T-stat & control valve acting funky

[Overboost]

Originally Posted by workingonit

The pointer of the coolant temperature gauge in the instrument cluster is located in the mid-position at coolant temperatures of 75oC - 113 o C in centre position.

I'd want the dash gauge to warn me about that temperature approaching, long before it was reached.

Run this hex code mod on your cluster. You need PA Soft 1.4 but my buffer is 10C.

https://xoutpost.com/1121333-post23.html

[workingonit]

Originally Posted by Overboost

Run this hex code mod on your cluster. You need PA Soft 1.4 but my buffer is 10C.

https://xoutpost.com/1121333-post23.html

Eventually, I'll get a cheap laptop with coding ability so I can get useful info on the display while driving. I'm not a programmer, but i'll give it a try. I already tried to use the BC programming trick, but it reverts back to ambient temperature.

So in the meantime, I'll use my Torque Pro App to monitor realtime coolant temps (I should've kept some gauges from my racecar!). Oil temp, oil pressure, transmission temp would be nice to have displayed as well. I can't find any BMW-specific PIDs to add to my TP app, either.

[Magister88]

@andrewwynn

My rule for non OEM parts is when it's easy to access and not mission critical (you don't live where it's life threatening if heater valve breaks closed) and won't damage or prevent engine from operating it's fair game (bent my own rules a bit not realizing how hard it was to swap an aux fan geez BMW).

Yeah i have been following similar rules for OEM/aftermarket parts, mission critical must be OEM or OE but with BMW logo scraped off.

@80stech

The coolant temp dropping at times is a function of the DME controlled thermostat heater and is normal and the reason why the dash guage is programmed to stay in the middle over that range.

@andrewwynn

The reason for the non temp gauge on the dash pointing to noon from damaging levels of hot pot to damaging levels of cold is literally to prevent customers asking too many questions during warranty period. (as according to tech builtin). They don't think the average user can handle the truth (literally).

@Clavurion

Coolant temp should drop when you accelerate and warming element on thermostat is activated. But the basic temp seems a little low.

Yeah i was under the impression it should stay fairly close to the set point temp. I think the stock t-stats is 95C for 3.0 and higher for the 4.4, 4.6 & 4.8. The one i got is 93C one. so the basic temp is inline i believe unless you are talking about drop to 81 not being normal. I know the idiot gauge does not change from 75 - 1?? hence why i was using the Test function in the cluster and the Ibus interface on the android unit. it is also more clear by reading the paper posted by Clavurion and it seems to be okay as far as operation goes unless i am misinterpreting what you are telling me


@andrewwynn

When the tstat fails open it will take longer to get up to temp and won't even reach temp when ambient is low.

Yeah it gest their quickly with < 10 minutes to 93C. so i guess its not going bad yet.

If your heater valve is stuck open you have an extra radiator running that is in the loop and cooling the engine even when tstat is closed. Logic dictates that will make the engine run a little cooler than the set point so your symptoms seem to match the conditions described.

Yeah this make sense, it would contribute to cooling the engine even more.

When it got stuck i believe (unless its electrical), the most noticeable is that the air of the driver vent starts to come in very hot when no other adj where made to climate controls and pass side is okay. connecting the scan tool:
Heat exchanger temp:
Left: 88 - 89C (190F) almost engine coolant temp.
Right: 22C (73f)

is that not enough evidence that the heater value is going bad?