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MG MGB Technical - Auxillary Electric Water Pump

While attending MG 2005 in Olympia Wa. I noticed that one of the particpants had an auxillary 12V electric water circulation pump installed in his lower radiator hose on his MBG. He said it cured his overheating problems. He said he found an article written up in some magazine. I think it was an overseas mag. He told me he ordered the pump from somewhere in Europe. I should have written down the info he gave me, but I did not. I would like to try this set up on my 1979 B.
although, I don't actually overheat. I do run very hot during the summer months. (timing is set correct, I replaced the radiator last spring and new cap on expansion tank.) I would like to try and add this electirc pump. So I am asking if anyone has heard of this and where I would be able to order one. I would like to get other opinions on this as a fix. He said that the extra circulation thru the system was the key to reducing the high temp of the coolant. Your thoughts and imput is greatly appreciated.
John Fraioli
1979 Inca Yellow MGB
PS: I was also wondering can anyone tell me which direction does the water flow in the lower hose is it towards the radiator or towards the engine?
John F

John. I cannot provide any information on the electric water pump, never having seen one.

As to the running hot/overheating issue, many of the vehicles I have examined show a fairly high reading on the dash gauge and, when the cylinder head temperature is checked with an IR thermometer, read between 180-185 degrees. Not an overheating situation, rather an old sending unit/gauge situation. Determining what your actual operating temperature is would be a good first step in troubleshooting any perceived problem.

Les Bengtson

Ah, gimmicks! I suspect that its presence in the bottom hose merely slowed down the flow of coolant, allowing it more time to absorb heat inside the engine and dissipate it into the radiator matrix. Did you ever try going to a smaller crankshaft pulley in order to accomplish the same thing? Such a device is just one more thing to go wrong.
Steve S.

They do exist, mostly used here on MMM cars with thermo syphon cooling
Stan Best

David Craig manufactures them I beleive the EBP have a 15'000 hour life and cost about 110.
K Harris

What do you mean by very hot? As Les stated, check to really see what your engine temp truly is.
How old is your water pump? Even if they don't leak they do wear out. The vanes on the impeller will corrode and disappear over time.
What temperature thermostat are you running? Not having a thermostat can cause overheating.
Are the fans working correctly? Ceck the air flow. Make sure the fins in the radiator are clear of obstructions, debri, bugs, anything that can restrict the flow of air.
Make sure the cooling system doesn't have air pockets.
Did you flush the cooling system?

I have owned my '79 B for 15 years now. It did boil over ONCE after I had had it for about a year and a half. It was when coming home from a rather long trip. the coolant leaked out from the weep hole in the water pump. When I removed the pump I was rather suprised that the impeller blades where hardly there at all. So I do know that they can wear out. I replaced the pump with one of the aluminum ones. That one went out on me about 5 years later. It now has another heavy cast metal water pump, which has been on there probably about 7 years now.

I did replace the temp. sending unit about 7 years ago also. I have used several different thermostats over the years. Some of them have been fail safe types others have had better flow openings. I run a 180 degree in the summer and a 195 during the winter. I have back flushed the cooing system with coolant system cleaner a couple of times. I always have fresh coolant in the system as I usually drain all coolant when I change out the theromstat bi annually. Hoses are always inspected regularly and in good condition. Last spring I replaced the original radiator. I admit the replacement was one of the cheaper radiators the ones that are made in Taiwan. But it looks to have the same number of rows and fin configuration as the original did. The original that I replaced felt much heavier when I took it out, so I am sure it was filled with years of sludge and corrosion. The car did not run quite as hot last summer as it had been the 3 summers before.

I have never measured the actual water or engine temp.
I wasn't sure how to go about that.

Les- I like your suggestion about the IR thermometer. I imagine that is a "Infra Red". Where can I get one of those and where and how close do I hold it near the head?

Steve- I would have never thought that less circulation of the coolant would help the engine to run cooler by disapating more heat. Sounds counter intuitive, but kind of makes sense. Are there different diameter crankshaft pulleys readially availabe? Would this have any effect on the alternator at idle speed?

UK friends- I'm glad to hear you guys there have heard of this in-line electric water pump. But I don't know who this "David Craig" you mention is. Do you have a web site or e-mail address for him.

Kimberly- I answered some of your questions in the above comments. My car was originally imported to Canada, and only had one pusher electric fan. I removed it about 4 years ago and put a 10 inch electric fan on the rear of the radiator as a puller. The fan comes on when the water temp rises. The fins on the radiator are clear. The radiator is less then one year old and looks brand new still. There has been times over the past summers when ambient air temps have been between 95 to 105 degrees. And the temp gauge has been all the way to the RED. Very scarry. My car does not have an oil cooler.

It's my understanding that the temperature of the themostat does not play a role in how hot the maximun coolant temperature is or will get to, it's purpose is to control the minimum temperature the engine will run at after it has warmed up. I also can't see how removing the thermostat completely would cause the engine to overheat. Unless by doing so would cause increased coolant circulation because of less restriction thereby supporting Steve's theory. Please explain.

John F

Going through my Summit Racing catalog I see that they carry electric water pumps for American engines. These are replacement pumps that have the same pump body but do away with the pulley in favor of an electric motor. They are meant to recover the couple of horsepower used up by an engine driven pump.
They may well have the in-hose models as well.

Rich McKIe

Dont know if David Craig has a site, check as they list them it might offer further info
K Harris

Davis Craig electric water pumps are sold/distributed in the USA.

Does the car over heat in stop and go traffic or does it only happen at highway speeds? If only stop and go getting more air flow should help. I have a feeling the replacement radiator you have may not be as good as the OE radiator.

Last week I stopped by TAPP, Inc. to look at their radiators. You may want to call Tony and ask some questions.
They are a small company, Tony owns an MGB, that is why you see an MGB aluminum radiator in his web site. His rubber bumper MGB was overheating so he built a radiator. I looked at some of his radiators and they a very good quality radiators. The MGB radiator has two rows of 1 in. aluminum tubes. I have no financial interest in TAPP and don't use their radiator. I would buy one if I needed a better radiator.

Most 10 in. fans don't have enough air flow to cool a car in stop and go traffic. The 10 in. Hayden that you see in many automotive parts places has about 580 cfm flow, you can get some high performance fans that have better flow. Spal makes a high performance 11 in. fan that flows considerably air. Keep in mind the fan only helps at low speeds.

An oil cooler would not affect the cooling system temperature.

You asked what direction the coolant travels in the lower hose. It flows toward the engine.

Clifton Gordon


Harbor Freight has IR thermometers from under $10. I have the one at and it seems to work quite well.


Larry Hallanger

I used my wife's electronic oven thermometer. Taped the remote sensor to the to hose outlet and read the degrees on a real time basis as I drove around. It turned out on my '67, the stock heat guage was within 5 degrees f.

Barry Parkinson

This thread was discussed between 19/02/2007 and 21/02/2007

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