Hello All,
I think it only polite to pass on some valuable advice for a change; regarding the 2.5D engine.
This is mostly in relation to the over-heating gremlins that seem to haunt these fine power plants.
I must give a big thank-you at this stage to Geoff who has imparted some invaluable guidance to me with this project from the start- legend!
After a recent head gasket failure, which followed a complete cylinder head replacement kit (purchased from AVA leisure)5 years ago I took the advice from a local mechanic, and good friend of mine to fit an auxiliary electronic water pump system.
His reasoning for this addition was largely based upon the volume of coolant in the system and the size of the mechanical impeller.
Basically, the impeller would work fine in the vehicle when it is moving at speed and having the benefit of air passing through the radiator. When the Bongo is idling or high revving with low speed, the cooling system has to move 13L ish of coolant with an average size impeller- not ideal.
This is also combined with the ECU controlled fans being (in my opinion) a bit slow to come to life. With a 2.5D, the ECU switches the radiator fans in at low speed at 96C and high speed at 108C (so I have been told).
With a Davies Craig (Australian) EWP system, you can control the temperature you would like the engine to run at. I have set mine at 82C given that this is when the thermostat opens.
The system works by pulsing the electric water pump slowly from start-up to monitor the coolant temperature (you have to drill a small hole in the thermostat housing to enable this). When it approaches the running temperature set, it ramps this up then (at 82C) it switches the water pump in fully, to regulate the coolant through the radiator. If the coolant goes 3C above the set temperature it switches in the fans at full speed.
By fitting a Davies Craig system as a back-up you get the benefit of both worlds. The impeller is still in use but it has the electric pump for use under low revs. Not to forget the fan control.
If the EWP system fails you can revert the fan wiring back to standard to run off the ECU providing you have allowed for this.
I have recently covered around 1500 miles from my home in Herefordshire to Belgium, then Brittany and back home. The only time the temperature got to 92C was under heavy load on a long steep hill. It mostly ran at around 82C on the flat with 5 passengers and lots of luggage.
I'm not saying that Mazda may have got things wrong a few years ago, but I have to say that there are an awful lot of owners of 2.5D Bongo's that have problems with cylinder heads cracking/gasket failures etc. All of these issues can be attributed to overheating.
By all accounts, please take the advice from everyone on the forums and fit a coolant level alarm and a cylinder head temperature alarm.
I can only advise (so far) that you also fit an EWP coolant system that will do its best to prevent overheating problems before they start.
I'm not an expert but I am happy to supply further information and guidance to any Bongo owners interested in buying an EWP.
Much respect and keep on trucking!
Ian
2.5 diesel cooling problems solved- fingers crossed!
Moderators: Doone, westonwarrior
2.5 diesel cooling problems solved- fingers crossed!
Clever people the Japanese.
Re: 2.5 diesel cooling problems solved- fingers crossed!
Much involved to fitting one and how much?
Re: 2.5 diesel cooling problems solved- fingers crossed!
Hello Alkers,
The EWP 115 is the recommended unit, these are around £300. Demon Tweaks stock them.
It took about half a day to fit the pump and temperature sensor and a bit longer to do the wiring and fit the controller. The only head scratching bit was working out how to wire the fan relays as the motors are dual wound.
You can run these as the sole cooling system if you remove the thermostat and impeller pulley but I wouldn't recommend this as the temperature fluctuates a lot.
The EWP 115 is the recommended unit, these are around £300. Demon Tweaks stock them.
It took about half a day to fit the pump and temperature sensor and a bit longer to do the wiring and fit the controller. The only head scratching bit was working out how to wire the fan relays as the motors are dual wound.
You can run these as the sole cooling system if you remove the thermostat and impeller pulley but I wouldn't recommend this as the temperature fluctuates a lot.
Clever people the Japanese.
Re: 2.5 diesel cooling problems solved- fingers crossed!
What preparatory work did you do before fitting the ewp , ie Radiator/condition of hoses / waterways / thermostat operating condition / AC radiator /pump flow rate.
Re: 2.5 diesel cooling problems solved- fingers crossed!
Hello teenmal.
Good question.
The hoses were replaced by the previous owner in 2015. I replaced the radiator in 2017 when the original cylinder head cracked.
The coolant system was repeatedly flushed until the water came out clean. The thermostat was checked and opened up nicely in boiling water, this was new in 2017.
I have previously removed the AC radiator because it has never worked and is located in front of the cooling radiator.
The pump flow rate was not checked.
Good question.
The hoses were replaced by the previous owner in 2015. I replaced the radiator in 2017 when the original cylinder head cracked.
The coolant system was repeatedly flushed until the water came out clean. The thermostat was checked and opened up nicely in boiling water, this was new in 2017.
I have previously removed the AC radiator because it has never worked and is located in front of the cooling radiator.
The pump flow rate was not checked.
Clever people the Japanese.
Re: 2.5 diesel cooling problems solved- fingers crossed!
Lemner wrote: ↑Tue Aug 16, 2022 1:26 pm Hello teenmal.
Good question.
The hoses were replaced by the previous owner in 2015. I replaced the radiator in 2017 when the original cylinder head cracked.
The coolant system was repeatedly flushed until the water came out clean. The thermostat was checked and opened up nicely in boiling water, this was new in 2017.
I have previously removed the AC radiator because it has never worked and is located in front of the cooling radiator.
The pump flow rate was not checked.
Yes, that's what I meant about the AC radiator it can get a bit restricted and also the coolant radiator, we often put a baffle between the two and hit them with the pressure washer. The biggest problem with the coolant system on these old vehicles is the poor condition of the system, and of course the position of the thermostat.