Radiator coolant pressure sensor

[Ray]

Hi,

looking at running a coolant pressure sensor in the radiator to monitor incase head lifts.

what type of sensor do you recommend please?

is there a sensor with a certain pressure range I need to use? I assume something that reads 0-100psi for eg?

[MichaelR32GTR]

I replaced my factory water temp sensor with a Bosch temp/pressure sensor in one 

works great 

[Ray]

Thanks for that. What are the Max/min values you see?

[Pete_89t2]

11 hours ago, Ray said:

Thanks for that. What are the Max/min values you see?

Never done this before, but in theory the maximum pressure you should see in normal operation would be the relief pressure specification of the radiator pressure cap you're using. So if the cap is rated at 16psig, that's the max you would see on a gauge. I would think a blown head gasket would increase coolant pressure, but only up to the point where the cap relieves it, so again if the cap is functioning it would be 16psig in this example.

[Ray]

True, although I would have thought that the velocity of the water pump would increase pressure as well as the revs increased. 
 

so what do you use the pressure sensor for? Is it set to trigger anything when a threshold is reached?

[Vaughan]

On 4/11/2021 at 6:21 AM, Pete_89t2 said:

Never done this before, but in theory the maximum pressure you should see in normal operation would be the relief pressure specification of the radiator pressure cap you're using. So if the cap is rated at 16psig, that's the max you would see on a gauge. I would think a blown head gasket would increase coolant pressure, but only up to the point where the cap relieves it, so again if the cap is functioning it would be 16psig in this example.

I would expect that the rad cap setup won't be able to flow enough volume to prevent noticeable spikes and I would expect there to be delays in its operation both of which would mean that sharp pressure spikes should be visible if you did have combustion gases entering the coolant system.

[434josh]

I used a 0-30 psi pressure transducer. It's interesting to watch the pressure rise and rise before the thermostat opens the first time. With a 20 psi cap the pressure gets up to about 25 psi then drops to about 9-10 after. 

[Emil]

@Adamw would you recommend a lower pressure sensor (eg, 2bar) or a higher pressure sensor (eg, 4bar) for the purpose of detecting coolant pressure in a failed head gasket scenario? 
 

Would you expect to see higher coolant pressure than what the radiator caps is rated in normal operating conditions? 
 

Thanks in advance 

[Ducie54]

Dam I run a 100psi sensor and have no issues with resolution. You can see the pressure rise as the temp goes up. Mine is mounted in the storage tank. Can post a log/trend if u would like.

[Brad Burnett]

I have been running a standard 150psi sensor on the coolant system with no issues.

[Adamw]

9 hours ago, Emil said:

would you recommend a lower pressure sensor (eg, 2bar) or a higher pressure sensor (eg, 4bar) for the purpose of detecting coolant pressure in a failed head gasket scenario? 

Its highly variable, but the few cars I have tested with thermostats you will see up to around 30psi pump pressure on top of the general cooling system/cap pressure.  So the bare minimum sensor I would want is 50psi, and up to around 150psi would be totally fine.  Michael's suggestion of the combined press/temp sensor is a good one if you have room to get it in the flow.  

[Grant Baker]

I run a 4 bar gauge pressure sensor which I had a batch made for this purpose and EMAP.