Acceptable Coolant Temperatures - help required

Hey,
The redline water wetta has got mixed reviews. Its often used in racing. It is not glycol based. It has some anti corrosive properties. It doesn't really have enough anti corrosive properties for a daily driver car. I am running a pretty strong coolant mix with 1 bottle of water wetta added to the 9L tank.

If your coolant mix is too strong it may cause it to run a little hotter.
Plain water cools better than when mixed with coolant, but obviously that is impractical.

87 deg was towing our c/t with all the gear loaded up :-)

Hi Scooby.

Thanks for the response. Your post is actually the most relevant to my car. I am very very interested in the temperature of other 5L non turbo hilux's. It gives me a guage to go by

I follow my temperatures closely - on a 30 - 40 degree day i get the following

90 km/h without ac = 91
100 km/h without ac = 94
110 km/h without ac = 97

90 km/h with ac = 93.5
100 km/h with ac = 97
110 km/h with ac = 99+ (never really gone there)

How do you measure your temperatures? The standard toyota guage or something else?

Are you getting similar results?

Cheers

Dan

Hi Dan,
I am getting similar results to you, 84 to 87 at 60km/h, on the free way tonight, 41degrees outside temp and 92 engine temp at 90 km/h. The highest temp I got was 104 degrees climbing the hill on Mills Rd Gosnells, towing my camper trailer. It was a hot day and I had the foot flat, 2nd gear, 40km/h. I measure my temps with an Engine watchdog, digital readout and the thermocouple mounted under the thermostat cover bolt. At 104degrees the stock temp gauge had moved off the centre and was getting towards the top of normal.
Regards
Scooby

Thanks heaps for your feedback Scooby. It makes me a bit more comfortable knowing others are pulling similar figures without too many drama's.

Sounds like I might have to accept my temperatures on a hot day will rise to 96/97

Hey Phil,

I like your thinking.
After reading your comments I actually took out my thermostat today and boiled both my thermostats in a cooking pot(my old one and my new one - [don't tell the wife I did this]) today after reading your post. I put the thermometer in the pot with them. Both thermostats stay fully closed until around 87 degrees. They gradually open. Both thermostats did not fully open until around 94 degrees.

I then took the Lux for a spin (its a hot day in Perth - perfect testing conditions) on the freeway without the thermostat in the car meaning full water flow. The car temperature behaved the way it has been with the thermostat in. The car ran 88 degrees in idle and around town. Once I hit the freeway with the a/c on and went 100km/h the coolant temps went north of 97 degrees until i dropped my speed and turned off the air con.

So in summary - My thoughts are: I agree that given I have an 88 thermostat I should give my temps some leway - and expect my car to run between 88 and 91 (maybe even 93 to 94).

But these 97+ temps have me worried - and any car that can't do 100km/h with the a/c on is pretty useless in my book.

Thanks for your comments - got me thinking. I'm still a bit unsure on what to do next.

running without a thermostat isnt a good way of testing either as ther is no restriction the water flows through the radiator too fast and doesnt stay in the radiator long enough to cool

Also if its the thermostat with the little foot on the bottom then thats there so when it opens it comes down and blocks a galley so the water will go through the radiator and not bypass it like it does when cold. If this is the design running without it can actually make it run hotter.

Yeah, I realise that running without a thermostat does cause too much water to run through the cooling system - therefore not cooling the coolant enough. However the car seems to heat up similar with restricted flow (thermostat in) or unrestricted flow (thermostat out)...I have already purchased a new thermostat. The thermostat is now unlikely to be the problem.

I did some more testing of the viscous fan tonight - appears to be fine.

Yeah,
I would love to know what other temperatures people with Toyota 3L and 5L diesel motors are getting from their coolant at the top radiator hose. I'm sure there are a few people with a similar set up around. Or the advise of a Toyota guru.

Hi All,

I'm with Bob on this one. No need to get too hung up on 100 C. It's the boiling point of pure water at sea level (1 Atmosphere absolute pressure). At any other pressure and/or with additives the boiling point is different and, as mentioned, at cooling system pressure the boiling point is much higher. From my experience anything up to 110 C isn't too much trouble but this may differ from vehicle to vehicle.

This whole tread explains why the standard coolant temp gauge in most vehicles is designed to reach about mid-scale at the thermostat opening temp and then stay there until the actual temp is well over 100 C before it starts to creep up to the "Red". Stops owners worrying about 'normal' temperature variations during different driving situations.

While not necessarily relevant to your vehicle, our '97 Land Rover Discovery 300Tdi saw 114 C coolant temp (in the radiator side of the thermostat housing) a few years ago before I noticed it. We were towing 2.2T in 45-ish ambients in the NT at the time. We then eased-off a little to keep it under 110 C for the next few hours until things began to cool down.

Since then the vehicle has done at least another 100,000km (292,000 in total now). About this time last year the head was off for a pre-emptive gasket change and the condition of the engine was excellent: no warping of the head surface, no cracks and the cylinder bores still showing good cross-hatching. No reason why it shouldn't do another 200,000.

Now I know other vehicles may not handle these temps as well, but surely even Toyotas can't be THAT weak? (Yes, this is BAIT!...)