Temp gauge question.

Hobbes

At what level should you get your cars engine checked.

I was told when doing ISM lessons many years ago that if your temp gauge goes to the halfway mark or over then there is something wrong with the engine and needs to be checked.

Others have been telling me otherwise. Personally my own car hasn't gone over the halfway mark (at worst 30% mark in heavy traffic).

mike65

It depends what the mark indicates! Most cars are between 80 and 90c at warm idle. If you've never seen the gauge 'head for the red' then everything sounds ticketyboo.

Mike.

Hobbes

well the red mark would be the last 10% of the gauge.

mike65

True! Once in the red its get moving or switch off pronto - lightweight aluminium heads don't like it in 3 figure territory.

Mike.

maidhc

Hobbes wrote:

I was told when doing ISM lessons many years ago that if your temp gauge goes to the halfway mark or over then there is something wrong with the engine and needs to be checked.

If it goes into the red then you have a problem, if it is climbing towards the red the you have a potential issue, but on most cars the needle stays around the halfway mark from my experience.

On the Ford focus if the engine starts to overheat there is an idiot light, and two cylinders stop firing to create a 2 cylinder aircooled engine! So the manual says anyhow!

colm_mcm

depends on how hot the weather is, and where you're driving. there's no major problem if it goes over the halfway mark, as long as it doesn't go in the red

Lex Luthor

all cars are different on the gauges

my wifes E39 is supposed to sit bang in the middle but there is no temp reference on the gauge
My 156 is supposed to be at 82deg and will go to 90/92 in traffic

I would guess a gauge only getting to 30% might point towards a t-stat stuck open, depending on the car

SonOfPerdition

maidhc wrote:

On the Ford focus if the engine starts to overheat there is an idiot light, and two cylinders stop firing to create a 2 cylinder aircooled engine! So the manual says anyhow!

never heard that before . .thats rather clever!

AMurphy

Hobbes wrote:

At what level should you get your cars engine checked.

I was told when doing ISM lessons many years ago that if your temp gauge goes to the halfway mark or over then there is something wrong with the engine and needs to be checked.

Others have been telling me otherwise. Personally my own car hasn't gone over the halfway mark (at worst 30% mark in heavy traffic).

Depends on the car, gauge, thermostat and calibration.
How long have you had the car... what is normal, doesn't matter where the gauge comes to rest.... generally the 50% in the middle of the needle sweep is OK.
What I'd look for is abnormal behaviour. ie normally it is at 25% and then 75%, but still in the green.
And just because it behaves abnormaly does not mean the engine is goint to blow anytime soon. Could be the dash itself, the sensor, a failed fan, a cloged rad internally, a failed thermostat, a sheet of paper, dust, grass, stuck in the rad reducing air, failed pump, slipping belt, timing off, etc....
Usually overheating is often accompanied with pinging. So, don't panic, learn what is normal first.
PS, if your head runs dry it is possible for the temg gauge needle to go down while the hed temp is going up... so do not rely exclusively on the gauge.

seamus

I'd certainly notice if my needle went any way above halfway (90 deg C), but I wouldn't be overly concerned unless it was the dead of winter or I'd been driving for hours without issue.

My bike had a digital gauge with little bars that showed how hot the engine was getting. 3 bars was normal. 6 bars was in the red. 8 bars was at meltdown point. I only ever saw it go to four bars, once. I was standing in a line of traffic for 20 mins.

never heard that before . .thats rather clever!

Indeed. I guess you'd notice if you were down to two cylinders, and then you still have at least some power to get thee off the motorway/to a garage/home/etc.