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Oil pump failure


Lukaswg

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Hi Keith,

               Looks can be disceiving !  If the battery was placed in an east / west configuration, it would only be about 50mm lower, than the standard position on the opposite side.

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However, in a north / south position, down on the chassis rail, it certainly would lower the battery closer to the centre of gravity of the car itself.

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The only  issue I foresee, is that it is on the opposite side of the engine to the starter motor & alternator, which would require new longer heavy duty cables rerouted.

Cheers Banjo 

 

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I'd forgotten you did the "battery move" years ago.  Just reread your post again. Thanks for the link.  Might just do that, as like you, I'm all for keeping the centre of gravity of everything, as low as possible. Like the idea of the short earth cable directly to the block.

Cheers Banjo  

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Went for an hours run last night, to pick up my daughter from Grandma's house.  (No my daughters name is not Goldilocks)  It was a cooler night, around 22 deg C, so I was interested to see whether this very efficient Echo radiator, could still maintain a required high coolant temperature.

Here is the graph of all logged parameters & their statistics. The fan switched on just once, when we arrived at Grandma's house & stayed there a few minutes, before leaving.

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The graph below is the same as above, but with only the top sensor displayed. Although the night was cool, you can clearly see that it only took 8 minutes for the coolant temp to reach 80 deg C.  After that, the new Hi Flow thermostat functioned perfectly, keeping the coolant temperature between 80 & 90 deg C.

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The "top hose" temperature sensor is actually fitted to the thermostat housing, just under the thermostat itself, so is very close physically to the thermostat expansion chamber.

I was going to fit the thermoswitch (TFS106) there also, in a spare threaded hole, but I accidentally ordered a 14 x 1.5M threaded thermoswitch, instead of a 16 x 1.5M one (TFS183), so just drilled & tapped the thermostat housing cover/spout, which is why it is sticking up vertical, in the earlier pics. It doesn't really matter, that it is beyond the thermostat valve, as by the time the coolant reaches either of the thermoswitches switching points (90 & 95 deg C), the thermostat is already fully open at around 87 deg C, with full flow.  I was thinking of doing away with the thermoswitch altogether, & varying the fan speed between 10-20% at 90 deg C, up to full speed at 95 deg C.  However, as the fan is on for such short periods, that is probably "gilding the lily" a bit, & I should just adhere to the KISS principle.

Cheers Banjo

 

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Hi Keith,

               Yes, there are still a couple of unanswered questions, which I still need to look into.   That's why I have done the mod. in stages, to see exactly what effect, each change has made.

At the moment, the return line from the rear of the head, uses the heater return pipe along the side of the head, behind the dizzy.  This line does not return coolant from the rear of the head to the top of the radiator, but directly to the inlet of the water pump. This makes sense for a heater return line, but not for the rear head coolant return, which should be returned below the thermostat.

I may even get around to doing this mod today, as I have another "lower" thermostat housing with a large spout on the LHS, that can be easily plumbed with the rear head coolant return line.

I'll then have to run a separate, heater return line to the water pump inlet. 

I'll then see what difference that makes.  The sudden fall in lower radiator hose temperature after the engine is switched off, is interesting.  It actually tumbles, very quickly, once the engine stops.  It is like once flow stops, the hot & cooler water separate quickly.  Hot water moving up, & cooler water moving down.  I think it is called segregation.

As to why the variation in lower radiator hose temperature is so erratic, by comparision to the top hose temperature, is still a bit of a mystery.

I have a theory, which I will look into.

Although I have labelled the temp sensor as "top hose", it is actually not in the top hose, but fitted to the lower thermostat housing, in a existing spare 16 x 1.5M threaded hole.  The sensor being mounted in the metal housing, dampens the response of the sensor, as it effectively has more mass.  However, the lower radiator sensor, is mounted directly into the lower hose, using one of those "Red Devil" type adaptors, you referred to.  The adaptor is made of aluminium, and has little mass.  It therefore reacts more quickly to changes in temperature, & therefore has a greater "swing range".  These adaptors were, I believe, designed for racing applications, so that faster response times of water temperature could be achieved.

The graph below is a small portion of the graph above, between 9:40pm & 9:50pm on the 28th March.  The graph just displays only the top/rear head & bottom radiator hose temperatures. 

5abd88eb37f79_CoolantAnalysis.thumb.JPG.886171a13630792694fe57170e857c94.JPG

 You can see that head front (top hose) & rear head temperatures mimic each other, with a differential of about 4-5 deg C.  The "top hose" temperature is flatter than the rear head coolant temperature.  This is because the rear head coolant temperature sensor is not in the head itself, but mounted in a "Red Devil" type hose mounting in the return coolant rubber hose, directly behind the head.  Again, like the bottom radiator hose, the response time for temperature changes is quicker, & this is reflected in the graph above.

