Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

VZ V6 running hot for no apparent reason

SKNOT9

All hope is gone
Joined
Feb 20, 2007
Messages
274
Reaction score
0
Points
16
Location
Lobethal, South Australia
Members Ride
VS series II Acclaim
Hi there. I have a 2005 VZ V6 and just recently it will overheat (little picture comes up on screen saying its overheating) and the guage is just about at the top. Im not quite sure that it is actually hot, because i pulled the car over and opened the bonnet and could rest my hand comfortably on the top of the engine, and couldnt feel much heat rising from the engine. It was a cool morning, i don't have any coolant leaks, the coolant has been full every month that i check it, there is not frothing on the engine cap which would indicate something was wrong. Im thinking it may be a temperature sensor just saying that it is hot? or maybe it is really hot and i just cant tell. the thermo fans are coming on when the guage is just above half so that seems normal. Im just wondering if this is common or if anyone knows what could be wrong? This has happened randomly 4 or 5 times over the last month or so.
 

richardpalinkas

Blown Alloytec
Joined
May 4, 2009
Messages
2,290
Reaction score
16
Points
38
Location
Gold Coast
Members Ride
Raptor Impulse VZ SV6
i heard the radiator cap or thermo may cause it?
 

richardpalinkas

Blown Alloytec
Joined
May 4, 2009
Messages
2,290
Reaction score
16
Points
38
Location
Gold Coast
Members Ride
Raptor Impulse VZ SV6
yea the thermostat.

i dunno, just what i 'think' i read somewhere on here
 

impulsive

Alloytec Racing
Joined
Aug 29, 2007
Messages
1,872
Reaction score
20
Points
0
Age
38
Location
Brisbane, QLD
Members Ride
VZ Alloytec
Thermostat could be the problem, Radiator caps have known to fall apart which causes the car to over heat, happened to me, check the spring underneath radiator cap it could be broken, if so replace it.

Generally with simple stuff like this it pays to inspect components of the individual system, check other things while your there, belt tension etc
 

bulldog79

New Member
Joined
Sep 20, 2005
Messages
75
Reaction score
1
Points
0
Age
44
Location
blacktown
Members Ride
vy calais .vs commodore
my sister had the same problem there was a falty batch of thermostats
 

Sean880

Well-Known Member
Joined
May 14, 2009
Messages
1,191
Reaction score
192
Points
63
Location
VIC / NSW
Members Ride
2012 VE SV6 ser 2 and 911 Porsche Carrera S 997
You should have had it professionally checked out the first time it occurred. Overheating problems do not fix themselves. Running the engine hot like that can easily result in blown head gaskets and damaged heads. ( Expensive damage).

2. If it is intermittent, it sounds to me like it might be a thermostat that is intermittently sticking. When the coolant is heated in the engine, the thermostat is sometimes not opening to allow the coolant to freely flow from the radiator through the engine. Hence a hot engine condition. I don't think you have a problem with a failed water pump because in that case the overheating condition would usually be a continuous problem.

3. The culprit might also be an intermittent blockage in coolant flow through the engine due to debris build up in one or more of the coolant passages in the engine.

4. Air in the cooling system, from inadequate bleeding of the system, can cause an air lock and consequential high temperature condition. It does not sound like that is the problem though.

Problems occur in cooling systems because they are often neglected. People often wait until they have a problem before servicing them and in the process risk engine damage.

Cooling systems need flushing at least every 2 years and refilled with the recommended coolant mix. Thermostats need to be working properly (plenty get replaced) and water pumps fail periodically and need replacing.

You will need to take the car to a competent mechanic to have the problem properly diagnosed and addressed before you do major damage to the engine by overheating it again.
 

Torquative

Sports Economy
Joined
Jun 21, 2005
Messages
1,584
Reaction score
20
Points
38
Location
Sydney
Members Ride
VE SV6 3.6L SIDI 6sp
alloytecs are known for having failing theromostats and as mentioned radiator caps
 

SKNOT9

All hope is gone
Joined
Feb 20, 2007
Messages
274
Reaction score
0
Points
16
Location
Lobethal, South Australia
Members Ride
VS series II Acclaim
thanks for all your help guys it is great!! i will replace the thermostat and check the radiator cap and if that is not the problem i will take it to a mechanic and get the system flushed and get other things checked out. Normally I would be on this sort of thing straight away but I have had overheating VS and VN and you could really tell it was overheating by the feel of the engine and when you opened the bonnet just a wave of heat hit you, but with this car it just seems like its running fine so i figured it is a gauge error or something. Another thing i forgot to mention is that when it says it gets really hot, just sitting at lights, sometimes it will just drop back down to half temp in about 5 seconds, so it seems like a "glitch" if you get me. What temperature should my coolant be running at?? I appreciate all the suggestions :)
 

alex2_s

Member
Joined
Oct 24, 2008
Messages
197
Reaction score
2
Points
18
Location
Newcastle NSW
Members Ride
VFII SV6 Sedan Auto
what could the radiator cap have to do with it?

Radiator caps are rated to a certain pressure which it will hold pressure too until it allows the coolant to expand into the expansion tank. If the radiator cap cant hold pressure (or you just simply take it off) the car will almost certainly overheat straight away as the system wont be able to pressurise (coolant has a higher boiling point when pressurized)
 
Top