Thermostat issues ?

[thane1]

Hi there, new to site, so please forgive possible daft question ?
Having issues with temperature on recently purchased bongo.
Noticed temp gauge at max so put cabin heaters on to draw off some heat. No heat at all in cabin heaters .
Temp then came back to normal (middle on temp gauge)
Rad fans seem to be running all the time when very hot, but to no effect..
Tried again, seems dicky
Temp gauge reads hot = no heat in cabin fans, rad fans on
Temp gauge reads normal (half) = lots of heat in cabin fan.
All during normal driving round town in cold outside temp

Does this suggest sticky thermostat ?
Checked water levels, all ok

Thanks for any advice



Rob

[Bob]

Hmm...

This doesn't sound good.

Which engine do you have?

If it's either of the 2.5 ltrs the cooling system must be bled if the coolant drops below the header tank. This takes 45 mins/ 1 hour, and there are 3 videos on You Tube if you have a Google.

It is very common for the diesels to crack the head if overheated so I would recommend you don't drive it until the problem is sorted.

If you bought it from a dealer I'd ask them to collect it and fix, sadly no come back if it's a private sale.

Good luck

[thane1]

Its the diesel engine
Private sale
Was all fine for around 300km ,
Then noticed around a week ago

Seen the bleeding videos, but doesn't seem to be anything on how to remove water from system? Reading on forum, bottom of rad , offside ?

Is it possible airlocks causing sporadic problems, or do
I go for thermostat with drain down and see how it goes ?

I was thinking stat , as temp went from high to normal very quickly (say 10 seconds or so) with return of heat to cabin fans

Thanks for a very quick reply

Rob

[g8dhe]

The cooling system is a bit fraught in a Bongo, being mid-engined. The air heater matrices are continually fed engine coolant (control is managed on the air side of things) so if the gauge showed hot and no heat from air con then that suggests a circulation problem, not a thermostat problem. Basically an air lock somewhere and for a diesel that can be EXPENSIVE as its likely to damage the head. Here is a diagram of the coolant system in action;

[thane1]

Handy schematic, thanks

I guess a blockage or air lock would have that effect

What is the cure mind please ?

Re balance as per 3 videos online ?

Thanks again

Rob

[Bob]

Goodness Geoff

That's one neat diagrame.

Anyhow, firstly you need to find out how and why air got into the system and address that problem. Pressure test would be a good start to see if there's a leak, and use the 'search' function on here to read all you can.

Tip - Put 'and' between key words to make it more specific, maybe 'coolant and leak' or 'pressure and test'.

Once you've sorted the cause then it's bleed and hope you've got away with it.

If using a garage make certain they know Bongos, list on here somewhere, or maybe someone can suggest one near you. Sadly far too many tales of experts who won't be told about the Bongo cooling system them make things worse, claiming the damage was already done before they got it.

Fingers crossed for you.

[Bob]

Sorry, yes, there's a drain tap on the bottom of the rad, driver's side.

Remove the rad and header tank caps and the rate of flow will give a bit of an idea if the system is clogged, but in any case I'd flush it while you're about it.

[g8dhe]

The diagram is courtesy of Steve Widdowson when he did his original investigations into the cooling system, the posts are still on here. I took a copy of all the images before photosite did the nasty! Hence I can repost them from my server!
See http://www.g8dhe.net/bongo_images/widdo ... /index.php to see them all !

[Bob]

Splendid foresight, Geoff.

[thane1]

Thanks very much for your help .

I will get on to it as weather permits.

Watch out for no more questions !!! I hope ☺

Rob

[Bob]

Good luck, and as said,I wouldn't drive it until it's sorted.

[mikeonb4c]

First thing of course, have you checked coolant level in header tank.

Next, does header tank show any signs of rust stains or any other crud. Either of these might suggest historical neglect has resulted in crud building up in radiator matrices etc. Another test worth trying is to squeeze the top hose. If it feels hard/crunchy it has scale lining the inside.

It sounds like you either have air in the system or else v badly compromised circulation. You'd be best advised not to drive it until sorted.

Good luck and keep us posted.

[thane1]

Right finally taken a look as weather permits

Was thinking on trying the see saw remove air bubbles as shown on video .

But. No bleed hose apparent

I have looked at video again and definitely nothin to this effect on my bongo ?

I know this machine has been serviced well by known garage in Swansea

Is it possible there is another way ?

I will try them tomorrow if no further advice .

Ho hum.... happy new bongo year

Thanks again

Rob

Oh.... will try to post picture of 'no hose'

[Bob]

Ahhh...

Have a search, there's been a very similar thread recently.

It's likely that the head has failed and been replaced with a Ford Ranger one. Pretty much identical but no bleed pipe.

There's a way of 'T' ing one into the turbo feed, from memory, but it's been described not long ago.

Good luck.

[Bob]

Info here:

viewtopic.php?f=3&t=70823&hilit=t+piece+turbo+pipe