I have an issue with the switch for my radiator cooling fan. The fan doesn’t come on when the engine coolant gets hot. One of the ways to diagnose the problem is to disconnect the switch and use a paperclip to jump the connection. I did this, the fan worked and I replaced the switch. No joy. Either the new switch is faulty or I may have damaged the connector when I put the paperclip in during the test. I found out after the fact that this is easy to do and a not uncommon mistake. If I put the paperclip back in the fan runs. All the time, not just when the coolant is hot enough to trigger a working switch. What’s the danger of just leaving the clip in place and letting the fan run? I did it today and the cabin heat came up as it normally does. There is no danger of the clip contacting any metal where it is. The car has nearly 180K miles on it and is nearing the end of its useful life due to some other nagging problems.
You want the engine to reach operating temperarure quickly and the fan will slow that rate. Everything operates bettet fully warmed up.
I’d be tempted to run a switch to the dashboard to turn it on & off behind the wheel.
Look up the specs and see what temp the fan is supposed to come on at. It may not come on before about 213 or 212
Yeah, this. It will make the engine slightly less efficient. Otherwise, no biggie. It’s a bit of extra wear and tear on the fan, but the fan is designed for continuous duty anyway for days when it’s really hot. The fan should be able to handle it.
I do have to wonder if the switch was the actual problem to start with though. Are you sure you don’t have any air trapped in the cooling system? You might try bleeding it to get the air out. Air in the system might also be fooling you into thinking the coolant level is fine when in fact it’s low.
I wouldn’t bother. The car has 180K on it and has other issues. Losing a couple mpg until the car warms up isn’t worth putting much effort into.
Since the fans are probably not connected to the water pump, and the water is not circulating until the engine is hot, due to the radiator thermostat not being opened until the coolant is hot, the fans are not cooling the engine. They’re blowing on the radiator, but the fluid isn’t moving through the engine.
If the fans and water pump were belt driven, they’d be on all the time, but they wouldn’t be cooling all the time, because of the radiator thermostat.
So the engine comes up to temperature just fine.
Is there a fan relay? you may have blown the relay, and it could be a pretty cheap part. If it’s not that, then you may have just blown a fuse. There are fuses under the hood, in addition to the ones inside the cab by the firewall. Check your owner’s manual to see where the one for the fans is located.
I’d worry more about the paperclip not being especially secure. Does your temp gauge work reliably? Keep your eye on it.
I probably wouldn’t either. But I’d be tempted!
Your fan does not come on when the coolant gets hot it comes on at a very specific temp usually about 10 degrees higher than the thermostat. It can take a long time for the fan to come on if it is a cool day especially.
A typical trigger temperature for electric radiator fan operation is 220 degrees. If the engine’s not actually overheating there may not be a problem.
O.K. Among the other problems with this car is the fact that coolant seems to be disappearing. I add a little anti-freeze every couple of weeks - maybe a pint or so - I never measured it. No obvious leaks, no fluid on the ground and no smell of anti-freeze. I can live with that. The temperature gauge seems to work fine. After driving around for 45 minutes to an hour and when stopping at a red light (or shorty thereafter), the temp climbs and the needle is almost pinned at the hot end. I’ve stopped and checked the fans while this is happening and they are not running After a few minutes at 30-40 mph, the temp returns to normal. Youtube tell me that the paper clip trick is the definitive test for finding a bad switch. If the fans run, everything else is fine. I had the system bled but the problem returned. I’ll just keep driving it with the work arounds until Hertz starts selling used cars again in my area. The wife got an excellent deal from them and I’m inclined to follow suit.
Now that’s a problem, it usually means that coolant is leaking into the engine; that’s why you don’t see it. That’s not an easy fix (usually) and the repair costs may not be worth it.
Does the car make a big poof of white smoke when you start it?
We have a 2002 Audi that uses just a little coolant, but it uses only about a quart in six months, if that. It’s burning it somewhere, but we can’t see it out the tailpipe, and we can’t smell it. We have low-tox radiator fluid in it, so that should help.
It’s got just over 100k, it starts every time, handles really well, and the clutch is in very good shape; it has a lot of power and pick-up, and never overheats. And it gets really good mileage. It’s a compact (not a sub-compact) sedan 4-door, everything works on it, including the AC, and it gets about 36 mpg. So we’re going to keep driving it.
If the coolant use gets worse, though, we’ll see if it’s fixable for a reasonable price, and if it’s not, donate it some place, or sell it as a parts car. Since it’s an Audi A4, in good cosmetic condition with everything working, it’d be a great car for someone who restores Audis.