Overheating? Read this!

[Milsteads Garage]

So, I have been battling an overheating problem since putting my car back on the road in 2023. It was so bad I came up with a new acronym, ?AKBC? or ass kicked by car. What would happen is, the car would run about 30 minutes before getting to 220 and gushing out 3/4 to 1 gallon of coolant, always while getting parked at a car show. Makes for a very bad impression and embarrassing to boot. Needless to say, it took every repair method to fix it which I shall list here. So here is what it takes to get your car to run under 180* on a 100*+ degree day in Phoenix Az.

1) Water pump and belts. The water pump came from Mark II enterprises as a rebuilt unit. The belts were in stock at my local NAPA auto parts.
2) Recored radiator. As I was getting my car to the running good to test phase, pinholes developed. I took it to a commercial radiator shop and had them recore the radiator. I paid $500 for the job but I ?had the hook up? and would have likely costed more.
3) Exhaust diverter. This is the valve that is on the right side manifold that is a cold start aid. These often rust in the shut position and cause exhaust from the right 4 cylinders to then travel through the intake manifold out the left side exhaust creating a very hot top half of engine. This is often accompanied with excessive pinging while accelerating because of the excessive heat. You can either try to track one down and change it or leave it out which is what I did.
4)16lb Radiator cap or Thermocap. This does often help the situation of an overheating car. Pressure raises the boiling point. Here is where ?AKBC? or ass kicked by car comes into play. My temperature gauge was not working so in order to keep myself from adding a gauge and mucking up my dash board, I bought a 16 lb, Mr Gasket thermocap, a nice looking chrome cap with a gauge in the middle. I can tell when the engine gets hot or overheats when I hear the engine excessively ping or see steam. Needless to say after a 30 minute trip it would be spewing water while the gauge read 200. Needless to say, never trust a new part. This cap caused overheating by not holding pressure.
5)160* Thermostat. This is where I had some trouble to work through. When I first got my car in 2018, I was in the process of making the engine run. I knew it would be foolish and dangerous to rely on an original thermostat so what I did was take a pair of snips and cut the guts of the original thermostat out, leaving its shell still in place of the thermostat housing. So recently it became time to diagnose what was going on. As it got to 200* and started dumping water I used a temperature gun to diagnose upper and lower radiator temperatures. Both sides were equal meaning the radiator wasn?t cooling. Turns out, you can?t do that, not run a working thermostat. That causes an overheating condition because of too much flow. So to make a thermostat happen I ordered one from rock auto. I immediately noticed it was just a modern thermostat that comes with a bottom reducer and the two fit snugly in each other. The problem is the bell they supplied doesn?t fit in the thermostat housing. So remember me cutting the guts out of my old thermostat? Turns out it was the right move. Both pieces fit snugly in each other and the thermostat housing.
6) fan(s). It?s so hot in Phoenix that a regular puller fan is almost useless without a shroud which these cars weren?t equipped with. I took off my hood panel and installed a 16in electric pusher fan with a relay I mounted near the fuse box and tapped into the ignition switch for my key hot power.
7)Freeze plugs and engine block wash. This was one of many smoking guns I faced while diagnosing this car, I stupidly saved this task till the very end because I thought it meant having to pull the engine to do this. Long story short, you don?t. It?s not a bad task, just lying on your back and moving fast to avoid a shower in engine block sludge. It requires you to remove the oil filter and starter and drain the engine block at the plugs on the left rear and front right of the engine block. You have plenty of room to knock the plugs out with a drift punch. I couldn?t hardly believe it but my water jackets were completely packed with sludge. I had to dig out the cavities then stick a pressure washer wand in the holes and blast the sludge out. It took 4 tries to get the water passages clean. I assumed when I had my water pump off that the block could be flushed out using those ports. All it would do is blast the top layer off the packed in sludge. Obviously not enough and I should have done this service before putting the car back on the road.
Hopefully, you do all this and your overheating problems should go away but if they don?t from here, something could be haywire in the distributor causing odd timing or your carburetor causing a lean condition. Hope this helps, enjoy!

[jdsnoddy]

Morgan thanks for this. Many older cars overheat.
I think your freeze plug suggestion is great. Thanks for sharing.