Oil cooler fan

[Frank Sorbello]

I am now in the process of trying to get the oil cooler fan to work. I don't have a diagram of the wiring for the PT-422. Does anyone know where the relay to the oil cooler fan is? I have to broken coming off the fan to a toggle switch, from the toggle switch I am not sure where they go.

Thanks

Frank

 

[Marks481]

Sounds like you don't have the stock configuration, since they don't have a toggle switch to turn teh fan on/off.

On most of the PTs, the fan is wired to a temp sensor that is mounted on the inlet to the oil cooler up underneath the hood of teh engine compartment, and the wiring from there runs to the ignition switch. The fan only runs when the oil hits 120F or something like that. On cold days, it might not come on at all.

There is no relay for the fan.

 

[MossRoad]

On mine the temp sensor went bad several years ago. I now have a spade connector that I hook up directly to 12V before I start the tractor. Eventually I will wire it to a switch, rather than replacing the temp sensor, since so many people report failure of that part.

 

[Frank Sorbello]

My PT-422 has a toggle switch mounted on the engine cover. There are two wires coming off the switch that have been disconnected. I did find the the oil tmp sensor. Not exactly sure how to check if it is bad or not. It is connected. It has an inline fuse attached. I think it might be better to use the toggle switch when running. Do you know how to wire the fan direct?

Thanks
Frank

 

[MossRoad]

Find the wires coming off the fan. One should go to ground somewhere. The other should go to a switch, then to a fuse, then to +12V. You can either connect to +12V right off the battery or as in my case with the Kohler engine, there was a +12V lead coming off the engine. Better to go to a relay that is energized by the key switch, so you can't accidentally leave the fan on.

 

[MALandscaping]

So was running the PT today for the first time in warm weather (~80F) and after an hour or so the fan hadn't come on at all and I started to get a little surging like bad gas. Not sure if it overheated, but it definitely doesn't run as smooth at idle and has some oil in the carb and is not starting as easily. Going to check the valves and see how that goes. Running at 1/4 throttle feels the same as always.

Anyway, fan had a bad temp switch. All I did was run a jumper wire from one side of the switch to the other and the fan runs perfect. Turns out the positive lead from the battery to the temp switch is wired for ignition-on only, so if the PT is running, so is the fan. Two minute fix. Now I just gotta hope the lack of a fan today didn't do any damage.

 

[MALandscaping]

So was running the PT today for the first time in warm weather (~80F) and after an hour or so the fan hadn't come on at all and I started to get a little surging like bad gas. Not sure if it overheated, but it definitely doesn't run as smooth at idle and has some oil in the carb and is not starting as easily. Going to check the valves and see how that goes. Running at 1/4 throttle feels the same as always.

Anyway, fan had a bad temp switch. All I did was run a jumper wire from one side of the switch to the other and the fan runs perfect. Turns out the positive lead from the battery to the temp switch is wired for ignition-on only, so if the PT is running, so is the fan. Two minute fix. Now I just gotta hope the lack of a fan today didn't do any damage.

 

[Marks481]

...I started to get a little surging like bad gas. Not sure if it overheated...Now I just gotta hope the lack of a fan today didn't do any damage.

No worries.

I would bet $$$ that you were starting to experience vapor-lock in the fuel pump. The close proximity of the fuel pump to the exhaust can cause all sorts of bad behavior, and the extra heat under the hood without the fan probably put your engine over the edge.

 

[MossRoad]

I doubt you did any damage without the fan running. My fan has to be hooked up to +12 manually and sometimes I forget for hours and hours. Probably not good in the long run. But once in a while probably did nothing to be worried about. Rest easy.

 

[cqaigy2]

A little oil in the intake is normal too. And the surging sounds like a fuel issue.

 

[KMA]

I was having stalling issues when warm (e.g. mowing) due to vapor lock like MR mentioned. I moved my fuel pump and lines to the other side of the engine, away from the muffler and the engine oil cooler/filter assembly on the EH72FI. I also wrapped my exhaust manifold to try to reduce the amount of heat in the tub. No more vapor lock since. :crossfingers:

 

[KentT]

Don't want to threadjack, but has anyone found an aftermarket source for a 422/425 replacement fan? Mine is beginning to make noise, and I think the bearings will soon go out on it...

TIA!

 

[cqaigy2]

Maybe a wrecking yard might have one off a car that would fit.

 

[ponytug]

The one on my 1445 is a SPAL automotive fan; for the size, it is the one with the lowest power consumption, i.e. there exist two higher air flow versions. They are available at lots of auto parts stores. If you aren't looking for an exact replacement, you could try any auto parts store for a cooling fan.
All the best,

Peter

 

[KentT]

The one on my 1445 is a SPAL automotive fan; for the size, it is the one with the lowest power consumption, i.e. there exist two higher air flow versions. They are available at lots of auto parts stores. If you aren't looking for an exact replacement, you could try any auto parts store for a cooling fan.
All the best,

Peter

Just wondering what the alternatives are to calling Tazewell -- which would almost certainly be more expensive than buying locally.

Thanks!

 

[MossRoad]

I was kind of surprised that there is nothing listed at Surplus Center.

 

[SpringHollow]

for my 1850, i bought a pack of two on ebay for not much money.

Ken

 

[J_J]

Just go to a junk yard and find a fan that is approximate.

You should save quite a bit.

 

[SpringHollow]

The new 16" one for the PT cost $32 delivered.

Ken

 

[KentT]

The new 16" one for the PT cost $32 delivered.

Ken

That's definitely not a Tazewell price...