problem solved; engine 525D not reaching operating temperature.
02-24-2010, 08:19 AM
#251
Senior Members
Join Date: Feb 2009
Posts: 1,026
Likes: 0
Received 0 Likes
on
0 Posts
Guys I have a question about my engine temperature and I will very much appreciate your comments as I am a bit lost on this. I logged into the hidden menu and observed the engine temp for some time, using this extremely useful thread and the instructions (thanks to mini_me for starting it!). I have a 2004 530dAT.
What I noticed in the morning, when its around 10 degrees Celsius outside:
- Engine gets warm quite slowly: maybe 25-30 min at least to get to 76-78 C, in jammed city driving
- Then it sometimes stays at 76-78 C, when driven at normal speeds, 60-100 km/h, or...
- ..In other cases it gets to 90 C but ONLY after sit in jams at traffic lights, after that stays around 85-95 C
Overall, when driven a few times a day in the sity (i.e. engine flexing its muscles and warming up a few times) I notice some sort of dual behaviour:
1) it either stays at around 75-79 C, or
2) gets right up to 90 C, mostly when given the chance at heavy traffic jam
What I wonder is, and I hope you guys can answer the question:
Is it possible that my thermostat (the smaller or even the bigger) is partly broken?
- I.e. in the morning it does not work and engine stays cold, but...
- later in day, the relatively warm engine "wakes up" the thermostat and it starts working, basically closing to allow the engine to reach 90 C?
Or is it perfectly normal for the engine to warm up so slowly and get really warm only in traffic jams? I would not think so, but I dont know much about this..
When you observed your engine temp development, did you notice anything similar?
Thanks for any comments!
What I noticed in the morning, when its around 10 degrees Celsius outside:
- Engine gets warm quite slowly: maybe 25-30 min at least to get to 76-78 C, in jammed city driving
- Then it sometimes stays at 76-78 C, when driven at normal speeds, 60-100 km/h, or...
- ..In other cases it gets to 90 C but ONLY after sit in jams at traffic lights, after that stays around 85-95 C
Overall, when driven a few times a day in the sity (i.e. engine flexing its muscles and warming up a few times) I notice some sort of dual behaviour:
1) it either stays at around 75-79 C, or
2) gets right up to 90 C, mostly when given the chance at heavy traffic jam
What I wonder is, and I hope you guys can answer the question:
Is it possible that my thermostat (the smaller or even the bigger) is partly broken?
- I.e. in the morning it does not work and engine stays cold, but...
- later in day, the relatively warm engine "wakes up" the thermostat and it starts working, basically closing to allow the engine to reach 90 C?
Or is it perfectly normal for the engine to warm up so slowly and get really warm only in traffic jams? I would not think so, but I dont know much about this..
When you observed your engine temp development, did you notice anything similar?
Thanks for any comments!
02-25-2010, 11:09 AM
#252
In answer to the post above:
I'd say your thermostat (at least one of them) isn't working properly. They're mechanical items that have been immersed in coolant for 6 years - probably not quite as calibrated as they used to be. Sounds like one is sticking a bit.
As feedback on my EGR thermostat replacement:
I was seeing a reasonably fast warm up (say 10 mins, 8 miles) to 80C then the car runs at 81 - 85C.
I replaced the EGR thermostat - no change at all.
My friend's 2006 525d does exactly the same.
My other car, a 2.5V6 petrol Vauxhall, normally sits at around 85C when warmed up and takes a similar time/distance to warm up. However in this cold weather (in the UK) with ambient around 0C to 4C it tends to run at around 81 to 85C too.
I do think my 535d is running a bit cool but I think it has a lot to do with the design of the front bumper intentionally allowing lots of air in. I suspect that's why the SE models have the grill flaps. The sport models and the 535d don't because they're expected to be driven harder and may need all the cooling they can get.
I'd say your thermostat (at least one of them) isn't working properly. They're mechanical items that have been immersed in coolant for 6 years - probably not quite as calibrated as they used to be. Sounds like one is sticking a bit.
