Electric Water Pump, engine

Submitted: Friday, Mar 05, 2010 at 10:14
ThreadID: 76571 Views:3212 Replies:5 FollowUps:6
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Has anyone had any experience with fitting an engine Electric Water Pump (EWP) to lessen overheating, either as a replacement or as an addition to the mechanical pump ? If so does it work?
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Reply By: Member - Andrew L (QLD) - Friday, Mar 05, 2010 at 10:35

Friday, Mar 05, 2010 at 10:35
Making an increase in the velocity of water flow in a cooling system often does not improve the cooling ability or efficiency of a closed circuit cooling system like that in a vehicle engine.

This can be demonstrated by removing the thermostat, which in effect is a restrictor that regulates coolant flow to maintain a preset temperature. Removing it can cause coolant to flow to more quickly through the radiator which is the heat exchanger, the coolant flow is too quick to allow sufficient heat exchange from the coolant to the radiator structure and the passing/surrounding atmosphere.

It would help if you tell us what vehicle and what condition/s are that are causing the overheating.
AnswerID: 407355

Reply By: Member - John - Friday, Mar 05, 2010 at 11:16

Friday, Mar 05, 2010 at 11:16
Rod, G'day, trialled one of them a few years ago on a Patrol 2.8 TD, could not get it to cool the engine properly at all. Eventually got my money back. In certain applications I think that they can be effective, but not in the application I was looking at. Good luck.
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AnswerID: 407361

Reply By: Member - Mike DID - Friday, Mar 05, 2010 at 11:45

Friday, Mar 05, 2010 at 11:45
The only time an extra water pump will improve cooling, is if your engine is working very hard at low revs i.e when the mechanical water pump is turning slowly.
AnswerID: 407363

Reply By: B1B2 - Friday, Mar 05, 2010 at 12:50

Friday, Mar 05, 2010 at 12:50
G'day Rod,
I have a landcruiser 1996 1hz with DTS t/c and 3" exhaust. I have had overheating problems since new. Just enough to have the a/c stop working efficiently but not cook the engine.
On long hills towing the caravan as someone said, your revs drop and so does your water pump slow down. In soft sand fully loaded with reduced tyre pressures was another case. You may be able to drop back a gear to get your pump up to speed but I would usually back off the load.
I have recently replaced the radiator, and have also fitted a thermostatically controlled Davies Craig electric water pump on the bottom hose. It cost about $250 at super cheap, made in Melbourne. There is a sensor on the top hose connected to the thermostat which you can adjust.
I have only just completed this installation so I now need to roadtest it under load.
Another option would have been to fit a thermostatically controlled fan on the radiator, there is plenty of room. One advantage of the pump, is that it is wired to continuosly run after the engine is shut down until the temperature reaches your setpoint. Engine temperature rises quite a bit after stopping, which is a good reason to leave your engine idle for a few minutes if you stop at rest areas after travelling at highway speeds.
When I have fully load tested results with the EWP I will post them if anyone is interested.


AnswerID: 407372

Follow Up By: Member - Andrew L (QLD) - Friday, Mar 05, 2010 at 13:15

Friday, Mar 05, 2010 at 13:15
Did you get a bigger capacity radiator, or just a new one Bill?

The problem you had is similar to many aftermarket turbo 1HZ's, when towing a decent load uphill.
FollowupID: 677293

Follow Up By: Member - Ian H (NSW) - Friday, Mar 05, 2010 at 15:03

Friday, Mar 05, 2010 at 15:03
Bill. I have the same engine set up and have only ever seen the temp gauge move when driving in sand and the fan viscous coupling gave up. New coupling and bingo, no more trouble in 200ks.
FollowupID: 677308

Follow Up By: B1B2 - Friday, Mar 05, 2010 at 15:12

Friday, Mar 05, 2010 at 15:12
I had the problem before the t/c was fitted. I did have a bigger radiator fitted.
Other places that tested the cooling system were the Toowoomba Range, Moombi Hills and Gibralter Range
I tried to buy a lower rated thermostat as you can on other vehicles, but toyota dont sell them. I cut one coil off the spring of the thermostat to open quicker when loaded.
I am on my 3rd viscous coupling.

FollowupID: 677310

Follow Up By: Rockape - Saturday, Mar 06, 2010 at 08:22

Saturday, Mar 06, 2010 at 08:22
2 things here,
First one for Ian, you would be surprised how much your temp rises, before the ome temp gauge actually moves.

Second Bill, you may have already tried it. Keep your engines revs up, change down a gear, this will do three things, it will keep the water moving through the engine and radiator, it will lessen over fueling, thus reducing internal temps and it will allow the fan to cool better as it will be pulling more air through the radiator.

You may have have done this, only use a genuine tojo viscous hub.

Install an EGT gauge if you haven't already done so, and drive by that with your right foot.

Have a good one
FollowupID: 677402

Reply By: pop2jocem - Friday, Mar 05, 2010 at 22:12

Friday, Mar 05, 2010 at 22:12
Rod N

Most, I repeat MOST manufacturers have done their homework when they release a vehicle on the market. Unless you are asking your vehicle to do something it was never designed for, operating it in extreme ambients, have fitted accessories such as turbos or a bank of lights in front of the radiator that would do a 747 jumbo as landing lights and you have an overheating problem then I would suggest you look for a malfunction such as radiator blockage, thermostat or whatever rather than trying to overcome with an electric water pump. As far as lugging the engine to such low revs that the standard water pump can't do its job try shifting to a lower gear and letting the engine operate in a more appropriate rev range.

Cheers Pop
AnswerID: 407466

Follow Up By: B1B2 - Saturday, Mar 06, 2010 at 14:01

Saturday, Mar 06, 2010 at 14:01
G'day Rod,
I have previously owned a BMW 528i (a couple of years old at the time) and towed a poptop van with it,as they do all over europe. It got hot in heavy traffic and I blew the head gasket just as I arrived at a CP on the gold coast. The local BMW place reckoned it was a regular problem with all the Mercs and BM limos on the coast and they always fitted a lower rated thermostat. I did that, and it was fine after that. Toyota don't have one.
There is a bit of fuzzy logic involved in whether what I have done will be good or bad. If I drop back a gear to get the water pump running at a higher speed am I not putting out more HP and creating more heat?
Anyway I have gone down this path, and will report if it worked to my satisfaction when I give it a serious load test.
It didn't cost me very much. You have more faith in the vehicle designers than I have. Toyota recalls, Prius brakes, 200 series tailshafts etc.
I am still very happy with the vehicle's performance. I aready said I replaced the radiator with a bigger one and have no Jumbo lights fitted.


FollowupID: 677445

Follow Up By: pop2jocem - Saturday, Mar 06, 2010 at 22:11

Saturday, Mar 06, 2010 at 22:11
Fair enough mate (I assume you are addressing me) a BMW which is built and designed in Europe and probably works well in the ambient temps encountered in Europe even towing may be ok but in Oz and towing a poptop in Qld may be asking a bit much without mods such as a different thermostat.
I didn't know Toyota put out a 1hz with a turbo as standard???

Any engine is designed along with its cooling system to produce max power at a certain RPM. By lugging the engine below its optimum operating range you are losing kw's and forcing the cooling system to try to dissipate heat without the correct coolant flow. Now add a turbo and probably increased fuel up goes the heat generated by that and bingo...overheating

Cheers Pop
FollowupID: 677496

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