DSC00468sm.thumb.jpg.05431fcc6f06237a42f49b628d10d9ab.jpg

So where the front head & rear head coolant temperatures mimic each other, the lower radiator hose coolant temperature is a complete reversal.  ie:  when the top hose temperature goes up, the lower hose temperature goes down.   My theory is; that the ripple effect in the graph of the top hose temperature is actually the thermostat action, constantly opening & closing off slowly, to maintain a consistent temperature.  If that is the case, then the lower hose temperature reverse swing makes sense.  Top hose temp increases; thermostat opens slightly more; increased water flow; radiator has greater cooling effect on more water, & return coolant temperature to the inlet of the water pump drops.

The frequency of the "ripple" effect observed in the top & rear head coolant temperatures, appears to be fairly constant.  My guess is that this is a result of slight mismatch between the dampened response time of the thermostat, & the transport lag of water movement around the engine.  It takes a finite time, for the a specific sample of coolant to physically move from the outlet at the bottom of the radiator, until it exists the head into the lower thermostat housing, where the thermostat, can measure & react accordingly.

So until, some other piece of data, jumps out at me, & dispels my current theory, that's what I am currently thinking.

More to come, no doubt !

Cheers Banjo

 

  

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This line does not return coolant from the rear of the head to the top of the radiator, but directly to the inlet of the water pump.

OK, so its is raising the incoming coolant temp slightly and constantly.

Quote

(lower hose sensor) therefore reacts more quickly to changes in temperature, & therefore has a greater "swing range".

Yep, that makes sense.

Quote

(lower hose temperature reverse swing) & (Top hose temp increases; thermostat opens slightly more; increased water flow)

So top hose at 80deg, t'stat opens, more water flows through rad, heat mass drops & temp goes down?

..or...    at bottom hose 68deg the t'stat opens and water is pushed through the rad too fast to cool, so temp goes up to 72. Then t'stat closes and slows the water down so it cools more and temp drops back to 68deg.

I dunno, only the top temp change has a shoulder, the bottom one is very sudden. Top is closing, bottom opening?

I always assumed the t'stat ran at a fairly constant opening, but it looks like its very active. It cycles up or down every 10secs, like dropping one in a pot of boiling water. I wonder if the water pumps mixes it & flattens out the troughs & peaks??  or are the water jackets being subjected to the temp cycling? Can you see the burst of heat as you accelerate up through the gears and then cruise? Can you see when it idles??

Answers always just bring more questions!

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Agreed, the more you find out, the more questions it raises.  With a couple of heads working on this, I'm sure we will be able the nut it out.

A thermostat certainly is a "damped device", in terms of it's opening & closing  reaction time, to changes in coolant temperature.

Like you surmise . . .   if you drop a fully closed thermostat at room temperature into a pot of boiling water, it does take in excess of 10 seconds to fully open. 

However,  The whole coolant system has a response time also, which is controlled by the thermal mass of the block & head, & the flow rates provided by the water pump, along with the efficiency of the radiator itself, in terms of removing heat from the coolant.  I suggest, the coolant response time is much greater than 10 seconds, as the block in particular, acts like a great big heat sink.

I suspect, I will see some changes, once I have rerouted the rear head return line.  At present, I am running the data logger at 1 reading per 8 seconds. I will run it in a "fast read mode", at 25 readings per second (40msec), & we should see a picture of the upper & lower hose temperatures, with a greater resolution.

If the ripple effect is still there, I do have the opportunity, of lowering the Echo radiator efficiency slightly, by blocking air movement throughput, with a 100 mm strip of cadrboard, across the front lower section of the radiator core.

Let you know what this turns up.   Please keep your ideas coming.

P.S.  Just did a test on the kitchen stove with a new thermostat, suspended in a pot of boiling water.   Soaked it in boiling water, until the valve was fully opened.  Took it out, and watched it close. As soon as it was fully closed, I dropped it back into still "boiling water, (which was probably about 95+ deg C(, and started stop watch.  It was fully open in 21 sec.  Reset stop watch, & I then removed it, to room temperature (30 deg C), and started stop watch again.  It was fully closed after 30 seconds.  Therefore, the differential temperature that was applied to the thermostat, on "dunking" it in "boiling water", was about  15 deg C.  (97 - 82 deg C)

The differential temperature that was applied to the thermostat, after taking it out of the "boiling water", was about  65 deg C.  (95 - 30 deg C)

In real life where the differential temperatures would be around 10 deg C (90 - 80 deg C) the response time would be much slower than those measured above. 

