Coolant flow direction?

[POPEYE]

Can anyone point me towards a diag or info on which way round the coolant flows, in particular which is the flow and which is the return on the heater pipes? I am sure I used to know but it escapes me, going to sort out this sodding heater if it's the last thing I do, I did a search and come up with buggerall so any info you can provide will help

I am going to fit a 12v pump in the heater line to force coolant through, I have also ripped out ALL the heater from under the dash and intend to make my own unit, I did remove the air-con years back so the empty box that held the exchanger can go, also half the flaps and buttons don't work so the main unit can go along with the fan, got a little 7" fan coming and all being well I can use the matrix with this, all I need is demist, flap to the dash vents, fresh or circulation air and a viable rheostat on the fan, nice and simple
thanks, ian

[ST185pinjo]

[POPEYE]

Thanks Jef, I think that's a different engine to mine, mines the old 2'4 Japanese tractor engine, would the flow be different?

[ST185pinjo]

Would not that be the same Ian?

The hose with the valve in it is the inlet hose to the matrix.
http://www.toyotanation.com/forum/80...ant-flush.html

Take a look at post #5

[POPEYE]

Thanks, this is an old pic of mine from long ago before I "got at it"
I removed the hot/cold valve ages ago when I ran the pipework to the rear for the veg oil set up, so lost track of which pipe is which, so then the flow is the one with the valve,
just wanted to check before fitting an inline electric pump and having it work against the natural flow,
as for the original set up, I'm guessing that the valve will work whether it's fitted to either hose, the result will be the same, (to stop the flow) so I thought that the flow isn't automatically the one with the valve on,
Judging by the fact that I have never had great heat from the heated "ever" I think there is no real forced or pumped flow but more of a heat loss convection thing,
Anyway thanks for your help, much apprecieated mate, I will experiment when I get the pump, Ian

[ST185pinjo]

I think that the placing of the valve does matter. If you place it at the exit pipe, the hot water will flow in the matrix and it wil always be hot. The waterpump creates the flow. It would then circle inside tha matrix, I'm thinking...

I do not know for sure, but would make sens to me.

[POPEYE]

You may well be right, I'm going mainly on central heating, I know that with non thermo-static valves it didn't matter which end of the rad you fitted them, turning them off at one end of the rad stopped the flow, and the rad starts to cool, the flow is only important if thermo-static valves are fitted to one end of a rad, usually the flow direction is up through the stat valve and through the rad and out the non stat valve the other end (of course you can get reverse thermo valves the take the flow into them from the rad

anyway probably far removed from vehicle coolant pumps, need a bit of transparent pipe and some food colouring

[Karma Supra]

They always draw from the bottom of the radiator. (Toyota at least)

Any air will sit at the top, and get bled out as the radiator cap allows expansion.

[NiftyNev]

My concern is that by using a pump on the heater circuit you will change the flow from engine and radiator. More coolant may pass through the heater circuit and not get cooled by the radiator causing the engine to overheat. I'd just connect your heater and use the engine water pump as normal.

Nev.

[POPEYE]

I take your point Nev, never thought about it like that, that said though I have had a pump in the line for years, ever since I rigged up the veg oil tank and stuff, I had a 24v bosch pump (from a bus) and fitted it at the rear near the veg tank to help shove the coolant around, seem's to have worked ok, although I'm not sure it's still working, (must check it), at the time of fitting I tried it with a pipe in a bucket of water and at 12v it certainly pushed a fair amount out, I assume it was/is running at half speed at 12v?
ever since I got the truck the heater has not been great even after several good flushes, I now have the matrix out but yet to check it over, been bust with re-wiring stuff which I need to get don before mot time arrives,
I was thinking of a small pump near the heater as this one at the rear seemed to warm up the rear most piping fine but still sod all out the heater,
while I have it stripped out and intend to do away with the big bulky heater boxes under the dash I can really check the matrix out, if needed i'll get a new one, it does not need to be from a surf as I'm making my own less complicated heating system,
anyway i'll keep it updated

[tweak'e]

My concern is that by using a pump on the heater circuit you will change the flow from engine and radiator. More coolant may pass through the heater circuit and not get cooled by the radiator causing the engine to overheat. I'd just connect your heater and use the engine water pump as normal.

Nev.

not likely.
any extra flow through the heater will result in more heat going out from the coolant. it should cool the engine slightly more and heat the cabin more.

the only down side is during warm up. a bigger heater may mean the engine is a bit slower to warm up.

[POPEYE]

The main reason I'm junking the stock heater is as I have the dash stripped out I'd take advantage of it to sort out the cab heating once and for all, like I say ever since I got the truck the heater hasn't been great, at best Luke warm at worst stone cold, (I get more heat coming up through the trans tunnel where I removed the rear heater and forgot to seal up the hole)
I am sure some of the operations on the heater unit don't work and I no longer have AC so it struck me that this massive plastic boxing that contains the heater fan motor and the outside/inside air, the AC rad and the flaps and vents box can come out, replacing it all with a simple rad, fan on a rhea-stat for speed control, and a demist or vents flap (like my lads Landy, 2 sliders and a fan switch, simple but effective, it pumps out more hot air than you can stand)
the pump will only work when the heater fan is on, this will not be too often as I don't like it too hot, but in cold weather it would be nice to have a decent demist and some warmth in the cab,
If when I get the matrix out of it's casing I find it partially clogged and I'm unable to clear it I will get a unit from a scrapper or eblag,
as for this pump I would re-position the one have but it's too big to fit anywhere near the heater, and don't really want it under the dash, so we will see how it goes,
all I needed to know was the flow direction so I wouldn't fit the pump working against the engines pump, I may well have had the old Bosch one wrong but it did seem to get hot cooland to the rear and back ok, I'd remove it but I have a radiator over the back axel with a fan on linked to the two back-up ons on the front (the old 2.4 paranoia was high then, I'm better now though