[modeleng] Re: Cheap Coolant System

Hi Ken,

Not sure exactly what pump you bought, but I have had similar experiences 
with several pumps bought as "parts washer pumps". I do a lot of work on old 
engines for tractors etc and need a good parts washer. In short, what I have 
found out over the years is that all inexpensive plastic pumps being sold as 
parts washers are ex-pond pumps, water pumps, coolant pumps for water based 
based fluid, etc, are made in China, and are NOT suitable for petroleum 
based fluids at all. The seals often swell in oil based liquids, and the 
plastic housings can also break down. When the seals swell up, they grip the 
motor shaft and cause the motor to overload and overheat. On two of my pumps 
there was a thermal cutout switch to protect the motor but there wasn't one 
on the last Chinese pump I had. The motor on it caught fire, luckily I was 
working right over top of it and put it out quickly, and my circuit breaker 
powering it did trip and cut off the current. I was using Varsol/white 
spirit at the time which is not too flammable and didn't catch fire. If I 
had been using gasoline/petrol I would have been cooked. At least here in 
Canada the regulatory agencies are well aware of these problems but can or 
will do nothing. They are facing a tidal wave of this sort of unsafe crap 
coming in to the market with no traceability to the manufacturers and no 
regulatory or functional compliance check when it arrives. It is strictly 
buyer beware.

On the good side I have come up with a simple and reasonably priced 
solution. I use an ex car electric in-tank fuel pump with a screen on the 
inlet and a bypass tee with a valve on one branch on the outlet. The 
pressure these pumps produce is  high, the bypass tee allows me to spill off 
excess pressure back to the tank, while controlling a smaller flow to the 
washer pipe via the valve. The pump is totally immersed in the liquid in the 
washer sump (it is designed this way to be immersed in fuel in the car's 
tank).

I got the pump and valve at a car scrapyard for under $30 / 12 UK pounds or 
so.

I don't know whether they will work for coolant but if you can find a scrap 
one cheap it would be worth a try. There is also an inline style that some 
Ford trucks here use, it fits in the rubber fuel line hose with hose clamps 
each end. it is a metal canister usually fitted near the rear of the truck 
on the inside of the frame rail near the rear axle.

I did look into commercial washer pumps at the time of the fire. Several 
offerings at my local car parts store were the cheap Chinese ones. Snap On 
Tool Co offered a nice metal bodied professional one, fully guaranteed, but 
it was over $300 so price was prohibitive.

Hope it helps, Jeff Dayman


----- Original Message ----- 
From: <KJones9154@xxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Friday, February 13, 2009 4:38 AM
Subject: [modeleng] Cheap Coolant System


>A word of warning.
> I purchased a cheap coolant system from the stand of a well known  machine
> supplier at the last Alexander Palace Exhibition. Cost  65.00UKP
>
> It has lasted about 2 weeks.
>
> The problem appears to be that the pump is not up to the job as it is only 
> a
> basic ornamental pond type of unit.
>
> I have contacted the supplier and they require me to return the pump 
> before
> they will consider any further action. I am unhappy about this as I think 
> the
> cost of postage will be excessive without any guarantee of  reimbursement.
>
> I think my best move would be to cobble up some form of home made system 
> and
> I am considering a modified washing machine pump unit. The original  tank 
> and
> switch is just right.
>
> Has any member got any other ideas?
>
> Here is a clear case of 'cheap and cheerful' but I am very UNhappy!
>
> Ken Jones, disillusioned in Berkshire
>
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