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Tue Jun 03, 2008 1:59 pm

I added an oil cooler recently, including a fan. The whole shebang is in the hollow by the passenger-side tail light.

I haven't powerd the fan up yet because I'm not sure exactly where I'm going to draw the power. Is it okay to get it right off the alternator or should I run power all they way back from the battery or fuse block?

THANKS!

Tue Jun 03, 2008 2:04 pm

I wouldn't wire anything directly to the alternator. Seems like that would be a good way to fry things. I would tap into the fuse box personally. I've wired things directly to my aux batteries but not the primary one. Just my $0.02

Tue Jun 03, 2008 9:53 pm

The battery wire on the alternator goes directly to the battery. What's the difference between the connection there and the connection at the battery? Nothing. I would put an inline fuse near the alternator, though.

Tue Jun 03, 2008 10:11 pm

You can power it from the alternator or starter, but you need a way to turn it on and off that is 100% dependable.

Tue Jun 03, 2008 10:34 pm

FNGRUVN wrote: The battery wire on the alternator goes directly to the battery. What's the difference between the connection there and the connection at the battery? Nothing. I would put an inline fuse near the alternator, though.

That's what I was thinking. THANKS!!!!

Wed Jun 04, 2008 4:00 am

Any time you install an electrical device, it should be fused. This is the cause for many electrical fires in vehicles; owners that install boom box radios, and other electrical accessories without them being properly protected, with a correctly rated fuse for the device.

Don't connect directly to the alternator without installing a fuse.

Wed Jun 04, 2008 5:53 am

bucko wrote: Any time you install an electrical device, it should be fused. This is the cause for many electrical fires in vehicles; owners that install boom box radios, and other electrical accessories without them being properly protected, with a correctly rated fuse for the device.

Don't connect directly to the alternator without installing a fuse.
Bet your bippy, that's sound advice. Use a relay to controll it.

Wed Jun 04, 2008 6:24 am

bucko wrote: Don't connect directly to the alternator without installing a fuse.

Yep, you betcha. Got the fuse and a relay already wired in. Just wasn't sure about where to get the power!

Again, THANKS!!!!!

Wed Jun 04, 2008 10:57 am

So how is your relay triggered? I'm assuming you have a thermoswitch to turn on the fan, but what control are you using so the fan only runs with ignition on? Or are you going to let it do the VW radiator-fan mambo, where the fan can run at any time until it does enough cooling to open its thermoswitch?

Wed Jun 04, 2008 12:49 pm

tencentlife wrote: So how is your relay triggered? I'm assuming you have a thermoswitch to turn on the fan, but what control are you using so the fan only runs with ignition on? Or are you going to let it do the VW radiator-fan mambo, where the fan can run at any time until it does enough cooling to open its thermoswitch?

Theremoswitch? Oh, you wish I was that smart. So do I.

The relay is powered off of - what is it - P or G? Whatever one is hot when the engine is keyed on. Sitting here right now I can't remember. And the thermo switch is typing right now.

The cooler as-is without the fan engaged seems to be doing good. At extended highway speeds across the Texas hellscape I am getting 40psi at 4k rpm even on a mild climb or better. On the biggest extended hill climb it may have dropped a bit below 40psi. There are no major, major climbs near me so I don't know how it will do going from Phoenix to Flagstaff at high noon. I'll find out in a few weeks. In the city it does 40-50psi or so at 4k or better.

So the fan will be triggered by me until I get one of those thermo-switches. It ain't fancy but budget-wise, that's where I am.

Wed Jun 04, 2008 1:03 pm

I have mine with a thermo-switch AND a relay that is controlled off the front radiator switch, if it comes on(front radiator) , the fan on the cooler comes on., or the thermo-switch turns it on.

I also have an over-ride switch on the dash that turns on the cooler fan and the stock radiator fan.

I'm a control freak...I'll admit

my power is comes from an auxillary fuse box I made, that is mounted beside the factory fuse box , and I use AGC glass fuses.

http://www.kayakwesty.com/oilcooler.html

Wed Jun 04, 2008 1:03 pm

Use a relay with primary power from the alternator (with a fuse :? ) and switching power from the coil (Or a thermoswitch).

Wed Jun 04, 2008 6:20 pm

Inline oil thermostats look like this:

http://www.cbperformance.com/catalog.asp?ProductID=1330

They suggest installing it on the inlet side of the cooler, but it's better to put it on the return side. No point in overcooling the oil. You do want it hot, just not too hot.

You could come off the alternator + pole for power if you want, as a supply for the relay. As signal, I don't favor coming off #15 on the coil, as it lowers the voltage there and tends to cause problems with the ignition. Instead, and closer to your application, test the two wires on the power steering pump switch: one of them goes hot when ignition is on. This one is safe to use as a switched signal source. Tee onto that, route it to the inline thermoswitch, and finally to the coil of your relay, the other side of the coil going to ground. Or run the signal power from the PS switch to one side of the relay coil, and ground the other side via the thermoswitch. Either way will work.

Glad you're going to oil cooling. I think it's an essential mod for engine longevity and peace of mind.