thermostat

[TheyDontWantMusic]

so, the VL was taking a while to get up to temp, and wasn't keeping the temperature as steady as I would have liked.

so, I replace the thermostat, new coolant, and new hose clamps (about $80 worth total)

and now it gets upto temp quicker, but it doesn't maintain the temp properly, and gets hotter (too hot)

as you may know, the VL has 6 bars on the temperature scale, where should it be sitting?

after about 5 minutes of driving, its upto 2.5 bars... after another 15 minutes, its slowly climbed upto just over 3 bars... put it under slight load (Adelaide freeway) and it makes it way upto 4.5bars, and this is at night, with the ambient temp below 15 degrees.

the old thermostat, it never got this high, but would also sit lower with city driving.

[VL Berlina 5speed]

genrally a good cooling system sits around 1/4 to half on the guage

did you bleed the cooling system properly??? when you did this

[TheyDontWantMusic]

genrally a good cooling system sits around 1/4 to half on the guage

did you bleed the cooling system properly??? when you did this

yup.

hose in the top of the radiator, air bleed valves removed from the intake manifold, and wherever the other one is.

filled it up till it was bubbling out of the lower bleed valve, put the bolt back in there, kept filling till it was bubbling out of the top bleed valve, put the bolt back in there, and then I removed the hose from the radiator filler neck/cap thingo.

with the old thermostat, it would take 20 minutes to get upto operating temperature, and generally wouldn't get above 2/3 on the temp gauge, driving faster made it run cooler due to the increased air flow through the radiator.

perhaps the fan isn't working properly, but it used to run cooler!

[Panama]

you need to have the engine running when you bleed it so the waterpump pushes water into the air pockets better.

[jatsvl]

you also need to have the heater on when bleeding to get the air pockets out of the heater core.
i seem to recall someone posting that aftermarket thermostats run alot hotter than genuine.

[leslloyd]

I just got back from a trip up to longreach,3500km and the temp never went above 1st bar.
So i just changed everything (oils,pads,uni's)these last few days as well as the thermostat(triden from supercheap$40)and it now runs on the 3rd bar.Not to worried and hopefully will improve consumption(best 9.42,worst 11.76,av 10/100 km).But i'd be worried if it went over the 4th.
I'd take it back and say you're not happy with it and get a replacement.
colin.

[etch289]

compare and read both old & new thermo stamped temp values watever 82" cel etc
maybe new is higher than old one

[TheyDontWantMusic]

compare and read both old & new thermo stamped temp values watever 82" cel etc
maybe new is higher than old one

thats kinda difficult when its in the car.

the old one was the standard, 76.5degrees, genuine Nissan part.

I believe my radiator may be half blocked.

so with the old thermostat, it opened too early, never allowing the engine to get to proper operating temperature, till I got to the freeway, and gave the engine a work out, but seeing as the engine was colder to begin with, it never got as hot.

now, with the new thermostat, it gets up to correct operating temperature, but because the radiator is half blocked, when you give the engine ****, it overheats because it was hotter to begin with.

make sense?

[leslloyd]

Na,doesn't make sense to me.The blockage would cause a backup still the same in real life.Easiest to try another make thermo.
Sounds more like a sticky thermo to me,by the way my new one seems to move around a little temp wise,as though it's dumping then closing,in cycles and i'm going to see supercheap today and see whether they'l replace it.I just don't want it to be the cause of head problems later,better to feel comfortable than have a nagging suspicion.
cheers
colin.

[maxpower QLD]

I panic when mine reaches the 3rd bar mainly becouse it rarely goes to the 3rd bar unles i have the air con on which isn't to often , very soon i'd like to replace all this stuff seeing as summer is coming and i don't wanna be stuck on the side of the road with a cracked head .