Cheers Banjo

 

 

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OK, so yesterday, I finished replumbing the return coolant line, from the back of the head, to join the exist coolant from the front of the head, mixing directly under the thermostat, in the lower thermostat housing.

You can see the mods in the following pics.

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So prior to even fitting the Echo aluminium radiator & integral electric fan, I had consistently obtained differential coolant temperatures between the front & rear heat exit water points of 6.2 - 6.5 deg C.

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5ac198751ffac_Wed28-03-2018.thumb.JPG.8667d7ed7c5d9e9886655de1fca84994.JPG 

I was hopeful that replumbing the rear coolant flow to under the thermostat, would get these two temperatures, even closer together.

Well, to my surprise, the complete reverse resulted, with a differential of almost double that at 10.7 deg C.

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Hmmm !   So back to the drawing board. 

Would love to be able, to have a look inside the block & head water jackets, & see where the water flows actually travel.  As I can't do that, then the only thing is to change things, & see how it affects the graphed results. I might "throttle" the flow in the rear head return line, & see what affect that has.

Maybe it requires a separate thermostat for each head exit coolant point. However, that getting away from the KISS principle.

Cheers Banjo 

 

 

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Well, do you think you've got better flow from the rear of the head now??  What worries me was the flow in the first trial setup, from the pump to the back of the head.

Was there a way to check how much flow you had and in which direction??  Is that heater connection is on the positive pressure side of the pump, so were you pushing cold water to the back of the head, maybe over a very slight pressure differential so hardly any flow..  or were you pulling 75deg water from the back of the head and slowly adding it to the water pump to cycle round again?? Were you holding 70deg water at the back of the head until it heated up to 75??

Now you're taking 70deg hot water that has just come up from the block and actually getting it flowing quickly to the front while the rest of it winds past the combustion chambers going up to 80deg.

Have you increased the flow through the block so the water is flowing from the block to the head is 5deg cooler??  If the head is more restrictive to flow than the head gasket, you may have just increased the flow noticeably..

Even MORE questions now!

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Hi Keith,

               Good morning !  One thing I have not fitted on my coolant system, during these tests, is the thermostat bypass hose.  My theory has always been, that here in the northern half of Australia, where it rarely gets cold, that the bypass hose wouldn't do anything much that was useful.  To me, the bypass flow, would only lengthen the period of initial engine coolant warm up, which you want to be as quick as possible.  Currently, without a bypass, my graphs indicate that period is about 8-12 minutes, from a cold start.  Once the thermostat cracks open, the bypass hose function is basically redundant, to my mind.

However, in reading up on it overnight, there appears to be several reasons for it's inclusion.  One is to stop steam pockets forming in the head, during the warm up period, and the other is to prevent the water pump impellor from cavitating, which could happen during warmup, whilst the thermostat is completely closed.

So this morning I thought I might remove the "block off caps" I currently have on there, and insert a piece of hose.

It was then that I realised I have a mismatch between lower thermostat house bypass outlet point, & water pump bypass inlet point. I have a lower thermostat housing with a bypass 8mm outlet & a water pump with bypass 15mm inlet, on the LHS of the engine. 

It appears that somewhere during the K series development, Toyota in their wisdom changed the size of the heater bypass hose from 8mm to 15mm ID.

I noticed there were a couple of pics in a thread you contributed to back in early 2015.

This one clearly depicts the 8mm bypass hose on the LHS of the water pump, viewed from the front of the engine.

5ac2bf1bbda55_8mmBypassHose.JPG.8b9ed1cbd6dca7648f69734eb32e72c2.JPG

However, on later K series engines, the bypass was increased to 15mm ID hose, & fitted to the RHS of the water pump, as depicted in this pic.

5ac2bfeab69e7_15mmBypassHose.JPG.3f97d782d60a65d24c836f1944efa978.JPG

I have the option of fitting either size to my existing setup, but I am wondering what was the reason Toyota increased the bypass hose size, & what existing issue with the small bypass hose size prompted this.  My guess is that, the smaller 8mm hose just simply blocked up, as I have witnessed over the years, but I was wondering whether it was to increase flow, & why.

Can you throw any light on this, from your experience ?  I'm just a bit concerned, that if I fit the 15mm bypass hose, whilst running the high flow thermostat, the thermostatic control, might not be as good.  I suppose, the proof will be in the eating.

P.S.  Going for a run shortly for about an hours trip, with the data logger set at 1 second logging rate, & see how that looks.

