What's a good coolant temperature?

Toyotafanboi · 19-06-2015 12:53pm #1

I know, i know. me again, coolant again. at my wits end. let me be brief.

car: 02 celica vvtl-i UK model.

- temperature gauge never got to half way, ever.
- asked on a celica owners club, done a poll, every member voted that their gauge went to half way within 5-10 minutes of driving.
- long story very short, changed thermostat to see would that rectify things, soon after discovered head gasket failure.

- long story really short, fitted a new engine, same engine but from a 1999 japanese import celica.

- just picked it up, drives like a dream, sounds and drives a lot nicer than my old engine. temperature gauge doesn't go to half way!!!!

- checked with OBD scanner and the engine temp while driving is a steady 69-71 degrees celcius, creeping into the low 80's if stuck in traffic or parked. pretty much the same as the old car.

- if left idling it will get to 96 degrees, then the fans will come on, cool it down to 90-91 and switch back off.

- my gauge never goes past position two

anyone who has anything even remotely constructive, please help. is 69-71 degrees an ok operating temperature? i would be semi-ok with the gauge reading low if i knew the temperature was ok to work with.

jimgoose · 19-06-2015 1:24pm

71C sounds a tad cool to me for a modern-ish yoke, but not madly so. If it's happy and steady there, well...

Could that gauge be a bit tired at this stage?

ShaunieVW · 19-06-2015 1:29pm

did you reuse a temp sensor? Completely different car but my previous golf did that and it was the temp sensor, also caused it to run a bit rough on start up.

Toyotafanboi · 19-06-2015 1:33pm

yeah, i just worry that the cool running of the old engine is what caused the head gasket failure (just an uneducated theory) and really want to avoid this again. can't understand this.

the only thing in it's favour is that this new engine will idle up from a cold start to 95 degrees in 10 ish minutes. the old engine could be idling literally for over an hour and would struggle to make 80 degrees.

the gauge seems ok imo, once the car gets over 80 degrees it rises to the normal position. but once the car is in motion it cools right down and stays steady @ 69-71 degrees.

i didn't carry out the swap, but from talking to my mechanic he said that he he lifted the complete engine out of the old celica and placed it into mine and just plugged my loom etc in, there was no exchanging of parts between engines, so i assume (dangerous thing to do) that it's not the old temp sensor being reused.

pain in the ****ing arse.

jimgoose · 19-06-2015 1:34pm

Toyotafanboi wrote: »

...the gauge seems ok imo, once the car gets over 80 degrees it rises to the normal position. but once the car is in motion it cools right down and stays steady @ 69-71 degrees...

Have you made any modifications to the nose of the car? Spoilers, intake mesh, any of this kind of thing?

Toyotafanboi · 19-06-2015 1:45pm

jimgoose wrote: »

Have you made any modifications to the nose of the car? Spoilers, intake mesh, any of this kind of thing?

totally stock.

interestingly, the aircon rad is the front most rad in this car and shields around 75% of the coolant rad.

it's looking like donedeal or a bonfire for this celica. i literally don't ever remember feeling this frustrated over anything.

Atlantic Dawn · 19-06-2015 1:53pm

On the petrol Toyotas I have driven including one with vvtli engine the temperature gauge always went around the 50% mark after around 10 minutes or so. Around here...

jimgoose · 19-06-2015 1:55pm

Toyotafanboi wrote: »

totally stock.

interestingly, the aircon rad is the front most rad in this car and shields around 75% of the coolant rad.

it's looking like donedeal or a bonfire for this celica. i literally don't ever remember feeling this frustrated over anything.

There's the oil/water differential theory of head-gasket failure. What sort of oil exactly are you running in it?

Toyotafanboi · 19-06-2015 2:01pm

Atlantic Dawn wrote: »

On the petrol Toyotas I have driven including one with vvtli engine the temperature gauge always went around the 50% mark after around 10 minutes or so. Around here...

http://i.ytimg.com/vi/yfUwerMi2Uw/maxresdefault.jpg

that's where all my other 1.4 and 1.6 vvti's have always sat.

jimgoose wrote: »

There's the oil/water differential theory of head-gasket failure. What sort of oil exactly are you running in it?

i'm using 5w30 fully synt...

jimgoose · 19-06-2015 2:01pm

Toyotafanboi wrote: »

...i'm using 5w30 fully synt...

Mmm. Doesn't get much better.

Toyotafanboi · 19-06-2015 2:05pm

jimgoose wrote: »

Mmm. Doesn't get much better.

would a ****ter oil retain more heat, thus somehow keeping the engine warmer.

epically clutching at straws i know!

jimgoose · 19-06-2015 2:08pm

Toyotafanboi wrote: »

would a ****ter oil retain more heat, thus somehow keeping the engine warmer.

epically clutching at straws i know!

