Celica Gt '96 Gen 6

[GT Driver]

Guys,

It takes my Celica (see above for model) around 15 minutes to get warm from cold. Is this normal?

I also noticed that when warm (temperature gauge pointer half way mark) and drive on the motor way (normal sorta speed) the temperature needle dips noticably below the half way point on the temperature gauge. Is this normal, if not should i be worried? Any ideas for the cause?

Cheers

[T600]

Both normal. Well, I'd probably expect it to warm up a bit quicker than that, especially now the weather's getting warmer, but it's healthy I'd say.

The dip in temp shows your thermostat is working - when you first start it's closed, stopping the water going through the rad. The water in the block warms up quickly and that opens the thermostat, at which point a radiator and various pipes worth of water come flooding into the block causing the meter to see a sudden fall in temp. How many minutes is it usually before that happens?

You could check the operation of your fan; if that's stuck permanently on then that might cause it to take a bit longer to warm up perhaps. But as long as once the stat has opened the temp gets back up towards half way fairly quickly then it's fine.

[GT Driver]

Both normal. Well, I'd probably expect it to warm up a bit quicker than that, especially now the weather's getting warmer, but it's healthy I'd say.

The dip in temp shows your thermostat is working - when you first start it's closed, stopping the water going through the rad. The water in the block warms up quickly and that opens the thermostat, at which point a radiator and various pipes worth of water come flooding into the block causing the meter to see a sudden fall in temp. How many minutes is it usually before that happens?

You could check the operation of your fan; if that's stuck permanently on then that might cause it to take a bit longer to warm up perhaps. But as long as once the stat has opened the temp gets back up towards half way fairly quickly then it's fine.

I think the fan is operating as normal. It does come on but doesn't stay on. As for the temperature dip; it usually takes 5-10 minutes of motorway driving (note that this is the only time i notice a dip. All other driving is fine) before i notice a dip in temperature. The dip in temperature is sustained for as long as i maintain motorway speeds and returns to normal when driving at urban speeds.

I didn't think this is normal. Surley the thermostate should keep the engine at optimum temperature...?

Is there any chance the guy who had my car before removed the thermostate for some reason. This would allow water to continually flow round the block regardless AND prevent the engine from maintaining optimum temp when driving at sustained speeds. Just a thought though...

[T600]

I think the fan is operating as normal. It does come on but doesn't stay on. As for the temperature dip; it usually takes 5-10 minutes of motorway driving (note that this is the only time i notice a dip. All other driving is fine) before i notice a dip in temperature. The dip in temperature is sustained for as long as i maintain motorway speeds and returns to normal when driving at urban speeds.

I didn't think this is normal. Surley the thermostate should keep the engine at optimum temperature...?

Is there any chance the guy who had my car before removed the thermostate for some reason. This would allow water to continually flow round the block regardless AND prevent the engine from maintaining optimum temp when driving at sustained speeds. Just a thought though...

Oh, I thought you meant a brief dip after a few minutes. On most cars I've had, the temp would then warm up again fairly quickly.

Maybe the stat's missing - or perhaps it's sticking, or opening at the wrong temperature. It's dead easy to test it with a pan of water and a thermometer if you're in doubt. Sounds like a stat problem is a possibility, but I'd put it no more strongly than that.

I don't suppose it being a bit cold is a huge problem - certainly better than over-heating, but sounds like further investigation is worthwhile.

Has the car been modified to allow more air to pass the radiator than standard? GT4 bumper perhaps?

[GT Driver]

I think the fan is operating as normal. It does come on but doesn't stay on. As for the temperature dip; it usually takes 5-10 minutes of motorway driving (note that this is the only time i notice a dip. All other driving is fine) before i notice a dip in temperature. The dip in temperature is sustained for as long as i maintain motorway speeds and returns to normal when driving at urban speeds.

I didn't think this is normal. Surley the thermostate should keep the engine at optimum temperature...?

Is there any chance the guy who had my car before removed the thermostate for some reason. This would allow water to continually flow round the block regardless AND prevent the engine from maintaining optimum temp when driving at sustained speeds. Just a thought though...

Oh, I thought you meant a brief dip after a few minutes. On most cars I've had, the temp would then warm up again fairly quickly.

Maybe the stat's missing - or perhaps it's sticking, or opening at the wrong temperature. It's dead easy to test it with a pan of water and a thermometer if you're in doubt. Sounds like a stat problem is a possibility, but I'd put it no more strongly than that.

I don't suppose it being a bit cold is a huge problem - certainly better than over-heating, but sounds like further investigation is worthwhile.

Has the car been modified to allow more air to pass the radiator than standard? GT4 bumper perhaps?