Cheers Banjo 

 

 

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OK, so went to the Dentist & back, & recorded the trip at 1 second intervals.

Here is the complete trip.

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This following graph is the trip home.

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The differential between the front & rear of the head is still around 9 deg C.

However, despite that, the thermostat is working perfectly, maintaining the coolant temperature between 80 & 90 deg C.   The graph below shows that clearly, and the thermofan kicking in, whenever the car physically stops, & the temperature shoots up over 90 deg C.

5ac309b206097_1sectophoseonly.thumb.JPG.3616b52d4aee307fffb7096be7eaed93.JPG

Next step will be to reinstate the radiator 15mm bypass  hose, & see what transpires, after a run with that.

P.S.  Still can't believe the lower radiator hose temperature drops so quickly to around 50 deg C, after stopping the car.

Cheers Banjo

 

 

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Well, the back of the head gets cooler than the bottom hose...!!  That sudden rush of flow when the t'stat opens every 5min means very little cooling gets done and the bottom hose temp gets hotter than the back of the head. Then it cools for 4 minutes or so until the next pulse. I thought the t'stat would have a more even flow, but all three measuring points show the same cycle of up and down..

.. and both bottom and top hose have a max temp of 93deg, so no cooling w/o the fan when stopped.

Now you'll have to add a throttle position recorder to see when the heat is being produced...

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. and both bottom and top hose have a max temp of 93deg, so no cooling w/o the fan when stopped.

Hi Keith,

Although initially it sounds strange, that top & bottom of the radiator could be at the same temperature.  When you think about what is happening, it is not so strange at all.

Here is a graph of that small period of the previous graph.

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The Rolla had only been stopped at the Dentist for about 30 minutes, after the trip there, so the coolant was still at an elevated temperature above ambient, at around 48 deg C, when the car is started.

The fan is not running at all, but the water pump is. However, by the time the temperature reaches say 87 deg C, the thermostat is fully open, & as water pump is running, so coolant flow through the radiator is constant, & therefore top & bottom radiator coolant temps are at the same temperature.  However, as soon as the temperature of coolant at the thermostat area reaches 92+ deg C, the electric thermofan switch automatically kicks in. The radiator then does it's thing, & the bottom hose temp instantly drops rapidly.  That cooled water then feeds through the engine block/head, and within 30 secs. the top hose temp starts to drop off also, to then be controlled by the thermostat, & held at between 80 & 90 deg C.  All good, as should be. Note the fan ran for only 40 seconds, before it dropped the top hose temp; to the point where the fan was not required any longer. Your earlier point about the fan hardly ever required, is proving very, very true.  What a waste of power driving that old plastic fan all the time.

Quote

Well, the back of the head gets cooler than the bottom hose...!!  That sudden rush of flow when the t'stat opens every 5min means very little cooling gets done and the bottom hose temp gets hotter than the back of the head. Then it cools for 4 minutes or so until the next pulse. I thought the t'stat would have a more even flow, but all three measuring points show the same cycle of up and down..

Ideally, every component in the system should be matched in terms of performance.  However, in this case in mild ambient conditions, the aluminium radiator appears to be more efficient than needed at that time, & therefore the system cycles a bit, at around 4-5 minutes as you describe.   As the ambient temperature rises, to say a very hot 40 deg day, I would expect the 4-5 minute cycling to decrease, & the top hose temperature to be fairly flat. The only way to prevent this "cycling", would be to fit thermostatically controlled louvers in front of the radiator, as are common in big trucks, to control the amount of air through the radiator; or fit an electric water pump, as are common in some racing cars, so they can control engine temperature to a very tight controlled point. It will be interesting to see what reinstating the radiator bypass hose does in terms of control, & "the cycling" you have identified.

Just waiting on a 16 x 1.5M barbed 14mm hose adaptor to arrive, so I can reinstate the bypass function.

Actually, I have an old TPS sitting around here.  It wouldn't be too hard to hook it up & log how hard I push the accelerator pedal.

P.S.  As the bypass hose is very close to the point where I am measuring the "top hose" temperature, (under the thermostat), I thought I might move the measurement point to the bypass hose, which would allow it to react quicker, like the rear head sensor, which has a hose each side of it.

Cheers Banjo 

Edited by Banjo
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& therefore top & bottom radiator coolant temps are at the same temperature.

only if the car is not moving. 3 or 4 minutes stopped? 11.37.30 to 11.40.30??

Are all three at the same temp before you start the car in the morning??

I can't get my head around the bottom hose being hotter than the back of the head! Something is not right...  Swap those two sensors over! The back of the head and the top rad hose  follow each other well, but the bottom hose.. 

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