XJ Turbo Diesel Water Pumps, Cooling

[SilkRoad]

Has any one any experience with the Craig Davies Electric Water Pump. From their website you can use one to supplement standard water pump or remove impeller and use as a stand alone. Will the much higher flow rate help to keep the temperature at normal? or is my logic not logical?

[The Smiths]

No experience of them - but I would stick to the standard one and keep the cooling system clean - less to go wrong that way

[turbomart]

Having a higher flow rate will not neccassarily help, I know of vehicles that o/heated on the h/wy but ok around town, turned out to be smaller water pump pulley spinning pump to fast.
Its a fine balancing act getting flow rate fast enough to cool engine but not so fast that radiator doesnt have time to cool coolant.
This is why davies craig suggest the controller be used with it.
I personally have no experience with the pump, but unless your standard pump is stuffed I wouldnt bother.
Theres other much better ways tro improve cooling in my opinion,ie bigger rad. ,bonnet vents,external trans cooler, thermo fans.

[SilkRoad]

Yeah. Thanks for that. It seems obvious when you think about it. Just that everyone talks about not letting the diesel get hot but unlike the petrol motor nobody seems to have come up with other ideas that I can find.

[dxj]

Hi,

The diesel runs fine with a good cooling system.

It is just a turbo motor, just like any other turbo motor, don't drive it if you have ANYTHING wrong with the cooling system.

THE biggest issue is that all jeeps have a mediocre cooling system, add a leak or any other fault and any turbo motor will die.

Get a 3 core brass/copper or Aluminium radiator. Keep it clean inside and out. That damn plastic tank rubbish they fit at the factory is near useless.
Pressure test and fix any leaks. Keep coolant full.
Make sure clutch fan works properly.
Make sure fan shroud has the extra piece to close off around the bottom of the intercooler.

I bought a pressure tester on ebay. It is amazing what faults you find when you check what appears to be a good cooling system.

[SilkRoad]

Thanks DXJ. That seems to be the message. ie keep everything ship shape and regularly serviced.
Unfortunately Adrad don't make a radiator for the TD so different radiators need to be especially made. If you have other advice than that I'd love to hear it.
As you say Jeeps have a mediocre cooling system so any other thing to supplement it seems like a good idea. (Might just help on that occasion when something goes wrong on a long trip and you have to try to get back to civilisation). Eg Bonnet vents, Red Line Water Wetter, synthetic oils, electric fans (both replace original and a push fan as well). If the water pump isn't working properly would I be better off to remove the impeller from the original and then use an electric water pump? (Supposed to take some drag off the motor and result in improved performance at any rate so a way to increase available power)

[dxj]

Hi,

Riverstone radiators in Sydney made my 3 row copper/brass custom one for about $700.
They got the core from Qld and added some custom tanks.
I think some guys got ones made cheaper elsewhere.
I just gave them my crappy one with the plastic tanks and they copied it.
Make sure they fit the air vent bleeder pipes, he forgot first time round for me.

Extra core row adds 50% more water in the radiator so, for same engine speed, water flow rate in engine is same, but with larger cross-section in rad, water spends 50% more time exposed to air flow before returning to the engine. A little more water iin there too.
Be absolutely certain your electric fan is working, should come on a little while after the A/C is on. Some diesels misssed out on thelectric fan, if so, fit one!
Be certain the clutch fan works too.

With the diesel running at low revs the water pump drag is the least of your problems. All XJs are mainly limited by the amount of air flow rather than anything else.

Mine has no problem with water flow. When the engine is hot the rad is hot too. The air flow is the limiting factor by a long shot.
Assuming you block/head are real clean inside coolant should not be an issue.

To prevent head damage be a demon on finding pressure leaks, if your cooling system doesn't hold pressure then your boiling point is much, much lower.
So when your turbo is on full boost and plenty heat inside there you will boil water inside the alloy head and -----CRACK---- you are up for big bucks.
Nearly all XJs (including 4.0L) when in perfect condition seem to have about 674 places where they leak pressure. Old one have 4,892 coolant leak points

Only real diff is that the 4.0L is cast iron and uses petrol to cool the heads when there is no coolant or pressure( just joking!)

Hi flow water pumps are for ultra large block engines.
Electric water pump will solve some problems but create others.

If you have a cooling system that really is sealed to 15psi and run around 33% glycol than your problem will be the radiator and air flow.
Note with much higher specific heat, plain water is a much better coolant (carries much more heat away per volume flow), you need the glycol for a bit extra antifreeze, anti-boil and anti-rust.

Cheers