There is a theory knocking about that engine heads are cooled more by coolant, while the block tends to be cooled more by the oil. Therefore, there are times when there will be a difference in temperature between the two, and the greater the temperature difference the more "shear" on the HG due to expansion. Also largely theoretically, this could be at least partially counteracted by using a hideously expensive full-synth oil, even a grade lighter than recommended to improve flow.

Pov06 · 19-06-2015 2:09pm

My 1.0 Yaris goes up to 85 degrees Celsius in about 10 minutes and pretty much stays there.

nd · 19-06-2015 2:15pm

hmmm given that if idling it gets up to above half and enough for the fans to kick on, it seems like that when on the move the rad just does a very good job of cooling it down. But if other people's same version celica is going to half way, I can see how it'd be head wrecking.

Does the heater get hot fairly quickly and stay hot when on the move?

Interslice · 19-06-2015 2:27pm

The temp guage in the alfa like yours sits just above 70 and slowly goes to just below 90 if you stop. OBD follows suit. Apparently normal in these. most other cars just sit in the one position to stop panic and threads like this all over the internet

. Thought when I first got the car I had a thermostat stuck open. Was that poll on your exact model and engine?

Tea 1000 · 19-06-2015 2:30pm

You might have a problem with the heater system maybe?

Toyotafanboi · 19-06-2015 2:33pm

Interslice wrote: »

The temp guage in the alfa like yours sits just above 70 and slowly goes to just below 90 if you stop. OBD follows suit. Apparently normal in these. most other cars just sit in the one position to stop panic and threads like this all over the internet . Thought when I first got the car I had a thermostat stuck open. Was that poll on your exact model and engine?

yes, the poll was on my exact car and engine. i'm aware that in real life, the temperature is fluctuating and that most gauges rest at half way reading 90°C when really they could be +/- 15°C or whatever, i just thought that a constant 70 was particularly cool?

i had a punto before too where the gauge was pretty active too, would drop a little while driving and only be half way in traffic, it's just annoying me because all other celicas seem to make half way and stay there.

Interslice · 19-06-2015 2:37pm

Toyotafanboi wrote: »

yes, the poll was on my exact car and engine. i'm aware that in real life, the temperature is fluctuating and that most gauges rest at half way reading 90°C when really they could be +/- 15°C or whatever, i just thought that a constant 70 was particularly cool?

i had a punto before too where the gauge was pretty active too, would drop a little while driving and only be half way in traffic, it's just annoying me because all other celicas seem to make half way and stay there.

Could you ask someone to log their temps on the obd? I logged mine with torque and they do exactly as yours plus/minus a few degrees

Tea 1000 · 19-06-2015 4:36pm

Atlantic Dawn wrote: »

On the petrol Toyotas I have driven including one with vvtli engine the temperature gauge always went around the 50% mark after around 10 minutes or so. Around here...

7,000 rpm, eh?

That'll warm her up alright!

toastedpickles · 19-06-2015 5:16pm

Complete opposite end of things here, I had that problem with my 900, so i changed, the coolant temp sensor, and repositioned the thermostat as there was a little valve on it, which had to line up with a bleeder valve or something, done this and it works like a charm now, it's over in the build thread somewhere i think! Could actually be a faulty gauge?

Toyotafanboi · 19-06-2015 5:21pm

Thanks everyone. I'm inclined to think the gauge is ok as it has risen to around a quarter by the time it's around 70 degrees and it's perfectly in the half way position when the car does get to 80 degrees +.

Really really stumped.

I can't even bring myself to say it but does this sound like a faulty thermostat and should i change this one too :P

Atlantic Dawn · 19-06-2015 5:23pm

Tea 1000 wrote: »

7,000 rpm, eh? That'll warm her up alright!

That's where the vvtli magic happens

nd · 19-06-2015 5:41pm

might it be that there is a circuit or w/e that normally stabilizes the needle in the middle like interslice was saying. If it is within a specific temp range. And that that part of your gauge is not working.

Teddington Cuddlesworth · 19-06-2015 6:05pm

Sounds like the thermostat isn't closing to me.

For the cost of a new thermostat its worth trying. Ensure the cooling system is properly bled after replacing it.

Special Circumstances · 19-06-2015 7:21pm

Teddington Cuddlesworth wrote: »

Sounds like the thermostat isn't closing to me.

For the cost of a new thermostat its worth trying. Ensure the cooling system is properly bled after replacing it.

