Davies Craig EWP - preliminary results

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Ok folks new data, everywun poot yer deerstalkers on and fill yer Calabash pipes.

So, I topped up the coolant to the max mark in the tank before I left for holiday and the dipping issue was bad on the way down. On the way back it was still happening and the heater air was tepid. The toward the end of the journey it stopped and the heater air was hot more or less.

Now today when I checked the level it was just below the min mark. I went down to Coventry and up again which is a fair run and it didn't dip once that I noticed. Heater air was still a bit sporadic but the temp seems to have stabilised.

So, could the level now be "wrong" for the new system and might too much coolant cause some kind of pressurisation problem in the cooling circuit? Why would my heater air be so unpredictable?

If you haven't been following and you're about to write "HGF burn it" you have two options: A - Feck orf, or B - Read the fred. This int no ordinary Freelander cooling circuit.

Thoughts?
 
Air lock coz
A) they are notorious for them
B) the Ewp could be drawing air in through the coolant bottle if there is now negative pressure in that area when the EWP cuts in.

Don't think either are likely, but its all new.
 
The Mad Hat Man said:
Air lock coz
A) they are notorious for them
B) the Ewp could be drawing air in through the coolant bottle if there is now negative pressure in that area when the EWP cuts in.

Don't think either are likely, but its all new.
Click to expand...

Hmm sound theories. An airlock sure would explain the heater air issue. Well at least it doesn't overheat like it used to when it got an airlock. It could be that the temp dips are due to the pump working hard to clear the airlock?

Got any bright ideas about how to test all this? Other than bringing it up to temp and bleeding I'm not sure where else to go.

I'm hoping that one day I'll be able to get to an answer. The when that one person comes here looking for the answer it'll be here somewhere :rolleyes:.
 
The temp dip could be when the sensor is in air, rather than water.

Try running it up to temp while watching coolant level, or rigging up a supplementary coolant tank?
 
Right, DD and I had a bit of a natter today and we reckon we now know what's going on. We think that the temp dips and erratic cabin heater are connected. You may remember that we had to re-route the expansion tank feed hose so that it was downstream of the EWP. We reckon the same problem is happening in the heater matrix - it's under pressure now from both ends whereas before it was under vacuum forces from the cool end and pressure from the hot end. This problem has come up because the return hose is now downstream of the pump whereas before it was upstream.

The heater problem is being caused by a bunch of hot water being shoved into the heater and then getting stuck because it is being pressurised at both ends - by the flow from the EWP into the coolant rail and by the flow out of the engine outlet. So it gets stuck and gets completely cold through the convection action of the heater. Then, something happens to dislodge all that cold water and it gets dumped right into the coolant rail which then goes into the engine causing it to be disproportionately cooled - which shows up as a temporary drop on the temp gauge.

So, our plan is to connect the heater matrix return hose to the already re-routed header tank feed hose via a T connector - this should solve the problem as then the return hose will be downstream of the pump and the pressure imbalance should be negated. The heater matrix return hose will be connected to the straight portion of the connector as it will have the larger flow rate, and the tank feed hose will be on the perendicular nozzle. We know this worked beautifully with the header tank problem so we're pretty confident that it will fix these problems too. This will also speed up the time it takes for hot air to comes through the heaters which is going to be critical for winter driving.

The bottom lin is that by repositioning the pump we have essentially reversed the pressure distribution across the cooling system, so everyting that was downstream of the pump in the old circuit needs to be re-routed to be downstream of the EWP.

I'll post back with the results :).

Will.
 
Sounds a reasonable hypothesys Will. Might be worth going back to looking at the original cooling circuit and comparing the "new" one to see how flows and position in the cooling system compare. Would fitting a dummy mechanical Water Pump be of any use (long term)?
 
The Mad Hat Man said:
Sounds a reasonable hypothesys Wayne. Might be worth going back to looking at the original cooling circuit and comparing the "new" one to see how flows and position in the cooling system compare. Would fitting a dummy mechanical Water Pump be of any use (long term)?
Click to expand...

Yes I had we had a bit of a Eureka moment when we were imagining how the fluid was passed around with the old circuit. The key thing is that the pump in the old circuit is between where the cold water gets turned into hot water. The whole system is designed so that all cold water inlets are plumbed in before this point and all hot water outlets are plumbed in after it. Moving the pumping body to the permanently cold side just screwed that whole system up. So essentially all the auxilliary connections on the coolant rail need to be blanked off and the hoses that were there must be re-routed. There is a water pump in there which is still connetced to the timing belt but we removed the vane head so it's little more than a pulley now and has no effect on the flow.

I'm pretty sure that we are going to be alot closer to unlocking this systems true potential once we've done this :).
 
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Have you thought about replacing a rubber pipe with a temporary clear section so you can see the coolant flow/speed? I'v used this method many times for car engine conversions!!
Last time I used an ewp I found it worked best in line with the original pump or at least where the original pump was.
 
Last edited:
Nodge68 said:
Have you thought about replacing a rubber pipe with a temporary clear section so you can see the coolant flow/speed? I'v used this method many times for car engine conversions!!
Last time I used an ewp I found it worked best in line with the original pump or at least where the original pump was.
Click to expand...

Nope haven't tried that, sounds like a good idea though if we still have trouble after this then I may well try that.

The EWP is a fairly bulky thing compared to the original pump and you have to mount it in a floating position to avoid vibration and it has to be on the lower radiator hose or it gets cooked. So you're quite limited in where you can put it. But I've put a big T connector into the rad hose which allows me to plumb in the necessary return hoses so it should be ok.

I've ordered the bits, I'm very impressed with carbuildersolutions.co.uk they've been great with the parts I've needed for this job :).
 
Hmm. Results inconclusive. With the new setup the heater took ages to warm up but we were sat in traffic, also then the heater blower packed up somehow so that kindof screwed with the results. But once it got hot it at least stayed hot - even it it took ages to get there.

So tomorrow I've got to ferret out the blower problem before we can go any further.

DD theorised that the reason the heater take so long to warm up is due to the deletion of the thermostat. The thermostat has a smaller aperture than the 32mm hose and now that this has been removed the coolant has much less resistance in the main system loop. It's possible that because of this there is less hot coolant going up the heater feed hose because it's taking the path of least resistance. So we think we have two option, fit a simple flow restrictor into the upper radiator hose or fit a small booster pump in the heater loop somewhere. I like option A as it sounds cheap.

What a ballache.
 
The Mad Hat Man said:
yup -get an adjustable valve and play around with the settings?
Click to expand...

Looks like that's the best way, take it out with the reader and see what works best. The jeep guy seems to have had great success with it, and it stands to reason that more hot coolant will make its way around the heater matric with a bit more pressure in the main loop.

IF I CAN FIX THE FECKING BLOWER :mad::mad:
 
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