noises.

The coolant level in the recovery tank is normal and steady, meaning I am not losing any coolant.

There is no coolant in the oil, and no oil in the coolant.

I have new coolant hoses all around (upper and lower radiator, upper and lower recovery tank, and both heater hoses leading into the firewall)

I have not replaced the thermostat, but since the car takes about 8-10 min to get to operating temp and does not overheat at speed I am confident that this is not the issue.

I have not replaced the coolant temp sensor but I am not getting any other symptoms other than the coolant fan will not come on when the car is hot.

Suggestions...?

 

Same boat as you. I used a 12v 3way (ground to frame where blue cable meets. attach wires into the socket from the ecu, 2 yellows) switch and rigged it up right under the edge of the hood past the fuse box. You just reach out the window and flip it low or high. lol no current if it rains.

But i'm ordering a new engine temperature control sensor, probably FCP. will post, but most 2nd most likely from the stealership parts department. Relay is #1

 

I realize that this post is almost 3 weeks old, and there has only been 1 reply, but I thought an update was in order.

In my quest to solve this problem I replaced the relay, made sure that the fan was in working order, and verified that the temp probe was, in fact, sending good signals to the ECM...at no time did I think to check that the relay was actually getting power (this epiphany came to me at around 1:45am last night).

DOOH!!! [insert face palm here]

I believe my problem originated from the replacement of the starter, and some poor diagnostic work on my part which created this headache/nightmare.

You see, as many of us have replaced the starters on our "Bricks" with less than adequate lighting, we may not notice that one of the wires that we removed got pushed behind the new part when we reassembled the car.

In my case the fusable link wire that supplies power to the relay was not connected so even if everything was working properly there was no power to send to the fan motor.

Let my mistake be a lesson to all of us...check the basics first before looking for the complicated solution.

 

My 850Van 1996 need overhaul,Is there any over size pistal ring for the old pistal.Other way how I can do to the engine

Thanks for any coments