It does sound low (to me, caution not a mechanic) during driving, and it also seems to me as if the thermostat is open for longer than it should be.... But iirc the stat was done recently.

19-06-2015 7:34pm

Toyotafanboi wrote: »

.....

the only thing in it's favour is that this new engine will idle up from a cold start to 95 degrees in 10 ish minutes. the old engine could be idling literally for over an hour and would struggle to make 80 degrees.

the gauge seems ok imo, once the car gets over 80 degrees it rises to the normal position. but once the car is in motion it cools right down and stays steady @ 69-71 degrees.

....

pain in the ****ing arse.

Classics stat symptoms

nd · 19-06-2015 7:50pm

In the morning when the engine is cold, how long approx after it's running does it take for the internal car heating to get warm? If a long time imo the thermostat is probably stuck open/not closing properly. If it gets warm after 5 mins imo it not stuck open.

Toyotafanboi · 19-06-2015 7:53pm

Special Circumstances wrote: »

It does sound low (to me, caution not a mechanic) during driving, and it also seems to me as if the thermostat is open for longer than it should be.... But iirc the stat was done recently.

Yeah you see, with my original engine that was problem i had. But i drove it on like that for like 6k miles or more like a jackass and pretty soon after i fitted a new thermostat the head gasket gave in.

Now i've had a replacement engine fitted, just picked the car up today and same story. Runs great and i assume if the mechanic only ran it at idle it would have went to half way on the gauge and looked fine but on a run it sits at a quarter.

I'd hardly be so unlucky as for the thermostat to be goosed in the new engine too :pac: but it does seem that way.

Augeo wrote: »

Classics stat symptoms

See above,but yeah, i'm coming around to that way of thinking. Luckily i have an array of thermostats here to suit the car. Next time i have 4 hours free i'l pop one in :P

Be ok to drive it a few miles to work over the weekend before i change it?

I get heat a minute or two after cold start, and it stays good and hot.

nd · 19-06-2015 8:23pm

You'd be grand to drive it even with no thermostat. It'd just mean heating would be slow to warm up. It's if it's stuck closed that'll cause it to overheat.

dieselbug · 19-06-2015 8:30pm

"See above,but yeah, i'm coming around to that way of thinking. Luckily i have an array of thermostats here to suit the car. Next time i have 4 hours free i'l pop one in :P

Be ok to drive it a few miles to work over the weekend before i change it?

I get heat a minute or two after cold start, and it stays good and hot."[/QUOTE]

Surely you dont intend fitting a used thermostat.

It would be good practice, standard practice really to fit a new stat when changeing the engine, just like you would fit a new timing belt or new filters etc.

Fit a new genuine one from Toyota and flush the system first if it's dirty.

Toyotafanboi · 19-06-2015 8:38pm

No, i have 3 new thermostats here for that engine, 2 gates and one Mr.T used for around 150 miles. Long story :pac:

A lot of new parts were fitted during the engine swap, clutch kit, water pump, lot of new seals etc, it's a chain driven engine. The thermostat was overlooked, but not to worry.

Special Circumstances · 19-06-2015 9:20pm

Ah I thought the stat was on your list. Tbh I've never had an engine swap so I wasn't sure what you'd keep from the old.

Noccy_Mondy · 20-06-2015 11:22pm

Any of the cars I do drive go to just very slightly under the half way mark, so about 87/88 degrees. Takes about 10 mins to get to it.

CJhaughey · 21-06-2015 6:33am

I know that some Toyota's have a stabilised temperature gauge, they fit some resistors to stop movement of the coolant needle during normal use. There is a couple of big resistors in the clocks to make them read around the 50% level all the time in normal use, they will show high readings but by the time they do it will be very hot.
http://forum.ih8mud.com/threads/93-97-coolant-temperature-gauge-modification.64252/

Toyotafanboi · 24-06-2015 12:33pm

OK, posting what i hope is a the final installment to this mess, 2 engines, 2 months, 2 thermostats and the guts of €2000 later.

fitted a new thermostat to the new engine this morning.

took the car out on the road, temp got to half way nice and fast but instantly shot to the red zone, overheating

pulled in as quickly as i could, probably around 60 seconds after noticing the overheating.

following the instructions of so many members on so many celica owners clubs i carefully opened the expansion cap as soon as i pulled over (did i say carefully) and the car took a massive gulp of coolant and instantly emptied the reservoir. sat straight back into the car, turned the key to "on" and the coolant gauge was straight back at the halfway point

massive airlock.

drove home (around half a mile) and the gauge stayed at half way with the rad fans coming on and off intermittently.

bled the coolant again (:rolleyes:) and topped it up again, rinse, repeat, several times. hooked up my obd scanner, drove the car for miles and miles and miles and miles.

the car is now a very stable 85°C while on the move and at worst i seen it at 91°C in traffic.

if my brief airlock/ overheat incident didn't goose the head gasket in the new engine i am in the clear i think.

if it has goosed the new engines head gasket i will be, lets just say, less than happy. but the odds of that are low enough?

renofan · 24-06-2015 1:12pm

Seriously doubt you'll have done any damage. Good to hear it's finally sorted! Great car, my sister had one.

