1973 C10 "The Purple Truck"

[mrk5]

I have a couple of the big block radiator factory top plates and could have given you one.

Didn't even think to throw up a request in the Wanted section. I did check the local pick n pull with no luck. I heard a story that "chrome will get you home" so I figured the chrome plate was a good investment.

I was too sleepy last night to go into more detail, but my splurge on the electric fan install was a Derale PWM controller. I was looking for the Spal unit @kgblazerfive used, but apparently they don't make it anymore. The reviews on the Derale unit were a little mixed but mostly positive. I really want to try it because it has a soft start feature and runs the fans a variable speed depending on need.



It runs both fans together. It has an AC override that I haven't hooked up yet since it's winter, I figured it can wait. IIRC, the A/C override kicks the fans on a 60%.

The only thing I had an issue with on install is that I used larger power leads than they provide. I used 8ga and my ring terminals we too big for the space available under the cover. I had to trim them down a little.



The soft start definitely works. Nate and I were warming the engine up to get the coolant level set after the radiator swap. We kept looking at the fans but they hadn't turned on. The temps never got much above the thermostat setting and we kinda forgot about it. Eventually I realized the fans were running at a low speed. So they had come on and we didn't even notice.

Perhaps the most interesting thing about the controller is the temperature sensor. It tapes to the outside of radiator header above the OUTLET on the cold side. It's supposed to be more proactive rather than reactive because it's on the cold side.

 

[kgblazerfive]

I like that one. Spal controller is basically the same thing works the same way.

 

[mrk5]

Finished up the radio install.



I only have the new center dash speaker hooked up and it works well enough, but definitely eager to have the sub hooked up.

As I mentioned before, this is the most basic RetroSound radio. Biggest thing is a lack of bluetooth. Also the next higher level radios may have pre-amp outputs, but I'm not sure. This one does have an AUX connection on the back. That works just fine for me using the Echo Auto. The only thing I'm missing is the hands free calling stuff, but the cab is small enough the mic on the phone in the holder picks up my voice fine.

One feature of this radio I REALLY like is a setting that drops the volume to a set number when you restore power. It happens to me all the time, you end up with the volume up pretty high by the end of the drive. So the next time you get in the vehicle, radio is blasting. With the setting on this radio, that doesn't happen.

Another favorite thing is this truck has the windshield antenna. Works just like any other antenna on the other vehicles I drive, but I don't have an antenna poking up out of the fender.

 

[ashman]

My '78 Monte Carlo had a windshield antenna. I miss it. Worked great and clean lines.

 

[folkenheath]

Perhaps the most interesting thing about the controller is the temperature sensor. It tapes to the outside of radiator header above the OUTLET on the cold side. It's supposed to be more proactive rather than reactive because it's on the cold side.

View attachment 324641

You deraled your own thread?

Those soft start units are pretty cool. As for the sensor, that seems kind of backwards, it sensing the temperature of the hose that the coolant is in after it was already cooled by the radiator, so that's the coolant going back into the engine, not how hot the actual engine is by the coolant coming out of it. I usually like to get the sensors that directly measure the coolant temp in the engine rather than a more indirect measurements of the radiator fins or the rubber hose. But if I had that sensor I would prefer it on the hot side, not the cold side.

 

[mrk5]

The sub behind the seat rounds out the sound very nicely. But I do feel like it's a little odd with all the sound being in the center of the cab. I have the brackets to mount the rear cab corner speakers, so I think I'm going to do that to get some sound on the out on the edge of the cab. Kind of fill out the sound more.

My question is, do I need to remove the cardboard tray thingy to install the speakers?



I'm thinking I might just be able to cut a hole in the cardboard to clear the back of the speaker. Or I might just cut the end off the cardboard tray.

 

[Truckman4life]

I would just trim to fit as needed.

 

[mrk5]

This is what I ended up doing.





The speaker bracket overlaps the cardboard tray so it helps hold it in place. On the passenger side I can be a little more "surgical" now that I know how much needs gone.

 

[mrk5]

I had to flip the speaker brackets so the speaker ended up in the pocket of the cab corner. I tried searching everywhere for pictures, but the only one I found of the factory brackets was installed like I started with mine.



Makes me curious if there's a difference between 70's and 80's cabs and how the speakers fit.

Irritated I had to drill additional holes to swap the brackets, but happy they work. The sound is much fuller now.