Car hasn't had any mods (as far as i can tell, quite confident though). Ok, here's the scoop:

I purchased my motor of some fella and not long after having it i had the coolant bled. Cam out a funny kinda light brown. Thought nothing of it and put new coolant in. A couple months after the heater matrix starts to go. The car is still drivable (with the heating off) but i now twig the potential problem with the temperature reading as i'm starting to think these are contected.

Here is my theory:

Thermostate malfunctions.

Engine boils over. Fries the heater matrix (and/or connecting hoses) in the process.

Owner removes the thermostate rather than replacing it AND poors some kind of sealant (brown stuff i was talking bout earlier) into the cooling system rather than fork out for new matrix + fitting.

Mornone (me) sees a Celica GT for sale and buys it.

Mornone tries to find out exactly what is potentially wrong with car on a Celica forum so he can fix it... lol

There are no Gasket issues as i had that all checked out at my local garage, so i'm pretty happy bout that.

Any ideas? Could you give me more details on testing the thermostat? I'm ok with cars but not amazing

[Sump]

I think the fan is operating as normal. It does come on but doesn't stay on. As for the temperature dip; it usually takes 5-10 minutes of motorway driving (note that this is the only time i notice a dip. All other driving is fine) before i notice a dip in temperature. The dip in temperature is sustained for as long as i maintain motorway speeds and returns to normal when driving at urban speeds.

I didn't think this is normal. Surley the thermostate should keep the engine at optimum temperature...?

Is there any chance the guy who had my car before removed the thermostate for some reason. This would allow water to continually flow round the block regardless AND prevent the engine from maintaining optimum temp when driving at sustained speeds. Just a thought though...

Oh, I thought you meant a brief dip after a few minutes. On most cars I've had, the temp would then warm up again fairly quickly.

Maybe the stat's missing - or perhaps it's sticking, or opening at the wrong temperature. It's dead easy to test it with a pan of water and a thermometer if you're in doubt. Sounds like a stat problem is a possibility, but I'd put it no more strongly than that.

I don't suppose it being a bit cold is a huge problem - certainly better than over-heating, but sounds like further investigation is worthwhile.

Has the car been modified to allow more air to pass the radiator than standard? GT4 bumper perhaps?

Car hasn't had any mods (as far as i can tell, quite confident though). Ok, here's the scoop:

I purchased my motor of some fella and not long after having it i had the coolant bled. Cam out a funny kinda light brown. Thought nothing of it and put new coolant in. A couple months after the heater matrix starts to go. The car is still drivable (with the heating off) but i now twig the potential problem with the temperature reading as i'm starting to think these are contected.

Here is my theory:

Thermostate malfunctions.

Engine boils over. Fries the heater matrix (and/or connecting hoses) in the process.

Owner removes the thermostate rather than replacing it AND poors some kind of sealant (brown stuff i was talking bout earlier) into the cooling system rather than fork out for new matrix + fitting.

Mornone (me) sees a Celica GT for sale and buys it.

Mornone tries to find out exactly what is potentially wrong with car on a Celica forum so he can fix it... lol

There are no Gasket issues as i had that all checked out at my local garage, so i'm pretty happy bout that.

Any ideas? Could you give me more details on testing the thermostat? I'm ok with cars but not amazing

It's likely your Thermostat isn't functioning correctly - roughly speaking, I had exactly the same symptoms on my UK 6th Gen GT, and its often mentioned re. 6th gens on this forum - you can get the Thermostat for about £10 if you look around, and its a straightforward-ish job to replace - just a bit awkward to get to one of the bolts.

Have a quick read through these 2 threads in this Celica section - you'll recognise very similar symptoms:

http://toyotaownersclub.com/forums/index.p...p;hl=thermostat

http://toyotaownersclub.com/forums/index.p...p;hl=thermostat

As said, Head Gaskets are fine on these 6th gen GT's - they can rev all day quite happily, even with 90,000 miles on the clock - besides the Thermostat, another common issue with the 6th gen's is the rear suspension bushes - you'll hear a slight clatter under gentle breaking - these can also be replaced cheaply.

[GT Driver]

Guys,

It takes my Celica (see above for model) around 15 minutes to get warm from cold. Is this normal?

I also noticed that when warm (temperature gauge pointer half way mark) and drive on the motor way (normal sorta speed) the temperature needle dips noticably below the half way point on the temperature gauge. Is this normal, if not should i be worried? Any ideas for the cause?

Cheers

Hey guys,

Thermo' was absolutely fried! Have put a new one in and will let you know how i get on. In the process of changing the Heater Core/Matrix as well... that was fcuked too. Took me around nine hours labour to get at the thing and a minute to swap it over. Now putting things back together.

I have taken a fair bit of video so will try and put a walkthrough together as it may be helpful to someone someday.