Coolant is still running too cold?

[UncleFrosty]

Thanks for your masterclass Dom (elaborate metaphors n all)!
Wish I'd had such practical explanations a coupla decades ago. Might've saved me failing Thermo a few times...
Eastop and McConkey is still on my shelf somewhere... stopping the dust from resting on that bit of shelf.
Cheers

[dom14]

Just out of curiosity, your viscous hub isn't locked on or anything like that is it?

Also, does your thermostat have a little bypass nipple on it? I know this is a weird question, and my rb30 has the nipple on it and runs 78-82. But when chasing an issue with my xr6turbo where it simply wouldn't heat up quickly, and would cool down on long freeway stretches (to the point the heater was cold). Turned out to that it had one of those nipple holes in it for some reason. Put one without the nipple thing and it's been perfect since.

Yeah, all the thermostats come with that little nipple thing or similar device afaik. It's basically a bypass valve to allow any expanding steam, water, ice etc to escape from the engine block into the low pressure side of the coolant system.

The ones that doesn't come with the nipple thing on the thermostat comes with a different setup that works with the engine block thermostat hole cavity, I think.
I'm guessing in your xr6turbo, the problem would've caused by the "nipple" valve being stuck open or something, which would constantly leak the water into the low pressure side of the coolant system(coolant entry hose from the radiator to thermostat/engine block). That would mess with engine temperature control and constantly remove the engine heat from the engine and prevent the engine from reaching the operating temperature. As far as installing a thermostat without the bypass valve? I'm not if that's a good idea though. Freezing of coolant is not likely to happen in Melbourne, but I reckon it's still handy with letting any steam bubbles to get out of the engine block, in case they develop by overheating(thermostat stuck closed) or bit too "feisty" water pump action, etc. I reckon the bypass nipple valve is a good "fail safe" redundancy device. If the engine block coolant system is designed to have a thermostat with a bypass "nipple" valve. then it's a good idea to replace with a one just like the factory one.

Make sure the thermostat you replaced on your RB30 has that bypass nipple on it. It can save the engine in a not so common situation(like a situation where a faulty thermostat stays stuck closed).

[dom14]

Just updating guys,
I put the temperature sensor in the rear coolant port on the engine block.(as in the diagram below).
Temperature goes upto 73 degrees celcius of so(the highest so far).
And this was from driving on the highway, freeway and uphill for few hours.
So, the thermostat is definitely not upto scratch(which I already know from all the "fiddling" so far).
Obviously I haven't replaced the thermostat yet. I wanted to finish all the temperature "sensor spot testing",before I replace it
with a brand new.
Next job is to replace the thermostat and also install the the second aftermarket temperature gauge/sensor.
I haven't figured out where to install it yet. I'm thinking cylinder head or engine block(not in the coolant system).

[dom14]

Thanks for your masterclass Dom (elaborate metaphors n all)!
Wish I'd had such practical explanations a coupla decades ago. Might've saved me failing Thermo a few times...
Eastop and McConkey is still on my shelf somewhere... stopping the dust from resting on that bit of shelf.
Cheers

Hey RossKal,
I just found out what you meant by "Eastop and McConkey".
If you've been through Engineering Thermodynamics books like that, then you understand the cooling system quirks far far better
than I would ever do.
I've never got into Engineering Thermo, but if you wanna debate, Quantum mechanics and relativity, I'm your man.

BTW, here is a link to download the "Eastop and McConkey", in case you've already stepped into the 'space age' & read books as ebooks on tablets, as I do these days.
I won't get into Engineering thermo like you did though. The subject gives me headaches and constipation, as you've seen from my long posts in this thread.

https://onedrive.live.com/?cid=4816E...%21111&o=OneUp

or here

http://www.mediafire.com/download/tp....+McConkey.pdf

[dom14]

Just out of curiosity, your viscous hub isn't locked on or anything like that is it?

Nah. I checked it while ago. Viscous fan moves freely, though I can't say for sure whether the viscosity/resistance of the silicon liquid inside it is in the same condition as it was years ago or not.

I've been thinking...it would've been great if the viscous fan has as some kinda better thermo liquid & switch that prevents it from spinning the fan until the thermostat opens up?!!
I guess there's no such thing. Even if there IS, it's lot simpler to use electric thermo fan system.
Without a fully contained fan shroud, it would've been not too safe to have a fan that comes on like that anyway, even if the fan starts turning gradually.

I'm thinking, down the track some day, to come up with an electric fan cooling system, including an electric water pump, just like Davies Craig system, except I will be building it myself from scratch, except the electric water pump, which I would have to buy. The rest of the electronics and fan system is not to hard to build from scratch.

http://daviescraig.com.au/electric-water-pumps

I like to think these efficient coolant systems can add quite a few years of good life to the engine's lifespan.

https://www.youtube.com/watch?v=ew9Dn9NnwSo

[UncleFrosty]

Hi Dom
Thx for the link. I'm still old school paper version, though interestingly it's still 5th Ed 20yrs later! I pretty much hated Thermo at the time, but it was one of the units required to pass... P's make degrees (in my case anyway...)
No fear of QM debate bud - my scant knowledge only covers what the LHC is an acronym for! As far as quarks/neutrinos etc - no idea at all, but it is interesting stuff.
Now onto the really interesting stuff...
A simple paddle-type flow switch on top side of thermostat, with a relay to an air-con type clutch attached to fan (somehow replacing viscous coupling) or relay to elec fan, should cover your needs?
More stuff to go wrong IMO, but could delay fan enough to stop things cooling down too quickly?

[GeeYou8]

I was thinking of running a PWM controller for radiator fans on speedway car, a bit more elegant than the bang on bang off of a relay.
Would need a bit of tuning to get gain, derivative & integral mixing right.
Graham

[dom14]

Hi Dom
Thx for the link. I'm still old school paper version, though interestingly it's still 5th Ed 20yrs later! I pretty much hated Thermo at the time, but it was one of the units required to pass... P's make degrees (in my case anyway...)
No fear of QM debate bud - my scant knowledge only covers what the LHC is an acronym for! As far as quarks/neutrinos etc - no idea at all, but it is interesting stuff.
Now onto the really interesting stuff...
A simple paddle-type flow switch on top side of thermostat, with a relay to an air-con type clutch attached to fan (somehow replacing viscous coupling) or relay to elec fan, should cover your needs?
More stuff to go wrong IMO, but could delay fan enough to stop things cooling down too quickly?

Yeah, that's true. But, that's nature of the animal, isn't it? More electrics/electronics, more things can go wrong.
Efficiency comes at a price, always. I like the idea of a system like Davies Craig with all electric/electronic cooling system, but as you pointed out, the control unit, electric thermo fans and electric water pump add more failure points.
Which, obviously means I can't go cheap on those parts, which is the way i usually prefer to do it with new ideas for budget related issues.
I think, decoding what you're saying above, I leave the things alone as it is for the time being.

[dom14]

I was thinking of running a PWM controller for radiator fans on speedway car, a bit more elegant than the bang on bang off of a relay.
Would need a bit of tuning to get gain, derivative & integral mixing right.
Graham

I can only pretend to understand what you were saying above, mate.

[Robo]

The viscus fan.
How far does it spin when you give it a good spin by hand 1/4 1/2 3/4 full turn.
Remember a viscus hub thread or read on forum somewhere.
(only spin about 1/3 to 1/2 if I remember correctly! )