rodgling
|
| posted on 3/4/14 at 06:27 PM |
|
|
oil temperature
I have an oil cooler with thermostat fitted, which until last year was very effective - however, a while ago it stopped doing very much, so if the oil
gets hot, it takes a long time to come back down as the only cooling (I assume) is from air running over the sump - it used to cool down very very
quickly.
So... what could cause this? I've just swapped the thermostat with no improvement. Could the cooler itself have got blocked up? Externally it
looks alright and it's got the same airflow its always had.
|
|
|
|
|
snapper
|
| posted on 3/4/14 at 07:16 PM |
|
|
I was told by an ex submariner that is now a commercial turbine engineer told me oil coolers loose a good proportion of their efficiency quite
quickly
To retain cooling they fit much larger coolers or replace when cooling drops
I don't know if you can flush an oil cooler but its worth a try
The other issue may be the thermostat, by pass and see
[Edited on 3/4/14 by snapper]
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
|
|
|
coyoteboy
|
| posted on 3/4/14 at 08:15 PM |
|
|
Why would it lose efficiency? Unless it somehow became massively contaminated on all surfaces?
|
|
|
rodgling
|
| posted on 3/4/14 at 09:42 PM |
|
|
Well I replaced the thermostat today, which didn't help so I assume it's not that (unless I've been unlucky with the replacement).
BMW don't actually offer a part number for the stat as they never break, so it shouldn't be that...
I've tried flushing the cooler previously but that didn't help.
Hmm... tempted to remove the stat from the housing and see what happens. It's a pain to swap though.
|
|
|
britishtrident
|
| posted on 3/4/14 at 10:22 PM |
|
|
Have you actually checked the oil temperature ?
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
rodgling
|
| posted on 3/4/14 at 10:26 PM |
|
|
Yeah, I have a temp gauge, which is how I noticed the problem, so I bought a digital temperature reader with a couple of remote probes and attached
them to each inlet/outlet of the cooler, then drove around with the old thermostat (haven't tried with the new one). IIRC there was very little
difference between the two sides.
The cooler did get hot, but smoothly - it never jumped as I expected it should when the stat opens.
|
|
|
britishtrident
|
| posted on 3/4/14 at 10:30 PM |
|
|
quote:
Originally posted by snapper
I was told by an ex submariner that is now a commercial turbine engineer told me oil coolers loose a good proportion of their efficiency quite
quickly
To retain cooling they fit much larger coolers or replace when cooling drops
I don't know if you can flush an oil cooler but its worth a try
The other issue may be the thermostat, by pass and see
[Edited on 3/4/14 by snapper]
Unlike marine heat exchangers car oil coolers are unlikely to suffer from barnacle growth.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
|
|
|
snapper
|
| posted on 4/4/14 at 08:09 AM |
|
|
You lot are really not open to the advice of a turbine engineer are you
It was a comment made to me when I was fitting a cooler
They loose efficiency quite quickly that's why I fitted a 16 row in place of the 13 previously recommended and fitted
Make of that what you will but most oil cooler set ups send grotty oil through the oil cooler before the filter and you know what lurks in the bottom
of your sump
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
|
|
|
rodgling
|
| posted on 4/4/14 at 08:52 AM |
|
|
I have flushed it in the past, which didn't appear to reveal any problems or make any improvements :-(
|
|
|
Nash
|
| posted on 4/4/14 at 09:10 AM |
|
|
Two questions from me
1. Do you have an in line filter before the cooler inlet?
2. Are you comparing winter and summer ambient temperatures as that will impact cooling.
A change in flow rate will impact cooling. Viscosity, contaminants,.......
........... Neil
[Edited on 4/4/14 by Nash]
It's What You Do Next That Counts.
Build It, Buy It, Drive It:
Southern Kit Car Club
|
|
|
rodgling
|
| posted on 4/4/14 at 09:18 AM |
|
|
1. Not sure if the filter is before or after the cooler - it's the stock M3 arrangement, with the thermostat and oil cooler take-offs built into
the filter housing.
2. No, it's had this problem since last summer. It seemed to start quite suddenly, it wasn't a gradual degradation of performance.
I tested the replacement (used) stat yesterday by sitting with the car stationary at 3k rpm until it got to ~110 C, then driving around gently at ~70
mph - it took ages to come back down even to 100 C. This is same behaviour as the old stat. Back when it was working it would have taken ~30s to cool
down again.
|
|
|
Mr Whippy
|
| posted on 4/4/14 at 11:48 AM |
|
|
maybe your gauge is wrong
|
|
|
rodgling
|
| posted on 4/4/14 at 01:29 PM |
|
|
No, gauge matches my IR pyrometer and a digital temperature probe. So it's definitely right!
|
|
|
Nash
|
| posted on 4/4/14 at 05:43 PM |
|
|
Oil viscosity and flow rate? When was the last time you changed the oil? Also, are the fins clean on your cooler? What's the air temp increase
across your cooler ?
It's What You Do Next That Counts.
Build It, Buy It, Drive It:
Southern Kit Car Club
|
|
|
