I replaced the fan over a year ago with a new thermostat for it. The other day, the cars temp shot up at a light. The fuse was fine. Figuring it was the temp sensor, I bought a new one & just installed it. I also ran 12V direct from a spare battery to the fan & it spun up fine. Checked the Relay - clicked with power applied During the 25mph test drive, same thing - Temp started to climb. Parked & checked - no fan spinning. Next to check?
Had exactly this on my 348. Fan ran off spare battery. Turned out to be a faulty connector on the loom side. Worth a look with a meter to check feed.
Water level is fine, though taking out the thermostat plug in the radiator, very little spilled out. maybe 1/4 cup.
Working on my right fan same issue today with same working parts as yours Clyde. Changing temp sensor and adding coolant today. Going to check wiring continuity today. I did just swap l/r relays as a relay check although it sounds like yours is working.
Relay clicking doesn't mean it's good. Contacts could be be shot. The other issue would be the temperature switch at the top of the LH radiator. You can pull the connector and short the terminals in the connector with a paper clip to bypass the switch. If the fan runs the switch is bad.
Besides clicking, I checked for continuity. It seemed fine. Relays swapped anyway. A new one is on the way. I'll jumper the switch & see if the fan sparks to life. Good luck with yours, Bob. While mine is probably mechanical, yours might be electronic. That's just hassle & Cost
Check both sides on your fuse box in the passenger side foot well. I have seen the terminal at the fuse box / fuse holder melt.
And you with such an immaculate car! How could that happen? I jumpered my fan sensor & the fan kicked right on. So it's either a bad (new) sensor, the relay that I swapped yesterday (I'll swap it back) or the water isn't getting to it. Maybe an air lock
Some contact cleaner and compressed air and they look fine. I think they used some kind of paste/conductor in those. The same that was on the headlight motor inside. It gets funky. Not sure it's a problem but looks bad. Cleaned up well Image Unavailable, Please Login
I swapped the relays back - the fan still fired up when the temp switch was jumpered. Pulled the switch out & popped it into a pot of water - it opens up as it should at about 85. Check what I think is the OEM switch - 85/76 one from superformance about 1 yr old - 88/82 one from GT Car parts (newest) - 88/82 so at this point, I have to say it's an air bubble in the system and I"ll have to figure a way to get it out.
Open the coolant tank cap, Fill it to the right level with coolant Run the engine until it gets hot. Close the cap.
Son of a gun, that did it (or so it seems). temp climbed past 190. Shortly after I had a bunch of air bubble out and it settled back down. The temp dropped to 190 where it usually sits. Then the fan came on. So much for self-bleeding coolant system
Took her for a 20mile drive. It's about 87 here & a bit humid. Started out great. Then I noticed the temp gauge would swing from a mark below 190 to a mark above 190 at lights. Start going & it would drop to average 190. My last recollection of the guage is it is generally rock-steady at 190. Get home, fan is not on. The fluid is fine. I'm still thinking air bubbles Anybody? And I'm thinking the system shouldn't need the cap ajar to bleed air. I'm thinking any air bubbles it's way up and into the tank. Pressure > 90lbs (as memory serves) and the cap releases pressure/fluid into the overflow.
The gauge should oscillate bit around 190 when sitting still. It gets hot, the fan comes on, it cools down, fan stops, cycle repeats. Although a whole mark above 190 seems high and your fan is not on is not good. Again, check fuse, relay, short out the switch to make sure fan comes one. I think you have a new thermal switch, right? Then, open the cap and run the engine until the fan comes on. If the fan comes on while you are idling, it should come on while you are driving unless your radiator is blocked. How is your water pump?
These are typical signs of a small leak at a cylinder head gasket. Small amount of combustion gasses are being pumped into the cooling system with every combustion stroke eventually forming a larger air (gas) pocket. A way to diagnose this is run the engine with the tank cap open and look for a few bubbles coming up after every brief engine rev. Better way is with a combustion leak tester. If gas leak is confirmed, you can try re-torquing the heads. If this doesn't work, new gaskets.
The potential of some sort of a combustion chamber leak also crossed my mind as I read through the symptoms. Hope that's not the case, but fairly easy to confirm or deny.
new thermal switch - yes, checked fuse, put a new relay in. let the engine idle again, fan didn't come on. I saw the fluid circulating in the tank.
Think I found the problem: the wiring loom's female connector at the fan collapsed. It was making intermittent contact. WIth a couple dentist picks, I was able to open it back up. For another day, I'll buy a pin extractor & do it right.
this is every tri-state's nightmare - hot, humid & stuck at a river crossing. For me, today, it was twice. This morning about 8am I sat in 3 miles of 45min traffic on the crossbronx. she held constant at just a smidge above 190. Outside was 65%humidity & 98 degrees. I think the engine bay got so hot, the starter got stuck 'cause I shut her down briefly and not even a click when I went to start her. For those familiar with traffic and the tristate, your probably shivering now. Yep, 3 lanes squised down to one and folks in this heat passing a Red Ferrari on the shoulder. There was no sympathy here. to the guy in the pickup truck who shouted "Should have bought a Chevy". yah. ha ha. Park yours next to mine and we'll watch yours rust. then coming back the GPS routed me through mid-town. You know its bad if your best option is across mid-town. 30 min in stop-and-go traffic at Dyer at the Lincoln. my cell said 111 degrees. the radiator temp gauge said 190 (ish). so at least she wasn't overheating. and I took RifleDriver(?) suggestion - slip a plastic sheet on the top of the door/body breather barriers to the radiator with two-way tape (rather than rivet) to separate air flow & hot air return and sure enough, even with this kludge she ran smoother.
