Radiator

[Hippotastic]

Alacrity I have no concerns, anything that allows the system to keep things in check is a boon. I have a new radiator, and so the ATF fluid should be kept as cool as a new bongo, but I just think that with the Bongo being 4 wheel drive, that I need that extra. I just have a feeling that with the caravan, (600Kg by the way, not heavy) its just too much on a steep incline.

[Alacrity]

I too have a new rad but would never tow without an extra tranny cooler. As I have said plenty of times before, what would you rather fork out for - a cooler or a tranny rebuild?? A no brainer really.

[Hippotastic]

ok, time for an update. Sorry to drag up an old thread, but this has been taking a long time to resolve.

If the Admins think a fresh thread is best, please detach and move this.

I took the bongo back to the garage, and they accepted it each time without argument. This last time I asked for the water temp sensor on the drivers side of the engine to be replaced. I think they were at a loss as to the continued problems, and they were happy to take any advice I had on the possible problem. All I know I have gleaned on here, so thank you all for your advice and kind words.

I had the sensor changed, and when the nice chap was removing the sensor it broke apart in his hand. The ceramic bit that holds the two wires for the sensor was broken, one of the wires looked clean and the other looked corroded. I think this was the cause of my erratic cooling issues. We took it out, and replaced it with the new part I had brought along, and then I got involved with bleeding the bongo myself, showing the mechanic the funnel on the bleed pipe method. He was impressed with the method, and it was bled in no time, bottom pipe red hot and no bubbles in the funnel.

Well I took it this weekend to Shropshire, and it ran good. Still ran a bit hot for my liking at times, but it was stable, and when downhill and removing the load on the system it cooled off back to 12 o clock, and it gradually heated up when on a long gradient, but never right up to /H. It got close a few times at the end of 3-4 hours towing, but then I got home. It seemed fine on the drive, I let it tick over for 5 minutes, and the needle went back to 12 o clock, so I turned it off. Scavenger fans did not come on. I replaced that sensor too for good measure as I have not heard these fans on all at for ages. Any idea of how to short the circuit to test the fans are working?

So I am quietly optimistic that I have got to the bottom of the trouble. A new radiator, Mazda thermostat, new water temp sensor, new scavenger sensor, and I think it is settling down now.

Anyhow, sorry for the long post, but I hope in this thread there might be something that helps someone else.

David

[missfixit70]

To test the fans are working, just disconnect the plug with the iginition on, scavenge & rad fans. The scav fan doesn't often come on & doesn't play a part in cooling the engine as such, just removing the heat from the engine bay, more for cabin comfort & to stop external components cooking I reckon.
Sounds like you may have got it cracked

[mikeonb4c]

Sounds like you may have got it cracked

injudicious choice of word there Kirsty

Hope its fettled and settled there Hippo

[Hippotastic]

thank you both. I am off to Scotland in two weeks, so if it ain't sorted by now, I might break it good and proper then.

It was hot over the weekend and it moved around a lot, but it never went too far across the dial.

Kirsty, as someone who has their waterways pretty clean (ooer, you know what I mean) how far does your needle move acroos the dial when you were up and down mountain in Italy? Did it hover in the top end of the range? If 12 o clock is straight up and H is three o Clock, mine hovers from 12 to 2.30 depending on hill gradient.

Just looking for more information to satisfy myself it might actually be fixed.

Oh my front heater changed also. It was blinding at hot or cold before this temp sensor change, and now I only get heat at 32oC, any less and its cold. any ideas what that could be?

[missfixit70]

Needle position is a bit subjective, each bongo seems to be slightly different, but mine once warmed up operates between about 12 & 2 I'd say. Top hose temp is generally controlled between about 82 & 88 degrees, with @ 85 being the cruising norm, this is just past 12 0clock on the mason modified gauge. Fans kick in @ 92/93, which is about 2 oclock by your 1- 3 oclock scale. My Mason is set to start bipping at @ 91, which point I can just get to by caning it up Abbotsbury Hill which is a nice long 1 in 5 hill.
If you want to bring the temp down quicker after a long hill or comming off the motorway, drop the gears so that engine speed (& pump speed) increases relative to road speed, increases coolant flow over the fan while the stat is fiully open & brings the temp down a nice & quick
I've just put a new JAS rad & waterpump on mine too, virtually no difference to how it was before, so old rad & pump were doing their job fine. If anyone is fitting a new rad, make sure you flush it thoroughly before fitting, this is a fraction of what came out of mine, fine ally swarf by the looks of it

[Hippotastic]

hello again.

Just done the Scotland trip, all nearly went well. We covered 1150 miles in 6 days, so worked the bongo hard, with no problem with the waterworks, apart from the fact that my fans are on all the time now. I have no idea why, I had to disconnect them to bleed the bongo before we left as I could not get enough temp to get the bottom hose hot. With the fans off, the thermostat opened, the bubbles subsided, I put the fans back on and it has run well for the last week.

New issue though, yesterday in Gretna, I got a nasty vibration, felt like the front wheels. So I headed for the next exit to get off the motorway, and just as I cleared the off ramp, the front transfer drive shaft broke. Ended up waiting for two hours for the AA to arrive. When he did I suggested we just whip the shaft off and I can drive home 2 wheel drive. We did that, and it ran sweet all the way home.

It has me thinking now, was it wear and tear, windup in the 4 wheel drive, front tires? What forced the break in the CV joint? But the good thing is the bongo feels... err lighter? It pulls up to speed faster, temps are lower, corners better, and I am convinced I used less fuel on the way back. Maybe my temperature problems are related to the extra friction I am sure has gone now that the front wheels are not connected to the rear.

So shall I put a new drive shaft in? Probably not at the moment, not until the thing just works as I want it too. And I have to get the fan issue figured out, probably put a new temp sensor in the engine block and see if that fixes it. The one in there is only 6 weeks old though... Shold have got a Mazda original I guess.

All I got to do now is a new exhaust, new back brakes, new drop links, new steering rack, new drive shaft, new tires.....

I wonder why sometimes I persever with it all, then I wake up on a camp site and remember why I want this Bongo. It has not really let me down so far, even with the on going problems that seem to marr the joy. It drove back from Gretna to my home, over 7 hours on the motorway, with no dramas.