Teddington Cuddlesworth · 26-06-2015 5:34pm

Glad to hear it's all sorted.

Toyotafanboi · 09-07-2015 8:58pm

3 weeks in, all is well bar one tiny thing.

Every time i start the car from cold, for one brief split second i hear a gurgle behind the dash, which i'm assuming means there is still air in the system?

The coolant level and temperature have have been perfect since the new thermostat went in. Would it be ok to leave that tiny air pocket in?

The reason i ask is that i can't get it out. I made double sure that the thermostat jiggle valve was at 12 o clock and I've tried everything and it just wont **** off. The correct bleeding procedure for this car takes 45 mins to an hour to complete and i've done it 5-6 times now to no avail. I've even improvised by jacking up the front of the car and hanging the resevoir from the open bonnet to ensure it's the highest point as where it usually sits is at least 150mm lower than the highest point of the system.

Every time i carry out the bleed process i get sporadic bubbles like this, rarely any bigger or greater in quantity. is this ordinary looking? You might get 15-20 seconds of those then 15-20 seconds of clear coolant on and off. It seems like they are never ending, the reason i usually stop bleeding is because i'l have had the car ticking over for up to an hour stationary which cant be good for it?

edit: linking youtube is not my strong point, it's here https://youtu.be/EkWOHXHTXDs

https://www.youtube.com/watch?v=EkWOHXHTXDs

Interslice · 10-07-2015 12:46am

Would that be the coolant boiling because it's not under pressure or is it cold?

Interslice wrote: »

The temp guage in the alfa like yours sits just above 70 and slowly goes to just below 90 if you stop. OBD follows suit. Apparently normal in these. most other cars just sit in the one position to stop panic and threads like this all over the internet . Thought when I first got the car I had a thermostat stuck open. Was that poll on your exact model and engine?

In other news apparently not, just someone posting ****e on the internet. Need a new thermostat

Toyotafanboi · 10-07-2015 5:34pm

Interslice wrote: »

Would that be the coolant boiling because it's not under pressure or is it cold?

good theory, could well be. fairly pissed off with it at this stage. think i'm just going to drive it on.

Toyotafanboi · 30-07-2015 5:34pm

So, in this never ending saga, i've still been getting a very very quick gurgle behind the dash, just for a split second on cold starts... the coolant level has been steady so tbh i have been so ****ed off with it that i just left it so. today, i crumbled. i got into the car to head into town, heard the gurgle and just lost my mind, threw caution to anything i ever knew about mechanical sympathy, combined every tip i ever found on every forum about bleeding these cars.

- i unbolted the airbox
- i unbolted the coolant reservoir and suspended it from the bonnet catch
- i put a trolley jack under the front jacking point and jacked the front end as high as i could
- i connected a hose to the bleeding hole on reservoir
- i connected a small reservoir to that tube that i also hung from the bonnet catch
- i filled it with a coolant mix
- i ran the engine until the coolant fan kicked in
- i then cycled the engine from idle - 2500rpm - idle repeatedly until the cooling fan kicked in 3 more times
- i nearly scalded the hands off myself removing my makeshift reservoir
- i drove the car
- i topped up the coolant
- i anxiously await the next cold start

the first time the rad fan kicked in, i nearly immediately got 2 or 3 big bubbles out of the reservoir but other than that there wasn't really any at all, so this too may not have worked.

it's an ill wind that blows no good, as i tied the reservoir onto the bonnet catch so tight, i straightened back out that disgusting panel gap that it used to have

all nice and straight now!

cnoc · 30-07-2015 5:46pm

Best of luck. Keep us posted.

Hachiko · 30-07-2015 6:36pm

looks like its on a IV drip

good job that tfb. have you done a thermostat replacement on this or water pump? forgive my ignorance if you have or if not related.

Toyotafanboi · 30-07-2015 11:03pm

I did think that about the drip :P

This engine has a new water pump, coolant and thermostat amongst other things.

Cold started it... gurgling! Why thr **** is this happening? Seriously? Anyone?

What's a good coolant temperature?

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