Running hot troubleshooting

[vitus992]

Hi all

I have a 2.5 diesel and I have modded the temperature gauge to get a better idea of the temperature. On long uphill climbs she steadily climbs to a rather uncomfortable near the H side of the gauge.
The coolant has been flushed recently, hoses look ok and no coolant loss.
Initially when I got the bongo the scavenger fan never seemed to come on so I fitted a scav fan override switch and all of a sudden the scav fan now kicks in of its own accord when I park and its warm (which is good).
I never notice the radiator fans kicking in so I am wondering if this could be the next on the check list, I have removed the plug from the water temperature sensor and the fans kicked in proving they work, but are they kicking in when they should?
Would I cause any damage to the ECU if I get her up to temperature, pull over, remove the plug from the water temperature sensor so the fans kick in and take her up a long climb to see if this makes any difference to the temperature? If it does it means the Sensor needs replacing, if it doesn't then that's another thing ticked off.

Any help appreciated.

Many thanks.

[mikeonb4c]

Or can you assess if the temp sensor is working by measuring resistance across it when cold and when hot. Might need some input from our electrical gurus here.

Scavenger fan coming on after engine off is unusual - mine's never done it. Significant if its only happened after the switch mod?

[Northern Bongolow]

get one of these and see whats really going on.

http://www.ebay.co.uk/itm/Digital-Handh ... Sw2GlXKMWj.

all the trigger temps for all the sensors are in the manual plus the temp when the stat opens so its possible to select any pipe and read whats going on.

the problem with the temp gauge on a bongo is its oil filled to dampen it, if you remove the fans from the system the first thing you will see is the gauge going up, but the engine will be hotter than the temp shown unless you wait for it to catch up.

if your going to the stourport big bash i will test your system for you. includes pressure test for leaks, trigger temps for fans etc.

[mikeonb4c]

I'd thought the temp gauge was electrically damped and that the Mason alarm (or similar) modification removed the damping?

[vitus992]

Cheers for the input folks, So to clarify coold I run the engine with the coolant sensor plug disconnected so the radiator fans are constantly on with out doing any damage to the ECU? this way I can either rule out or find as the fault if the sensor is shot and not kicking the fans in?

Sadly not going to the meet, would have loved to meet up with this great crowd.

Daren

[rita]

get one of these and see whats really going on.

http://www.ebay.co.uk/itm/Digital-Handh ... Sw2GlXKMWj.

all the trigger temps for all the sensors are in the manual plus the temp when the stat opens so its possible to select any pipe and read whats going on.

the problem with the temp gauge on a bongo is its oil filled to dampen it, if you remove the fans from the system the first thing you will see is the gauge going up, but the engine will be hotter than the temp shown unless you wait for it to catch up.

if your going to the stourport big bash i will test your system for you. includes pressure test for leaks, trigger temps for fans etc.

Does that mean that I need to stock Speedo Oil, can you tell me what grade to get and how do I fill the speedo, or check the level.

Thanks.

[BongoBongo123]

I cannot comment of the efficacy of a modified dash temp gauge.....

Scavenger fan comes on based on engine compartment temp as far as I understand. I can only offer one bit of advice : be seriously careful cause if the dash temp gauge reads hot and the scavenger fan is coming on the engine is getting far too hot. So whatever you do do not risk further damage. I know only enough to advise to be very careful at any sign of overheating.

As I have found out, and as you mention the rad fan, an aging rad fan switch can cause late activation of rad fans. Rad fan is typically fairly quiet. I pay a lot of attention to Bongo sounds and can just about hear the rad fan when it activates and spins.

[vitus992]

Many thanks for the input. My next test will be to run it with the temperature sensor disconnected after it has heated up. If the temperature stays good then I will replace the sensor, if it doesnt then perhaps a new thermostat and a good flush. Im just trying to avoid opening up the coolant system until absolutely necessary.

[Northern Bongolow]

Does that mean that I need to stock Speedo Oil, can you tell me what grade to get and how do I fill the speedo, or check the level.

Thanks.

speedo ?????, theres non in the speedo, just the temp gauge and the fuel gauge, they are both damped with thin oil, dont know what grade though never filled em, dont need to i have a low level alarm on them and its never gone off