LS2 water pump dying?

[Dylan Gotovac]

So here are the symptoms:

Car temp displayed on cluster usually sits at the 1/4 line and fluctuates minimally (maybe halfway to the halfway point). Last week or so it has been sky rocketing when in traffic, almost hitting the red portion at hot. Thermo fans come on full blast to cool it but doesn't seem to have much effect till driving. I have installed an aftermarket water temp gauge located in the centre of the top radiator hose. This temp doesn't seem to move and is relatively cold (80-95 degrees).

Am I on the right path thinking it's the water pump considering I'm getting 2 completely different readings from 1 sensor in the block and 1 in the radiator hose?

Also to consider when I pulled in at home tonight the radiator cap was not hot but when opened coolant was bubbly. Is going into the mechanics tomorrow just wanting some more knowledge on the situation.

 

[greenacc]

Or a blocked radiator perhaps

 

[graham7773]

So here are the symptoms:

Car temp displayed on cluster usually sits at the 1/4 line and fluctuates minimally (maybe halfway to the halfway point). Last week or so it has been sky rocketing when in traffic, almost hitting the red portion at hot. Thermo fans come on full blast to cool it but doesn't seem to have much effect till driving. I have installed an aftermarket water temp gauge located in the centre of the top radiator hose. This temp doesn't seem to move and is relatively cold (80-95 degrees).

Am I on the right path thinking it's the water pump considering I'm getting 2 completely different readings from 1 sensor in the block and 1 in the radiator hose?

Also to consider when I pulled in at home tonight the radiator cap was not hot but when opened coolant was bubbly. Is going into the mechanics tomorrow just wanting some more knowledge on the situation.

If the radiator cap is cool but coolant is bubbly, I would suspect a blown head gasket. Not good news, I know but radiator place can confirm this. They have a device that registers fuel/air mix in your radiator.

 

[07GTS]

if the actual coolant isnt heating up like u mention the second gauge still reads up to 95 deg and if ur in the red with main fans on u will be well over 110 deg dosnt sound right, what i would do is go into the display mode where u can see the temp actual degrees and watch it as u are driving cos the water usually goes up slowly a deg at a time so if its fine one second and jumps 5-10 deg at once then it could just be the coolant temp sensor playing up which changes the ecu and dash temps so will bring fans on, also if u have bubbles in the coolant id get that looked at as mentioned its an easy test to do may just be air from not being bled or may not

 

[exanVZ]

could maybe be a stuck thermostat? not sure how it is setup on the LS2 but i have had a similar issue before with a alloytec.

 

[TheWade]

Are you losing coolant as well? Usually when the waterpump is screwed you loose coolant and the pump itself makes an awful noise. probably not an LS2 in a VZ either would be an L76 or L98 and while these aren't LS1 they aren't LS2 either.