JensH
Senior Member
Hi all,
I had a new (Behr) radiator fitted about 3 weeks ago. No apparent cooling system problems until this week-end.
After the visit to the workshop, though, I found that the aircon (Diavia, dealer fitted) had stopped working. The compressor would not switch on.
I had for some time, anyway, had a problem with a flashing recirculation button, indicating either a non-functioning temp sensor (air or evaporator) or a short. The A/C had been working fine, though.
After the radiator, I had the A/C system re-gassed from 350 kg to 850 kg (the former being what the original Diavia instructions say, although this now appears to be a misprint; the latter being what the general forum consensus seems to be on the correct level). In fact, I now understand (thanks to member GSXR) that Diavia advises 800 +/- 20 kg. The system had actually previously been working ok at 350 kg (extract from original Diavia instructions attached). It is presently still at 850 kg.
On a closer look I found that all the push-on connections to the relay for the auxiliary fans had been pulled out during the time in the workshop (by accident). This was an easy fix, but did not cure the A/C problem.
On Saturday, in about an hour, I sorted the A/C, by removing the O/S facia, disconnecting, removing, cleaning and reconnecting the Diavia ECU-MAN CPU (two multi-connectors, mine has no RPM sensor). The flashing button has stopped and the system A/C is cooling fine, BUT...
There is now a coolant loss problem.
On the way down to the Kent coast on Saturday, the coolant warning lamp came on soon after I set off from London. I found the reservoir down to about an inch of visible fluid. I keep a good stock of the correct formula coolant in the car, so topped up.
On the journey, in high'ish 20s heat, I got stuck in the 90 min delay caused by M2 closure at Medway, after an incident. The coolant temperature increased dramatically, although I realised this was initially attributable to me leaving the A/C on, and in the Min setting - silly me on two counts.
The needle never actually hit the red, but was very close. The two Diavia auxiliary fans did NOT engage (they supposedly do so above 105°, but mine have always been slow to kick in). Once I was clear of the jam, I pulled into a service station and found that the coolant reservoir was empty. As the engine cooled, I step-released the pressure with the cap, which caused modest bubbling up and overflow of remaining coolant. There is no scum in or around the reservoir. The coolant had clearly been very hot.
The overall coolant loss in little over an hour was dramatic. The system needed in excess of 5 litres to refill.
Since then, there is an ongoing loss of coolant, and on the return trip, a further shorter hold-up also saw the temp gauge rise with A/C on, but settle back to just above 80° (nornal) with A/C off.
There is some evidence of coolant escape behind the front O/S wheel arch and also collecting below the radiator on the sump guard (small spot patch below). There is no evidence of major gasket issues. There appears to be no coolant loss at standstill/overnight (checking this morning).
Yesterday there was a slight sweet coolant whiff in the cabin but I reckon this is just down to the aftermath of some coolant spillage in the engine bay entering through the vents.
I will drop in to the workshop, to see what the mechanics say, but it seems to me that the following may be the cause/contributors:
Connections to new radiator seeping somewhere (not readily visible);
Air in system after new radiator (explains amount of top/up?);
Coolant temperature sensor;
Small leak somewhere else in the hose system;
Water pump/seal;
Hairline crack in coolant tank.
Any tips/thoughts very welcome, including as to what events/circumstances, if any, might trigger significant one-off coolant loss, e.g. a rapid and dramatic overheat?
Attached 4 pictures, the Diavia 350 kg spec, reservoir as at this morning, small spots behind O/S wheel arch, single spot below sump guard.
Cheers,
Jens
I had a new (Behr) radiator fitted about 3 weeks ago. No apparent cooling system problems until this week-end.
After the visit to the workshop, though, I found that the aircon (Diavia, dealer fitted) had stopped working. The compressor would not switch on.
I had for some time, anyway, had a problem with a flashing recirculation button, indicating either a non-functioning temp sensor (air or evaporator) or a short. The A/C had been working fine, though.
After the radiator, I had the A/C system re-gassed from 350 kg to 850 kg (the former being what the original Diavia instructions say, although this now appears to be a misprint; the latter being what the general forum consensus seems to be on the correct level). In fact, I now understand (thanks to member GSXR) that Diavia advises 800 +/- 20 kg. The system had actually previously been working ok at 350 kg (extract from original Diavia instructions attached). It is presently still at 850 kg.
On a closer look I found that all the push-on connections to the relay for the auxiliary fans had been pulled out during the time in the workshop (by accident). This was an easy fix, but did not cure the A/C problem.
On Saturday, in about an hour, I sorted the A/C, by removing the O/S facia, disconnecting, removing, cleaning and reconnecting the Diavia ECU-MAN CPU (two multi-connectors, mine has no RPM sensor). The flashing button has stopped and the system A/C is cooling fine, BUT...
There is now a coolant loss problem.
On the way down to the Kent coast on Saturday, the coolant warning lamp came on soon after I set off from London. I found the reservoir down to about an inch of visible fluid. I keep a good stock of the correct formula coolant in the car, so topped up.
On the journey, in high'ish 20s heat, I got stuck in the 90 min delay caused by M2 closure at Medway, after an incident. The coolant temperature increased dramatically, although I realised this was initially attributable to me leaving the A/C on, and in the Min setting - silly me on two counts.
The needle never actually hit the red, but was very close. The two Diavia auxiliary fans did NOT engage (they supposedly do so above 105°, but mine have always been slow to kick in). Once I was clear of the jam, I pulled into a service station and found that the coolant reservoir was empty. As the engine cooled, I step-released the pressure with the cap, which caused modest bubbling up and overflow of remaining coolant. There is no scum in or around the reservoir. The coolant had clearly been very hot.
The overall coolant loss in little over an hour was dramatic. The system needed in excess of 5 litres to refill.
Since then, there is an ongoing loss of coolant, and on the return trip, a further shorter hold-up also saw the temp gauge rise with A/C on, but settle back to just above 80° (nornal) with A/C off.
There is some evidence of coolant escape behind the front O/S wheel arch and also collecting below the radiator on the sump guard (small spot patch below). There is no evidence of major gasket issues. There appears to be no coolant loss at standstill/overnight (checking this morning).
Yesterday there was a slight sweet coolant whiff in the cabin but I reckon this is just down to the aftermath of some coolant spillage in the engine bay entering through the vents.
I will drop in to the workshop, to see what the mechanics say, but it seems to me that the following may be the cause/contributors:
Connections to new radiator seeping somewhere (not readily visible);
Air in system after new radiator (explains amount of top/up?);
Coolant temperature sensor;
Small leak somewhere else in the hose system;
Water pump/seal;
Hairline crack in coolant tank.
Any tips/thoughts very welcome, including as to what events/circumstances, if any, might trigger significant one-off coolant loss, e.g. a rapid and dramatic overheat?
Attached 4 pictures, the Diavia 350 kg spec, reservoir as at this morning, small spots behind O/S wheel arch, single spot below sump guard.
Cheers,
Jens
