Rad Fan "always on" ?

Duiske

Hi guys, Just a quick question. A mate of mine is thinking of buying a '97 celica. When viewing/testing the car he noticed that the radiator fan stays on constantly. When he asked why, the guy said that it had been that way since he bought it 18 mths before, and it had not caused him any problems. My question is could the thermostat have been by-passed to mask an overheating problem ? Or if it is just a faulty thermostat, would an always on fan affect performance by keeping the engine TOO cold ?

blastman

Is it an import? My import does the same thing, the fans are always on, but I've not noticed any problems. I suspect it's to minimise the heat in the engine bay entering the engine itself, as colder air carries more oxygen, so there's a tiny power gain to be had (in theory, anyway).

BrianD3

Duiske_Lad wrote:

Hi guys, Just a quick question. A mate of mine is thinking of buying a '97 celica. When viewing/testing the car he noticed that the radiator fan stays on constantly. When he asked why, the guy said that it had been that way since he bought it 18 mths before, and it had not caused him any problems. My question is could the thermostat have been by-passed to mask an overheating problem ? Or if it is just a faulty thermostat, would an always on fan affect performance by keeping the engine TOO cold ?

Yes the thermostatic fan switch could have been bypassed so that the fan is now on all the time. This is a common enough bodge to try and get an overheating engine to run cooler. I doubt that the fan was designed by Toyota to stay on all the time, the whole idea of a thermostatically controlled electric fan is that it only comes on when needed.

As for the effect on performance etc. if the car warms up properly and resaonably quickly (keep an eye on the gauge) then it shouldn't have much effect. If the engine is running too cold economy will suffer and engine wear will be accelerated.

MercMad

If it is a Jap import it most likely has aircon in which case a fan could remain on constantly !

mike65

I would'nt worry about it, unless you have the engine runing a lot as that might cause rapid enough bearing failure, if you just spend, say 40 odd mins a day commuting it should'nt be a concern.

Mike.

Duiske

Cheers for replys. The air con system in the car has been disconnected, so maybe that has something to do with it. My mate had the car for an afternoon, and took it for a spin from Carlow to Kilkenny. He noticed that the temp gauge did not rise very much. About 30-40% of what he would expect in his current car. My own thoughts would be that car makers would set the thermo to turn fan on when engine reaches optimum performance temp. Mike, the car would be going Carlow-Dublin and back everyday, so I guess he will have to look into it a bit more before buying.

mike65

Your friend could always use the cardboard covering half the rad trick.

Mike.

Anan1

I'd be inclined to walk. A car running cool for 18 months could have significant bore wear from overfuelling.

BrianD3

Yeah I'd walk away too. Disconnected aircon, temp gauge too low and fan on all the time would make me suspicious.

damo605

I would definitely be suspicious of this.... Is there two radiator fans on the car (often cars equiped with a/c have 2 fans)? If so, which one is running constant? ie. is it the one that would normally run when the air con is switched on or is it the normal engine temp control fan?
One of the most important jobs of a car's cooling system (besides stopping the car from overheating) is allowing the engine to warm up as quick as possible, ie. reach optimal operating temperature asap.... So the situation with this Celica is not ideal - Maybe it's an innocent side effect due to the way the air con was disconnected or the fan could be running constant to mask a much more serious problem.
I think it should be investigated very carefully....

AMurphy

Duiske_Lad wrote:

Cheers for replys. The air con system in the car has been disconnected, so maybe that has something to do with it. My mate had the car for an afternoon, and took it for a spin from Carlow to Kilkenny. He noticed that the temp gauge did not rise very much. About 30-40% of what he would expect in his current car. My own thoughts would be that car makers would set the thermo to turn fan on when engine reaches optimum performance temp. Mike, the car would be going Carlow-Dublin and back everyday, so I guess he will have to look into it a bit more before buying.

Don't know what you mean by the A/C is disconnected, the AC clutch is disconnected or the gas has been purged or the belt to the compresser cut?.

Anyway, can I then assume you have a larger rad with 2 fans?. and possibly 2 complicated rad fan relays, which can switch between, 1 fan, 2 fans at half speed and 2 fans at high speed?.

I had a problem with my Camry where the rad fans ran at 1/2 speed constantly, including some minutes after leaving the car..... eventually that became until the battery ran flat. Turned out to be the 2 relays, one of them fused the contacts.

Now in addition to this, if the ste, non-AC temp switch is disconnected on any Toy, the fan(s) run at full speed, inbuilt cheap & cool way of checking the fans. So I'd first suggest checking the Temp sensor that drives the Fan(s) with the AC off is 1) connected, 2) functioning.

Also, check the thermostat is OK and OEM, Toys have a habit of reacting badly to loose spec non-OEM thermostats.

Normally, with the engine hot and ideling, the rad fans should cycle on and off about every 3~5 min.