Simmering over 440 Overheating Issues – Part 2


A progressive update on my working on my overheating problems.

I decided to to troubleshoot this problem one step at a time.


Here a new Milodon hi flow thermostat, similar to the look of a hiperf Mopar piece I saw on Ebay.


The first thing I did was change the thermostat. First I drained the coolant into a new 4 gallon oil drain container so that I can reuse the coolant if needed.

In preparation to replace the thermostat, I ordered a new gasket and some gasket sealant from Jegs, but I will continue to use the current gasket until it breaks or no longer seals. There’s sealant on both sides of the gasket, but I am able to remove the coupling without damaging the gasket. If you know you’re going to be disconnecting this joint several times, I’m not sure if I could have used a technique I used on my Mustang valve cover gaskets to allow reuse and ease of removal of the valve covers to adjust the mechanical lifters. If you do this trick on your valve covers, apply sealant to the valve cover and tack on the gasket to the valve cover. In the thermostat’s case, the gasket is tacked to the block side.

Parts I ordered that I didn't need.

Parts I ordered that I didn’t need. Save for next time.


I forgot to take pictures of replacing the thermostat because I was busy explaining to my 10 year old son the idea of the Scientific Method in trouble shooting, changing one variable at a time to be able to isolate the effects on any given change.

Here' s the one that was in there, a no frills unit.

Here’ s the one that was in there, a no frills unit.


With the coolant drained from the radiator, I could see I have a 3 core/row radiator and gunk covering or partially covering every down tube I can see from the opening.

Not good, though a probable indication where the problem is. The last time I sighted the upper tank channels I didn’t see this crud. After an experience like this, that coolant (what ever I am going to use) is going to be changed more often.

Yuk! This looks like chit.

Sighting into my rad after draining the coolant. Yuk! This looks like crud.

I took a small pick to check the consistency of the crud stuck in the upper channels and it breaks apart like mineral sediments despite the gooey looking appearance. Geez, that looks nasty.



I took the car out for a drive around town and out on the highway and  I could sense even around town the temperature was slowly rising. By the time I made a high speed pass on the highway, the temperatures went high out of the “normal” temperature zone.

With the temp needle out of range and getting hotter as I approached my driveway, I started smelling what reminds me of overheated electrical or burnt electrical motor windings. Not sure what the source is but I’ve noticed the smell a couple times now when the engine gets too hot, hot enough to fill up my overflow unit to maximum capacity.



So I proceeded to take my radiator out to clean it. Removing the radiator on an old Ebody especially with a manual transmission (no tranny lines) is pretty simple. Removing the battery and washer bottle allows easy access to the four screws that mount the radiator tot he frame and then you can remove the four clips that hold the shroud to the radiator.

Removing the lower hose (after draining coolant) is easier if you remove the attachment to the water pump first, then using a blunt pointed object, push the lower hose connection off the lower radiator outlet as the coolant lubricates the operation.

Before lifting radiator out of car disconnect fan shroud and place protection like a fender cover over fan to avoid accidentally damaging radiator fins on fan blades.

Disconnect the fan shroud from the radiator and you do not need to remove the fan. Protect the radiator during lift out by placing a protective material (fender cover) to prevent gouging your radiator with the fan blades. Remove lower hose before lifting radiator out.

Disconnect the fan shroud from the radiator and you do not need to remove the fan. Protect the radiator during lift out by placing a protective material (fender cover) to prevent gouging your radiator with the fan blades. Remove lower hose before lifting radiator out.

I flushed out the residual coolant in preparation for cleaning.

I flushed out the small amount of residual coolant in preparation for cleaning.


Well…. it depends who you talk to when you pickup the phone.

I made a couple of calls this morning to get a recommendation to get the radiator rodded out, but have not found one yet. One guy said this isn’t done much any more due to toxic materials. Not sure about that.

I spoke with another guy I’ve worked with and having some experience with restored cars was able to recommend a couple of radiator shops which I will keep in mind if I want to recondition my radiator. It certainly ought to be cheaper that buying a new radiator and the fit will be without question.

A sight at the lower tank and the bottom of the channels shows no indication of crud build up, so I am going to try loosening the crud at the top with distilled white vinegar (as suggested by my friend Jeff Marcey who lives in a hard water paradise).



instead to taking my radiator to get rodded out,  I went to the local grocery store and got what I needed to try the poor man’s approach to dislodging the mineral/crud buildup at the top go the radiator channels by using distilled water and distilled white vinegar. I’ve read using anything from full strength to 1 part vinegar to 4 parts water mixture. I suppose it depends how long you want to leave your parts soaking.


High Tech Materials from the local mexican grocery store

I’m trying laying the radiator flat and using boiling hot distilled vinegar water and soaking overnight, then draining (careful to notice any sediment or debris)  flushing out with the water hose and then rinsing out with distilled water. Inspect the upper channel crud level and repeat if necessary.



I would be nice if this works. BUT If there isn’t a dramatic improvement, I’ll have to think about what is next. Do I find a shop to rod out the radiator or go a for 4 core radiator for insurance and upgrade?


Using kitchen appliances for quick boiling of NON-TOXIC radiator cleaning solutions.

I just needed something to plug the overflow hole so my vinegar solution didn't drain on the ground.

Other use for overflow unit. I just needed something to plug the overflow hole so my vinegar solution didn’t drain on the ground. Looks like an IV.


I’ve read people using an aftermarket flush or Arm and Hammer WASHING SODA (NOT baking soda) to neutralize the vinegar acidity. I suspect the rinsing qualities of Washing Soda is better. Maybe it’s finer, I don’t know. I’ll look for some the next time I’m at the store. I like these non-toxic ideas.




A word about GANO filters. GANO filters are a novel product that you install in the upper radiator hose. You need to cut a hose and  clamp the cut ends on the ends of a this clear plastic device with a wire mesh screen that traps crud coming from the engine before  it gets trapped in your radiator. It’s a great idea but let me suggest an idea way to use it based on my experience.

I ran one of these on my open track Mustang but it cracked at the track and I had to take a spare hose from a fellow tracker and replace my upper hose. What I may do later is buy a new cheap radiator hose and put a GANO filter on it and then run it long enough to catch any crud in a period after flushing the system after putting a new or cleaned out radiator in.

For long term reliability, I would install the regular Mopar upper hose. The last thing I need is getting stranded on a highway with a busted GANO filter.

I did look at the GANO website and they offer strong non-plastic versions but naturally, you will need to disconnect your radiator hose to see what the crud condition is.


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The Dodge Kid in his youth about 1976. I think I wore this hat everyday through my Freshman year in high school. Photo by Nick Yee

The Dodge Kid in his youth about 1976.

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