Cooling system diagram

[widdowson2008]

If this post has achieved nothing else, folk are actually pulling in the same direction this time
Certainly got some late night input as well - check out the time on some of the posts - and I thought I was the only sad one burning the midnight oil.
Still aint got me diagram finished yet - see subject of post (waiting for input) - but the 'think tank' are on the case (I hope)
May change my loggin to 'Staffy' - Ive bitten and I aint letting go till I get what I want. You dont get rid of me that easily.
So c'mon - input required

[missfixit70]

4.20 am I know ...sad.
Just want to jot down my understanding of the cooling system.

It is 2 systems....a small bore heating/cooling system SB
and
A large bore cooling system LB
these are linked together at the stat like a mixer tap.

Early morning = cold Bongo
SB circuit fully open LB closed tight.
off we go and the coolant heats up quickly and is pumped around the SB circuit and gets the heaters nice and hot and in doing so loses a lot of heat and this is enough to keep the engine happy under normal running conditions..

We open Bongo up a bit on the motorway or tow the shed along...SB no longer keepingn up with the cooling requirements and the Stat starts to open (mixer tap)
Stat opens a third to halfway and then radiator is brought into use...cooling things down and at the same time heating the cabin. This is as hot as it should get and everything is fine.

Now the bad news....Our Bongo has a half blocked rad or there is some other fault in the system....Stat fully opens and this shuts off the SB circuit......cabin heaters start blowing cold (no...not a air lock) co's no SB circulation...Rad cannot cope with the extra cooling requirements and we are now in a irreversable meltdown.This all now makes sense to me and a lot of the old info is out of the window.......i.e. heaters blowing cold was always put down to air locks....
I also belive the pump pumps the coolant round the SB circuit all the time, right from the off.

From the above I would guess that the stat never fully opens in a good cooling system, half open is plenty and should it ever fully open we are in trouble,,

Thoughts anyone??

Not sure about this bit, looking at the pics of the stat on Allans site http://www.allansvehicleservices.co.uk/32132.html the stat shuts off the bypass circuit but NOT the heater circuit, this has continous flow along with the turbo doesn't it? therefore the heaters will run hot all the time, Unless there's coolant loss/ airlock won't they?
I think it's more like 3 or possibly even 4 systems, depending on how you want to split it up,
The bypass cooling system which should cope with normal running,
The heater system which has constant circulation,
The turbo system (ok not exactly a system), again with constant circulation,
The main radiator & bottom hose, fully open stat - bypass system closed.

I also, don't agree that the stat fully opening is a bad thing in a "good" system, it just means the system is pushed a bit harder & is coping happily as it is designed to. When the stat opens fully, the rad fans don't instantly kick in, they are the "next level" of cooling that will kick in if necessary IMO, still not a "bad" thing in a well maintained system. It just means the engine's been working hard, eg driving up a mountain in Italy in 30 - 40 degees C for nearly an hour fully loaded with gear & a back box. This I have experienced & it coped fine, no adverse effects, temp gauge staying well within range & heaters still pumping out hot air.

The problems come when that stat doesn't open at all, doesn't open fully or opens too late, or when the rad is blocked & can't do what it's supposed to when called upon.

[bongobaz]

I'm Lost think i'll take fact sheet to garage for flush out and hope for the best

[bongoben]

I also, don't agree that the stat fully opening is a bad thing in a "good" system, it just means the system is pushed a bit harder & is coping happily as it is designed to. When the stat opens fully, the rad fans don't instantly kick in, they are the "next level" of cooling that will kick in if necessary IMO, still not a "bad" thing in a well maintained system. It just means the engines's been working hard, eg driving up a mountain in Italy in 30 - 40 degees C for nearly an hour fully loaded with gear & a back box. This I have experienced & it coped fine, no adverse effects, temp gauge staying well within range & heaters still pumping out hot air.

The problems come when that stat doesn't open at all, doesn't open fully or opens too late, or when the rad is blocked & can't do what it's supposed to when called upon.

Almost exactly right Kirsty, you are much closer to the truth.

[haydn callow]

Hmmmm!!!! hadn't thought of that.....even more pipes.....It all made sense at 4am.
It's like snakes and ladders.......you think you've got it then you go back a step...
I will study Steve's drawings some more. Then try and get under the Bongo with my "detector"

[missfixit70]

The trouble is, taking readings while it's running & static is completely different operating conditions to while its driving Anyone got a rolling road & wind tunnel we can borrow?

[bongobaz]

Let me know when its sorted.
Something simple for a first timer.
I know about putting wet stuff on hot stuff and pipes n hoses

but this is all Greek to me.

[widdowson2008]

I'm Lost think i'll take fact sheet to garage for flush out and hope for the best

When you see the diagrams, It may be clearer (I hope)
and it really aint as complicated as it appears to be - involved? YES, complicated? NO

[widdowson2008]

The trouble is, taking readings while it's running & static is completely different operating conditions to while its driving Anyone got a rolling road & wind tunnel we can borrow?

