Radiator Outlet Temp Doesn't Change | 05 L322 4.4 M62

[irubix]

Hi brains trust,

When looking at live data from my IID Tool, the radiator outlet temp stays at 90deg constantly. As soon as the car is switched on it is at 90.

I've just replaced the lower rad sensor to fix the below error, which fixed the code, however the issue of the 90 deg still remains! (see attached photos)

0x47D Radiator Outlet temperature sensor fault

Very strange! Anyone seen this before, or have some advice on where to start the troubleshooting steps? As above have completed the following:

1. Change lower rad outlet sensor
2. Visually checked connector
3. Sprayed connector with contact cleaner

One thing I did note, was that when I changed the sensor the coolant looked brown so ill be doing a quick rad flush over the weekend w/ a look to pulling the whole cooling system out and giving it a powerflush + checkup later on down the track..

I went for a drive to Costco today which is about 40 min from my house, temps were holding as follows on the highway however these were lower than i normally see getting around town:

Coolant: 105deg
Rad Outlet: 90deg (broken)
Gearbox Temp: 105deg
Transfer Box Oil: 116deg (yikes?)

Thanks!

[p38arover]

I've never checked mine. If I remember, I'll check tomorrow.

[irubix]

Will shoot the GAP guys an email if it is the same on yours.

[irubix]

I've never checked mine. If I remember, I'll check tomorrow.

Hey Ron, did you get a chance to check?

[p38arover]

No, I haven't. If it stops raining, I'll go out and do it.

I don't have the BT version so I may need my laptop connected to see live values, therefore I'll need to run an extension lead as the laptop battery will be flat.

[p38arover]

Mine's a little different to yours.

My radiator coolant temp moved up and down a fair bit on a drive but the coolant temp pretty much sat at 90.0 deg C. It moved a small amount from 89.7 to 90.7 but soon came back to 90.0

I'll check again tomorrow when the engine is cold.

The question(s) is/are - where is the coolant temp measured and why? Is it after the thermostat?

Note that I no longer have the original thermostat, I've replaced it with a conventional 88 deg C thermostat.

[irubix]

Okay great, similar..

I've actually just ordered the 88deg thermo too (740d version), incoming from somewhere in the EU. A bit on the nose at 200aud delivered!

Heres the cooling flow.. A little cross eyed looking at this one tbh. My current understanding is that the lower rad sensor is the outlet, and therefore, as per IID tool, the 90deg value. I took another reading just now after the car has been sitting for a few hours and still, same value. Does the outlet temp sensor control the fan? Cause the fan is generally always on, even when first started in the morning, jet plane, immediately [smilebigeye]

158662

158663

[p38arover]

A run to the coffee shop and back (about 12km) this morning had the coolant temp at 90 deg C and radiator coolant temp at 76 deg C.

I plugged my ScanGauge back in (it’s usually plugged into OBD port) and coolant temp was 89.7 deg C so I think we can assume it’s measuring the coolant temp, not radiator.

The ScanGauge often shows temps well over 90 when the car is working hard or in hot weather.

Before the thermostat change, seeing 104 was not uncommon.

[irubix]

Interesting, okay I'm going to email GAP to get some feedback on this, maybe its something to do with my IIDTool

Thanks for your help sir.

[FisherX]

Hi lads,

I checked my temps with my "Launch X431 pro" the other day and my Radiator temp started at 27 deg and rising to 78 deg, while my coolant temp steadily rose to 114 deg. My gearbox came up to 116 deg.

(As far as I'm aware the standard thermostat is 115 deg with a electrical override switch for high load conditions. I'm not happy with running such high temps as I have a gearbox heater not cooler and I do get problems with high gearbox temps while towing. I do see a drop in coolant temps to 95deg when the gearbox reaches 128 deg, but by then it is too late).

[irubix]

Yeah the temps scare me a little to be honest, the previous owner had the car overheat with loss of coolant at some stage (head off rebuild). Not sure if he nailed the root cause which is why I'm making sure shes in tip top.

When this thermostat arrives (Behr 2.548.88) I'll be doing a full flush w/ Nulon Flush & Clean + new OEM BMW coolant. So I'll report back numbers after. I think a trans pan drop, filter and refill is in my future too. I feel like the trans oil could possibly be a bit cooked. Oil has 30,000k on it currently, but at 115deg it would have degraded quickly.

PS, if anyone is looking for a place to get BMW/M62 parts, I use Clickable Automotive. I've been using them for years for my BMW. 10/10 shop. BMW coolant is $15 a bottle (1.5l) which is 50% of the dealer cost.

Australia's online BMW parts specialist | Clickable Automotive (https://clickableautomotive.com.au/)

Stay safe!

Reuben

[p38arover]

(As far as I'm aware the standard thermostat is 115 deg with a electrical override switch for high load conditions. I'm not happy with running such high temps as I have a gearbox heater not cooler and I do get problems with high gearbox temps while towing. I do see a drop in coolant temps to 95deg when the gearbox reaches 128 deg, but by then it is too late).
It’s a 104 deg C thermostat with an electrical heater to open it if needs be.

[irubix]

Well GAP came back with very little, they just asked if the tool is updated to the latest version + didnt appear to want to run through the issue with me unfortunately.

Response..
" If it works, leave it alone. But normally, you can see the engine temp in the engine ECU. "

Yes clearly.

[irubix]

Okay so i worked it out..

I tested continuity back to the ECU and only one wire was working. Referenced the wiring diagram for the sensor. Initially i thought it was the socket, someone in the past yanking on it or something but after sourcing a new connector and cutting the old one, still no continuity on the wire.

Ended up unravelling the wires in the loom and tracing it back. Using the fingernail trick where you drag it along the wire and feel for a break the wire just pulled apart in my hands. Joined her back up, taped everything and its working now. The faulty sensor wire was causing my aux fan to go at 100% all the time so the truck was very noisy. Now i can hear the lifters tapping away lol [bighmmm]

I also installed the Behr TI 32 88 together with a full coolant flush and new BMW coolant. It looks to be working well and keeping temps in check and under 100c

Another thing i noted was that the Transmission Oil temps still went to 110c while the coolant was around 95c.

Would this indicate the Oil cooler is blocked or the oil thermostat might be a little tired?
Does someone know the normal operating temp of the ZF5HP24? I can see some people have said around 100-110, but going for a drive up the gorge the other day saw it climb to 120+. Is this normal?