Temperature gauge sits at 3/4

[andrew270681]

Hi guys,

I bought this Vr senator about 2 weeks ago and i seem to be having problem after problem with it.

Ive been keeping a close eye on my temp gauge. It will sit at about half way which im fine with but if i start to rev the car it will rise to 3/4 and stay that hot.
If i sit still and rev the car to 2500rpm it will go up to 3/4 within a few minutes.

The gauge will start off and work its way up to the quarter and sit there for a while, then go up to half way then up to 3/4 but it will only go up to 3/4 if i start to rev the car or if im sitting in traffic with or without the aircon on.
All this is happening while im commuting to work down the M5 motorway.

I have changed
thermostat,
radiator and some hoses (had it pressure tested and no leaks) also had system flushed
engine oil.
guage sender
tried a new gauge

My fan seems to be working fine.

Im not too sure about water pump but if it was a problem the car would definatly overheat (wouldnt it?)

Yesterday after i changed my sender it got to the 3/4 mark so i turned the car off and i was watching the gauge and it went all the way to red.

This has got me puzzled and is pissing me off really bad now so any help is appreciated

thanks

[_R_J_K_]

If i sit still and rev the car to 2500rpm it will go up to 3/4 within a few minutes.

The gauge will start off and work its way up to the quarter and sit there for a while, then go up to half way then up to 3/4 but it will only go up to 3/4 if i start to rev the car or if im sitting in traffic with or without the aircon on.
All this is happening while im commuting to work down the M5 motorway.

Solution: stop reving your car.

Why do you need to sit still and rev your car for a few minutes? Driving (i.e. moving) helps to push air (cooler air at that) through the radiator. While sitting still, this doesn't happen, and you reving it only makes it worse. The thermo fan will only do so much while you are sitting still.

As for the sender, could be faulty. Just because it's new doesn't mean it will work.

[ragrim]

Might be worth bleeding the cooling system. dunno if its the same on V8's but my ecotec was doing the same and turns out i had to bleed the air out of the system.

Let the car get hot, then undo the screw at the top of the cooling system (its on the thermostat housing on an ecotec) let the air out untill there is a constant stream of water comming out.

after doing this my temps dropped from 3/4 while idling to 1/4

Also, does turning on the air con help? air con turned on makes thermo fans fun at full speed regardless of engine temp.

[_R_J_K_]

Also, does turning on the air con help? air con turned on makes thermo fans fun at full speed regardless of engine temp.

V8 fans are belt driven, so turning on air con will probably make it get hotter.

[andrew270681]

Solution: stop reving your car.

Why do you need to sit still and rev your car for a few minutes? Driving (i.e. moving) helps to push air (cooler air at that) through the radiator. While sitting still, this doesn't happen, and you reving it only makes it worse. The thermo fan will only do so much while you are sitting still.

As for the sender, could be faulty. Just because it's new doesn't mean it will work.

I reved the car at a standstill so i can see how quickly it will heat up. If i hold revs at 2500- 3000rpm on a motorway travelling at 110km/h it will overheat as well.

Im going to change the clutch fan tomorrow as it will only cost me $100.00

[dirt drifter]

i had a look at my workshop manual for vr-vs. it says, after ruling out the bits u have already replaced, the problem could be:-
water pump on its way out
water pump belt loose
fan clutch broken (i assume u are still running the stock engine driven fan, with the shroud still on there)
ignition timing out. 10 degrees at idle with the diagnostic mode on is what u want so the book reckons (look for a rectangle plug down below the steering column, starting at the top left pin count across to the 5th and 6th pins, join them up with some stray wire and ur in diagnostic mode)
im sure you filled it up with decent coolant, was the heater set to max heat at the time so the heater tap opened up?
if its puking coolant into the overflow bottle a new, possibly higher pressure radiator cap might be the go, the springs in them can lose their tension over time

[hako]

I reved the car at a standstill so i can see how quickly it will heat up. If i hold revs at 2500- 3000rpm on a motorway travelling at 110km/h it will overheat as well.

Im going to change the clutch fan tomorrow as it will only cost me $100.00

Maybe I'm missing something but how can you rev the engine to 2500-3000rpm whilst travelling at 110km/h?

The car should run at about 1/2 gauge reading whilst cruising and should go rapidly to 3/4 when stopped....so maybe you are worrying about nothing.

[Vee-ard]

Maybe I'm missing something but how can you rev the engine to 2500-3000rpm whilst travelling at 110km/h?

The car should run at about 1/2 gauge reading whilst cruising and should go rapidly to 3/4 when stopped....so maybe you are worrying about nothing.

Hako - exactly. Im sick of posts about "my commodore sits at 3/4 !!!! HELP"

VR/VS COMMODORES RUN HOT. This is evidenced by the fact that, like clockwork, there is about one post every 5 days from someone different along the lines of their car running hot.

If you have a mate or your mate has a mate of a mate who's commodore sits on 1/4, his thermostat is probably stuck open among other possible things.

Andrew - Mate you've tried the following:

"thermostat,
radiator and some hoses (had it pressure tested and no leaks) also had system flushed
engine oil.
guage sender
tried a new gauge"

Sounds like its intended to sit that high.

[strgas]

Sound more like a blocked rad .

