Another Overheating Question

[mgm60]

I know about a million words have been written on this subject but here's the questions anyway. This past weekend I replaced my upper radiator hoses because the old ones were mismatched. I included a picture of the new ones which are the same 1.75" I.D. as the old ones. First drive afterward the Temp gauge topped out after about 10-15 minutes. Had a small amount of overflow from the radiator, but could hear coolant bubbling in the engine. Tested the gauge, which is the old liquid type, and at 180 degrees in hot water it shows 3/4 to top line Normal and at 190 right at top line. This is the range the car ran at before the hose swap. Also tested with an Infrared Thermometer after a test run (temp gauge topped out again) and read 190 at the upper outlet and inlet and 210 at the water pump and top of the block. Not running any thermostats and setup with a Mallory Electronic Distributor.

Any thoughts on what to check next?
Mark

[alchemy]

Make sure you have fuel in the tank, and someplace to go?

I guess I don't think 190 is really high. With a pressurized cap the boiling point is probably 230 or more. Is something obviously wrong to you?

Some guys drill a 1/8" hole in the outer edge of their thermostats to let the water burp as it's getting filled. The bubbling sound you heard might have just been the coolant equalizing in the engine and radiator.

[mgm60]

Thanks Alchemy. I'm not running any thermostats and the only obvious thing I have out of whack is the temp gauge now maxing out on me now when it's never done that before. As I said when I tested the gauge to get an idea where it would read at 180 it was reading what I usually see when driving. To get the gauge to max out I had to get my test water temp up to 215 degrees so that's what I assume the coolant temp is in the head. Seems high.

[40cpe]

It is unusual for the temp at the top of the tank to be cooler than the water pump. The water pump is taking cooler water from the bottom of the radiator. Have you measured the temp at the bottom of the radiator? Are you aiming at the metal on the tank, or at the hose at the inlet to the tank?

[mgm60]

40cpe I took the reading at the inlet at the top of the tank on the hose. I'll get readings on the bottom as well, on the metal and the hose. Picked up a couple of Water Temp Gauges at the parts store today and will install those tomorrow in each head.

Also forgot to mention I'm running dual pusher fans in front of the radiator.

[Tinker]

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So were the hoses you replaced the same style as the accordion hoses you used this time? Could the ridges cause turbulence? Shot in the dark as you mentioned this is all you have changed.


I use those type in my 38 truck currently, no issue.


infrared temp guns are cheapish from most home dept stores. Usually work well.

Best of luck!!!

[deuce5wndw]

From your statement about bubbling in the engine I think you have air in your system, and it will straighten itself out with heating and cooling cycle. Had that happen on a 36 LB engine after changing the hoses

[19Fordy]

I think that taking readings off the hose will give you inaccurate readings.
Take your readings on the radiator fins.

[Tim Ayers]

https://www.amazon.com/OEMTOOLS-8700...01A2CQSU6?th=1

I use when filling up the radiator. I keep it attached to the rad neck and keep water in it as it runs. The air bubbles out as it runs. May help you to get the air out if there is any still in the system.

Any over fill will come out the overflow tube and eventually, as mentioned with heating and cooling cycles, it will find it's level.

[alchemy]

I don't own an infrared gun, but I would think the best place to get a reading would be a smooth metal surface in direct contact with the water. A tank on the radiator, or the surface of the head down close to the water, not a fin.

[farmertom]

hey Mark,good place to point thermal gun right where water temp gauge sender in cyl head. got my temp gun from harbor frt. cheap works well,and says exact temp as red liquid in gauge. Tom.

[farmertom]

hey Mark,good place to point thermal gun right where water temp gauge sender in cyl head. got my temp gun from harbor frt. cheap works well,and says exact temp as red liquid in gauge. Tom.

[joe 1950]

deuce 5 and tim ayer’s are on the right track we had those coolant funnel’s at the shop where i worked and they did work great b4 we had them we used to jack up the front of the car and slowly put in the mix and keep waiting for the bubbles to stop in the radiator i think you have a air block good luck

[38coop]

I like your air filters. Just curious as to where you got them.

[mgm60]

Thanks all for the advice. Got the new temp gauges in tonight so will give it a test tomorrow. 38coop the air filters are from Grace & Company. Here's a better picture and you can find them at lakeheaders.com.
Mark

[38coop]

Thanks for the info on the air filters.

[mgm60]

Update on the overheating problem:
Yesterday installed new electric temp gauges. and took a test flight. In less than 10 minutes ran hot, left side at 220, right side at 215 and bubble gauge topped out.
Today, completely drained coolant which is in really good shape and measured the amount, hmmm, only 4.2 gallons. As you can see from pictures somewhere along the line the radiator filler neck got relocated, so you can't see down in the tank to measure coolant level. Slowly put the coolant back in, added about another gallon of distilled water, jacked up the front end, ran for a few minutes with the cap off, then let it rest.
Took another 10-15 minute test flight, got up to 65 mph, temp was stable and all is well. I don't run thermostats and today the ambient temp in Colorful Colorado is a sweet 61 degrees. You can see from the gauges I ran 165 on the left head and 160 on the right.

Morale of the story is sometimes it's the simple stuff that can keep you up at night. But I do like the way the gauges turned out. I have a custom pair coming from Classic Instruments to match my other original gauges so this was a good test fit.

Thanks again for all the advice.
Mark

[Tinker]

Thanks for the follow up! Glad you figured it out. Sounds like you are running a high pressure system.

[mgm60]

Thanks Tinker. Not a high pressure system, its a 4 lb cap. Also you mentioned the hoses maybe being a contributor since they are the flexible type. I thought that might be a problem as well but these hoses from Dayco are actually smooth on the inside. This whole thing started out with me trying to build some custom hoses with stainless steel tubing. When I ran into trouble I found these off the shelf at Advance Auto Parts for, get this, $10 each. A perfect fit too with 1.75" at one end which fit the radiator, 2" at the other which fit the outlet at the head and just the right length. For now I have abandon the stainless steel idea.
Mark

[BrianCT]

Could you post the item # for those hoses? Sounds useful.