Thermostat issue? Motor runs very cool.

[DJ-Bolan]

usually a cars temperature gauge should be little under 1/3 the way. enough so the clearances are correct/factory and also not hot enough to cause any damage. it being cooler is better than it being hotter. get into your car in a cold say, and try to flog it. does it sound right? hardly. all the oil needs to heat up and to coat everything so obviously it needs to be hot, not cold.

but being too hot your engine head and all the clearances are expanding and can cause less compression which means more fuel due to less power.

change the thermostat to be sure, they only cost $20 and they're easy to change. if you don't change it, it will end up costing more than $20.

if you don't change it. and the thermostat seems to be ####ed. you can remove all the the guts of the thermostat for a quick simple fix, but do not drive more than 20 minutes (15ish minutes on a really hot day) as it might over heat.

-D

 

[Rexy28]

exact same with mine, 3rd engine changeover,
and needle doesnt go past even a quarter, in traffic and around town it'll get up to about a third of the way.

 

[Vee-ard]

but being too hot your engine head and all the clearances are expanding and can cause less compression which means more fuel due to less power.

If your engine expands to the point where the clearances cause a loss of compression something is seriously wrong with your engine.

Actually no, that statement is just plain wrong. The only place bar worn rings or rooted valves you can lose compression is by increasing the combustion chamber, and if you just gained that much clearance so that compression dropped by a noticeable amount, you've just blown a head gasket. Getting even hotter than this, the piston and rings are going to expand to the point they contact and grab at the bore and seize your engine, long before you lose compression from overheating expansion.

 

[shadetreemechanic]

To reply to the OP, put your mind at ease and yank the stat to check its stamped temperature (you could even whack it in boiling water to verify 100%)

There's a few things to add:

- the stat's temp is when it begins to open (eg. 82 deg, 88 deg, 91 deg etc). It won't be fully open until about 10 deg past that

- the 3.8 V6 runs HOT from factory. It has a 91 deg stat and the coolant will be around 100? deg when operational. That's a lot and could be lowered safely, especially when chasing performance. People on here seem to be running 82 deg hi flow stats when running mods, unsure if they account for it in the tune or not

- it's an urban myth that higher coolant flow absorbs less heat. Higher coolant flow will ALWAYS result in higher heat transfer. Coolant cannot absorb heat after it reaches it's pressure corrected vapor point.

 

[nathanVY]

Yep sounds fine to me, most commodores I've driven in don't usually go past 1/4 especially when it's cold.

As long as your temp gauge IS moving up and down and around then you know your thermo isn't stuck open.


edit: mine sits just below 1/4 but I have the termo fan kick in temp adjusted lower in my tune.

 

[HOLDENFAN]

You guys must just have super cool systems, mine runs pretty much 1 line above a quarter, gets to half in traffic, but fan takes care of it from there. I do need a coolant flush though, my heater isnt as great as it should be....

 

[VS_Pete]

^^^^^^
Keep an eye on your heater tap.

 

[HOLDENFAN]

yeah although its not leaking, it looks old a crusty as ####, something I wanna do soon, as well as flush the core out. Just looks a prick of an area with abs in the way, my mates VP has so much more room in the bay than my VR

 

[hako]

Remember that the temperature gauge is mass-produced to a price...it is not a laboratory grade instrument and really is only a guide. If your car runs OK and steady on a certain gauge reading be it 1/4 or 1/2 and you know your cooling system is in good order then rest easy.

 

[VS_Pete]

yeah although its not leaking, it looks old a crusty as ####, something I wanna do soon, as well as flush the core out. Just looks a prick of an area with abs in the way, my mates VP has so much more room in the bay than my VR

Yep I took some bark off I tell yea.