01-17-2020, 04:50 PM | #23 | |
Captain
268
Rep 609
Posts
Drives: F31 330D xDrive MPPK ACS
Join Date: Aug 2016
Location: Edinburgh & Glasgow, Scotland
|
Quote:
In various petrol cars when I've had an issue with a thermostat a downhill coast has knocked down the coolant temp by 25% and it is nowhere near as bad as that in this case.
__________________
F31 Mineral Grey 330d Xdrive, ACS, Adaptive, MPPK.
Gone but not forgotten: 1967 Triumph GT6 Mk1 (6 pot 2 litre widowmaker) 1966 Triumph TR4A (4 pot 2.2 litre, huge torque, lovely car) 2004 Audi TT 3.2 DSG Quattro (weak springs & nose heavy) 2006 VW Golf GTI (brilliant on good tyres) |
|
Appreciate
0
|
01-18-2020, 04:18 AM | #24 | |
Lieutenant General
6663
Rep 15,858
Posts |
Quote:
We don't appear to be having the same thermostat issues with N47/57 engines as we did in the M47/57 versions. The N47/57 has just the one thermostat, not the added EGR thermostat which confused the mode of failure. The mode of failure for the main thermostat is usually opening early, gradually dropping from ~88°C, rather than sticking open. Was the case with my M57, gradually dropped back to running ~85°C. When it dropped below that figure, I was prepared to change it. |
|
Appreciate
1
1966-TR4267.50 |
01-19-2020, 11:56 AM | #25 | |
Banned
1669
Rep 3,967
Posts |
Quote:
The weather was around 2c so quite cold and the coolant temp registered as 1c before starting the engine. The journey to the garden centre was quite short just over 10 miles but the oil reached the correct running temp of 100c a Couple of miles before reaching the destination. Coolant initially warmed up quicker than the oil reaching 70c by the time the oil lifted slightly off the bottom (50c) on the gauge. Note: The oil gauge is very accurate on my car more or less identically matching the oil temp on the hidden menu whenever checking this. As the temps got closer towards 90c the oil temp temp caught up with the coolant temp gradually though and surpassed it by the time it reached over 90c. As the oil had reached optimum running temp of 100c maybe a couple of miles before reaching the destination I monitored what the coolant was then doing in the cold weather with the heater also on high (missus was cold) potentially drawing a little heat from the engine. With the oil at optimum temp the coolant averaged 90-92c dropping no lower then 89c on very light load going downhill. Once reaching the garden centre I let the car idle a couple of minutes and the coolant sat at 90c. We left the garden centre after around 25 minutes and both the oil and coolant had dropped to just above 80c after starting up the car back up. The Coolant went back up to 90c quicker than the oil and again stayed around 90-92c most of the time on the 6 mile drive to the next destination. The lowest the coolant dropped to on the second journey was again 89c on light load and the highest it reached this time was 94c accelerating up an incline. On reaching the destination I again let the car idle a couple of minutes and this time the coolant sat at 91c. As expected even in colder temps the coolant doesn’t fall back below 88/89c again once the engine is fully up to 100c oil temp with a thermostat that appears to be working correctly. Note: last time I checked the hidden menu temp was during summer in warm weather and the coolant reached a max of just over 100c on load, but that’s also with the AC on high rather than the heater drawing heat away. |
|
Appreciate
2
1966-TR4267.50 HighlandPete6663.00 |
01-19-2020, 02:43 PM | #26 | |
Lieutenant General
6663
Rep 15,858
Posts |
Quote:
I've just looked at some trips in the 330d, at 1 - 3°C, (new thermostats). After 10 miles the ECT was still climbing, but only 82°C, dropping back to 78°C on the easy descent over 1/2 mile. Another trip, after 13 miles at 6°C, the ECT was still climbing, but only 87°C. There are several factors which come into play. Battery condition and whether the electric PTC auxiliary heater is running full capacity, assisting cabin warm up. The mpg during the warmup phase, engine loads over the mileage. It's one thing I notice with the 535i, all spare heat is used to heat the cabin, no electric auxiliary heating element to help the HVAC system. That definitely slows the warmup phase. Consider the engine load factor, in the 330d. The above example was reading 36.2 mpg at the 10 miles mark. That's a light fuel consumption, from a 2°C cold start. Another example in the 330d was 'up the glen' at -4°C, climbing about 200 metres in 8.3 miles. ECT was just tipping from 87 - 88°C when I turned around. OBC was recording 21.5 mpg. Return trip to home, immediately dropped back to 85/86°C. After the 8.3 miles to home was just 83°C. OBC showing 29.1mpg. Load and mpg reflecting not enough work to heat the engine, simply cooling down over distance. |
