[PJN]

Always hot in Phoenix. Would replacing the radiator with an aluminum one help to improve the cooling so that I would be able to use the a/c when it is 110 outside?

When accelerating I get a shudder/thumping from the rear. It feels as if the rear axle is shuddering with aggressive upshifting and acceleration. No shuddering/thumping when not being aggressive with acceleration and shifting.

pjn

 

[Andrew]

Even in AZ, these cars don't normally run hot. So I'd say first diagnose and solve whatever problem you have. Clogged radiator, bad thermostat, no thermostat, etc. Normally these run right on the thermostat temp (180 or so).

Hard to diagnose the second one via the internet. Could be bushings in the rear end, trailing arms, trunnion, bad u-joint, driveshaft problem. Jack the car up, support it, get underneath and wiggle/check things. Or take someone knowledgeable along for a ride for diagnosis.

Andrew

 

[rhamphorychus]

My aluminum radiator definitely helps lower the temperature.

 

[hans2]

An exhaust component placed too close to a body part will produce this shuddering, as will a binding driveshaft. Because sound has a funny way of propogating through the body, the exhaust interference could be in the center of the car.

 

[jarrington]

Always hot in Phoenix. Would replacing the radiator with an aluminum one help to improve the cooling so that I would be able to use the a/c when it is 110 outside?

When accelerating I get a shudder/thumping from the rear. It feels as if the rear axle is shuddering with aggressive upshifting and acceleration. No shuddering/thumping when not being aggressive with acceleration and shifting.

pjn

My old '87 Quad stayed plenty cool with the A/C blasting in 100 degree+ weather. The R12 based system was ice cold, too. The cooling and A/C systems on the later Bosch Spiders work very well when they're in good stock condition.

There are lots and lots of parts that could be causing your second problem. Transmission mount, Giubo (rubber donut on the driveshaft), center driveshaft mount, u-joints, trailing arm bushings, trunnion to differential mount, sway bar end links, etc. Like Andrew said, get under there and start wiggling stuff. If you see a likely suspect take some pics of the possible problem and post it to the BB for analysis.

-Jason

 

[Alfajay]

Always hot in Phoenix. Would replacing the radiator with an aluminum one help to improve the cooling so that I would be able to use the a/c when it is 110 outside?

pjn:

Maybe I'm just echoing what others have said, but...

Sure, IF your radiator is the problem, and if you replace your old radiator with a new one, the engine will probably cool better. But, that doesn't mean that aluminum is somehow better than copper - In fact, copper conducts heat better than alumnium (*).

I would start by diagnosing the cooling issues as Andrew advises - if the radiator is found to be the problem (they do clog with time), then having a radiator shop service it might be the first step. If you're lucky, they can do an operation called "rodding" which basicly clears out the crud. If it's too far gone for that, they can replace the core. Replacing a stock core with a higher-capacity one will increase a radiator's cooling capacity.

Putting in a heavy-duty aluminum radiator will increase the cooling capacity too, but again, not because aluminum is better than copper. Aluminum's main advantage is that it's cheaper and stronger.

--------------
* A little Wikipedia research came up with the explanation of thermal conductivity at http://en.wikipedia.org/wiki/Thermal_conductivity To make a long story short, copper has over 2X the thermal conductivity of aluminum alloy.

 

[Andrew]

As you're in AZ, you've got the hardest water on the planet, full of minerals. Even with religious use of antifreeze, you've probably got deposits in the system, unless the car has used distilled water with no tap water its whole life.
The Berlina I bought in Phoenix, which had been in AZ, NM its entire existence, had the most corroded head/block/head gasket I've ever seen.
A good flush, and checkover by a radiator guy (maybe a "rod out") would be a good step. If you're able, take the radiator out and take it in to a shop to have it assessed. As we say above, these systems can handle the heat if they're working right; if the radiator and/or block is full of calcium deposits and fossils, it won't do as much cooling.
You're not experiencing head gasket issues are you? Or using water?
A 50/50 mix of water/antifreeze is recommended most times and places, but them more water in the mix the better it'll remove heat.
Of course, in Phoenix if the air temp is higher than the water temp, the car will cool the surrounding air, rather than the reverse.
Andrew

 

[jarrington]

Not entirely on topic but a good story nonetheless:

I took my Super's radiator to a lowlife dirtbag cheat of a radiator guy back in VA who proceeded to soak it in a tank, spray it (poorly) with black rattle can paint and called it "rodded out" for something like $100 bucks. The car still overheated like crazy. Once I got to UT I found a well regarded radiator guy and asked him to recore the rad, thinking that if it was still bad after the first guy was through the core was toast.

The new honest radiator guy actually did some work on it, and found that the rad was completely clogged - with nuts, seeds, grains, etc. Apparently while the car was disassembled some critter found a nice place for his winter stash, which the lazy dirtbag cheat didn't even budge. He gave it a good cleanout and the car's been much better, though it still runs warm and a recore is still probably in my future.

-Jason