Cooling schematic - lets see if we can draw one

alphabetter · Post by **alphabetter** » Mon Apr 09, 2007 9:07 pm

I am splitting this off from this thread because it was getting a bit difficult to manage.

Lets see if we can agree a Bongo cooling schematic which we all think is right. I think it would be a really useful tool for people trying to debug cooling problems.

Based on the above thread, my own observation and the data in the Bongo parts database I have taken a stab at creating a first draft.

Click on this thumbnail to see the full-size version

I am pretty sure that most of it is right, but I don't know about the flow direction around the turbo and the funny hose that links the top of the thermostat to higher up the block.

What do you think?

francophile1947 · Post by **francophile1947** » Mon Apr 09, 2007 9:14 pm

Looks good alphabetter - like you, I don't know about the turbo and that other hose.

Dannyboy · Post by **Dannyboy** » Mon Apr 09, 2007 9:22 pm

I think it is largely correct Alphabetter. Certainly the flows to and from the radiator and the expansion tank are spot on. The rest of the layout is also correct. The only thing I am not sure about is the direction of flow to and from the heater matrices and the flows at the thermostat.

dandywarhol · Post by **dandywarhol** » Mon Apr 09, 2007 11:04 pm

Looks about right AB, I'll have a look around the stat area tomorrow too.

Is there any possibility that there's a temperature sensed valve in the radiator allowing it to be split into 2 compartments

Just before we split up for Easter, a colleague gave me a BMW radiator (crossflow) which had the end tank removed and there were tubes and valves inside. I didn't look carefully at it as the pub beckoned

but there was definitely something different about it.

Anyone care to discect their old rad - jamesnjane, dannyboy???

mikeonb4c · Post by **mikeonb4c** » Mon Apr 09, 2007 11:08 pm

What a great idea alphabetter - this could help avoid a lot of overheating amongst the membership once the diagram is finally agreed amongst the experts (a picture is worth a thousand words etc.). I hope Ozric may put in on Bongoogle as well as Ian getting it and relevant text onto a BF factsheet. Its good to see the BF knowledge base expand.

best

Mike

alphabetter · Post by **alphabetter** » Tue Apr 10, 2007 9:18 am

Thinking about it, and also reading the latest updates on the other thread I am almost sure I've drawn the flow direction round the bypass on the engine block and through the turbo going in the wrong direction. I'll update it tonight.

If anyone can confirm any internal details that aren't obvious from looking externally it would be great. eg
Any info on internal structure of the radiator
Does the thermostat block any of the other circuits when it opens?
<Edit>Or indeed any info on water flow within the engine block.

Taxiback · Post by **Taxiback** » Tue Apr 10, 2007 5:01 pm

I have added the bleed hose, this comes off the head as do the 2 other hoses so I would think they are all hot (while the thermostat is closed) coming from the same pipe.
Once the thermostat opens they all cool down.
What seems odd is the cooling of probably the hottest part of the engine (the turbo).
I have also altered the front heater and the hose from the back of the block to the rear heater.
Anyway you may call me a plonka if I am totally wrong.

[img][img]http://img337.imageshack.us/img337/9378 ... ul1fv7.jpg[/img][/img]

francophile1947 · Post by **francophile1947** » Tue Apr 10, 2007 5:23 pm

Just looking at the diagrams, can it be right that the water circulates in different directions round the front and rear heaters? I would have thought they would flow in one big loop BUT I haven't got a clue, it just seems logical.

alphabetter · Post by **alphabetter** » Tue Apr 10, 2007 7:28 pm

Thanks for the comments and Taxiback for proposing the updates. I have looked at TB's diagram three times today and each time it has been different. That is what I call real time editing.

<Edit> Make that four versions! The final one the heater flow is back to the same as the one described below.

Actually I agree with most of the changes apart from the heating flow and the flow direction through the turbo.