As feedback on my EGR thermostat replacement:
I was seeing a reasonably fast warm up (say 10 mins, 8 miles) to 80C then the car runs at 81 - 85C.
I replaced the EGR thermostat - no change at all.
My friend's 2006 525d does exactly the same.
My other car, a 2.5V6 petrol Vauxhall, normally sits at around 85C when warmed up and takes a similar time/distance to warm up. However in this cold weather (in the UK) with ambient around 0C to 4C it tends to run at around 81 to 85C too.
I do think my 535d is running a bit cool but I think it has a lot to do with the design of the front bumper intentionally allowing lots of air in. I suspect that's why the SE models have the grill flaps. The sport models and the 535d don't because they're expected to be driven harder and may need all the cooling they can get.
02-26-2010, 12:32 AM
#253
Senior Members
Join Date: Feb 2009
Posts: 1,026
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the info,
Over the last few days with ambient temp around 10 C, on my way to and from work (7-8 miles city, lots of traffic and traffic lights, low revs) in the 25 mins that I'm driving it the car gets to c. 80 C.
Also I notice that whenever I get te chance to increase speed on a longer stretch of road, for example late in the evening, engine temp drops immediately to 74-76 C.
It seems something is wrong indeed.
I will clean up my EGR anyways when the weather gets warm, and I will use th opportunity to see whether the EGR thermostat is stuck open. If yes, I will get a new one and see what happens; if not, I will have to find an indy to dig out the big therm at a reasonable price...
Over the last few days with ambient temp around 10 C, on my way to and from work (7-8 miles city, lots of traffic and traffic lights, low revs) in the 25 mins that I'm driving it the car gets to c. 80 C.
Also I notice that whenever I get te chance to increase speed on a longer stretch of road, for example late in the evening, engine temp drops immediately to 74-76 C.
It seems something is wrong indeed.
I will clean up my EGR anyways when the weather gets warm, and I will use th opportunity to see whether the EGR thermostat is stuck open. If yes, I will get a new one and see what happens; if not, I will have to find an indy to dig out the big therm at a reasonable price...
02-26-2010, 12:58 AM
#254
Senior Members
Join Date: Jun 2004
Location: Copenhagen, Denmark
Posts: 1,229
Likes: 0
Received 0 Likes
on
0 Posts
I can reach 90C if I'm stuck in traffic. However my operation temperature is usually 82-83C, with drops to 79C sometimes at open roads at night at 150-160 km/h.
I will change the EGR thermostat myself in the spring and see if that helps.
I will change the EGR thermostat myself in the spring and see if that helps.
03-07-2010, 02:26 AM
#255
For those of you that are having a go at changing the EGR Thermostat I have a few tips:
The vacuum hose that's in the way of the rear 10mm bolt securing the EGR Thermostat is the trickiest part of the job. There's a short length of rubber hose attached to a piece of rigid pipe. About 30cm along the rigid pipe there is a flexible joint so you can move the rigid pipe about. The connection to the vacuum pump is a single Torx screw but the joint needs to be pulled out at least 1cm to disconnect it. On my car the engine lifting bracket prevented any movement. So... the answer was to put a very large flat bladed screwdriver through the hole in the lifting bracket and apply pressure, this flexes the bracket and gives the 1-2mm clearance you need to pull the rigid + flexibible + joint up and out of the vacuum pump.
The vacuum hose that's in the way of the rear 10mm bolt securing the EGR Thermostat is the trickiest part of the job. There's a short length of rubber hose attached to a piece of rigid pipe. About 30cm along the rigid pipe there is a flexible joint so you can move the rigid pipe about. The connection to the vacuum pump is a single Torx screw but the joint needs to be pulled out at least 1cm to disconnect it. On my car the engine lifting bracket prevented any movement. So... the answer was to put a very large flat bladed screwdriver through the hole in the lifting bracket and apply pressure, this flexes the bracket and gives the 1-2mm clearance you need to pull the rigid + flexibible + joint up and out of the vacuum pump.
