Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

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draky13
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Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

Post by draky13 »

hello everyone.i have a 1991 gsi cavalier she has been of road few years im slowly getting her back to her glory. The temp gauge after car is running 15 mins shoots straight to 100 and sits there. First i changed temp switch then thermostat and then the radiator flushed the system also. Went another drive straight to 100 and as i drive it goes up and if i throw car in neutral it goes down lol. Also checked water pump.It actually went near the red today and i checked pipes straight away no pressure. Any help id be grateful
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ilovedmymantas
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Re: Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

Post by ilovedmymantas »

Hi & welcome :wave

No pressure sounds like the water pump to me. I'm assuming it was checked visually rather than removed ( It may be spinning externally but dead inside).
When was the last time the water pump and drive-belt kit were changed?
If the car's been unused for a few years that's the first thing I would do ( as I would with any used car I'd just bought ).

-matt
" It's not rust. It's age-related patina " ;)

1980 vauxhall cavalier MK1 1.6L, 1982 opel manta berlinetta 1.8s, 1985 opel manta 2.0 gte, 1990 cavalier 2.0 gl ,1994 cavalier sri x20xev

-1995 cdx x20xev

---------------
Matt
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Robsey
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Re: Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

Post by Robsey »

Hmm - no pressure at all in the water pipes?

That suggests a very bad air lock.
I know you flushed the coolant, but did you squeeze the pipework to expell all the air with the engine running.

I do this by removing the header bottle cap,
Squeeze the fat hose between the thermostat and the radiator several times, and then run the engine for a few minutes with the cap off long before it gets to full running temperature.

If the needle stays around the 100°C mark, then I would not worry.
Dependent upon the accuracey of the sender and the gauge, anything as high as 103°C could be considered normal.

What you didn't mention was whether the radiator fan kicked in or not.
I would expect the fan to kick in between 95 and 103°C.

From experience, water pumps can fail in many ways, but for me it is usually that they dribble coolant before failing completely.

The anomoly is that only today, it nearly got into the red.

The fact that the pipe pressure is quite low thankfully points away from ahead gasket fault.

Are you losing any coolant?

There are four reasons for overheating.

1 - Lack of coolant. (Loss of fluid) or not bled properly.
2 - thermostat failed in closed position.
3 - radiator fan motor or thermo switch failure - or Duff radiator fuse
4 - water pump failure. - impeller separated from the pulley.
draky13
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Re: Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

Post by draky13 »

hello everyone many thanks for replies. Car is blowing great heat only checked if water pump was flowing threw the coolant bottle have a new one here. We also removed the cap and drove we bit to dry bleed the system ive been driving car flat out now last few days and im driving it thinkin the temp gauge could be faulty going to change the waterpump and flush the system again. Also you know vauxhaul fan switches are terrible so i have fan to croc clip when i put fan on it still doesnt go down if anything it goes up lol
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Robsey
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Re: Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

Post by Robsey »

If it still gets hot with fan on -
I would check: -
1 - thermostat failed in closed position.
2 - water pump failure.

Have you checked the temperature sender for cleanliness. If it is corroded, it will affect the gauge readings.

But I am still thinking it is one of the two items above.
Note - it is not common, but new parts can fail. So don't rule out any part just because it has been replaced recently.
draky13
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Re: Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

Post by draky13 »

thermostat is new will have it checked water pump and timing kit going in on thurs going check sender this evening. Am i effecting the car by driving it like this??
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Robsey
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Re: Temp Gauge sitiing at 100 NO Pressure!! need help plz !!

Post by Robsey »

I would not do any un-necessary miles, until I knew the cause of the very high gauge reading.

Overheating could cause head damage, which is a whole lot more hassle and worry that you do not need.
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