Bongo Fury

Loss of coolant

Thought I would just post my findings on coolant loss on my Bongo.
For the past 2 years I have been suffering from coolant loss and have been topping up the reservoir with about ½ litre every couple of weeks. I had always suspected a head gasket failure or cracked head, especially after reading all the posts on the forum.
There was never any engine performance issues, but after completing the temp gauge modification I noticed it was always running very hot.
The other week one of the perished coolant hoses which runs from the engine block, over the starter motor to the rear heater split and dumped all the coolant, fortunately on my drive.
I decided to change the following :-
1, Obviously the burst pipe
2, Engine temp sensor (with the more expensive genuine Mazda part).
3, Radiator
4, Thermostat (with the more expensive genuine Mazda part).

Whilst changing the thermostat I also noticed that there had been some corrosive build up where the aluminium pipe(which holds the thermostat) joins the lower coolant hose. I cleaned up the aluminium pipe and connected back up with a good quality band clamp.
After flushing through the system and filling/bleeding with new coolant mix everything was OK.
So far there has been no loss of coolant and the engine is running a lot cooler, never going past 1 o'clock on the gauge.
The whole job cost me £270 (parts from JAS) and a few evenings work.
I wish I had done this 2 years ago. Fingers crossed it's fixed.
Hope this helps other Bongo owners.

Did you establish where the original leak was from?

gazza wrote:Loss of coolant

Thought I would just post my findings on coolant loss on my Bongo.
For the past 2 years I have been suffering from coolant loss and have been topping up the reservoir with about ½ litre every couple of weeks. I had always suspected a head gasket failure or cracked head, especially after reading all the posts on the forum.
There was never any engine performance issues, but after completing the temp gauge modification I noticed it was always running very hot.
The other week one of the perished coolant hoses which runs from the engine block, over the starter motor to the rear heater split and dumped all the coolant, fortunately on my drive.
I decided to change the following :-
1, Obviously the burst pipe
2, Engine temp sensor (with the more expensive genuine Mazda part).
3, Radiator
4, Thermostat (with the more expensive genuine Mazda part).

Whilst changing the thermostat I also noticed that there had been some corrosive build up where the aluminium pipe(which holds the thermostat) joins the lower coolant hose. I cleaned up the aluminium pipe and connected back up with a good quality band clamp.
After flushing through the system and filling/bleeding with new coolant mix everything was OK.
So far there has been no loss of coolant and the engine is running a lot cooler, never going past 1 o'clock on the gauge.
The whole job cost me £270 (parts from JAS) and a few evenings work.
I wish I had done this 2 years ago. Fingers crossed it's fixed.
Hope this helps other Bongo owners.

Going by what you have experienced I guess the loss of coolant was from a pin hole leak in the rear heater hose (over the starter) it seems from the Bongo's including my own to be a weakness point, just after the block pipe ends inside the hose...it ages and pin holes start which eventually lead to splits......at least you were at home....
The Temp sensor is a Denso sourced ( I got a mazda packaged one) and I have found the same sensor used on 90% of current Mazda models as indeed the 'stat for the WL-T engine is plus for the latest Jaguars ....and if you buy it from Jag yer save £15 ...I changed mine as it was an unknown to me and the coloured connector block was getting discoloured.....so I just changed it to be sure....
Glad to see you have joined the 12 o'clock club..... and for me the main culprits for higher engine temperatures have been dealt with during your maintenance .... well done....

widdowson2008 wrote:Did you establish where the original leak was from?

I'll take that as a NO then?

No didn't actually find the leak, hope it was a pin hole in the pipe that finally failed.
Could have been a small leak in the radiator.

Fingers crossed it's stays OK now.

gazza wrote:No didn't actually find the leak, hope it was a pin hole in the pipe that finally failed.
Could have been a small leak in the radiator.

Fingers crossed it's stays OK now.

Sounds like your sorted going by they original post.....
just had an old Mk2 Astra in, not used much and was losing coolant slowly...the elderly owner checks it every week before he goes out.....so in in came....soon found the leak...top hose had a pin hole leak which would open up when in traffic and after the fans had spun up....it closed....
In essence the old chap runs to the shops and errands once a week around the town and so each week it spurted out from the pin hole and needed a small top up the following week......all sorted now with fresh coolant etc....Now to get busy on a '72 Fiat 500

gazza wrote:No didn't actually find the leak, hope it was a pin hole in the pipe that finally failed.
Could have been a small leak in the radiator.

Fingers crossed it's stays OK now.

I'm glad to hear you got it sorted Gazza.

I've a new water pump from JAS awaiting fitment to my bongo, my existing pump is fine, I'm simply replacing the pump as a preventative maintenance measure when i replace the coolant/stat/temp sensor in the next few weeks.