As I later found out my EGR Cooler didn't actually sit flat on its 3 mounting points (no idea why but I think it has been off in the past judging by the screw heads). Mounted as it was it was under a bit of tension on the top bracket. When I flexed the engine lifting bracket I created a tiny crack at the weld in the EGR cooler. Very unfortunate because the weld must have penetrated the coolant jacket and been weak. Anyway I ended up with a pinhole leak that was very hard to find. The EGR cooler is £230+VAT (March 2010).
However, there is no other way than to flex the engine mounting bracket because you can't remove the EGR cooler until the EGR thermostat is removed because you can't get at the bolts...so be careful.
03-07-2010, 02:43 AM
#256
I do think my 535d is running a bit cool but I think it has a lot to do with the design of the front bumper intentionally allowing lots of air in. I suspect that's why the SE models have the grill flaps. The sport models and the 535d don't because they're expected to be driven harder and may need all the cooling they can get.
My 535d was running cool, but it was due to the main thermostat. I've changed my main thermostat (not a trivial task) and instead of running 80-85C it now warms up faster and gets to 92C and stays around there. The old thermostat was identical to the new one and both have 88C stamped on them.
I've only given it a single test drive so no more info on temperatures or economy but I've never seen above 90C before changing the thermostat. The car also started a DPF regen on the (short) test drive!
03-07-2010, 09:20 AM
#257
Senior Members
Join Date: Feb 2009
Location: Scotland
Posts: 452
Likes: 0
Received 0 Likes
on
0 Posts
I wrote the quote above and it's partially right and partially rubbish!!!
My 535d was running cool, but it was due to the main thermostat. I've changed my main thermostat (not a trivial task) and instead of running 80-85C it now warms up faster and gets to 92C and stays around there. The old thermostat was identical to the new one and both have 88C stamped on them.
I've only given it a single test drive so no more info on temperatures or economy but I've never seen above 90C before changing the thermostat. The car also started a DPF regen on the (short) test drive!
My 535d was running cool, but it was due to the main thermostat. I've changed my main thermostat (not a trivial task) and instead of running 80-85C it now warms up faster and gets to 92C and stays around there. The old thermostat was identical to the new one and both have 88C stamped on them.
I've only given it a single test drive so no more info on temperatures or economy but I've never seen above 90C before changing the thermostat. The car also started a DPF regen on the (short) test drive!
03-07-2010, 01:42 PM
#259
Senior Members
Join Date: Feb 2009
Posts: 1,026
Likes: 0
Received 0 Likes
on
0 Posts
I wrote the quote above and it's partially right and partially rubbish!!!
My 535d was running cool, but it was due to the main thermostat. I've changed my main thermostat (not a trivial task) and instead of running 80-85C it now warms up faster and gets to 92C and stays around there. The old thermostat was identical to the new one and both have 88C stamped on them.
I've only given it a single test drive so no more info on temperatures or economy but I've never seen above 90C before changing the thermostat. The car also started a DPF regen on the (short) test drive!
My 535d was running cool, but it was due to the main thermostat. I've changed my main thermostat (not a trivial task) and instead of running 80-85C it now warms up faster and gets to 92C and stays around there. The old thermostat was identical to the new one and both have 88C stamped on them.
I've only given it a single test drive so no more info on temperatures or economy but I've never seen above 90C before changing the thermostat. The car also started a DPF regen on the (short) test drive!
Average speed was about 65 mph, temp went up to 74-78 when I was under longer acceleration, and dropped to.. hold on.. 58 degrees on multiple occasions when going downhill for a longer time!
In result of this I now have something additional to worry about - the DPF regeneration, as also hinted above. The DPF needs coolant temp of at least 75 degrees to start regenerating. As mine almost never reaches this level, I wonder just for how long has the DPF not been able to regenerate?? If you wonder what happens if it doesn't, check Anzafin's DPF thread in the DIY section. Alternatively prepare 1,500 EUR + install for a new DPF.
In short: Everyone that has not done this yet, do check your engine temp and do fix it if its low, particularly if you have a DPF installed!
