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Temp Gauge Position


lammy
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Could sombody tell me where the needle on the temp gauge should sit when the engine is at normal running temp. Mine moves a bit between just off the blue when sitting idleing to just over half way when at motorway speeds.

I went to check the thermostat but it is missing,so just want to know what is the correct position,its a GTE 1987 if it makes any differance.

Cheers

Raymond.

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.i would expect it to cool off at motorway speeds and heat up to halfway on idle with no stat .

the voltage regulator behind the dash can go a bit funny and give high readings for temp and petrol . check if there is a difference in the readings with engine running vs ignition on .

should be similar if its working ok .

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First thing i would suggest is fit a thermostat as its meant to be there for a reason, not sure why someone would have removed it in the past i'm sure they had a reason.

But whatever problem they were trying to cure should have been solved without removing it.

As for your question there isn't an exact answer to that as they all differ slightly.

Just over half way at motorway speeds sounds like its where it should sit on your car, but without the thermostat it will fluctuate up and down dependant on air flow through the rad.

The standard voltage regulator isn't that precise and can vary from one to another but also the gauges themselves are slightly different.

I changed a set of clocksin the past and had just below 1/4 on the original one at normal operating temp and the new one was just over 1/2 and that was with the same voltage reg swapped across so there is alot of variation.

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GET A THERMOSTAT IN STRAIGHT AWAY

3) I would make sure it is the right thermostat. GTE ones have a large flat washer on the other end to the mounting flange. As the stat opens in the mounting ring the washer closes off a passage way behind. Without this kind of stat they don't circulate properly

When swapping dashes people forget the 1.8 run hotter then GTE by design

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Well had a crap day with the Manta,Fitted a new stat,cleaned all the area but now the car just over heats into the red,tested the stat in a pot off water and it opened at 91 degres so thats okay and stayed open down to 82.

Flushed the system in both directions.

The top hose is hot to the touch so is the small hose from the stat chamber to the pump but the hose from the base of the rad on the left side to the stat housing is cold to the touch.

Any help with this would be great as next on my list is the pump.

Cheers

Raymond.

Ps

The temp gauge is reading pretty good as it said the car was hot and it was bloody hot alright.

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I cant do pictures but i found one the same on ebay.

This is the sale number 310391104895

It is a QH part number QTH313K bought from Halfords today.Its posibly the wrong part but they said it would fit as it is the same part.

Cheers

Raymond.

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It could be a faulty pump but I'd check the voltage regulator next.

If that failed and was giving high readings it would explain why someone removed the thermostat, thinking it was the problem.

From cold it should take a long time, well over 15mins at tickover for the engine to get warm enough for the thermostat to open, and until it opens the bottom hose won't have any heat in it.

If the pump had failed it should have overheated when driving even without the thermostat fitted.

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Did more tests on the car tonight with a temp sensor in the water pipes, 2 different places and both times i could not get the car to go over 85 degrees at varied revs for more than 30 mins, temp gauge was off the scale.

Am i corrrect in thinking that is fine as the water gets pumped around the engine and it stays under 87 degrees there isnt a problem so the stat should only open if the temp goes over 87.

The heater is fed with hot water before the stat so the heater in the car works as osoon as posible.

This concludes with the temp gauge being goosed so next i need a voltage regulator. As i was told at the start.

Does this make sense or am i just desperate now.

Cheers

Raymond.

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as far as i can remember removing the wire from the sensor on the side of the thermostat housing & replacing with a 40 ohm resistor to earth should test the guage by making it go about half way. this would prove the voltage reg faulty.a very common fault.if you can get a known good one & swap it then youde be sure(a bugger of a job thou !)

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ive had problems using QH stats before ,they often got stuck closed .to fix it i ended up with an audi 80 one (first line) that opens at 82 ... solved my overheating and is still good years later .

when you fill it up , take off the top heater hose to help let the air out .

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Yeah sounds like its a dodgy voltage regulator, which someone didn't know about so took the thermostat out to fix the issue :wacko:

It can be a pain to change but if you remove the heater ducting from the airbox to the dash vent on the drivers side it opens up the access a lot easier.

But you do need to be lying upside down with your head by the pedals to see what your doing.

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I used to mount a set of 52 mm external aftermarket gauges in the two vent holes in the mid of the dashboard (they fit straight in) one for water temp, and one for oil pressure as none of the instruments in the Manta´s are worth counting 100% on. Nothing on the original dashboard shows the exact and correct figures.

The way you have done it is the only way. By the way if the engine really overheats you will never be in doubt. The first thing you will notice is a knocking and you will also most certainly see white whater steam coming from the bonnet (the original lid for the radiator has a pressure valve that opens if the pressure gets to high, and this will in the case of over heating literally let out the steam :)

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Thanks for all the help guys, I decided to fit an aftermarket gauge in one of the heater vents like monzta did with his car. This works great and is a fully reversable mod so no harm done and it sits at 87 degrees all the time so very reasuring. Dont know how long the stat had been removed but i hope running cold all the time hasnt done any damage. I did a full fluid change,oil flush,plugs etc and it runs so smooth now and sounds so much better.

Thanks again guys.

Cheers

Raymond.

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