SBF Water pump not working.

Paul W · 11-11-06, 04:04 PM

Just been for a spin in the car, got 5 mins from the house and the temp was up at 100 degrees. I pulled over to the side of the road as this sort of temp usually takes around 15 mins minimum on a warm day - today is about 12 degrees in London. The water level is fine, and the header tank is cold. The heads and inlet manifold are really hot and the belt on the waterpump/alternator looks fine. Anyway I let it cool off and went straight home. I'm pretty sure its not an airlock as I have a rear bleed off the inlet manifold back to the header tank. I checked the belt was turning the pump pulley - it is. The water level in the header was still fine when I got back and the heads are still really hot. The coolant pipes to the rad are hot in the engine bay but cold at the front of the car and the heater isn't getting warm. It seems like the impellor has come loose inside the pump housing - anybody seen this before or have any advice ???

Bernard · 11-11-06, 04:57 PM

Paul, your problem looks like if your thermostat was blocked in closed position. To be sure, you have to remove it (empty partially your radiator before to open the thermostat housing) and to test it. Test can be done as follow:
Put it in a saucepan of cold water, then heat it on the cooker and observe the opening temperature (it should be open between 165 to 185°F according to your thermostat type). I believe that yours will not open

After test in order to avoid any familly problem, don't forget to clean and to order the saucepan in the kitchen

Paul W · 11-11-06, 05:13 PM

Thanks Benard but I'm sure the heater would still be working as there is a bypass around the thermostat for it to get hot before the radiator. Also the large hose that comes off the thermostat is really hot all the way down to the bottom of the bulkhead - as far as I can reach, so I think the stat is open - just no flow of water.

Larry · 11-11-06, 06:13 PM

I had the water pump impeller separate from the shaft and had overheating like you described...that would be what I would check first.

Russ Noble · 11-11-06, 06:32 PM

If the car has been OK before and this is a new phenomenom then something has gone wrong. If you are not getting circulation through the heater or the radiator, it would appear that either there is nothing to ciculate ie air in the system, or there is a blockage, or you are not getting a pressure differential across the pump. You may have answered your own question. Make sure you've actually got coolant in the engine, flush the pipes with a hose to make sure you've got no blockage, then pull the pump!

Cheers

Bernard · 11-11-06, 06:41 PM

You are right Larry, it is probably this second possibility. Water pump impeller could be disconnected of the pump shaft even if it is not a frequent trouble. If the heating in the car doesn't work, it means that the water pump is out of order

Paul W · 11-13-06, 08:17 AM

So I pulled the pump yesterday and it seems fine ??? So it must be air in the system - checked my bleed line off the heads and there's the problem - it was blocked ! Looks as though air has built up in the heads over time and that caused the boiling.
On a positive note it was an opportunity to tidy up a few bits on the front of the engine and put some sealing foam around the bulkhead cover which I forgot to do in the build. I did a swift drive around the motor temp rose to 70 degrees and didn't budge.

Mark Clapp · 11-13-06, 10:36 AM

Paul, do you also have a bleed line from the top of radiator back to the filler tank? This one is critical as well since flow will be impeded or blocked through the rad as air builds up.

Paul W · 11-13-06, 01:00 PM

Yes I have the bleed off the top of the radiator, I got a bit fed up of having to keep bleeding the radiator.