Temperature gauge issue/ thermostat or sender ?

[snooze]

Hi all,

Bit of a nob so be easy .. :bow:

Basically my problem is the temp gauge in the dash does not move at all, sits exactly where it is when the car is off as when it is on, even after driving 30mins.

I wasn't to sure if this would be related to the thermostat or the (no idea what it is called) but i assume sender or something (whatever it is that measures the coolant temp and sends the signal to the temp gauge in the dashboard)?

It has been like this for the past 2 weeks (surprisingly after i got my car back to get couple things fixed in the mechanics). Yesterday after driving the car for about 20-30mins through traffic I got home and lifted the bonnet to see if the fan had come on but it hadn't and it seemed fairly hot, i left it running for a while still didnt see the fan come on (didnt hear it come on during driving neither). I assume the car didn't get hot enough for it to come on or the thermostat hasn't told it to?

Sorry for rambling but trying to best explain it as i can. Has anyone got any thoughts? I was going to get the old man to change the thermostat for me next week although that is a good 150km drive.

One other thing, whether it is related or not i dont know but occasionally the car will have an extremely rough idle (shaking, almost sounds like it is about to stall) but then after warming up runs fine, and doesnt always do it on a cold start ??

Car is a VS commodore series II (1997)

 

[Cursed CX8]

Welcome to the forum
There are 2 coolant temperature sensors on the VS commodore engines (ECOTEC), one is connected to the computer and helps control the fuel maps and the fans etc. The second is a single wire which clips onto the thermostat housing and is used only for the temp gauge - make sure this is connected. The VS and VR have a common fault with needing to hit the top of the dash to get the gauges to read, this is due to a dry solder, it might be worth checking out.

The thermofan (engine fan) wont come on till the engine is very warm, the coolant needs to be 104c before it will come on. If the car is moving and the thermostat is working correctly it is unlikely that the engine will get to the 104c mark and the fans needed.

good luck
CC

 

[Harvs82]

Hi all,

Bit of a nob so be easy .. :bow:

Basically my problem is the temp gauge in the dash does not move at all, sits exactly where it is when the car is off as when it is on, even after driving 30mins.

I wasn't to sure if this would be related to the thermostat or the (no idea what it is called) but i assume sender or something (whatever it is that measures the coolant temp and sends the signal to the temp gauge in the dashboard)?

It has been like this for the past 2 weeks (surprisingly after i got my car back to get couple things fixed in the mechanics). Yesterday after driving the car for about 20-30mins through traffic I got home and lifted the bonnet to see if the fan had come on but it hadn't and it seemed fairly hot, i left it running for a while still didnt see the fan come on (didnt hear it come on during driving neither). I assume the car didn't get hot enough for it to come on or the thermostat hasn't told it to?

Sorry for rambling but trying to best explain it as i can. Has anyone got any thoughts? I was going to get the old man to change the thermostat for me next week although that is a good 150km drive.

One other thing, whether it is related or not i dont know but occasionally the car will have an extremely rough idle (shaking, almost sounds like it is about to stall) but then after warming up runs fine, and doesnt always do it on a cold start ??

Car is a VS commodore series II (1997)

Sounds like your temperature sender isn't working at all. Its about $8 for a new one from Holden, and its located just under the top radiator hose connection to the thermostat outlet. The connection is a black rectangular shape, with a green wire coming from it. The actual sender itself brass coloured, and it simply screws in, just under the thermostat outlet.

 

[snooze]

Thanks Classifi3d Calais and Harvs82.

I did what Classifi3d Calais said about giving the dash a good whack and fiddled around with what Harvs82 said with the wire going into the temperature sender, left the car running for 5mins and the temperature gauge has now moved to the first little bar, so like 1/10th.

Although the car again, seems to be doing it more regularly now, has a very rough idle on a cold start - after about 30secs- 1min of running it is back to smooth. What do you think that could be ?

Should i just replace the thermostat and temperature sender and see how it goes? I'm assuming to do this I will lose a bit of coolant? so is it best to just bleed it all out and put new coolant in?

 

[Harvs82]

Thanks Classifi3d Calais and Harvs82.

I did what Classifi3d Calais said about giving the dash a good whack and fiddled around with what Harvs82 said with the wire going into the temperature sender, left the car running for 5mins and the temperature gauge has now moved to the first little bar, so like 1/10th.

Although the car again, seems to be doing it more regularly now, has a very rough idle on a cold start - after about 30secs- 1min of running it is back to smooth. What do you think that could be ?

Should i just replace the thermostat and temperature sender and see how it goes? I'm assuming to do this I will lose a bit of coolant? so is it best to just bleed it all out and put new coolant in?

