Driving with failed thermostat - safe?

[saj77]

Hi all.

I think I know the answer after doing research online but I am after some reassurance.

I have the 3.0 N52 with the infamous electric thermostat and water pump.

Using the Torque app, I get a P0597 error code which apparently relates to my thermostat being faulty.


It doesn’t show in INPA and I have no warning lights on dashboard and temp gauge stays bang in middle once warmed up. Car drives absolutely fine and heater blows hot.

Earlier I started the car and let it idle and made a note of temperature rise.

Results =

95 C after 25 mins

100 C after 30 mins

Maxed at 102 C and stayed around that.

Again no warning lights on dash and temp needle bang in middle.

My question is - is the car safe to drive, with the ‘possible’ detective thermostat?
Also, any experience on how accurate the Torque app is?

From what I have read if the thermostat has failed, it fails in the safe position.

I have purchased a thermostat and plan to change it along with the pump but was hoping car would be useable in the mean time.

From what I’ve read I should be ok as long as nothing changes regarding over heating.

Thanks

Saj

 

[mjennings23]

Might be that it isn't closing, as those are normal operating temps. If it isn't opening you might notice the temperature dropping under motorway driving and it being slow to warm up, and if that is the case it won't do any harm other than worsening fuel economy.

For comparison, even in the near freezing temps we just had, my M54 engined car was showing as 90+ degrees within about 10-15 minutes of use. Thermostat was changed last year and it warms up much faster now, albeit I never had an error code.

 

[saj77]

Thanks [ref]mjennings23[/ref], I can live with bad fuel economy if that’s the only down side, as it’s only my weekend toy. :driving:

 

[Chris_D]

A thermostat failing is mucg safer than your waterpump failing.
Yes, it usually falls in the open position which means it will be overcooling

I recently went through this with the stat on my m54 and used torque to monitor temps before and after replacing the stat and coolant. It's very accurate and sometimes i still use it to monitor the coolant temp on some trips.

Depending on how old ur waterpump is and especially if its still on the original one it's probably well worth swapping in a pump too.

 

[saj77]

Cheers Chris.

Car is on 89k still on original pump - I believe. I have only done 1800 odd miles in the year I’ve had it.

I will change the pump along with the stat, when I do it.

Glad to hear Torque is accurate. I’ve bought an Android tablet and car mount. Will fit it when I go out for a drive so I can monitor the various parameters of the ECU.

 

[srhutch]

Mine failed on for N52. Dealer wouldn’t have it and said it was working. Turns out the just ran the car out the back, which of course got up to temperature, instead of driving it where it took a lot longer to get even slightly warm.

 

[colb]

I would change the pump and Stat as soon as you can, it may have failed in the open position but I would be worried that the internals of it may collapse and allow it to close, you run the risk of overheating then with the increased risk of head gasket failing.

 

[ph001]

The heater control of the mapped thermostat is not critical at all - it just means that the thermostat operates like a conventional stat.

The heating element just means that the wax 'control element' (present in all thermostats) can be artificially melted at other temperatures and make the thermostat operate at modified engine temperatures to reduce emissions and / or fuel consumption.

I wouldn't worry about it too much but would defo change the pump while you are in there.

 

[saj77]

Thank you everyone for all your input and advice.

Think I’ll limit the cars use just be on the safe side until I can get it sorted.

With that said, I’m going to go for a drive out (circa 30 miles) as need to get out of the house.

I’ve set up my tablet and Torque app to keep an ‘extra’ eye on things.

 

[baconJazz]

I've just had a diagnostic from BMW Sytner. It was carried out because of a mis-fire issue which turned out to be faulty spark plugs. At the same time , a code was flagged up regarding a fault with the thermostat . BMW told me that if the vehicle was running at the correct temperature etc not to worry about it as it's not yet critical . :driving:

 

[saj77]

Well, the car drove perfectly :driving: - no abnormalities with my temp gauge (both on car and Torque app) or heater blower.

Will use car sparingly until my local garage is available again to fit my new stat and pump.

 

[saj77]

Had new water pump and thermostat fitted today.

Off for :driving: now

 

[ph001]

Great. Let us know if the car got to operating temperature any quicker then previously.

 

[baconJazz]

Had new water pump and thermostat fitted today.

Off for :driving: now

What was the charge for that ? :driving:

 

[saj77]

A mechanic friend did it at my house - still with social distancing for £70

Water pump was £250, thermostat was £25 (new from forum), G48 coolant ready mixed £36.

So nearly £400!!

 

[saj77]

Great. Let us know if the car got to operating temperature any quicker then previously.

Didn’t time it on this occasion but it definitely seemed to be quicker than the previous 30 minutes....