[Engine] Exhaust problems and fan stays on?!

[minisandfords]

Right, latest issues are...

The exhaust was getting louder when driving today, then suddenly got really loud!  When I stopped and popped the bonnet I spotted a big hole in the top of the downpipe where it joins the manifold and the (lambda?) sensor flapping about!

So I'm fairly sure it has rotted out and left a big hole and no lambda sensor.  Obviously this means a new downpipe (and possibly lambda sensor)? Not a major issue.

However, when I stopped it both cooling fans stayed on.  For ages (20mins)!  Even when engine cooled down, cold to touch.  Disconnecting battery stopped it and it didn't restart, but when I ran the engine (even for only 30sec) cooling fans came on and stayed on again.

Sounds to me like either i) a sticky relay or ii) the sensor that was in the manifold not switching the fan off?

Any ideas, usual people?!  Thanks in advance!

[ffrenchie]

Sensor in the manifold ? Cooling fans don't detect anything off the exhaust so it will most likely be an electrical fault somewhere else as you say, the relay is the immediate suspect.

[minisandfords]

I did think it was odd having a temp sensor in exhaust manifold, but it's a weird coincidence that it sticks on when the hole just appeared? Also noticed this am it's been on all night as I reconnected the battery, so left it disconnected! Battery had enough charge to start the car amazingly! Will maybe disconnect fan for now and watch gauge carefully as not needing car much until I get to bottom of it.

Read on another forum that relay is on fan itself and sometimes sticks, which makes sense.

[Landmark]

Hi, The lambda sensor has nothing to do with temperature, it measures the O2 content in the exhaust gases before and after the cat to ensure the emisions are ok. You may be able to put it back in the new exhaust section if you can unbolt it.
Griff

[minisandfords]

Stop press- fan still running on even when battery disconnected and reconnected, so sounds like stuck relay. Is relay on fan itself? Have taken fuse out for now and will be watching gauge carefully!

And have replaced exhaust but getting front section to seal is a bugger! Might have to resort to paste/gum!

[Agri_Yuppie]

Stop press- fan still running on even when battery disconnected and reconnected, so sounds like stuck relay. Is relay on fan itself? Have taken fuse out for now and will be watching gauge carefully!

And have replaced exhaust but getting front section to seal is a bugger! Might have to resort to paste/gum!

Hi minisandfords, which engine does your Berlingo have. 
I am currently suffering with similar problems with my 52 plate 2.0Hdi The fan is running and red stop light is flashing on the dash, when the engines just started from stone cold.
What number fuse did you pull ? I have changed coolant sensor with no joy.
I am getting perplexed with it !!

[minisandfords]

Mine is 1.4 petrol! Fuse is one of the 20A big ones in the engine bay- I identified this by following wiring from fans.
Haven't got a red stop light on mine though- car runs quite happily with fuse pulled- just watching temperature carefully!
Planning on doing relay this weekend- will keep posted how I get on!

[bikergraham]

I would suspect that when the lamba sensor went walkabout the engine went on to " limp home mode " as the electronics picked up a fault ,as it would, i strongly suspect that if you replace the sensor you will need to remove the fault from the ECU before the car will run properly again.

[minisandfords]

That's an interesting point- is it a Lexia connect job to remove error mode? Car doesn't feel like limp mode (no loss of power) and no engine management light though?

Might replace sensor and have a look. Thanks!

[bikergraham]

That's an interesting point- is it a Lexia connect job to remove error mode?  Car doesn't feel like limp mode (no loss of power) and no engine management light though?

Might replace sensor and have a look. Thanks!

I have to be honest and say i'm not sure how to answer your question,but,i had a problem with my fathers Renault a few months ago which turned out to be a ht coil problem.After i had replaced it ,i had a few other strange faults manifest ,i then took the car to a dealer who plugged in a diagnostic tool and cleared the fault codes left in the ECU ,needless to say the car now runs perfectly.
 It just came to mind that if the Lamba sensor had failed perhaps the ECU thought it could compensate by running the Fan as the fueling could cause the engine to overheat if it went into lean running mode,maybe im wrong and im no mechanic just an enthusiast,but it would seem sensible to assume that this could happen.Good luck.