C'mon, a bit of lateral thinking required - Strap the missis to the chassis
Job done

[widdowson2008]

Let me know when its sorted.
Something simple for a first timer.
I know about putting wet stuff on hot stuff and pipes n hoses

but this is all Greek to me.

Not long now I hope - Just waiting for confirmation from 'Them that know in the Think Tank'
I am a simple bloke and the diagrams are the same - they replace thousands of words (which all appear to be saying the same thing) and bring it down to a level I can understand (for me anyway )

[dandywarhol]

Not sure about this bit, looking at the pics of the stat on Allans site http://www.allansvehicleservices.co.uk/32132.html the stat shuts off the bypass circuit but NOT the heater circuit, this has continous flow along with the turbo doesn't it? therefore the heaters will run hot all the time, Unless there's coolant loss/ airlock won't they?
I think it's more like 3 or possibly even 4 systems, depending on how you want to split it up,
The bypass cooling system which should cope with normal running,
The heater system which has constant circulation,
The turbo system (ok not exactly a system), again with constant circulation,
The main radiator & bottom hose, fully open stat - bypass system closed.

I also, don't agree that the stat fully opening is a bad thing in a "good" system, it just means the system is pushed a bit harder & is coping happily as it is designed to. When the stat opens fully, the rad fans don't instantly kick in, they are the "next level" of cooling that will kick in if necessary IMO, still not a "bad" thing in a well maintained system. It just means the engine's been working hard, eg driving up a mountain in Italy in 30 - 40 degees C for nearly an hour fully loaded with gear & a back box. This I have experienced & it coped fine, no adverse effects, temp gauge staying well within range & heaters still pumping out hot air.

The problems come when that stat doesn't open at all, doesn't open fully or opens too late, or when the rad is blocked & can't do what it's supposed to when called upon.

With you on this one - heater circuits open all the time IMO

[widdowson2008]

Not sure about this bit, looking at the pics of the stat on Allans site http://www.allansvehicleservices.co.uk/32132.html the stat shuts off the bypass circuit but NOT the heater circuit, this has continous flow along with the turbo doesn't it? therefore the heaters will run hot all the time, Unless there's coolant loss/ airlock won't they?
I think it's more like 3 or possibly even 4 systems, depending on how you want to split it up,
The bypass cooling system which should cope with normal running,
The heater system which has constant circulation,
The turbo system (ok not exactly a system), again with constant circulation,
The main radiator & bottom hose, fully open stat - bypass system closed.

I also, don't agree that the stat fully opening is a bad thing in a "good" system, it just means the system is pushed a bit harder & is coping happily as it is designed to. When the stat opens fully, the rad fans don't instantly kick in, they are the "next level" of cooling that will kick in if necessary IMO, still not a "bad" thing in a well maintained system. It just means the engine's been working hard, eg driving up a mountain in Italy in 30 - 40 degees C for nearly an hour fully loaded with gear & a back box. This I have experienced & it coped fine, no adverse effects, temp gauge staying well within range & heaters still pumping out hot air.

The problems come when that stat doesn't open at all, doesn't open fully or opens too late, or when the rad is blocked & can't do what it's supposed to when called upon.

With you on this one - heater circuits open all the time IMO

......and the current diagrams agree also - with everything Kirsty and Dandy said

[haydn callow]

agreed !!!! sounds sense.

[mikexgough]

With you on this one - heater circuits open all the time IMO

Absolutely .....

[widdowson2008]

The more I learn, the more there is to find out Correct me if my thinking is 'out of line'
Which of the following statements is wrong?
1. There is an optimum running temperature at which any engine should be to get maximum efficiency. I think this is a fact.
2. Any deviation, above or below, this temperature results in a drop in efficiency.
3. Dumping cold coolant into a hot engine results in thermal shock causing localised rapid contraction of metal components, which results in cracking taking place.
If the above is true, then it is not unreasonable to assume the the Japs have spotted this and put the necessary stuff in place to deal with it.

Does this sound reasonable?
I have been informed that the 2 main radiator fans are not the same as each other. I have not checked this yet cos its bucketing down outside, but the source is A1.
I am told they each have a different number of blades. If this is true, then they must have different 'blow' rates. That poses the question WHY different 'blow rates and which part of the radiator is the bigger 'blow' rate fan covering? and again, WHY?
Coupled with all that lot, does anyone know if they have the same size motors? And the next question is, do they both work at the same time, or can they cut in and out independent of each other? and another, are they the variable speed type .... The list goes on.......and I haven't even mentioned the scavenger fan yet.

What I was wondering, going back to the original concept that there is an optimum running temperature, could the Japs have built a system here which will, through the various devices mentioned, be infinitetly controllable to control the temperature within tight limits.

Or is it late and my brain has gone into fantasyville

Thanks A1 source of information - more to think about.

And all I want is a * ****ng diagram