94 850 Turbo - Cooling issues RESOLVED, fan relay

zero324 · Post by **zero324** » 28 Jul 2013, 20:17

I just recently started having a cooling issue where the gauge looks normal but randomly it will flutter and then go up in temp in between hot and the middle. But after a few seconds it goes back down to normal. This all happens most of the time while stopped. I hooked my ODB-II up and saw that it's reading anywhere from 195 - 235 degrees. The cooling fan does turn on but only for a few seconds at a time when the ac compressor kicks on. There are sometimes where it will run for a few min but it's rare.

I knew it had the original thermostat and temp sensor so I did a flush and replaced the thermostat and temp sensor. I am still getting the same issues. Any ideas?

Post by **Ozark Lee** » 28 Jul 2013, 20:55

A bad fan relay comes to mind.

The fan should be on full time when the AC compressor is running. You can test the fan relay by alternately grounding the relay pins associated with the Yellow wire and the Yellow/White wire on the center connector one at a time. The fan should toggle between both speeds if the relay is functioning properly. If the low speed side of the fan isn't working that would account for your temperature swings.

...Lee

zero324 · Post by **zero324** » 29 Jul 2013, 13:50

So I checked the relay and it was toast. So I went and got a new one. Right away the fan started working normally.

The issues that I have noticed and I dunno if this is normal or not. When I am driving and I hit the throttle any like to speed up I notice my temp via my ODB-II goes up. The needle stays in the center but my temp reads around 220 at times but as soon as i'm off the throttle and cruising it goes down under 210 and stays in the 190's in traffic.

Is that normal?

Post by **abscate** » 29 Jul 2013, 13:53

Boiling point of 50-50 coolant under 1 bar pressure is about 245 F.

220F is fine.