VZ 2005 Executive Overheating

[clarko41]

My 2005 VZ Execuitive has overheated twice in the in the last month. Seems to be fine until i get caught in a bit of traffic and the gauge starts wondering up. I have noticed the coolant level going down a bit over the last few weeks then completely forgot about it and it overheated last night. I cant see any leaks, is it most likely the Thermostat? Im a bit strapped for cash at the moment im hoping its easy and cheap to fix?

[andyman]

replace the radiator/motor cap, they are only cheap, normally the rubber seal on the expand and the crimped spring seperates, thats generally the first thing that goes on them

[the_trademarc]

The radiator cap is 20 bucks from Holden, and that fixes the problem if you've picked it up early. If you let it go for longer you might have water pump troubles as well.

[Azkatro]

I've had a similar thing to this too just recently on my 2005 VZ. The temperature gauge stays firmly on a hair above the 1/4 mark as long as I stay on the motorway. What's weird is at 60-70km/h it climbs gradually, then within about 20 seconds of hitting the onramp (100-110km/h) the gauge literally drops from the limit down to the 1/4 mark in about 10 seconds flat.

Also I've discovered that the temperature gauge stays under control at the 60-70 speed if I limit the auto gearbox from changing too much ([2] at the lights then into [3] when I've hit cruising speed).

The only symptom I have found is that the fan is getting a good workout when the gauge has been high, at no stage have I found any leaks or signs of leakage in the engine bay. Although I'm an amateur at knowing where to look ...

I have just now checked the coolant level and it's hard to tell - I thought it normally had a green colour but the coolant dipstick has no sign of green on it, just clear but to the right level. Also I tried taking off the radiator cap and it looks kind of dry in there... turned the engine on with that cap off and didn't see anything running through there which has got me worried and feeling a bit stupid now. Is it a simple case of coolant's gone and I'm putting water pump on death row? What seems strange about it is the way the gauge drops to normal as soon as I hit 100...

[desert-eagle]

Same thing happened with me today.

No leakage at all.
Car temp normal at 60 -70 speed
climbing hill temp gone up to 80% near red area
took the car to mechanic he reckons radiator needs service.
Booked the car for wen.
Azkatro if you find anything let me know.

[SBM]

I'd say the thermostat is jamming or your radiator is a bit blocked.

[desert-eagle]

how hard is to replace thermostat ? Any How to would be appreciated.

[desert-eagle]

I did noticed when I started the car the temp gauge went to 20% and fans didn't kicked off. So will that be thermostat ?

[KrisHolden]

I had a similar problem. Kmart auto simply let the radiator bleed all the air out and they thought that in the last service when they flushed the system they didnt take out all the air an a air bubble was causing the problem. They also topped up the fluids. A pressure test showed no signs of leaks etc After all that and now 3 months after still no issues

[desert-eagle]

If the temp needle is at 20% is it normal that fan won't run ?

[db_notso]

not again.... if over heats when in traffic and fans work (can hear) and resevoir level slowly getting lower...
you have a leak and an air lock in the sytem because of it..


air locking is a common problem in these motors
another complaint i hear is it overheats with a/c off but not when a/c on

when its cold engine off
take cap of radiator and fill with water till stops bubbling
if you have a bleed screw top rhf of radiator loosen it
top up again until water comes out screw
LIGHTLY NIP UP SCREW (they break easy if overtighten)
refit cap
overfill resevoir (too top)
take r/h and l/h engine cover off
get a bright torch
run car at idle till top radiator hose feels tighter or temp gauge is at half (either or)

now look for leaks common ones below
with torch check 2 heater hoses at firewall (rhr of motor) all the way to their metal fitting on motor (heater tap or hose fittings/clamps)

with torch look down rear of motor lh and rh near where motor meets the transmisson and look for white or coolant coloured stains (thermostat)

at front of motor middle pulley is water pump look for stains or wet under it AND above it on the front of the motor ABOVE the crankshaft pulley (biggest one) (water pump and coolant outlet o-rings)

last look under radiator (below it) for drips or stains

when you find the leak ring up and get a qoute to fix it in the meantime
do this from above when cold before you drive it to extend the life of the engine
no gaurentee you wont kill it though this would be the minimum if my car was overheating

also drive with a/c on heater on hottest setting and fan speed 2 this will drop engine temp a little bit more.

when its cold engine off
take cap of radiator and fill with water till stops bubbling
if you have a bleed screw top rhf of radiator loosen it
top up again until water comes out screw
LIGHTLY NIP UP SCREW (they break easy if overtighten)
refit cap
overfill resevoir (too top)

[desert-eagle]

there is no sign of leak.Funny thing is that it only started happening after I got my Transmission serviced. Mechanic said it could be just coincidence.

[db_notso]

if after doing all that i said up there it still over heats and no leaks that i listed in common places....

the uncommon places are the heater core (inside car wet carpet near middle of dash at floorpan)

auto cooler inside radiator (milky coolant OR auto fluid) check dipstick of auto for milk

head gaskets or cracked cylinder heads (milky oil or coolant)

i will bet one of the common things is leaking or its air locked but, check again....


if its only happened since the auto fluid was done thats suspicious.....
if they were a little ruff and they might have taken an auto cooler line off to flush the auto
they may have cracked the auto cooler or the radiator where it bolts into the tank (on the radiator)..... i would check for milk in auto fluid and for leaks on the plastic tanks on the radiator paying attention to where the metal hoses come out of the tank....

[desert-eagle]

I am from sunny coast also db_notso . If you know any good reliable mechanic , Please let me know. Thanks for all the help

[db_notso]

i could give ya a hand to diagnose it i guess pm me what area you live in if its close i could stop in, gonna cost you a beer~!