Bongo Fury

All, I'd like your advice as I'm struggling a bit with this one.

Last week I changed the timing belt, tensioner and spring on the Bongo (diesel 2wd 1996). I was really careful to line up the timing marks top and bottom. I followed the fact sheet and used the Service Manual.
When finished I actually felt the engine was a little quieter/smoother but that's probably just my subconscious justifying the job. I didn't need to realign the sprockets at all but the previous belt did seem to have a fair bit of slack in it.

At this point I should note that I have a cube alarm monitoring two engine temps, 1 - the coolant measured at the engine hose stub) and 2 - the head temp measured at the back of the head.

On the test drive temp 2 (the head) seemed hotter than I was used to (up to 98c on hill climbs). Temp 2 remained in the range it's always been in 78-88.

So I did a full coolant flush (which took ages), changed the thermostat, a few hoses and bled the system up according to the Youtube vids.

The coolant temp is now lower and very stable, but the head temp is still operating in the same range.

My concern is before I did the cam belt change the Head temp seemed to operate cooler than it is now.

So, my thinkings on what's causing this: -

1. I've not got the timing right and would need to take it to bits again to recheck the marks.
2. The new belt has returned the Bongo to its correct timing (as the slack has been removed) and it now operates in the correct temperature/power/efficiency range.
3. When I cut the wires to the head temp probe and reconnected them with spade clips (too tired to get the soldering iron out) I've added additional resitance to the circuit and increased the temp reading at the Cube.
4. Post job paranoia - I should stop worrying and just get on with it

Any ideas? Thanks

Can I put a fiver on option 3?

missfixit70 wrote:Can I put a fiver on option 3?

It's an easy one to rule out that's for sure. I'm thinking about getting out there with the soldering iron. Only thing is, the temps on both sensors are equal up to about 60 degrees then temp 2 (head) stats to create a lead...

OK - just to close this off, after much head scratching I decided that this was nothing to do with the timing of the engine - it was either a radiator issue, thermostat or bleed issue (or all three). So last night and this evening I started to work this through: -
[*] First to check the rad, I removed the bottom hose, top hose and flushed from the top hose through -the flow indicated there was no blockage.
[*] I then flushed water between each of the main hose runs and between the thermostat housing and the top engine hose. Again no blockages or crud in the coolant.
[*] I then removed the stat (which is new) and did another boiling water test. Opens great no issue.
[*] So I rewatched the You tube bleed videos. I've bled the bongo a number of times before but not from a 'completely empty' starting point. Whilst filling up the rad Id been pegging the funneled bleed hose to the handbrake cross member. I realised that this was actually keeping the majority of the 1 meter bleed hose below the level of the cylinder head. I pegged the funnel instead to the passenger side grab handle and filled the system according to the vid. I then bled prorerly waiting for the stat to open at 82c (and then kept going for a while to be sure).

After a few test drives it's working perfectly. Temps are exactly what I was wanting, bottom hose getting warm when the water temp goes above 80c. Head temp no more than +10 degrees of the water temp even on hills.

So I'm still not completely sure if this was a bad-bleed issue or ifwhilst I'd been flushing and back-flushing the rad I'd actually blocked it.

I'm just glad I've fixed the thing!!

it sounds like an incomplete bleed issue to me, the bottom hose should get very hot during the final stages of the bleed,this indicates that the stat did/has opened.
if it just got warm then the chances are there is still air in the head,as noted with hot head readings.during bleeding the stat often opens and closes again(giving a warm bottom hose).
i would suggest you bleed it again to be sure.
if you can hold the bottom hose for more than 10 secs when bleeding, it aint open enough to purge the air out of the head.

Northern Bongolow wrote:it sounds like an incomplete bleed issue to me, the bottom hose should get very hot during the final stages of the bleed,this indicates that the stat did/has opened.
if it just got warm then the chances are there is still air in the head,as noted with hot head readings.during bleeding the stat often opens and closes again(giving a warm bottom hose).
i would suggest you bleed it again to be sure.
if you can hold the bottom hose for more than 10 secs when bleeding, it aint open enough to purge the air out of the head.

Cheers NB, It's definitely back to running perfectly now after that final bleed. I've learned a few lessons on this one!