Radiator fans

Aethelric · Post by **Aethelric** » Wed Jun 19, 2013 1:10 pm

Just had an overheating episode on the bongo and the radiator has burst - I think no harm done to the engine although I do know what to look for.
I think the problem may have been caused by the fans not coming on. I notice that the fans are NOT coming on when I switch on the A/C with the ignition on but with the engine cold and not running. Can anyone confirm (or otherwise) that they should come on in this situation.
Cheers
Dave

jaylee · Post by **jaylee** » Wed Jun 19, 2013 3:54 pm

Hi Dave,

Sorry to hear about yer trouble.. The fans should cut in with the AC on.. However there is a pressure sensor for the refrigerant... Part 61-503 http://lushprojects.com/bongopartsmk2/c ... 02.html#22 If the refrigerant is too low the fans wont cut in...

Personally, i think its was just a case of the rad had had it... But it is worth checking the continuity regarding all the fans...

If you disconnect the pressure sensor connector to the refrigerant tank & bridge it even with the pressure down, the fan should cut in with the AC on... Check there isn't a dry connection first..?

Aethelric · Post by **Aethelric** » Wed Jun 19, 2013 6:45 pm

Thanks Jaylee - I only put the rad in 3 years ago. I got a warning on my engine over temp sensor - but when I switched off the ignition and switched it on again the warning stopped - but I noticed the temp had dropped to the bog standard 11 o-clock position. I think it was still too hot. Then up an incline - steam and water from the top of the rad. I stopped quickly. I'm pretty sure I saved the head.

Anyway bridging the sensor on the refrigerant tank did not help did not help. There does not appear to be any power gping to the fan connectors although there is 12V on the bridging link on the sensor.

The A/C has never worked - (pump gone) although I'm sure that it used to switch the fans on - I've just noticed that the light on the A/C isn't coming on either. Fuses mentioned in this post are ok

http://igmaynard.co.uk/bongo/forum/view ... ge#p501207

Just disconnected head temperature sensor and the fans start - but the temp guage is not moving - I thought it would go to max!

teenmal · Post by **teenmal** » Wed Jun 19, 2013 7:06 pm

Hi Aethelric ,I would forget about the AC side of things a concentrate on the coolant side.It would be worth checking the ECT (Engine Coolant Temperature Sensor)If you disconnect the plug/connector the fans should come ON.

Good Luck.

PS have you checked the fuse.?

Aethelric · Post by **Aethelric** » Wed Jun 19, 2013 7:20 pm

Yep fuses all OK and fans start when sensor disconnected.

teenmal · Post by **teenmal** » Wed Jun 19, 2013 7:35 pm

Aethelric wrote:Yep fuses all OK and fans start when sensor disconnected.

It would probably be worthwhile changing the ECT sensor and thermostat when you change the radiator.

PS does the vehicle have any additives in the cooling system.

Aethelric · Post by **Aethelric** » Wed Jun 19, 2013 7:44 pm

ECT reads 2.46K which is I think is normal at room temp. Its been running fine for 3 years. Anyway new radiator ordered. Lets see if she bleeds ok. (Done it lots of times before).

teenmal · Post by **teenmal** » Wed Jun 19, 2013 8:01 pm

Aethelric wrote:ECT reads 2.46K which is I think is normal at room temp. Its been running fine for 3 years. Anyway new radiator ordered. Lets see if she bleeds ok. (Done it lots of times before).

Good Luck

Aethelric · Post by **Aethelric** » Sun Jun 23, 2013 1:46 pm

New radiator fitted. System bled OK and bongo now operational.

BUT I'm still worried about the original cause of the overheat. An hour or so before "the incident" my temperature alarm went off as I was pulling away from filling up with diesel. It soon stopped and I put it down to "one of those thing".

The fans CAN work and switch on if I disconnect the Engine Temperature sensor. The sensor seems to work. The cold resistance is about 2.5K and hot its about 260 ohms. But at 260 ohms, should the radiator fans have switched on?
I have a 500 mile trip coming up (Cornwall to Fife) and I think to be safe I may leave the sensor disconnected and run the whole way with the fans running - or maybe fit a manual switch in the sensor.

Any ideas?

jaylee · Post by **jaylee** » Sun Jun 23, 2013 4:07 pm

What about the scavenger fan.. have you tested that..? From memory if you disconnect the fan sensor connection by the handbrake while the engine is running the fan will kick in.. It's a bit disconcerting because the glow plug light will flash too... But it will also stay running when you turn off the ignition.. Until it's plugged back in. (Maybe flick the ignition on & off again, then it stops.?
I fitted a flashing warning led light on mine...

teenmal · Post by **teenmal** » Sun Jun 23, 2013 6:56 pm

Hi Dave,Did you check the thermostat and the ECT,the reason that I asked if you had used any additives is that some can coat the sensor and give sporadic results.The only values that I have for the sensor are...

20c 2.2-2.8

80c 0.29-0.4.

If in doubt change it.This sensor is also used for other functions.

Good Luck.

Aethelric · Post by **Aethelric** » Sun Jun 23, 2013 8:22 pm

It all seems fine now - only faulty component seems to be the radiator. I've put a switch in the ECT line just in case but it all seems OK.We will see - I'm about to set of on a longish drive.

Oh - no additives other than usual anti freeze.

Aethelric · Post by **Aethelric** » Mon Jul 15, 2013 9:02 pm

Around 1000 miles done since replacing Rad - no other problems - looks like it was just a duff rad.

Radiator fans

Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans

Re: Radiator fans