This is a weird situation I'll try to describe as best as I can. Earlier today after my '74 Dodge Dart had been parked in a cool parking garage for several hours, I fired her up to head home for the day.

About ten minutes down the road I stopped at a redlight. Just then I smelled a burning rubber and/or burning plastic odor. Just as I smelled the odor I notice a small cloud of dark smoke come out from under my passenger side firewall over the front right tire.

As I noticed the smoke I looked at a guy in traffic in the lane to the right of me and asked him if he saw that smoke come from my car. Because it happened so fast, I wasn't sure if it was me or not. And my car was idling fine.

The guy in traffic said, "It looks like you are overheating." Just as he said this to me, I looked at my temperature gauge and it was pegged all the way to the right indicating an overheated engine. So I quickly pulled off onto a side road, turned off the ignition and got out to inspect the engine. Keep in mind though, that the car was acting totally normal.

As I looked under the hood the first thing I noticed was that there was no signs of an overheated engine. In fact, I could touch the head and it was only mildly hot to the touch. There was no steam coming from the radiator or anything that appeared flawed with the coolant system at a glance.

I also checked to make sure I didn't burn off a belt anywhere and also checked to see if somehow a rouge piece of rubber or plastic had somehow made it's way onto the exhaust manifold or exhaust linkage. For example, I once ran over an empty black trash bag in traffic before and had it wrap around my exhaust just below the manifold which in turn melted severely and caused a burning plastic smell for over a week before it finally all just burned off.

Anyway, still, reality of today's situation is that my temperature gauge is pegged, there was a small cloud of smoke and a burning smell. I removed the radiator cap expecting a burst of steam but the engine was not really hot at all as I mentioned earlier. I then left the cap off and cranked the engine up to return and see what the coolant level was and whether or not it was flowing.

Upon inspection of the coolant level with the motor running, it was microscopically low but flowing like a river. So this ruled out a bad thermostat in my mind. Although this is not to rule out a failing thermostat I guess. In meaning that my thermostat could be going bad and not opening correctly or fully.

I always carry a jug of premixed coolant in my trunk and decided to top the radiator off for good measure. But it only needed a tiny, tiny amount of coolant. Barely any worth mentioning really. So, full of confusion and a bit of paranoia, I closed the hood and drove back into traffic. With the temperature gauge still pegged, I drove 20 miles home and all was well. Everything seemed fine.

So, I allowed the car to cool down fully for four hours. I went back out and cranked the car up. Immediately the temperature gauge pegged to overheat. So, I have some sort of crazy electrical thing going on and have absolutely no idea what is happening. I am going to flush the radiator out tomorrow because I didn't do it yet for summer season anyway. And I figured since I am draining the coolant, I might as well slap in a new thermostat for piece of mind.

However, the pegged meter and the brief burning smell along with the very brief cloud of smoke has me utterly boggled. Because whatever happened today in traffic is connected with the now clearly damaged temperature gauge.

Thoughts?

Check the temperature sending unit wire it may have gotten burnt in some way.

You have a short in the wire that connects the temperature gage to the temperature sensor located near the top radiator hose in the head. The burning plastic smell was that wire melting.

Based on your previous queries regarding your cars electrical system at a minimum I think a it is time to chase every wire and connection replacing as needed, or your car may fall victim of the fire gods.

Until you are able to correct your wiring problems I recommend installing a "Battery shut-off" switch at the battery so you can quickly kill the power to the electrical system incase of a major melt down. Wal-Mart has these devices with the little green knob for 7 bucks, and they mount on the negative battery terminal. I install these on my old cars.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Okay, that does it. I am buying a "Painless Wiring Harness" and getting rid of any more electrical madness.

Here's what happened:

Upon total inspection of my electrical system, the power wire that sends a return charge from my alternator back to the battery became frayed and arced off the steel body of my Dodge against the rear firewall. This in turn resulted in all of my electrical wires that were taped together to melt into one big giant mess of burned wiring.

This was the black puff of smoke I saw. And this was why all of my meters in the dash began reading inaccurately.

My temporary solution on Saturday was to clip off every single wire and cut out a 12 inch section where everything was fused together. I then painfully rewired every single wire by hand. But again, this is a temporary fix. I need the car for my commute to work.

After rewiring the car, all gauges began working properly again and the car idles better and simply drives great. It has more power, etc.

But as a testament to just how tough old Dodges and the Slant 6 really are, the car ran for three days with melted wires directly off straight battery power. Again, I was not recharging my system at all after the meltdown.

But to be honest, my car is not original in any way nor will it ever be. I run MSD electronics and so forth. Thus I am going to install a "Painless System" unless someone has better suggestions of which I am all ears as they say. Because the Painless System may be "painless" to install. It certainly is a pain in the bank account. Over $500!!!

Thanks Friends!

Uh...stop. The latter does not even begin to follow from the former. In fact, if you buy that "painless" junk, you will spend a whackload of money to buy yourself a great deal of hassle (i.e., pain).

If you have wiring problems, fix them. If you need a new wiring harness, get the correct one. It's not costly or difficult from Evans Wiring.
Fun stuff. What is the amp rating of your alternator? If you have one that produces substantially more than stock output, it may be partly to blame.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Luuuckeeee, the Fire Gods have been benevolent to you my friend.

Dan is correct, Evens makes up good stuff. If you have some custom electrical connections he will accommodate if possible.

I had problems with my wiring system on my '67 Dart, not much worked when I got it winter of '08. This was the forth car (toy) in the fleet, and was not needed for daily service.

Faced with the cost of a new harness, or a comprehensive conductor by conductor repair job, I chose repair. Being a semi-talented piker with the necessary skills & tools to do the job, all it took was a lot of time, and a lot less dollars. One benefit of chasing each wire, and following the schematic has given me a good understanding of how the Dart's electrical system works.

I did purchase a new old stock bulkhead connector, and a few wires that have MOPAR specific molded rubber connectors such as the coolant sensor, and brake pressure wire terminals from Evens. I also replaced all the brass male & female connectors. Evens was on time with good workmanship.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I agree 100 percent with that statement. My valiant is my first project car and along with this board, the FSM, and hands on I have learned ALOT. Except for why the backup wire goes through the radio? I dunno. But anyway I've been rewiring the car due to burned wiring and because of that I've found out why certain things work or don't work. Plus I'm able to increase the wiring size and add in fuses and new connectors and whatnot. The only problem I really had was the dash cluster and the round connector - after I got it off I couldn't get it back on with the cluster installed. So I finally ordered an amp wiring harness from terminal supply and did away with the old connector. And the other reason I went with wiring it myself was the cost of the wiring harness kits, I didn't have the fundages. -Dan

dncoles: Keep researching those two circuits.

Up Dated Comments:

After rechecking the online 74 wiring schematic you are correct, the radio is fed along with the heater blower, and back-up lights by the same fuse. I was working off of a poorly printed copy where the bottom of the page did not fully print. Sorry if I mislead you.

Your radio would be well served if you were to install an inline fuse after the splice that feeds this radio branch circuit. My '67 calls for a 5 A fuse to the radio. It is a factory AM transistor set. If you have an after market set you will need to look up its power requirements and fuse accordingly.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Haha!

The Fire Gods got me twice this week!!!! You fine fellows warned me! And it happened twice. Both times were arcs from frayed wires. I have since rewired all burned wires by hand until I order the new harness. And I am going with the one you guys all referred. Not the painless system.

I'll keep you updated on my progress.

Have confidence; I just today received my new Evans underhood harness for my '71 Dart. It is A-number-1 workmanship with top-quality materials.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.