|
Appreciate
0
|
01-19-2020, 03:53 PM | #27 | |
Banned
1669
Rep 3,967
Posts |
Quote:
Speaking of Battery the car is just over 5 years old and on its original battery, although I’ve had no low battery warnings at all yet. The auxiliary heater was definitely in play today, there was warm air coming through to the cabin in less than 2 miles! What I find aids engine warm up is accelerating a little on the inclines whenever possible, but of course not revving it too high while the engine is not up to temp yet. You do see coolant temp drop back when off load if the engine hasn’t had chance to get completely heat soaked fully and up to optimum temp Yet. While mine was still warming up it dropped back from 80c to 76c going downhill, but once the engine was at the optimum oil temp of 100c you didn’t get any coolant drop back below the initial thermostat opening temp of 88c again. Your example above in -4c going downhill on the way back home and dropping back to 83c from around 87c was down to the engine never quite getting heat soaked enough to it’s optimum running temperature before starting back down hill in the cold. |
|
Appreciate
0
|
01-19-2020, 04:23 PM | #28 | |
Lieutenant General
6663
Rep 15,858
Posts |
Quote:
There are no issues once the ambient temperature is above ~7°. Then it is progressive heating and holds above the thermostat opening temperature. Radiator shutters are definitely the answer. |
|
Appreciate
0
|
01-19-2020, 05:56 PM | #29 | |
Banned
1669
Rep 3,967
Posts |
Quote:
|
|
Appreciate
0
|
01-21-2020, 03:39 AM | #30 |
Lieutenant
173
Rep 468
Posts |
I've been monitoring my 335xd for a while now with a BimmerLink app and the optimum coolant temp seems to be around 80/85c. No higher then that ever.
Oil temps take a while to warm up and also stay around 80c when fully warmed up. If you drive the car hard the oil will go to 90c for very short periods and then back to 80c.. Bear in mind that with all this cold weather the car will use more fuel, as it takes longer to get upto operating temps as cold start injection will continue to run untill car is at least over 60% on the coolant temp. I can also notice decline in mpg but i defo put it down to the weather |
Appreciate
0
|
01-21-2020, 04:27 AM | #31 | |
Lieutenant General
6663
Rep 15,858
Posts |
Quote:
Oil temperature is also much too low at 80°C. |
|
Appreciate
0
|
01-21-2020, 04:49 AM | #32 | ||
Lieutenant
173
Rep 468
Posts |
Quote:
When the regen is on the temps go up to 87c which proves the stat is working fine, which means it won't let the temperatures exceed that value. I guess if the stat was faulty the temps would be even lower especially when cruising at high speed as the radiator is being cooled. The 88c figure might have been for older cars, unless there was a change in the thermostats in the newer vehicles. My mates M4 runs at 79c and that is the range for M motors. Screenshot from dpf regen |
||
Appreciate
0
|
01-21-2020, 05:15 AM | #33 | |
Lieutenant General
6663
Rep 15,858
Posts |
Quote:
There won't be fault codes on the 335d, as it uses a mechanical thermostat. M4 is different, that is running a map thermostat, ECT will be monitored including load, to run an appropriate temperature. My N55 engine runs a map thermostat, the mechanical part is rated at 97°C, with a 'map' similar to the M4's. Typically runs at ~102°C, once stable. |
|
Appreciate
0
|
01-21-2020, 05:34 AM | #34 | |
Banned
1669
Rep 3,967
Posts |
Quote:
How long are your journeys that you are monitoring the temps on? .. Have you tried monitoring the temps through the hidden menu rather than the phone app? I’m just wondering if it’s reporting the correct temp on the app or not. |
|
Appreciate
0
|
01-21-2020, 06:37 AM | #35 | |
Lieutenant General
6663
Rep 15,858
Posts |
Quote:
Both engines are definitely reading low. The M4 should be reading an ECT of over 100°C, in normal running. The thermostat (mechanical function) is rated to open at 105°C. |
|
01-21-2020, 10:58 AM | #36 | ||
Major General
6456
Rep 8,520
Posts |
Quote:
__________________
Current : F31 330sD, remapped, Ohlins Road & Track, Millway camber plates, Quaife LSD, Stoptech brakes + Pagid RSL1 pads all round, Weichers front strut brace, Eibach front & rear anti-roll bars, Michelin MP4S.
