ANOTHER OVERHEATING BONGO, HOPEFULLY SORTED

[Jamesnjane]

is it possible to get the stat to open when bleeding??? because people cant when driven hard, so why does it say wait for bottom hose to get warm when bleeding? is that still just heat soaking through? im understanding better now, thanks

[Vanmanerik]

It wasn't me that came up with a flow diagram for the Bongo, it is in one of the other 'overheating' threads but can't just find it, ready to go to pub and Mrs is getting impatient for her weekly fix.

Here something to think about.
Can you fit the thermostat the wrong way round?

Due to the ‘unusual’ location of the thermostat on the inlet side of the engine, the thermostat must be placed ‘backwards’ in the housing to allow the bypass flow to cross the bulb – i.e. the thermostat is orientated in the incorrect direction for most efficient hydrodynamic flow.

Can it be this simple??

Ta ra 4 now.

[haydn callow]

The stat opens when bleeding by letting the engin idle for a while then reving at about 2500 revs for quite some time (10 mins) and repeat if not yet open (bottom hose HOT). The reason it does open is co's there is no rammed air flow over the engine whilst stationary, hence it gets well hot. (I think)

[Peg leg Pete]

I fitted new stat by feel If I remember correctly it would only go one way and had to be orientated into position Enjoy the Pub

[Peg leg Pete]

Haydn I bled my bongo sucessfully without revving at 2500 r.p.m. and removed a large airlock, stat must have opened to allow flow through the radiator

[Jamesnjane]

you cant fit stat other way, wont go

[Peg leg Pete]

James I agree

[haydn callow]

I give up !! But I still think i'm right. I think where some get it wrong is they feel the top hose and not realising the flow is upwards through the rad assume the bottom must be hot. But as the flow is up the rad this is not so!!

[Peg leg Pete]

surely if the flow is up the radiator and the radiator is cooling correctly the water coming out at the top should be cooled

[francophile1947]

Just found a good article of a similar problem on MGF car. Its well worth a look at as it offers good reasons for heads cracking on engines with themostat on lower hose, good test data to prove it, and an inexpensive answer.

http://www.mgfmavhh.ukf.net/

What doo you think?

Brilliant!!! - sounds very similar to the Bongo system and makes perfect sense
Now where do I get 2 Renaults and a Porsche?

[Peg leg Pete]

The diagrams in the article show cool water from radiator top, not hot as with the bongo

[haydn callow]

Peter. The top of the rad is hot co's the bypass circuit goes in and out of it. Follow the pipe from the expansion tank and feel how hot it gets,

[francophile1947]

They would do Peter, the MGF system doesn't have the bypass/header tank system heating the water at the radiator.

[Peg leg Pete]

So in reality the systems are different, I hope so do not like the sound of cold water entering the engine block, sure way to crack the head

[francophile1947]

Yep, but as you say Peter, the Bongo has a large radiator - so when the stat opens, there is a large quantity of cold water, mixing with the hot at the top of the rad, before going to the head. If, as seems almost certain, the Bongo's stat doesn't open very often, there will be a large variation in the temperature of the coolant going to the head.