Technical Temperature gauge jumping up while idling or engine shut off

yes I do have them both .the one that got stuck open when I took it out I just tapped it with the wrench in it finally closed and I do have the 160 I took out all so I can test them when I get home tonight

 

Cool

 

When you fill up the cooling system, do you have the heater control valve open?

 

I would try jacking the front end up in the air, and running the engine to see if all the air will come out of the system. Let it cool and see if you can add coolant to the radiator while still jacked up.

 

What you are hearing is called "water hammer" or "steam hammer" I think you have air in system, also is water pump bypass hole blocked by gasket ? When the t-stat opens the hot coolant coming out of block comes into contact with air in the top radiator hose and BAM. a tee fitting on the hose feeding the heater piped into the threaded hole in the t-stat housing will fix it.

 

Heater control valve is open. I run the engine without the radiator cap on for about 15 minutes to get the air out of the system

 

Not that that it should make any difference but or 65 had a 195 Thermo and was mounted in the cylinder head stock. There was also 2" ring shroud. Good luck..

 

After running it without cap for 15 mins what is the temp showing on gauge? stat might not be open in 15 mins. level in rad should drop when it opens then add some more.

 

The temperature is good it gets up to about 175 180 thermostat opens, drops down goes back up and hovers around 175 just sitting there. Driving home from work just now 25 miles the temperature sits just below 180. Got home and sat there for a minute and heard a couple of the noises and the temp went up to about 185 then came back down to 180. no more noises so I shut the engine off and then the temp went up to about 195 with engine off .

 

It doesn't look like you have any spot in the system that might be an air trap from what I can see in the photos. Unless there is a spot in the upper hose that is higher than the top of the tank. That would create and air pocket.
Outside of the banging noise the mechanical temp guage located in that spot will react quickly to any temp change and a lot quicker than an electric guage.
I'm thinking the gauge on my 48 is tied into the same area around the thermostat housing and the temp fluctuates quickly depending on conditions. I know I could tell exactly when the thermostat opened and see the temp change as soon as the air flow slowed down as I have the crappiest fan in the world. That thing isn't worthy of the name fan.

 

I still think you have too much of a temperature/pressure differential between the block and the radiator the top tank and half of radiator should be almost as hot as the coolant in the block and under the same pressure so that thermostat opens smooth and coolant flows without hammering. The bottom tank of radiator will naturally be cooler it might help to add another 1/8 inch hole to tstat if you don't want to pipe the hose into the thermostat housing like I suggested earlier to equalize pressure.

 

Just checked all my available thermostats I had on hand.6 -160 and 3-180.all seemed to open at the correct temp.some before others but within range.the (higher ) quality ones did open sooner. going to swap in a high-flow thermostat in a minute cuz they do recommend I have one with my high flow pump. who knows give it a shot

 

How about trying without a thermostat? might give you a clue.

 

So far no noises or temp spikes with the high flow t stat.just drove to work and back.

 

think you found your problem. do they mention why the hi flow t stat?

 

I would maybe do a preassure test on the cooling system pump it up and set there and watch the needle cold and then try an do it while the engine is hot look at your exhaust with it running is it wet or water dripping and i personally hate a clutch fan i always run a direct drive race fan or an old 4 blade heavy steel fan could the clutch fan be popping? Maybe one of you guys have some advice but i actually have something going on with my chevyii temp gauge too runnimg an going up road it dosnt harly get above like 120 or something like that the engine feels hot and radiator feels hot and have a new thermostat and temp gauge is right under the water neck its a 230 inline 6 the only issue i see is a pin hole in my radiator that leaks a little but i this gauge is new the first time i installed it did fine temp come up after that it started acting weird

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It's still doing it.......I'll pressurize the system tomorrow and see what happens.gonna pull the plugs,check em and do a compression check too

 

High flow thermostat is definitely doing something to help. the noises are less and the fluctuations are less so makes me think I do have a steam pocket or compression is leaking into the cooling system or something along those lines.Haven't had time the pull the plugs or do a compression check but I did pressurize the system and there's nothing leaking as far as the gauge tells me .i pumped it up to about 20 psi and it set there for an hour.n never dropped.

 

That's good news.

 

Have you tried tying the two heater hoses togeather near the outlets?

 

I'll share an experience I had going from a stock water pump to a high flow. Suddenly the thermostat would slam shut after above normal rpm was used. Only way to get it to reopen was to shut engine off. This would allow water pressure built up behind to bleed back. As a test I removed thermostat and problem went away. Next I installed a high flow thermostat to have a thermostat again only to have thermostat slamming shut again.

I don't recall and I'm lazy so rather than reread this thread. Have you tried removing the thermostat to see if any change happens?

 

Leave the pressure tester on it over night,it should hold pressure.

 

You bring up a good point that reminds me of something I witnessed. Both heater hoses where connected at separate outlet sources. What would happen if both were connected to separated inlet source?

 

He has them on the proper nipples, years ago I had a heater problem and opened up the top hose at the firewall and quite a bit of air puked out ,while running mind you. I could be blowing steam out my ass but worth a try. lol

 

^^^^^ OK your making me do it. I went back