(Home) 2ct cooling new twist in the tale

In short, I fitted a 2ct engine to a Landie SIII LWB with full roofrack. The temperature often use to hover round the 100+ area (VDO gauge measured at top outlet) especially cruising on the highway. The result a blown head gasket. In the end I removed the thermostat (just left the housing/frame to ensure correct diameter), blocked the cold start bypass with a 16mm welsh plug and fitted a 82 c thermostat at the top outlet pipe. End of problem. I live in SA and with temperatures hitting 40+ the engine haules this huge vehicle no problem at 110km an hour with the temperature sitting between 82 and 92C. I thus suspect that there is some serious problem with the thermostat at the bottom. It sounds totally illogical, if you think about it, everytime it opens it will be closed by a gush of cold water. But severall vehicles today have there thermostat at the bottom (golfs, and our local Ford and mazda pickups too). Maybe it is just airlocks, cause the thermostat at the bottom makes it extremely difficult to bleed. Because of the vehicle running to cold in winterm, I recently relocated the stat to the bottom (removing welsh plug) and back to square one. There seems to be constant "airlock forming), as soon as the vehicle warm up (say 85) and you open the radiator cap, you have to add a lot of water (500ml). I have decided to live with the cold engine in winter and am putting the stat back at the top and blocking the bypas.

- (#10616) Leon, 5 Sep 03 1:57

Assuming the whole system is airtight and you have the correct rated pressure cap - you could try making something up (drilled out pressure cap with rubber gaskets, tube and a bottle upside down with bottom cut off)to extend the cooling head higher than heater box etc. then let it idle for half an hour (revving a few times) to allow any trapped air to emerge and let it draw the expanded coolant back overnight

- (#10617) chris turner, 5 Sep 03 17:21

Hello Leon

The thermostat is mounted on the return radiator hose at the bottom of the engine block. In order that this can work effectively, there is a metal plate mounted in the thermostat housing on the inside of the engine block, that acts like a heat sink to the engine. When the thermostat is closed, it is sensing the temperature of the coolant. As it begins to open, it makes contact with the metal plate, and is sensing the temperature of the engine. Once the engine has cooled to near 82°C, it starts to close.
As the coolant flows from the bottom of the engine towards the top. The temperature in the top will be much higher than 82°C, (100°C would be about right). Putting the thermostat at the top will obviously reduce the temperature from 100°C to 82°C.

What sort of expansion tank is fitted to your landie?
What is the level of coolant in it?

Dave Bright

- (#10618) dave Bright, 6 Sep 03 2:43

Hi Dave

There is no problem with the expansion tank etc and the cooling is full. It gets damn hot here in summer and this 100 temp let the headgasket blow before. I have tried again this morning to see if there are airlocks, It was very cold and the thing went to a 105 no problem, I parked it up a steep hill to see if any air would come out, but nothing. I am convinced the thermostat is not opening, I am going to put it back at the top, I have had enough, it works there so am going to leave it at that (unless there is a major airlock righ at the stat). The heater is not connected (its a Landie they hardly ever work). Other then that its a fine engine with good consumption. If you just cruise around it sits at 88-90, once you step on the pedal it rises alarmingly to over a 100. Also no problem with pressure cap etc, it pushes water into the expansion tank at startup, but that is normal and then stops. It sucks it back in after switch of, I have done all the checks, no leaks. I have noiced a lot of people drill holes in the stat to overcome the heating problems, to me that is a clear indication that there stats are not opening. To put a lower temp rating stat in also would not make much of a difference. If the engine and radiator are desighned to operate at a certain temp, it will go to that eventually, the lower stat will just let it take longer, thats my opinion. my work vehicle is a Ford, also with stat at the bottom, that seems to work in this case, but i cant figure out where the difference is between the ford and the 2ct. it seems pretty much the same.

If you have any other suggestions, please let me know.

Regards

Leon

- (#10619) Leon, 6 Sep 03 3:39

Have you got a good coolant flow through the rad and is the viscous functioning properly - also as engine is not in intended vehicle you could check the air flow through the rad as the viscous will be relying on lots of hot air to spin efficiently.
You could try the cotton or the rolled up newspaper trick on the fan blades to see - at your temps it should be roaring away.
I had a recent experience where the equipment I was using to measure the cooling temp was gradually going out of calibration - caused me loads of grief, worrying/checking etc. - you could check your sensor in boiling water and see if it measures 100c

- (#10620) chris turner, 6 Sep 03 5:36

Ah, heater not connected? Are you aware that the heater matrix (along with the thermo wax on the inj. pump)form the bypass circuit?

- (#10621) david miller, 6 Sep 03 7:38

Hi David

Could you please ellaborate. With regards the other points, fan radiator etc are fine - a R100 note sticks to the grill if the fan is on, and that only happens when the temp goes over a 100. When the thermo was at the top it hardly ever went on and the temp never came close to a 100 it sat round 92 and this is cruising the entire day on the highway, through semi desert at 110km/h. I blocked the cold start bypass hole, the small one you see when looking in to the block, if you leave it open and take the thermo out the engine will also overheat as the flow wont be right as not all water going to radiator. With the thermo out engine does not even get to 80 (bypass blocked) on the highway at 110. After 3 hours travelling on this outing I covered half the radiator with a piece of cardboard to get it to go to 80. You could touch the pipes and head they were all cool. The gauge works it is a VDO, and the Landie gauge is also still connected. I am convincened the problem sits at the thermo. But please carry on with the heater story, where can I get a diagram on the system, we cant get manuals here, it is impossible. My radiator guy and I suspected that somewhere the hot water was not getting properly to the thermo to keep it open, The inj pump pipe is still connected and flowing. We get these engines by the container load and things are simply cut of. I noticed at the top of the outlet hose there was a thin pipe that was welded off. I put the VDO sensor gauge there. Someone told me its the heater pipe but said it would make no differnce if closed off. Surely the vehicle should still cool without the heater connected, I mean you dont want the heater on when it is 40.