[clubby_you]

yeah half way to 3/4 is normal on a 5litre after new rad new hoses new water pump new temp sensor myn sits on halfway in peak hour but was allways in the upper half before all that and so does my mates 2 vs ss's

[andrew270681]

i had a look at my workshop manual for vr-vs. it says, after ruling out the bits u have already replaced, the problem could be:-
water pump on its way out
water pump belt loose
fan clutch broken (i assume u are still running the stock engine driven fan, with the shroud still on there)
ignition timing out. 10 degrees at idle with the diagnostic mode on is what u want so the book reckons (look for a rectangle plug down below the steering column, starting at the top left pin count across to the 5th and 6th pins, join them up with some stray wire and ur in diagnostic mode)
im sure you filled it up with decent coolant, was the heater set to max heat at the time so the heater tap opened up?
if its puking coolant into the overflow bottle a new, possibly higher pressure radiator cap might be the go, the springs in them can lose their tension over time

Checked all of the above and seem im on a role of pissing my money against the wall with this car i bought a new water pump but still no fix!

[andrew270681]

Hako - exactly. Im sick of posts about "my commodore sits at 3/4 !!!! HELP"

VR/VS COMMODORES RUN HOT. This is evidenced by the fact that, like clockwork, there is about one post every 5 days from someone different along the lines of their car running hot.

If you have a mate or your mate has a mate of a mate who's commodore sits on 1/4, his thermostat is probably stuck open among other possible things.

Andrew - Mate you've tried the following:

"thermostat,
radiator and some hoses (had it pressure tested and no leaks) also had system flushed
engine oil.
guage sender
tried a new gauge"

Sounds like its intended to sit that high.

Tried all that. Tried with no thermostat and i tried with a warmer and cooler thermostat.
The car overheats to the red now while sitting at lights

[andrew270681]

Sound more like a blocked rad .

I have replaced the radiator, and have checked all flow through the whole system and its fine

[andrew270681]

Im begining to think ithe head is ****ed.

Yesterday i spent the whole day making sure the system was free of air etc but no luck

I think when i flushed my system i must have dislodged chem i weld which the dis honest asshole prob put in there. I think this because it wasnt so bad to begin with. (ive only owned the car for 2 weeks)

Im going to do a TK test on it tomorrow and also a compression test and take it from there.

[dirt drifter]

yeah the head gaskets are a known weak link in the 5.0L. hopefully its just them and not the heads themselves, in the unfortunate event that u need new heads make sure u get them pressure tested first, just in case some dodgey bloke is trying to sell u something no better than whats on there already

[andrew270681]

I dont trust mechanics (no offence to anyone). I do most of my work myself. I take my time and do it properly.

My problem is that i wanted to do some work to the engine but i wanted to do it next year so i can save some money. but now i need to fix this shit up.

Im going to take my car to a mates workshop and do some testing this arvo. Wish me luck!

[Vee-ard]

yeah the head gaskets are a known weak link in the 5.0L. hopefully its just them and not the heads themselves, in the unfortunate event that u need new heads make sure u get them pressure tested first, just in case some dodgey bloke is trying to sell u something no better than whats on there already

Mate, you know jack all about the 5.0L dont you? There is nothing wrong with the head gaskets on the 5.0L. Even the timing cover would be more prone to failure.

If you think the head gaskets are a weak link, try running your car with some sort of liquid in the radiator instead of air, or dial back the supercharger to 9PSI instead of 20.

[andrew270681]

Mate, you know jack all about the 5.0L dont you? There is nothing wrong with the head gaskets on the 5.0L. Even the timing cover would be more prone to failure.

If you think the head gaskets are a weak link, try running your car with some sort of liquid in the radiator instead of air, or dial back the supercharger to 9PSI instead of 20.

I have spoken to heaps of people including a close mate of mine and everyone is convinced its not the head. On that note i did a TK test and didnt show anything. So thats in the clear.

[dirt drifter]

Mate, you know jack all about the 5.0L dont you? There is nothing wrong with the head gaskets on the 5.0L. Even the timing cover would be more prone to failure.

If you think the head gaskets are a weak link, try running your car with some sort of liquid in the radiator instead of air, or dial back the supercharger to 9PSI instead of 20.

don't get smart, all i was saying was if a 5.0 has had the arse flogged out of it, or run with bugger all water like u say then it could be a possibility, amongst other things. old mate only bought the car a few weeks ago so god knows what happened to it before he got it

[andrew270681]

Everyones help is appreciated :thumbsup

[Vee-ard]

don't get smart, all i was saying was if a 5.0 has had the arse flogged out of it, or run with bugger all water like u say then it could be a possibility, amongst other things. old mate only bought the car a few weeks ago so god knows what happened to it before he got it

all you said was that the head gaskets are a known weak spot on 5.0L's

They arent.

You didnt say "if the car was flogged it may blow a head gasket".

[dirt drifter]

my bad, i should have elaborated a bit more. i meant if a 5.0 is thrashed or fed a gutload of boost/gas they have been known to pop the odd head gasket, apparently it's something to do with not having enough head bolts on there to keep the heads on. hence why torque power's holden based block and heads setup has 2 extra head bolts either side to help keep the heads on. however this does not appear to be the case with the car in question
speaking of which, how is the senator going, had a win yet?

[KOMNHOR]

do u ppl expect the sun to shine out of the exhaust of 5.0?
gee if they were perfect, y did they change 5.0 to 5.7 apart from more power?

[KOMNHOR]

never the less andrew, be persistent its prob nothing

[pjdm1980]

You just have to look at the car as a whole it could be a bad tune causing it to heat up most commodores I've owned sit between 1/4 and 1/2.