overheating

[dick dastardly]

I have checked thermostat, it's okay! But cannot get any heat through bottom hose to radiator! Help Please (new member).

[teenmal]

Have you tried bleeding the system properly.The "heat" does not go to the radiator via the bottom hose,the cooled coolant goes from the radiator to the engine via the bottom hose.The "heat" goes in via the top hose to the radiator to be cooled.


Good Luck.

[Titan1995]

When you say checked the Thermostat did you remove it and get it to temperature in a container of near boiling water on a stove or similar.

Personally I would replace as a matter of course when purchasing a bongo [Now gifted with 20/20 vision in hindsight.]

As all will tell you on here the bleeding process must be adhered to otherwise catastrophic head failure awaits.

I also keep harping on out how much easier it is to remove the thermostat housing from the block and then fit the thermostat on the bench.

As long as you get a replacement housing to block thermostat, this method pretty well puts pay to poorly seated thermostat and the possibility of cross threading the housing bolts.

I am sure others will have different thoughts.

[Bob]

Have to agree here, if the stat's out fit a new one,and the bleed process is vital.

Three You Tube vids if you do a search. If the system is not bled properly the head will fail.

And a very warm welcome to BF, we'll help all we can.

[Titan1995]

[quote="Titan1995"]

As long as you get a replacement housing to block GASKET, this method pretty well puts pay to poorly seated thermostat and the possibility of cross threading the housing bolts.

Sorry about the typo there.

[Northern Bongolow]

to get the stat to open you have to establish coolant flow through out the system, in a normal car set up this can be fairly easy, but in a bongo this is more difficult because of the coolant /heater system design.
there are two main systems on the bongo, the first is the heater system flow needs to be established so the heaters heat up first, to do this you have to bleed the system. the second is the engine cooling system this also needs flow and the water pump will not pump air. so also needs to have all the air out. these 2 systems meet in the stat housing and are blended to give an overall temp.
if you look at these systems you may see that the first hose out of the head to the rad goes quickly down hill, the air trapped here will not be pushed down so an airlock here gives no flow. the front heater matrix is mounted high up so again may make an air lock so give no flow.
the secret is to manipulate and massage these pipes to push air out of these trapped places until flow is established, this is usually done as part of the bleed process.

[Simon Jones]

It would help to know a little more about the problem e.g. what engine is it? what symptoms are you experiencing? any history of previous problems or work done on the cooling system?

[mikeonb4c]

to get the stat to open you have to establish coolant flow through out the system, in a normal car set up this can be fairly easy, but in a bongo this is more difficult because of the coolant /heater system design.
there are two main systems on the bongo, the first is the heater system flow needs to be established so the heaters heat up first, to do this you have to bleed the system. the second is the engine cooling system this also needs flow and the water pump will not pump air. so also needs to have all the air out. these 2 systems meet in the stat housing and are blended to give an overall temp.
if you look at these systems you may see that the first hose out of the head to the rad goes quickly down hill, the air trapped here will not be pushed down so an airlock here gives no flow. the front heater matrix is mounted high up so again may make an air lock so give no flow.
the secret is to manipulate and massage these pipes to push air out of these trapped places until flow is established, this is usually done as part of the bleed process.

Hi Ady. Just to make it clear to the OP, am I right in saying that you do still get flow of coolant around the system even with air trapped in the system, but the flow is not sufficient to push the air against gravity in order to move it on to the header tank as the highest point in the system in order that it can be expelled? The danger then is the air bubble will end up at a closed off high point in the system such as around the head (rather like air gets trapped at the top of an upside down u-bend). Where the air does lodge, coolant will not be in intimate contact with the metalwork of the head and so heat will not be conducted away from that area. Thermal stresses will thus be set up as different parts of the metalwork in the head heat up differently and this will likely result in the head cracking, especially if the design is prone. For this reason, the bleed tube take-off in Bongos is placed at the same height as the coolant channels in the head.