Is it getting too hot?

[Split_Pin]

I had heard that the temp guage in a 75 doesn't provide sufficient warning that the engine is in trouble, that'll be why!

[dollywobbler]

It's because the 75's coolant can vary in temperature a lot, especially the diesel which can run very cool (one reason there was a fuel-burning heater pre-project drive). It looks unprofessional to have a gauge that wanders about, so the needle is held in the middle by trickery. I suspect BMW's influence here. I'm sure it isn't the only car that does this.

[Stroller133]

No I suspect many newish car do the same. My 2003 mk1 focus did. 90 was supposed to be middle, but between 75 and 105 it stayed dead on 90. Most cars with this are probably ecu monitored and have a hidden menu which includes temp. On Fords you press and hold trip reset while turning on ignition. My focus would normally run between 70 and 80 so the gauge moved from 1/4 to middle frequently. I suspect the sender/ecu was at fault as the engine bay felt very hot at 75 and the stat was open as all pipes were very hot. Also even on a summer morning the cold temp was about 2 degrees! In 8000 miles the fan never came on, but the AC had a secondary fan, so I ran that all time.

[Stroller133]

Even my last company car a 59 reg Astra diesel fluctuated a fair bit. No gauge but could look at temp on hidden menu. Temp could move between 87 and 96. I suspect most drivers would panic nowadays if the gauge moved around.

Until I found out about forcing normal reading I thought it was amazing how steady temp was on modern cars!

[michael1703]

Hammer a smaller gauge over it?

 

 

How about pointing one of these at it and checking for hot/cold spots?

 

[purplebargeken]

  Quote

 

 

The one thing that annoyed me about my 75 was that it had a temp gauge which, once up to temperature, didn't move (unless the engine was overheating). Some kind of computer controlled bullshit. What the fuck is the point of having a temp gauge if it doesn't actually show you the engine temperature? 

 

 

Ha! NOW he tells me!

 

           

 

Ben actually told me before but I thought it might be humourous*. 

[Mr Livered]

The Volvo I bought the other day appears to go straight from cold to dead-centre in one go, and then remains there. The fan can be heard cutting in and out, but according to the gauge there is no change in temperature.

 

If there is trickery underfoot, by jove that's no better than just having a light for overheating, and no gauge.

[Split_Pin]

My dads Volvo s60 diesel has a temp guage which also stays dead on 12oclock regardless and I thought this eas great until now. My Vectra's temp was always fluctuating and driving in a 30 the fan would come on. Everyone else's was the same though!

[Station]

I've had loads of Astras, and they ALWAYS climb until the fans kick in. My current diesel also climbs and does the same when I'm in traffic. They have very good cooling systems. I drove a Cavalier and an Astra with a head gasket failure for years.

[Richard]

  On 05/07/2014 at 07:39, michael1703 said:

Hammer a smaller gauge over it?

 

 

How about pointing one of these at it and checking for hot/cold spots?

 

I was going to suggest one of those. Also useful for tracking down misfires, point it at the exhaust manifold to see which cylinders aren't firing- especially on V8s as you can't always tell by listening.

[xtriple]

Most cars now lie about their actual engine temp. It's not until there REALLY is a problem that the gauge climbs and by then, it's often too bloody late! My Merc SL500 (R230) had the temp gauge buggered about with by the previous owner to show actual temp and it used to freak me out how sodding hot it got! 105 was not uncommon... higher in traffic when it was chuffing hot.

 

Hated it. Give me a lying bastard any day for piece of mind.

 

It's the same with oil pressure gauges, spend 90% of my life looking at them, every miniscule variation another reason to worry.....

[Stixy]

I like to see an active gauge  that way i know everything is "realtime" 

 

Luckly i drive i twincam Sierra so when its happy the gauge  points to 8 o'clock   in slow traffic it quickly moves to 9 o,clock and ive manualy turned the fans on before it gets to 10  but they come on at 10 automaticaly then the gauge goes back 8 again  

[PhilA]

My Renault does similar- it would appear that the lines on the gauge are calibrated (even though unmarked) at about 10C intervals from 70 to 110. It'll rise up to about 95 then drop as the thermostat opens, then rise up appropriately to about 95 again. It'll get to the line just before the red then the fan cuts in and quite rapidly brings it down a line before turning off. It stays really very high, but that appears to be by design.

 

My Dodge has a 110 degree thermostat- apparently for efficiency. The gauge does wander about a little, but not too much. I suspect it lies to me, but given that the radiator would be at home in a fairly large lorry, who knows.

 

The gauge in my Victor would routinely go into the red. But that's because engine. I hate viscous fans.

 

Phil

[lisbon_road]

To cut a long story short, I tried measuring the temperature with one of those infra red guns.  Gave sensible readings off the hoses and when compared with another similar car, seemed about right.  Tried swapping some bits and a different temperature sender unit gave much better results at no cost.

 

Those infra red gun things are useful though the readings off the engine block and head were all over the place.  Seems to like dark matt things to give consistent results.

 

Not a very exciting conclusion but always best to close the case as it were.  Must have inadvertently swapped the sender at an earlier stage, anyway it is all history now.

[Sloth in a bowl]

In the skoda the water temp gauge rises to 90 and stays there but you can get oil temp to display on the dash and once up to temp that runs 103 to 107.

 

The Kia and Datsun have proper temp gauges that wander though both cars run a bit cool.

[New POD]

Have you tried turning the radiator upside down and flushing it through with a hose pipe?

[lisbon_road]

If you mean me, the temp sender seems to have solved it so I am happy.

 

The rad is new enough so should be fine, and the water/coolant is very clean.  Some confusion over rad sizes with these cars with so many different engines and variations, but it is ok now so history. 

[Lacquer Peel]

Does anyone know when the rad fan should kick in on a VAG 1.9 SDi engine? I know they're thermally efficient but I haven't heard it kick in yet.