I'd still replace the temperature sender anyway, and make sure that all the connections are clean and secure. It can't hurt to replace the thermostat at the same time too, and in doing so, its also an excellent time to totally flush the cooling system, as you can put the hose in where the thermostat goes, and completely flush out the block (of course you need to have the bottom radiator hose disconnected so that the water can flow out). Have a bit of a search around on the forums, there is a few threads on how to go about changing the coolant over. I'd highly recommend using either the genuine Holden coolant concentrate, or another brand that is specifically made for the commodore V6 engine, as the premixed stuff isn't suitable as its not strong enough.

Regarding your rough idling it could be a number of things, but I would start by looking at the throttle body and idle controller, give both of them a thorough clean with carby cleaner, and after that I'd check the condition of your spark plugs and high tension leads. If you are handy with a multimeter you can test the resistance of the leads to see which ones are shot, and lastly just make sure that all connections are clean and tight.

 

[jaws_one]

Hey there,

Just thought I'd throw my 2 cents in.

I recently bought one too VSII 97 S/W, first commodore, first Holden even, and I'm impressed. I have same issue as snooze.

I banged the dash instinctively and that fixed that. Still have to bang always to get accurate reading. Dry solder - can I remove the gauge cover on console to fix?

Regarding temp, fan cuts in about 2 bars from red and not sure if that's high or low fan - anyway, I thought that was a high temp so I did myself:
Sensor 70 bucks from Holden,
Thermostat just to ensure opening,
Fluid (Calibre Conc. from supercheap TypeA Harvs82 may disapprove)
Hoses
Flush and Bleed (with Blower going)
Ran radiator fluid treatment to cure gaskets
Oil etc etc.

She's fine. I ran her to Brisbane and back a few days later and didn't miss a beat, ran cold whole way 2-3bar. BUT yes, when it sits still, it climbs to the same point it did before I changed the sensor... before the fan cuts in.

Now I'm thinking this is normal especially after a heap of reading(lesson learned days later when attempting install of head unit and pulling off temp mixer dial for a/c - another sad sad story - it doesn't go back on unless you remove console cover lol my bad, fixed now)

So snooze, I'm in your boat, but I don't think we have too much to worry about. As long as the fan cuts in and it's not boiling over then should be ok. Can you smell coolant? Keep banging that dash! I do, it's solid.

End of day, there's option to install after market fan control and override. Oh yea, you didn't even mention if your fans have run at all. Have you let it sit there and get Hoooot?

What you can do mate is jump the relay with a bit of insulated wire with ends cut off. Jump circuit is done by removing relay, Black square things on LHS of engine bay as you face towards rear of car under plastic cover. They are named. Remove the one for Low fan or High fan, take your pick, go for high. The connections (still facing rear) appear as one at 12 - 3 - 6- 9 like a clock. Jump 6 to 9 and your fan should run with ignition on or off... this will tell you if your fan works and I bet it still does.

I think this issue may not be an issue. I think perhaps the actual temp gauge becomes uncalibrated or reads faulty. Or the engine gauge is simply set to read that way. It never gets higher than two bars away from red.

Let us know how you go with testing the fans. Now my rambling has far out done yours

Peace,
J

 

[Harvs82]

The main thing is to use a coolant concentrate of some description. Problem is when you drain the cooling system you never get all the water out, as its trapped above the heads. So point being if you put the crappy pre mix stuff in (which is already 33%) it gets even further diluted due to the water already being in the system. Hence why I suggested flushing the system as per several posts above and then using the concentrate only, as it gets diluted by existing water in the system. Everything in these motors is cast iron, which you can basically hear rusting, so that's why 50% concentrate v/v water is absolutely necessary.

Case in point, working on the parent's VS exec last weekend. Water pump replaced maybe 18 months ago, mechanic must have used premix coolant. Checked radiator and basically it was completely brown and full of rust, coolant overflow bottle literally had sludge in the bottom of it that had to be scooped out, as did the overflow pipe from the cap. I ended up flushing over 60 litres of water through the block before I had clean water running out of the bottom radiator hose. Radiator was just as bad, I'm surprised that it was even working at all to be honest. Also replaced thermostat, filled up with just under 6 litres of nulon concentrate long life coolant, and now it's very clean and green in the system. Didn't have to top up the system at all with any water, due to 6 litres already being trapped in there.

On a side note, Castrol make a little pack with coolant test strips, you dip them into your coolant and two squares change colour, showing the concentrate of glycol (how strong the coolant is in terms of a higher boiling point) and reserve alkalinity (corrosion protection), the two squares change colour and then your refer to a chart on the side of the bottle. Well worth checking out.

As for the gauge... as discussed on here a million times, particularly on the lower spec dash, the gauge is VERY indicative of temperature and it moves around a hell of a lot, heading up to 3/4 or a bit more is quite normal, especially when stopped in heavy traffic, but the fan will come on then. Check your relays and fuses if you think the fan is suspect. Low speed fan comes on around 105 deg C and then it switches to high speed above about 112 deg C from memory. One also has to remember that these engines do run hot, thermostat isn't even fully open until 99.5 deg C anyway!