Regards

Leon

- (#10622) Leon, 6 Sep 03 11:35

Do you know what vehicle the motor is out of? In my experience the hole you're refering to (directly behind the 'stat) is just that, a hole.
Right side of the engine is hot flow, left side is cool return. There has to be flow between each side at all times. There's a minimal flow through the wax stat, the turbo and oil cooler also allow a tiny flow. But in the townie, there's also the rear heater matrix plumbed in at all times. Don't know about other apps eg Camrys etc.
But it's important to have a bypass flow, especially as the stat's normally at the cold side of things, otherwise you could have a boiling head/ cold block scenario before the stat opens.
We have considered in the past the effect of the bypass flow arriving at the inlet of the stat, and reckon that while directing return from the heater at the sensing capsule might speed response, it could also do the total opposite...

- (#10623) david miller, 6 Sep 03 13:32

Hi David

No I don't know, as i say they come in here by the container load and we pick them up for between 3000 and R4500. I think you are right, there is a circulation problem, the head boils but the block stays cold. That hole is the cold start bypass. When the engine is cold it is open, but when it gets hot the "foot" of the stat extends and closes it so that the coolant circulates through the rest of the engine. I had a diagram of how such systems work (most modern vehicles). i think a pipe has been blocked of that should not be. A t-piece comes out the block just behind the stat housing, one part goes to the inj. pump, the other one is blankt of. I pressume that is the heater pipe. Now if the pipe that is blankt of at the top (that is where I put the VDO gauge) is supposed to be connected to that bottom heater pipe - well maybe that is the problem. If it is connected then there will allways be a bit of complete circulation, no matter if the stat is closed. The stat region will also receive uncooled water directly from the head. Does this make sense? You don't have a diagram perhaps or no where i can find one? Toyota SA wants nothing to do with these engines, so don't stock the manuals.

Regards

Leon

- (#10624) Leon, 7 Sep 03 14:34

Nope, no diagram, but you're right about the bypass loop. Methinks you've some type of overshoot situation down at the stat, but it'll always look rather different at the top of the head. Just run a hose from the top hose (if you're using the fitting already for your sender, cut the top hose and put a fabricated "T" there)to that pipe at the top of the stat housing, and give it a try...

- (#10625) david miller, 8 Sep 03 1:27

BTW it's not unknown for the thermo wax in the inj pump to silt up and stop flowing, then you'll get NO circulation from the top of the head down...

- (#10626) david miller, 8 Sep 03 1:28

Where do you find this thermo wax? Is it inside the pump? I hope not cause I aint touching that thing. Strange that there is flow when the stat is at the top. I am going to inspect the Ford's system and see how it works. As the stat is also at the bottom I am sure it must work the same. The t-piece that goes from the block to the inj pump with the one pipe blocked off, the blocked of pipe, is that for the heater?

Regards

Leon

- (#10627) Leon, 8 Sep 03 1:50

The thermo wax is the cylindrical device on the side of the pump with two hose stubs on it. It links with the timing control and the throttle lever.
Yes, the stub you refer to is for the heater...

- (#10628) david miller, 8 Sep 03 13:23

Hi David

If I understand you correctly, the inj pump gets water to regulate the idling, if its cold it idles fast till it warms up. Thats what the ford does. The landie not. So maybe there is a block there. Is it difficult to fix? With regards heater. Where does the heater re- enter? I pressume it is somewhere at the top of the block? I cant find any other blocked of pipes. If I understand correct, there is always a flow in the heater pipe, thus allways a bit of water flowing from top to bottom, bypassing the radiator. When you switch the heater on then it flows through the actual matrix heating the air. If this is the case, then one is virtually guarenteed getting hot water on the stat to open the bugger. That might also explain why no faster idling when cold, there is no water initially going to the inj pump, because that water has to come from the bypass flow?? Maybe you have solved the mystery, now it is just a matter of figuring out where that pipe goes in at the top. Could you please help again. Maybe the site should post a diagram on how the system works, because it seems to be a common problem. I think a big problem in standard townace situation is clogged radiator and pipes, when I got the engine I noticed a fair amount of corrosion, doesn't look like they believe in coolant in Japan, but lack of it is deadly for a TD engine.

Regards

Leon

- (#10629) Leon, 9 Sep 03 8:59

Flow for the thermo wax (yes it alters idle speed...) comes from the rear of the head onder no4 manifold inlet, and it returns via a "T" on that heater return pipe that is near the stat. The oil cooler should also return to that point after having looped round the rear of the block, if memory serves.
Supply to the heater comes from a "T" on the top hose's spigot...

- (#10630) david miller, 9 Sep 03 12:57

Thanks David

Thats most likely the blanked off pipe where I fitted the VDO gauge!!! I will see if I can make a plan to get the pipe back there and down to the bottom. Otherwise stat is going back to the top and we can have a cool engine. With my engine the oil water is on the other side. I think the T at the bottom of the stat must connect to the heater and then go back in at the top.

Regards

Leon

- (#10631) Leon, 10 Sep 03 2:42

Hi David

The thermowax bypass was completely blocked. I bypassed it, it starts fine without it in any case. Temperature still searing when you put your foot down, but I think I am still battling airlocks, they seem to take a while to get out. Will leave the heater as is for the moment (is there flow at all times through the heater system or only when you turn heater on?)

- (#10632) Leon, 11 Sep 03 3:07

the townie has two heaters, front and rear. the rear one has a permenant flow.

- (#10633) david miller, 11 Sep 03 10:56