Thread: AU Radiator etc in to 3.5V8 RRC

Okay so in a Tech Chatter thread, I sort of mentioned I'd installed the majority of cooling equipment out of my spare AU Falcon (4L inline six) into my 1987 3.5L EFI V8 RRC. I wasn't going to hijack the thermofan thread I was on, so here's a brief how-to on the installation.

First some notes:
Before I get started on the serious stuff, some background on the vehicle. I bought it 2 years ago as a wreck, bad LPG conversion done by fitter (no names mentioned aye sprint), EFI harness was rotten where they "soldered" connections. Long story short, the engine caught fire, everything that could burn and melt, did. So it probably goes without saying that the cooling system was put under a massive amount of stress, I had no reason to trust it and it eventually failed.

I should also mention that after the fire I had no intention of repairing the A/C system, so all A/C components are gone, including the condenser.

Header Tank:
The brass oem tank in my 87 sprang a leak on the seam, it was enough to depressurize the system and cause over-heating. I'd made a temporary repair (wrapped the damn thing in 3mm of fiberglass) it worked, but only temporary.
Radiator:
After I sealed up the old header tank, the radiator sprung a leak on it's passenger side seam. It was probably plugged and all sorts of other issues.

So out with the old:
--Header Tank
* Disconnect the hoses
* Undo the two bolts going through the supports and wheel arch
* Remove
-- Radiator
* Remove all hoses
* Drain coolant (responsibly)
* Undo and remove the two top mounts for the radiator
* The radiator should slide up and out with minimal effort
* While you're at it, remove the bottom hose and turn it around. Yes, turn it around, you'll find it's a near perfect fit if you swap it end-to end, it'll match up to the AU radiator with minimal fuss. See photo 3.

In with the new:
-- You'll need, nuts, bolts, washers and steel tube. I used 6mm threaded rod, ny-lock nuts, 10mm washers
* Locate where you want the tank to go - I put mine in the same location as the OEM
* Drill holes where necessary to attach the mounting bolts
* Cut your steel tube to length to raise the header tank away from the wheel arch.
-- If you look in the first two pics, you'll see the header tank raised away from the wheel arch, held in place by the hardware mentioned above. From the top down I've used:
[/ \] Ny-Lock Nut
---- Washer
=== Header tank mount
---- Washer
[==] Nut
---- Washer
| |
| | Steel Tube Spacer (cut to length)
| |
---- Washer
[==] Nut
---- Washer
=== Wheel Arch
---- Washer
[\ /] Ny-Lock Nut

Don't worry about the wires etc, it still needs tidying up. If you cut the steel tube to the right length, you'll end up with a very neat setup.

Next you'll want something for the AU radiator to sit on, I've temporarily used two old rubber dust caps from the top of the old AU's rear shock struts, sit the two plastic mounting dowels from the AU radiator in them. You won't need these until you've got the bottom hose on, it just makes it easier to connect the hose first, then put the rubber caps under it.

Temporarily connect the RRC top hose to the top of the radiator, this will hold it in place while you line up the mounting points. Since I've left the condenser (and the AU condenser) out of the equation, I've had a happy little miracle whereby the AU condenser mounts, line up with one of the steel bars the original A/C condenser fans mounted on. Line up the AU condenser mounting points with this steel bar, drill two holes, install bolts, Radiator installed. Don't forget the rubber caps on the plastic dowels at the bottom of the radiator.

Once you've installed the bolts and mounted the radiator, you can proceed to attaching hoses and clamps. The RRC top hose fits to the top of the radiator perfectly, the bottom RRC hose has to be flipped end-to-end and it lines up with pretty much no kinking or warping. Note the new route under the power steering lines.

The large hose from the header tank runs to the radiator, about half way down on the drivers side. A quick and dirty job would be to cut the hose to an approximate length as I have. But eventually I will be using new hose with 90deg brass fittings to eliminate kinking. For now, you'll see a hose clamp on there just to prevent the hose being kinked shut. Once the system's pressurized it's not a problem at all as the hose will expand.

Attach your coolant return hose to one of the small inlets at the top of the header tank, same goes for the radiator overflow/return hose

Thermofans:
* Slot the bottom of the thermofan housing into the slots at the bottom of the AU radiator, then install the two bolts at the top.

Now for the tricky bit, you'll need a way to trigger the fans at temperature, or wire up a switch etc.
For now, I've just wired them up temporarily, both fans are fed 12v straight from the battery, a relay switches their earth when ignition is in the on position. Yes this means they're on full time, but I did say this is only temporary.

That's it, that's the AU radiator, header tank and thermofans installed. Buy yourself a beer, or shout me a shot of Dram

Further Notes:
I am currently designing a circuit that will operate the thermofans from a 40amp PWM controller. This will operate based on the engine temperature signal which also runs to the dash. Basically I'll be splicing into the harness and using it's varied resistance to trigger a response in the PWM controller.

Shrouding is important. I had a spare piece of roof flashing laying around that was the perfect length and shape for an extended shroud. Once I'd cut a square out for the bonnet strut, it was pop-riveted into place. See picture 4.

Finally, you'll also see in the pics, a rather thick red cable attached to the battery and running along the top of the radiator. This is my 0gauge cable running to the alternator. By a happy coincidence, it fits snugly in the channel at the top of the AU radiator where a return hose used to run.

In a perfect world, I'd have bought all new OEM components to return the whole rig to a perfect, restored, mint condition truck. But the bank account and the hand brake prohibited this. So score one for ingenuity.

To create shock-absorbing spacers for the bottom end of the radiator, cut some appropriate cooling hose to 1 5/8", slip these over the plastic dowels on the bottom of the rad. They'll sit perfectly on the chassis rails to help support the rad. Also at this height, it's not offsetting the overall height of the rad.

So with this addition, the rad is now sitting parallel to the chassis, has room to move, is sufficiently supported at both ends and the lower hose has clearance over the mount on the chassis.