Sorry! Another water thread.

[frank rabbets]

What temperature does the water run at in the block, being the hottest part of the system ? I am wondering if, in UK, we need a pressurised system for Sunday driving, or perhaps could fit a rad cap with a lower opening pressure? This would take pressure off 30 year old hoses. I've been toying with the idea to replace all the hoses but looking at Toyodiy getting an accurate list together looks impossible. There are even 2 x small hoses for the cold start throttle up system. And then there's the heater matrix! Done that on an Audi coupe. What a nightmare but only had 1 x screw left.

 

[Towpack]

The stat shoud be fully open at 90 deg C but the coolant must reach over 100 deg or it wouldn"t pressurise, hence the instant boil over if you're foolish enough to remove the rad cap when it's up to full operating temp.
You could try one of those infra red temp sensor guns to get an approx figure on the side of the block or the head. One widely recognised problem with the cooling system is the inaccurate OEM temp gauge. There is, or was, a mod on IH8MUD which makes it much more useful and actually gives advance warning of rising coolant temp. IIRC it requires removal of the instrument binnacle and some PCB soldering work.
I think you might be over reacting/worrying unnecesarily Frank. I don't think these engines are any more prone to overheating or bursting hoses than any other.

 

[Towpack]

Here we are. The modding itself looks easier than actually getting the binnacle out. Depending on how hard it is to remove I might just have a go at this:

Gauge Mod

 

[Jon Wildsmith]

I'm measuring the coolant temperature in the outlet from the head (the one the top rad hose connects to) which is pretty close to the head and it sits between 85c and 89c once warmed up and depending how hard it's working. That's when it's running. It's gone as high as 104c after switching off and sitting a short while on a hot day. It was running a lot hotter before I topped up my fan clutch, but I didn't have a temp guage then to put numbers on it, just smell and feel.

Some of those little hoses are fiddly little buggers, but worth changing if they're original. Mine were in a terrible state inside but that may have been down to the PO.

 

[frank rabbets]

Thanks both. I'm not worried about results of failure now I have my pressure gauge. It's just that I won't be able to do any work in say 3 years time so might get everything changed now. I have worn out my left shoulder straining on cars and motorbikes since age of 13 or so. Shoulder is agonisingly painful if I catch it wrong but also aches after a few hours of work for days later.

 

[Shayne]

Towing thermostat opens at a lesser temp which should keep pressure down .

 

[felix2566]

Looks like quite a worthwhile mod and simple enough to make th needle show more accurate readings.
Will get the resistors for stock, until the cluster has to come out again, was out last year to replace a load of bulbs.