hi I have a 91 z with a 5.0 tpi and the problem is when I drive it on the highway the temp goes to 220-250 but if I drive in town it stays at 150-200 it does not have any leakes that I can see and does have coolant in it,,,any thoughts

thanks
steve

 

You got an Air-Dam?
Big black plastic thing under radiator.

 

yes and it is in tact I looked it ove rtoday while changing oil

 

maby the radiator is a bit blocked up and not cooling the water properly.

 

maybe you need a new water pump or your thermostat isn't opening up all the way to accomodate more coolant when the temp goes up

 

the thermostat has not been removed/done away with has it ?


if the pump or the radiator were messed up then it would have cooling issues at all speeds/rpm's


good luck

 

Thats a good point, IF youre RPM is high (2,000+) and you dont have a T/Stat to restrict the water flow youre water pump is pumping water through the radiator faster than it can cool it but in normal every day driving it wouldent realy effect it. If you don't have one I would throw a 180'F one in and see what happens.

 

ok so here goes I replaced thermostat then car ran 240 all time,,next did water pump same car ran 240 all time so I am thinking coolant temp sens. any thoughts????

and anyone know where it is on a 91 305 tpi??

thanks,,,,steve

 

you can pick up an aftermarket temp guage and use it in place of the OEM guage (i dont trust any OEM guage) you should get a new temp sencer with it.
I don't know about the later 3rd gens but the older ones the sencer was in the drivers side head.

My OEM guage would read 260'F (head) when my aftermarket guage read 235'F (intake). you would think since the coolent has to go through the head to get to the intake it would be hotter in the intake than the head.

OEM guages ar ONLY a guide, that is why most OEM guages only say C or H not numbers coz they are not acurate enough to need them.