Series 3 Puzzling overheating problem

I am sorry if this seems repetitive but I have tried everything I have seen on this and other online sources and nothing solved the problem.
Here is the description:
Engine is initially cold. I start and heat gauge gradually (very gradually) goes up.
After nearly half an hour of driving it reches the edge of red
I don't push it past that I stop.

I have flushed the radiator (Baking soda + venigar) and water coming out is clean
I added a ground in the dash and made sure the guage is powered from stabilizer as was suggested
I have removed and checked each hose and made sure it is open
the fan is working as usual
water pump is working (opened the hose to pump let the engine run water was coming out)
hoses are warm
The big hose on top of radiator does not inflate much
there is no thermostat on the truck
Very importan. When I slow downor I am stationary it heats up more than if I was driving at 50k/h
I am using water not coolant but that has always been the same

Does these indicate anything to you?
tx in advance

Have you got a handheld temperature gun to check actual temp of engine and rad?...

cold weather or hot and which engine

Shippers that is the one thing which I have not done. I am planning to do this later today (Come to think of it I think Joe had suggested it) I have to get a ir thermometer first.
James engine is 2.25 petrol normal temperature 20-24 degrees C. This problem started 2 weeks ago and weather had not been too cold or too hot.
thanks for replies

Is the lower hose from the radiator cooler than the top hose to the radiator. It should be. If it isn’t the radiator itself is not working.

Thanks for suggestions guys. Lower hose is cooler than the upper one. I invested in 2 liters of coolants (still showing high) and I did temp reading on engine and radiator and it seems like truck is not getting hotter than normal. Reading is wrong. I tested the sensor it was ok but I will change it to see if this will solve the problem. It is an electrical issue but what?
I can only guess what the future will be like with cars being all electrical!
UPDATE:
I changed the temp sensor. Now it shows even higher temperatrure!!! It is practically stuck to the end of red.

I am adding this in case anybody else had this problem in future.
After checking every component of cooling system without solving the problem somebody suggest checking the carb, distributor and valves.
We did a valve spacing adjustment and the guy used a timing light and checked the timing. He also made some adjustments to the carburator. Truck is not heating up anymore. So, valves and carb could result in over-heating too.

85Santana3 said:

I changed the temp sensor. Now it shows even higher temperatrure!!! It is practically stuck to the end of red.

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I had the same issue with a new sensor, I've got a feeling they're selling the wrong part number for the engine.
How can the tappets and timing make the difference between the gauge sitting in the red or not?

Rodeo Joe said:

I had the same issue with a new sensor, I've got a feeling they're selling the wrong part number for the engine.
How can the tappets and timing make the difference between the gauge sitting in the red or not?

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Joe I can only say what I saw. The logic of it I do not understand either. During the last 2 weeks I practically opened the cooling system piece by piece and had electritions doing hours and hours of wire checking and adding ground and changing questionable wires, etc. etc. nothing worked. Dial was right at the edge of red when I would stop. Then we changed the sensor and it actually showed more. Now it was at the very end on the other side of red.
(I put back the old sensor) However adjusting the valves and checking with the funny flash light and playing with the carb has brought the temp to middle of green where it should be. 5 years ago I overheated the engine and blew head gasket and it cost me a pretty penny to fix it. So this time I was worried and really tried everything possible to avoid that.
Maybe if engine gets wrong ratio of fuel and oxygen it heats up?
I've learned not argue with my truck. They are fun to play with but I don't expect logic

Incorrect ignition timing and weak mixture are both causes of over heating, either singly or together.
I also recommend fitting an aftermarket gauge that reads in numbers/degrees and know what the actual temp is.

I know we've touched on this before but as a matter of interest what sort of temperatures do you get at various parts of the engine. ie hose coming off thermostat housing to radiator. Mines a diesel and the hose can be around 70 deg. The top of the temp. sensor reads about the same with the heater pipes a bit less , does that sound within the right ballpark?

I spoke too soon. We are back to square one again!!!

What was the part number for the sensor?
Was it 560794?

Thanks for trying to help Joe.

Rodeo Joe said:

What was the part number for the sensor?
Was it 560794?

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I had put back the original sensor which was used for th last 5 years. So that can't be the cause.
I read the temperature of oil in the engine an water in radiator when it goes to red. Oil in the engine is 84.0 C and water in radiator is 83. They do not seem to be too high (agreed?). I noticed a small crack at the edge of radiator. Could it be that opening changes the pressure and reduce flow? I noticed that even when the gauge as on read I could open the radiator cap without any steam or water splashing out.

It sounds like the engine is cooling correctly for one with no thermostat, with engine oil and coolant at close the same temp.
Having the rad cap open or closed would make no difference at that low ish temp. You only get overflow/steam from opening the cap if the temp is at 100degrees
Pressure in a sealed cooling system ups the point at which the coolant boils, prevents localized boiling in the system and overheating. Which is why when you remove a hot engines cap the coolant suddenly boils and steam's and is dangerous.

85Santana3 said:

Thanks for trying to help Joe.

I had put back the original sensor which was used for th last 5 years. So that can't be the cause.
I read the temperature of oil in the engine an water in radiator when it goes to red. Oil in the engine is 84.0 C and water in radiator is 83. They do not seem to be too high (agreed?). I noticed a small crack at the edge of radiator. Could it be that opening changes the pressure and reduce flow? I noticed that even when the gauge as on read I could open the radiator cap without any steam or water splashing out.

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Are you absolutely certain the voltage stabilizer is ok......maybe its working intermittently, there are 2 terminals one for the fuel and one for the temp. is the temp one loose?

Fit an aftermarket gauge that reads in numbers/degrees and know what the temp is. Both electric and capillary are available. TIM and VDO are well known makes.

tottot said:

Fit an aftermarket gauge that reads in numbers/degrees and know what the temp is. Both electric and capillary are available. TIM and VDO are well known makes.

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I think the sender has to be paired to the gauge, I got a digital gauge that read too high with the sender on the engine hence all the hassle I had in another thread.

I don't think that the sender and gauge need to be paired but certainly designed and made to the same Temp/resistance scale. You have tried 2 different senders that have given the same result I think you need to change the voltage stabiliser or the gauge. Does the gauge go high straight away?
There was a post on here last year about what voltage to get of the stabiliser for the gauges I think it was something like 10.5volts but don't hold me to that.

Rodeo Joe said:

I think the sender has to be paired to the gauge, I got a digital gauge that read too high with the sender on the engine hence all the hassle I had in another thread.

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Good after market gauge's come with a matched sender if electric and are one piece gauge/sender if capillary type, You just need to order the right thread fitting for your truck