1989 VN - Temp not coming onto the gauge

[JimmyH]

Hi,

I recently picked up a series one VN v6, but it runs cold all the time.

After 5 minutes of running it comes up between the cold line and the first line on the gauge, but it doesn't get any warmer. Even in traffic, it won't get above the second line. If I sit in a drive through/traffic for a while it will get up to the second line, but the minute I start driving again it'll be back between the cold line and the first line.

To the touch the motor feels like it's running at a normal temperature, that is, it doesn't feel like it's boiling, but it's not cool to the touch.

Wondering what the potential causes could be, I'm thinking I'll replace the thermostat and the temp sensor but I'm not sure.

[LightningVP]

That's where it should sit, thats where mine sits, my step dads VP sits, my mums VL, and my step dads VS...C does stand for cold, but it doesn't MEAN it's "cold"...

-Merry Christmas-

[Morton]

That's normal Commodores do that. That's 'normal' for them. The cooling system in my stato is in top nick, and it never gets above the first line.

The "middle" is generally 100 degrees

A little above that is generally 110 degrees

And the red line up the top is around 120-125, which is approaching boiling point.

[JimmyH]

Okay, sweet.

I just wasn't sure if it was getting to temperature - wouldn't want to cause engine damage.

If all of them run that cold though, then that's great, cheers.

[KnobMuffin]

Mine does that too. I think it might be the actual gauge. If they all do that then you cant really replace it with one from a dismantler.

[DavoVP]

ohhh i had my vp up to 3/4 towing 1.2 ton on a ****ing hot day with the aircon on, oh and while running on gas :S, turn the ac off and itl drop back to half go figgure

[JimmyH]

Okay, well I'm gonna do the temp sensors this weekend... I think it's actually running wrong, the heater doesn't work unless it's idling in traffic. What I mean is, it blows cool air unless the temp gauge gets up past the second notch.

I'll do them and report back!

[Cheap6]

Okay, well I'm gonna do the temp sensors this weekend... I think it's actually running wrong, the heater doesn't work unless it's idling in traffic. What I mean is, it blows cool air unless the temp gauge gets up past the second notch.

I'll do them and report back!

That sounds more like a thermostat then.

There might be some useful info. in immortality's 'How To' on fitting a cooling fan bypass switch, as that developed into a bit of a discussion on Commodore cooling system operation in general.

If you have a voltmeter or ohmmeter available (~$15 if you don't), I would check the resistance or voltage out of the coolant temp. sensor for the engine management and see where it's actually running before replacing anything.

For anything related to VN-VP sensor outputs, it's really useful to make a diagnostic cable if you are able and willing to - < $10 in parts + an hour or so to collect and assemble them. The needed software is available as shareware or free trial.

[centy]

ok normal temp for a vpis about 95 degrees, that barely reads on the gauge.
try flushing the system and check to make sure the heater tap is opening.

[lsprewell]

I think you should really be looking at the Temp Sender, not the Temp Sensor. Big difference. One goes to the ECU and other goes directly to your Temp Gauge. Also it is pretty simple, if the cooling system is operating correctly, than on a decent length trip, your water temp should get to optimum temp, and you can tell this when your radiator fan kicks in. The fan should kick in roughly on half way on the temp gauge, but remember, the gauge is getting its signal from the temp sender and nothing else, it DOES NOT have a clue what the fan is doing, or what the ecu is doing. And if your fan is not kicking in thats another issue, fan relay, fan, temp sensor, or ecu as its the one resposnible for engaging the fan.

So Basically, its either a faulty Temp Gauge or Temp Sender if your gauge does not get to half way when your fan kicks in. (Providing other cooling system elements are correct)

Hope this helps.

[voxbox]

My VN is the same.. the only time the needle budges off C is when i've been sitting in traffic for more than 5 minutes. Thermo kicks in between the first and second marker, then once im back up to speed the needle drops back to C again