[etch289]

best thing is when u take it for a good run,
pull over now again etc and if u got thermomoter put it overflow bottle opening and take some readings
2 or 3 bar is alright imo

[TheyDontWantMusic]

Na,doesn't make sense to me.The blockage would cause a backup still the same in real life.

it actually makes perfect sense, unlike your reply

[Chirpstr]

I'm due to replace mine. Takes about 3/4 hr to warm up to just about a quarter lol.

[etch289]

its bad to have an overheating or under heating thermostat ( chew ur bores out ,uses extra fule )
motor should always be approx 180"

[TheyDontWantMusic]

its bad to have an overheating or under heating thermostat ( chew ur bores out ,uses extra fule )
motor should always be approx 180"

you mean 80 degrees, right?

[etch289]

180 farenhiet or 80 celcius thereabouts

[jatsvl]

a radiator blockage would cause the engine to heat up quicker by not allowing the coolant to flow through it to cool, pressure would build up and your coolant will run out your over flow lower the level then overheat then..........

the thermostat is suppose to open dump then close in cycles to maintain a constant temp in the engine and allow the coolant to cool in the radiator, if it remains open constantly eventually the entire system will overheat, when stationary and under load.

[leslloyd]

**the thermostat is suppose to open dump then close in cycles to maintain a constant temp in the engine and allow the coolant to cool in the radiator, if it remains open constantly eventually the entire system will overheat, when stationary and under load.
__________________
Interesting!As i noticed the temp gauge moving back and forth slightly,never seen this before tho.
I've just compared the original,76.5C with 2 Tridon moTrad's,they don't have any temp marking's but being TT268-170 on package I'll asume 170F.In the saucepan the original opens early and eventually opens roughly 3/4"when boiling.The motrad's take longer to start to open (good???)however both only open 1/4" at boiling.Seems like too little flow going on with these.3 bars with these fitted is a little warm for my liking and may not open enough for coming summer methinks
Now i'll try a dayco or new Nissian part no.
cheers
colin

[leslloyd]

Success,for me at least.My problem was basically the same as the original poster.
Took the motrad thermo's back to Supercheap and got a Dayco from Repco,another suprise,$10 cheaper at $30.
And fitted i'm getting midway between 2nd and 3rd bar so i'm happy.
Next project,ECU and it's little flickering lites.

colin

[TheyDontWantMusic]

the thermostat is suppose to open dump then close in cycles to maintain a constant temp in the engine and allow the coolant to cool in the radiator, if it remains open constantly eventually the entire system will overheat, when stationary and under load.

no it doesn't.

the higher the temperature, the more the thermostat opens to allow more coolant flow through the radiator.

once the temp gets to 90degrees, the thermostat it meant to be open fully, to allow the entire flow through the radiator.

how would the engine overheat if the thermostat is constantly, and fully open? when its fully open, its getting cooled as much as possible by the radiator.

[TheyDontWantMusic]

The motrad's take longer to start to open (good???)however both only open 1/4" at boiling.Seems like too little flow going on with these.

it should be open over 10mm at 90degrees I believe is what the manual says.

if its not doing that, then its not even suitable for the engine, and I have a feeling thats whats happening with mine.

[leslloyd]

Hi there
I doubt if motrad opened anywhere near 10mm,even when boiling.And both makes have a reduced dia for the water to flow thru,pity they didn't just copy the originalChecked GM and they discontinued selling them 2005.
Looks like you'll have to check it out to be sure ,the saucepan method with the old and new gives a good idea what to expect that's for sure.
colin.

[TheyDontWantMusic]

[VL Berlina 5speed]

you would have a block somewhere along your pipes i assume, if the new thermostat is working fine in test then your water flow is getting stopped somewhere,
check all your pipes for a sign of being blocked. try squessing to feel a block

have you thought your coolant sensor might be faulty?? try swaping it with one from a wreakers and see if your guage acts diffrent, this will also improve on fuel ecconemy if it is too, so thats a bonus

[maxpower QLD]

Sh!t thats high ? yeah thats about where mine was running at when my head shat itself
(my white Vl) so your sender must be different to mine then ?