Hey there,

Just thought I'd throw my 2 cents in.

I recently bought one too VSII 97 S/W, first commodore, first Holden even, and I'm impressed. I have same issue as snooze.

I banged the dash instinctively and that fixed that. Still have to bang always to get accurate reading. Dry solder - can I remove the gauge cover on console to fix?

Regarding temp, fan cuts in about 2 bars from red and not sure if that's high or low fan - anyway, I thought that was a high temp so I did myself:
Sensor 70 bucks from Holden,
Thermostat just to ensure opening,
Fluid (Calibre Conc. from supercheap TypeA Harvs82 may disapprove)
Hoses
Flush and Bleed (with Blower going)
Ran radiator fluid treatment to cure gaskets
Oil etc etc.

She's fine. I ran her to Brisbane and back a few days later and didn't miss a beat, ran cold whole way 2-3bar. BUT yes, when it sits still, it climbs to the same point it did before I changed the sensor... before the fan cuts in.

Now I'm thinking this is normal especially after a heap of reading(lesson learned days later when attempting install of head unit and pulling off temp mixer dial for a/c - another sad sad story - it doesn't go back on unless you remove console cover lol my bad, fixed now)

So snooze, I'm in your boat, but I don't think we have too much to worry about. As long as the fan cuts in and it's not boiling over then should be ok. Can you smell coolant? Keep banging that dash! I do, it's solid.

End of day, there's option to install after market fan control and override. Oh yea, you didn't even mention if your fans have run at all. Have you let it sit there and get Hoooot?

What you can do mate is jump the relay with a bit of insulated wire with ends cut off. Jump circuit is done by removing relay, Black square things on LHS of engine bay as you face towards rear of car under plastic cover. They are named. Remove the one for Low fan or High fan, take your pick, go for high. The connections (still facing rear) appear as one at 12 - 3 - 6- 9 like a clock. Jump 6 to 9 and your fan should run with ignition on or off... this will tell you if your fan works and I bet it still does.

I think this issue may not be an issue. I think perhaps the actual temp gauge becomes uncalibrated or reads faulty. Or the engine gauge is simply set to read that way. It never gets higher than two bars away from red.

Let us know how you go with testing the fans. Now my rambling has far out done yours

Peace,
J

 

[jaws_one]

Hey there,

Cheers Harvs. Sounds like a naughty mechanic that added the diluted stuff :boxing: lol

Yea, so based on what you have said :idea3: I feel much more confident now that the temp range change I am seeing displayed is normal for this model:surprise:. I've been driving a car where the fan runs off the belt, so it's always on the same temp, always, so seeing the gauge move so much and up towards upper end freaked me out at first.

You're right, it has been discussed on here, and on other sites many times and with that in mind I thank you for the awesomely quick follow up.

Am guessing that if snooze just hits the dash a little more often everything will be fine :wave:

Now on to my next problem in another thread - one of my rear seats the catch won't release:hiding:

 

[VS_Pete]

Have a look at my post No.7 for pic of sensors mate.

http://forums.justcommodores.com.au...93-1997/134170-vs-fuel-usage.html#post1521277

 

[astormsau]

Hi everyone,
There is another problem with the VS, early and mid production models had an issue where they had re-used the VR temp guage sender but put it in a different location (supposedly). This caused the guage to incorrectly represent the temperature of the coolant... making it appear hotter and rising quicker in hot weather than it really is.

Holden will sell you a new coolant temp sensor for the guage for about $15, it has a black collar on it and when you change it over your guage will read more realistically. On my car, with normal driving the temp would always stay at 2 bars on the guage... in warm traffic the temp would climb to 2/3rds of the guage before the fan would kick in on low speed. I found this absurd as it appears the car is getting very hot... the real fact of the matter is that with the original sender, the difference between 1/4 and 2/3rds was a matter of a few degrees. Replace with the revised sender from Holden and now it still runs at 2 bars when travelling around at decent speed, but when im stuck in traffic on a warmer day, it only climbs to half on the guage before the fans kick in.

For the members who are only having their fans turn on about 2 bars from the red, there are 2 fan speed relays in the engine compartment. One controls low speed fan which comes on at about 104 degs and the other controls high speed fan which comes on closer to 110 degs... It is possible that your low speed fan relay is playing up, this will cause the engine to heat up to nearish 110 before the high speed fans kick in and could be the source of your problem. The relay is in the main fuse box on drivers side under the bonnet near the coolant overflow tank. I believe it can be swapped with a relay of the same colour to test (same colour line on the top) or you could just replace it as a matter of maintenance...

Drew