Is it the water pump?

[Aussie John]

I have a problem where the car has started to run at 90c instead of 80c. I have changed the gauge sensor and checked temperature with a heat sensor gun and it is definitely hotter, can a water pump deteriorate, there are no leaks and the bearing feels good. cheers, John

[Trevor450]

I would check the condition of the radiator too.

[Aussie John]

Thanks for the reply, the radiator was recored 6,000 miles ago although that was 12 years ago, I have changed the coolant regularly and have never seen any rubbish in what came out, I put a new thermostat in and also a new otter switch, I,m at a loss where to go next, cheers, John.

[N7GTX]

When you say it is running hotter at 90, is this when the car is moving on the road or when you are stationary?
If it is on the road then the majority of the cooling is done by the radiator cooled by the airflow. If it is when you are stationary then it is the fans pulling the air through the cooling fins. But you do need the pump to push the water around through the rad for maximum efficiency.
If your heat gun is accurate, the thermostat and the otter switch are working correctly and the new temp sender is good and the temp rise is on the move on the road then I would be looking at the radiator and possibly the expansion tank cap in case it is failing and not holding pressure.
Assuming you have correctly bled all the air out of the system, get the system up to 90+ so the thermostat is open. While holding the top rad hose, rev the engine and you should feel the hose get firmer. If it doesn't then possibly the pump impeller blades are in poor condition.

[Aussie John]

Thanks Iain, it is when normal driving, I am going to connect a bulb to see if the fans are running under normal driving. I will try the hose squeeze tomorrow, regarding the cap being faulty I realise that the cap allows the coolant to run above the normal boiling point but the temperature gauge would still measure the same either under pressure or not [or am I looking at this wrongly?] cheers, John.

Edited by Aussie John on Thursday 18th May 20:44

[Frostiechim]

I'd be interested to see your outcome, I have a similar issue.

Every now and then I run at 80 degC on the move. Most of the time it's just under 90, confirmed by temp gun and rover gauge.

The Rad, water pump, thermostat, coolant flush, expansion cap, otter switch and fans have been replaced. I've had compression a decent compression test results for the milage, new head gaskets. As well as a combustion gas check on the coolant.

So now I'm back to the water pump...... which after doing the above with the top hose I am suspect that it is not working as efficiently as it should. Driving with high revs = cooler engine :S.

Just a little story of my journey.

David

[Aussie John]

I keep thinking maybe it's the pump. When I changed the temp. sensor no water ran out so before I replaced it I poured water in with a funnel in case there was an airlock. It didn't seem to make any difference.