The flow through the heaters is based on this diagram and my own observation. As you can see there are separate pipes either side of the car going to the front and rear heaters. The one on the drivers side is rather hard to see because it is tucked in to the bodywork. If you look in the middle of that diagram you will see two hands pointing to 1300 13-100 (actually this looks like a typo for 1030 13-100) and 1500 15-290. Based on this I would say the way I originally drew the heating circuit is right. I also can't see the "extra" pipe on the passenger side on the Bongo parts drawings.

For the flow through the turbo then as far as I can see the top connection on the engine block either has to be a water inlet or an outlet. Both tubes connecting to it either have water flowing away from the connector or towards the connector. I now think I had the direction wrong in my first diagram. Taxiback has corrected one but not the other. Another point here is that if the flow is away from this connector (as shown in this revision) why doesn't the vent tube spit water out when you unblock it? There is something not quite right here still I think.

Finally as an editorial point I decided not to draw the vent hose as either blue or red as it isn't an active part of the cooling system in normal operation.

Here is my revised diagram. Click for fullsize again.

Peg leg Pete · Post by **Peg leg Pete** » Tue Apr 10, 2007 7:32 pm

The Bleed/ vent tube spits out coolant on our bongo.

francophile1947 · Post by **francophile1947** » Tue Apr 10, 2007 8:01 pm

Still trying to get my head round the circulation. The water comes from the pump, through the top hose to the rad, through the bypass hose to the expansion tank, from the tank via the bypass hose to the stat. As the water is being pumped, how can the flow change direction at the rear heater hose? Would it not be pumped along the blue heater hose in the same direction as in the bypass hose?

alphabetter · Post by **alphabetter** » Tue Apr 10, 2007 9:02 pm

francophile1947 wrote:Still trying to get my head round the circulation. The water comes from the pump, through the top hose to the rad, through the bypass hose to the expansion tank, from the tank via the bypass hose to the stat. As the water is being pumped, how can the flow change direction at the rear heater hose? Would it not be pumped along the blue heater hose in the same direction as in the bypass hose?

I think that this is a problem with the way I drew the diagram rather than the logic. My theory is that there are three points on the engine block where water is pumped out (two on the drivers side and the top one on the passenger side) and one where water is sucked in (behind the thermostat).

The two blue pipes with arrows in opposite directions on the diagram are just two circuits joining at a "T" piece in to a common flow towards the "sucking" point at the thermostat. Think about it as two rivers merging if that helps.

francophile1947 · Post by **francophile1947** » Tue Apr 10, 2007 9:22 pm

I see what you mean but, without knowing how the waterways run in the block/head, I would have thought that the rear pipe on the driver's side was taking water into the engine, not out. Do you actually know that it is an outlet?
By the way, I'm not trying to be argumentative, it just sounds that way - a clear case of talking would be easier. Hopefully we'll get this cooling system sorted eventually.

alphabetter · Post by **alphabetter** » Tue Apr 10, 2007 9:33 pm

francophile1947 wrote:I see what you mean but, without knowing how the waterways run in the block/head, I would have thought that the rear pipe on the driver's side was taking water into the engine, not out. Do you actually know that it is an outlet?
By the way, I'm not trying to be argumentative, it just sounds that way - a clear case of talking would be easier. Hopefully we'll get this cooling system sorted eventually.

I agree it is better that everybody provides their input so we can try and get the best diagram possible.

Your question is very relevant. I don't have any proof that the rear drivers side pipe is an outlet. It is all based on the assumption that everything going to the thermostat is feeding an inlet, but as we don't know the internal construction of the block and we don't know exactly how the pipes around the thermostat connect there still has to be doubt here. What we do know for certain is that the expansion tank is connected to the internal heater circuit as shown and that on the parts list this pipe is labelled as a "bypass hose".

Anyone else able to help us?

dandywarhol · Post by **dandywarhol** » Wed Apr 11, 2007 1:00 am

I'm changing my rad hose tomorrow and will try to acertain the inlet/outlets as it warms up. The pipe will be hotter towards the source if that makes sense.