Keeping the PT cool

[jwangelin]

It was a rough winter. Early this winter I was doing a lighting upgrade and between my stupidly and some loose wires my PT425 went down. I blew both coils on the Robin engine. Fortunately I found a used set. Now it’s time for me to overthink things in the spring since it’s too wet to do anything. Seems like heat is the biggest enemy of the PT. I cut some luan and set it in the back of the engine figuring it will prevent the recycling of hot air. I also set a side fan but only with a manual switch. I would like to set it up and activated like the trans cooler but not sure where it would be activated.
Has anyone moved their engine oil cooler or installed a larger one? Finally finished moving the lights to a better location.
Any suggestions?
Thanks!

 

[ponytug]

You could add a high amp relay to the little temp switch that PT uses for the PTO cooler and have the relay output drive the two fans. If it were me, I would add a new power wire for both fans and fuses.

Nice mods!

All the best, Peter

 

[MossRoad]

It was a rough winter. Early this winter I was doing a lighting upgrade and between my stupidly and some loose wires my PT425 went down. I blew both coils on the Robin engine. Fortunately I found a used set. Now it’s time for me to overthink things in the spring since it’s too wet to do anything. Seems like heat is the biggest enemy of the PT. I cut some luan and set it in the back of the engine figuring it will prevent the recycling of hot air. I also set a side fan but only with a manual switch. I would like to set it up and activated like the trans cooler but not sure where it would be activated.
Has anyone moved their engine oil cooler or installed a larger one? Finally finished moving the lights to a better location.
Any suggestions?
Thanks!

On my 2001 PT425 there is a thermo switch in the hydraulics that activates the hydraulic cooler fan. It feeds the fan directly and has an in-line fuse. The switch died decades ago and I just run the fan all the time now.

If I was going to run multiple fans, or replace the thermo switch, I'd change it so that the thermo switch would activate a relay and the relay would feed the higher current to the fan.

So if you're thinking of running multiple fans off of your thermo switch, consider having it trigger a relay for each fan. The thermo switch will thank you and you can run larger wires to the fan to handle the current better.

 

[MossRoad]

You could add a high amp relay to the little temp switch that PT uses for the PTO cooler and have the relay output drive the two fans. If it were me, I would add a new power wire for both fans and fuses.

Nice mods!

All the best, Peter

What he said!

 

[marrt]

Would you mind sharing where you purchased that fan? 80W is an extremely low power requirement for a 12v fan.

As to the plywood in the rear I don't think this is a good idea. As you can see from your phote, the intake for the engine fan is already somewhat restricted by the rear tub cutout. Adding plywood around this area further impedes its ability to draw in cool air. Also, if I remember correctly the oil cooler is on the left side of the engine. It's probably not fed by the engine fan and relies instead on air naturally circulating around it (some are fan fed, some aren't). Plywood in the area shown would further restrict air circulation around the oil cooler.

I cut out the entire rear of the tub on my machine for another purpose (to fit a larger engine). But one side effect was improved air flow. I'll post a picture later.