Smaller Water Pump Pulley?

[Moss]

Originally Posted by jtb007

faster spinning pumps arent always good, you can get cavitation and things like that......

I'm only talking about increasing the flow by about 20-40% nothing too major. I don't think it would cause cavitation especially since its a closed loop.

[Steve F]

Originally Posted by Moss

....I'm a bit sceptical that air flow is the primary issue because when I'm on the highway (where there is plenty of airflow) it still gets hot and I have to turn the air con off. I understand that the engine is under extra load but it should be able to manage quite easily at normal highway speeds.

Then you have some other problem, at HWY speeds the fan is redundant and the coolant is already flowing at a decent rate etc. I'd be replacing that water pump as it could be corroded enough to not be efficiently circulating the coolant. A well maintained stock system will keep the XJ cool enough. I run 35's and did the Cape last year with no overheating issue despite being loaded up for a month away. Other than an aftermarket radiator and a heavy duty fan clutch my cooling system is stock.

Cheers
Steve

[Moss]

Originally Posted by Steve F

Then you have some other problem, at HWY speeds the fan is redundant and the coolant is already flowing at a decent rate etc. I'd be replacing that water pump as it could be corroded enough to not be efficiently circulating the coolant. A well maintained stock system will keep the XJ cool enough. I run 35's and did the Cape last year with no overheating issue despite being loaded up for a month away. Other than an aftermarket radiator and a heavy duty fan clutch my cooling system is stock.

Cheers
Steve

I just had a look at the water pump and it looks brand new. I have flushed the system twice this year (with coolant flush and a garden hose) and use CAT ELC. With the air con on and doing 110km/h on a hot day it will fairly quickly creep up to 105 but thats when I turn the air con off.

[Steve F]

Originally Posted by Moss

I just had a look at the water pump and it looks brand new. I have flushed the system twice this year (with coolant flush and a garden hose) and use CAT ELC. With the air con on and doing 110km/h on a hot day it will fairly quickly creep up to 105 but thats when I turn the air con off.

It looks new on the outside or inside?

Cheers
Steve

[anthonygubbin]

I searched on here yonks ago and have read many post re overheating. 9 out of 10 times it comes down to the clutch fan. Mine has started to get hotter than normal this year and the first thing I will be doing if it becomes probelmatic will be to change the clutch fan.

Regards A

[Moss]

Originally Posted by Steve F

It looks new on the outside or inside?

Cheers
Steve

The impeller looks new.

Originally Posted by anthonygubbin

I searched on here yonks ago and have read many post re overheating. 9 out of 10 times it comes down to the clutch fan. Mine has started to get hotter than normal this year and the first thing I will be doing if it becomes probelmatic will be to change the clutch fan.

Regards A

If were a fan issue than it would ok on the highway.

[Moss]

Originally Posted by kjparker

one thing you also need to consider, faster flow doesnt necessarily mean better cooling!

Some people actually slow the coolant down in order to get more stable temps and better performance!

Have a look at this link... http://jeep-xj.info/HowtoRadiatorRestrictor.htm

That's my point exactly, the cooling is working too effectively and they have to reduce the flow.

IT's not like a high flow electric water pump where the flow is consistent. You'd still have the flow proportional to engine RPM.