Combination Fluid Temperature and Pressure sensor

Hello,

I've been using the Bosch combination fluid temperature and pressure sensor pictured, but I've seen enough failures that I'm interested in hearing what options, if any, are working for folks.

Specifically the failure mode is fluid comes out the back of the sensor, goes into the wiring and when it's water, shorts things out.

Combination temperature and pressure is favorable from an ease of install standpoint on builds that aren't full motorsports grade, but if it turns out there simply isn't an option that's worthy, I'm also happy to be told that and stick to the separate units I generally don't have issues with.

Thank you in advance!

Thought I'd commented?

Anyway, are you positive they were genuine Bosch items, and not counterfeit - I would have thought one failure unlikely and multiple to be most unlikely for a reputable brand.

Also, do you have the sender model number, or the thread, pressure and temperature range, etc. details?

I seem to recall Honeywell* offering combination units, but may be mistaken, it's been a while. Failing that, some of the specialist motorsport companies may have something, but $$$s.

*Uh, looks like they're just offering industrial units - https://sps.honeywell.com/us/en/products/advanced-sensing-technologies/industrial-sensing/industrial-test-and-measurement/pressure-transducers

and

https://sps.honeywell.com/us/en/products/advanced-sensing-technologies/aero-and-transportation-sensing/aero-and-transportation-sensors

Hi Gord,

Thanks! It's the Bosch PST-F 1 which is a 0-10 bar fluid temp and pressure sensor.

I get them from Link Engine Management. Data Link provides:

Data from Bosch attached.

They also have a higher pressure version but it's 0-280 bar which doesn't suit my needs (oil and water pressure), then a version which costs a few thousand dollars per unit, which is too costly.

Does anyone have firsthand experience with the Honeywell option?

Hey Mike,

I have heard/read lots of positive things about Syltech sensors http://www.syltechsensors.com/

They have a few different options for combo pressure/temp.

Haven't had a chance to test one myself.

Scott,

Thank you. The 4 pin DTM 10 bar is by the numbers a great option for me. Hopefully someone will chime in that they’ve used it and it’s gone well.

Hi Mike,

I've never failed a Honeywell MLH sensor (including when I installed a 100psi one into the front brake line) in normal operation.

I'm surprised by the Bosch failures as well, do you know if they where sent back to Bosch for analysis?

The genuine Bosch sensors part number is:

Bosch 0261230340

I've heard of people having failure on them but the fact that Porsche and many other manufacturers use them at OEM level on mass production cars I'm betting the failure rate is a tiny percentage.

As OE are using them only on oil systems I usually recommend customers only use them for oil as well

Stephen,

I let Link know, but I have not treated it like something I expected them to warranty, haven't sent them back, and I'm really just looking for a more robust solution. I don't expect them to give me new ones.

Chris,

4 failed in oil, 1 in water so fluid type doesn't seem the concern.

Bosch makes great parts and it likely is a solid item in an OE environment with soft suspension and street use, but it's Bosch OE rather than Bosch Motorsport and on vehicles with stiffer mounts, stiffer suspension, more aggressive driving, the number of failures has led me to see what else is available. If Bosch had a reasonably priced motorsport version I'd certainly try it.

Hi Mike,

I was skimming over the text and missed you'd personally had the failures, your right, in a normal road car the sensors would likely last a little longer.

the Syltech sensors do seem to be a good alternative but I'd be almost tempted to stick to individual high-spec sensors if these didn't last

Yup if I need to go back to what I was using prior I will. I'm just hoping to save installers effort if I can.

I still use the Racegrade rebranded 0-150psig sensors for fuel pressure and that's what I'd go back to using for oil and water pressure if needed.

We started using these sensors about two years ago, never had a single issue.

Lately we are seeing a growing cases of catastrofic failures with these bosch combined sensors. All the cases are the same, the membrane seems to break and it leaks whatever it's attached to (oil, water or fuel, but it's most common to fail on oil readings).

The last case was this weekend during the biggest time attack in south america (Meet Brazil Racing - MBR). One of our cars had this sensor leaking so much oil that the mechanic thought the oil filter blew.

I'm very sad that this sensor is becoming no longer an option because it's very hard do find good quality pressure sensors in Brazil. These Bosch came in handy....

Mike, do you have a link to the racegrade 0-150psi sensor you use for fuel and it's data?

https://www.milspecwiring.com/150-PSIG-DTM-RaceGrade-Pressure-Transducer_p_459.html

outfuknstanding, mahalo

That's the one.

We've had a few more Bosch combo units fail the same way, so one of the guys is going to try potting a new unit and see how it goes.

Mike, do you have the part number from this unit that failed?

Bosch upgraded its part number for some reason...

these sensors have several different Bosch part numbers, for exanmple sensors ending with 414 have purpose for fuel pressure only.

340 was replaced with 482 for oil/fuel pressure.

Personally I never saw failed one with leaking, sold over 1000 pc. Few failed on pressure signal output and was showing always 4.8V.

Have some cars running 4 years in Dakar (over 40kkm), hard engine mounts and very rough surfaces/jumps etc

But also heard a lot stories about leaking sensors, just nobody woyld say where from they bought them

Bosch Part # 0261230482. If there's a more reliable one I'd love to hear about it.

Failures have occurred at many different installers, in various use vehicle use cases, but all were used for engine oil temperature/pressure.

All units purchased from Link ECU, but I imagine they're just buying from Bosch and repackaging them.

The performance market in Brazil is veeeery small. There is just 2 retaillers over here that carries bosch motorsport stuff. All the combined sensors comes from one of these to resellers. Basically it comes directly from Bosch Brazil.

We have a few sensors beeing used for a long time, and a lot of the newer ones failing in just one or two events. Very strange.

Mike, I think potting it will avoid the leaking, but the sensor will read wrong values if internally something is wrong.

That would be helpful if you are reading fuel pressure, because leaking fuel would be very dangerous.

Last month we had the first "not combined" Bosch Pressure Sensor failing exactly the same way. It leaked through the connector and the car caught fire (we were luck because it's was on a dyno run and someone saw it and we shutdown everything very quickly and put it out immediately).

0261.230.365

https://www.bosch-motorsport-shop.com.au/pressure-sensor-for-liquid-10-bar?srsltid=AfmBOopaviqm7vq7BGmrzi1o1IqK9JuqHakUrC1gUG5i770VqJrz0gtT

Haruki,

Thank you for the heads up.

I use Motec USA Racegrade sensors for fuel pressure.

I'm glad you were able to save the car!

Just talked to Bosch Motorsports and here is what they said:

Excess torque when installing the sensor can break it internally and it causes the leak in the connector.

They recommend 24 nm.

And there is two PN for this sensor:

0261.230.340 and 0261.230.482

482 have technical upgrades that they didn't tell me what it is. He asked me which one failed.