 

[mrk5]

I haven't had a truck with the factory coolant temperature gauge in a long time and there's something this truck does that baffles me. After it has sat for several hours, particularly on the first drive of the day, the coolant temp will climb all the way to nearly 250 before dropping all the way down to 180 and staying there. It's done that thru 3 different radiators, couple of thermostat changes, new coolant temp sender, and 2 different fan clutches. It almost seems to get the hottest on the coldest mornings.

Only thing I can figure is it's because the sender is in the head. The coolant hasn't really normalized the temperature through out the block, so the temperature in the head spikes until the tstat opens the first time. Just thought it seems odd.

 

[ktmoutfront]

Yep. I had one that did that. Sensor in the intake or on the thermostat housing fixes the high temp numbers on the gauge.

 

[6872xtc]

My experience had been that the thermostat is the problem. They don't make good ones anymore, nothing like the Robert Shaw ones from years ago.
That's why I drill a small hole in the flange of the thermostat so that there is better "signal" to it. It lets a little coolant flow past the bulb all the time. This isn't a 100% cure, but it seems to help a lot.

 

[imiceman44]

My experience had been that the thermostat is the problem. They don't make good ones anymore, nothing like the Robert Shaw ones from years ago.
That's why I drill a small hole in the flange of the thermostat so that there is better "signal" to it. It lets a little coolant flow past the bulb all the time. This isn't a 100% cure, but it seems to help a lot.

I now buy the one that has that feature, it's kind of a one way valve

 

[mrk5]

I kinda wondered if it could be a thermostat thing. I bought an Edelbrock brand hoping it would be a good one, but it doesn't have bypass holes. I did buy one with the holes for the crew cab and it doesn't do the temperature spike thing. Nate even mentioned that he drills holes in the tstats they put in the USPS delivery trucks. I should have asked this before I did the radiator swap.

 

[6872xtc]

We figured that you knew already...

I believe that moving the temperature sensor to the intake ignores what the head is seeing because the coolant in the intake dilutes the hot coolant coming from the head. This is only what I can think in my head, as I have had a couple of trucks do this and I was able to cure them by either changing the thermostat or drilling holes. This is also why I started buying the reusable thermostat gasket... because one I had to take one apart the same day.
I thought that I didn't need to drill holes in one brand.

 

[mrk5]

We figured that you knew already...

I believe that moving the temperature sensor to the intake ignores what the head is seeing because the coolant in the intake dilutes the hot coolant coming from the head. This is only what I can think in my head, as I have had a couple of trucks do this and I was able to cure them by either changing the thermostat or drilling holes. This is also why I started buying the reusable thermostat gasket... because one I had to take one apart the same day.
I thought that I didn't need to drill holes in one brand.

I bought one of those gaskets and when I was torquing it down, an ear broke off the housing. And I'm a torque wrench nut so I wasn't over-tightening it. That made me gun shy about using that gasket.

 

[6872xtc]

I bought one of those gaskets and when I was torquing it down, an ear broke off the housing. And I'm a torque wrench nut so I wasn't over-tightening it. That made me gun shy about using that gasket.

It could have been that the housing was already comprised. I have had that happen with standard gaskets and I saw a cheap chrome one warp with a standard gasket, so I don't know if the gasket would be the primary problem. Do you remember what torque you were heading for? Could it have been too much? I'm just wondering cuz I do that sometimes.

 

[mrk5]

It could have been that the housing was already comprised. I have had that happen with standard gaskets and I saw a cheap chrome one warp with a standard gasket, so I don't know if the gasket would be the primary problem. Do you remember what torque you were heading for? Could it have been too much? I'm just wondering cuz I do that sometimes.

I don't remember for certain. I want thru my digital manuals and created my own PDF with just the various torque value tables. Memory wants to say 25ft-lbs.

It probably wasn't the gasket's fault just the POP was quite traumatizing. I also had a problem way back on the K5 with one of those chrome housings with the oring wanting to leak. Seems like I always end up just putting Right Stuff on them.

 

[mrk5]

Since it's cooler outside, the fans haven't been running at a very high speed. I kept thinking "are they even working" but when I would walk around front I could hear it. At lower speeds the motors make kinda funny noises, like if you barely hold the trigger on a cordless drill. Which I suppose makes sense because it's probably the same concept.

I finally added a little LED status light. It's connected to the positive and negative on the fans so I know when the fans are getting power.



There were 2 holes in the panel under the steering column from the previous owner. I used 1 for the light and the other is a switch that is manual override of the Derale fan controller. You can connect a switch like I did or it can also be connected to the AC compressor so the fans kick on with the AC. A big reason I went to the electric fans was because of AC, but I decided I would still rather manually control the fans for that purpose.

 

[beags86]

How's the radio working? Where did you source that one again?