Waterpumps and Hot Running

Post by **CitroJim** » 13 Mar 2007, 22:03

Since I have had my Activa, I have been concerned it has been running a bit hot. Nothing serious but enough to bother me. I had already replaced the rad and thermostat (an 82 degree one) and still I felt it was running a little hotter than it should.

Over the weekend I swapped the cambelt and whilst I was there, replaced the water pump. The one I took out was perfectly OK but it appeared to have a plastic impeller with far smaller vanes than the Airtex (from GSF) I used as a replacement which has a much meatier metal impeller.

The engine is now running noticeably cooler and the temperature is remaining a lot steadier and not taking excursions above 90 degrees as it frequently did on the old pump.

alan s · Post by **alan s** » 13 Mar 2007, 22:48

Yep, they can be a real trap.
A while back a friend with a Nissan Turbo diesel 4wd had a problem of it overheating when he was on the open road but staying cool in town.
My first suspicion was the hose that is the intake to the pump, my reasoning being that at 100kph there should be enough air passing through the core to cool the coolant and that under load, this hose could be collapsing, a fault often found on cars a few years old where the hose has gone a bit soft. We replaced the hose and took it for a run and whilst it was improved, it was obvious it hadn't been fixed.
After changin, checking or totally removing just about every control and sensor associated with the cooling system, that left just one thing; the water pump and as usual, it was going to be a messy job to get it out. However, when it was removed, it was found that it had a brass impellor and the previous owner must have run the vehicle for some time on old coolant or simply tap water and electrolysis had goty to it and the blades on the impellor were almost totally gone.
Replaced, it now can be driven at any speed in any situation and never overheats, so I agree, the water pump is all too often ignored when strange cooling problems arise.
That car of yours sounds like it's becoming a better drive by the day.

Alan S

Post by **Peter.N.** » 15 Mar 2007, 11:33

Well you learn something every day! When I read the first post, I thought 'no way is it the water pump' but found citrojm's reply illuminating. The moral here being that just because in 50 years of motoring you hav'nt come across something. it doesn't mean it cant happen!

oscarloco · Post by **oscarloco** » 20 Mar 2007, 22:30

I know what kind of water pump you are reffering to. When I replaced mine, the new one had the metal impeller and the one removed, had that plastic impeller. The plastic didn't last too much, around 2 years. The one has 3 years and is still good.