620 still won't warm up

[79datsun620]

this weekend i removed my cooling fan,put a brand new nissan 88c-190f thermostat and covered 80% of the radiator with cardboard and it still maybe gets to 130f or 140f and the heat is warm enough but i think it would run a little better if it ran a little hotter.oh and i live in georgia so it don't get that cold outside.

[Z-train]

Check the guage with a known unit.

[datzenmike]

You removed the fan blades, covered the rad with cardboard and have a 190 thermostat and it does not seem hot enough to you.

 

Unless you have an aftermarket gauge with numbers there's really no way to tell what temp you have the. Auto makers use a running range temperature gauge without any numbers. If you are driving with the heater on it will act as a smaller radiator too. The main rad might get enough air flow through it when moving to stay cool but even with a 180 it should get hot.

 

What happens if you idle? It should definitely overheat. In cool weather it will take a good 15 minutes or more to warm up. I can drive 10 minutes to work and the bottom rad tank is ice cold. Top rad hose is warm and gauge is well into the run range at 1/3.

[79datsun620]

ive got it warm and checked it with an infered temp gun at where it runs normally is just below or just above the second line on the cold side of the gauge about 130f-140f.i sat in traffic the other day it was about 65 outside

and it got halfway in about 20min of no movement.i thought in the middle is where it should run but i would be happy if it would get above that second line and stay.

[Z-train]

Borrow a MECHANICAL water temp guage and hook it in tandem and see what is what on your dash guage.

[G FORCE]

Put a turbo on it, that will warm things up. ;)

[ggzilla]

checked it with an infered temp gun

You checked "it". What is "it"??? The temp of the radiator doesn't matter. It's the temp of the coolant inside the engine that should be at the rated 190 degree temp.

[79datsun620]

the upper hose,lower hose,thermostat housing upper and lower part and the radiator.the highest temp i got was 143f.i think the component that the coolant is in should be only a few degrees cooler than the coolant itself wright?

Edited December 29, 2008 by 79datsun620

[banzai510(hainz)]

most latter 78/79 620s had 3 core rads

Maybe find a 2 core??????????

[Z-train]

 

 

HUH?!!:eek::eek:

[Llittle_Llama]

wow, that seems really REALLY odd....

[Jester]

it runs normally is just below or just above the second line on the cold side of the gauge

 

That's were the Hustler would run ALL THE TIME! Just above the second line. When it started getting cold I had a problem with the defrost not working. I covered the top half of the radiator and it would then get just above the second line. This is with a

'79 three core radiator.

[datzenmike]

this weekend i removed my cooling fan,put a brand new nissan 88c-190f thermostat and covered 80% of the radiator with cardboard and it still maybe gets to 130f or 140f and the heat is warm enough but i think it would run a little better if it ran a little hotter.oh and i live in georgia so it don't get that cold outside.

 

Pull the Yellow/White wire of the sender mounted in the thermostat housing and ground it to anything. The gauge should read full scale. It probably will, but in the case it doesn't, then the gauge/sender is the problem and we can all go back in doors. :D

 

Once the motor is thoroughly warm grab the top rad hose. If you can't hang on to it, it's likely hot enough. If it's warm, and you can hold on then drain some rad juice to lower the level, remove the thermostat and verify that it closes properly. You sure it's a Nissan one and not some Chinese hunka junk sold over the counter. Nissan quality is usually pretty good but you could still have a bad one.

[yello620]

the upper hose,lower hose,thermostat housing upper and lower part and the radiator.the highest temp i got was 143f.i think the component that the coolant is in should be only a few degrees cooler than the coolant itself wright?

 

In order for all of those components to be at 143f at the same time the thermostat has to be open at that temperature. You need to remove the thermostat and check it in a pan of water on the stove with your infared temp gun.

 

You have a thermostat that is opening way too soon.

[79datsun620]

the thermostat is genuine nissan (im the nissan parts guy).i had a new chepo $2 thermostat in it and when i put the nissan one in it didnt improve.i did get different temp readings in different areas 143f was the hottest and that was the hot side of the thermostat.jester gave a good description of what my truck is doing.as werid enough as it sounds i might try putting a smaller radiator,but im going to wait and see how it does in the summer im sure ill have to put an electric cooling fan on it (livin in hotlanta).thanks for all yalls imput.

[banzai510(hainz)]

is the heater valve fully open???????

[ggzilla]

Temperature of radiator hoses and radiator does not matter. You need to measure the temperature of coolant *inside the engine block*. That's why the temperature sender is in the cylinder head, not in the radiator hoses or radiator.

 

So either the temp is off, or it is not. You can either test your thermo (pan of water on the stove) or test your dash gauge.

 

Or you can spend more money replacing stuff that does not fix the problem....your choice.