|
||
Appreciate
0
|
05-11-2022, 08:11 AM | #37 | |
Private
4
Rep 89
Posts |
Quote:
Highland Pete I have seen your discussions on other forums over the years and you usually have experienced and resolved those niggling issues that other people normally give up on. In this particular case though, I believe you might be wrong, as much as it would be easier for me to accept that you are correct. I replace the thermostat(s) on every BMW I buy as a matter of course. On all of my previous BM's such as the E36's, E46's, E39's etc, it was simple, replace the stat, ensure coolant temp is between 88 and 92 and that's it, job done, mpg is noticeably improved. On a good stat, the coolant temperature never ever dropped below 88c on these generation of BMW's no matter what the ambient temperature was. Then I bought my first E92 (330D) around 6 years back. The temperature band was a bit wider but even then after replacing the stat, the temperature did not drop below 88c for the first few years. MPG on a run (70 with cruise control) would be low 40's regardless of time of year. When I then had to replace my water pump a few years later I noticed the temperature would hit 88c and then on light load drop a few degrees below. I replaced both stat's with genuine bmw ones again. Problem persisted. MPG in exact same conditions was 37mpg. I eventually gave up after realising I was spending more on parts than I would on fuel. I've now bought an E93 330D. Same thing again, stats were shot so replaced with genuine BMW ones. Temperature now gets up to 88c within 5-10 mins but will easily drop below 88c on light load. MPG in the same conditions in 37mpg. This has been the case since I purchased it last year but after reading this discussion I thought I'd give your theory a try. Ambient temperature was 15c yet on light load the temp drops below 88c. It is not overcooling because of ambient conditions in my opinion. The only thing I can think of, which a manager at BMW mentioned to me was the gearbox thermostat. I did not even know this existed but at that point I could not be bothered to chase the issue any longer. Any chance your cars that exhibited these symptoms were automatic? |
|
Appreciate
0
|
05-11-2022, 11:23 AM | #38 | |
Lieutenant General
6663
Rep 15,858
Posts |
Quote:
Ah, the AT thermostat... we did beat that one to death in other topics. I know it was included in many of the E9x/E6x discussions where engine thermostats were changed and no changes to ECT. Often the temperature would not climb to much more than 75C, a bit like failed EGR thermostats. Without reading all the thread again, not sure we covered all bases here. If I remember correctly, I think on the E60 there is a hose that can be clamped to eliminate the AT thermostat. Can't recall without back reading, if there is a similar trouble shoot path on the E9x models. |
|
Appreciate
0
|
05-12-2022, 02:25 AM | #39 |
Captain
404
Rep 821
Posts |
I personally think its just crap engineering. You wonder how its still possible in this day, but BMW managed to make real clangers like the N20 engine so i wouldn't put it past them.
I've felt my main Rad on warmup - the hot water slowly bleads the full way across it while the engine idles away with the thermostat closed, this would be worsened by driving with a headwind. The Thermostat is downstream of the Gearbox heat exchanger AND the Rad so there's a huge amount of thermal conduction going on away from the engine block. Most manufacturers put the Thermostat directly downstream of the block and certainly upstream of the Rad. I also wonder whether ~10% coolant temp could contribute a whopping 20%+ to fuel economy. I certainly doubt that's the cause. The engine should be in closed-loop emissions control/fuel delivery well before that. |
Appreciate
0
|
04-22-2024, 04:12 AM | #40 |
Lieutenant
84
Rep 459
Posts |
Another thread resurrection...
I have been reading through this thread with much interest as I have similar issues with my E91 330D (MY2010).
Slow warm-up, hardly ever getting into the 80s C, and a good 15% thirstier than it was a year or 2 ago (now 64 k miles, full BMW service history and extended warranty). Catalyst temperature only occasionally getting above 350C (more normally in the low 200s). Dealer detected errors on 5 of 6 glow plugs, and GP control unit, replaced these, and after some pressure from me also replaced the main coolant thermostat. The improvement was significant, but very limited timewise. First drive home the fuel consumption got back to 42mpg (UK gallons), even in traffic (which is how it used to be), but has since rapidly declined to about 32mpg. Monitoring various parameters with the BMW Drive Analyser app, shows strange (to me) Lambda numbers, which constantly return to 1.40 once warm, with little variation as the accelerator is modulated. The only time the Lambda gets throttle sensitive is when the engine seems to get into a regen process (holding lower gears for much longer, cat temperature then climbs up to high 500s for a few moments). At this time the Lambda changes just as I would expect it to. EGR valve has not been replaced. I am tempted to change this myself, but do not want to invalidate the warranty. Please see attached link, where I go into more details. https://www.pistonheads.com/gassing/...f=72&t=2068053
__________________
Last edited by Tony B; 04-22-2024 at 04:18 AM.. |
Appreciate
0
|
Post Reply |
Bookmarks |
|
|