Yes, I have considered that. Is tank removal a bitch of a job?

Tony Brown

Yes, I have considered that. Is tank removal a bitch of a job?

Totally!

Sent from my SM-J320ZN using Tapatalk

Yes it's not the most fun thing I can think of for a Sunday morning and someone has obviously buggered up something doing it in the past or you wouldn't be enjoying the present bit of fun.
Another thing to take a peek at is the original nylon ? high pressure line from near the front engine mount across to the bottom of the fuel filter. Apes can very easily damage/ kink it while removing or installing the tank. They can be in a bloody bad mood with the whole world doing this job. It's under very high pressure and could spray a mist of fuel close to a hot exhaust manifold, turbine etc.
Have you removed the undertrays to look for the coolant leak?

I backed it up onto ramps and had coolant added long enough to see that it's forward of the rear wheels and I will have to take the undertrays off to investigate further, axle stands front and rear should give enough room I think.
 
I'll keep you posted....

Ok. so undertrays off, spotted two bolts in the lowest part of the stainless coolant pipes which I assume are drain plugs that appear to be leaking, when I touched one it fell out, the other screwed out by hand with what thread was left! The longer of the two only had about 4mm of its original thread remaining.
Two new hex screws fitted and no more leaks, for now.
Fill the engine and run it for ten or so minutes and it then blew the fitting off the housing which the thermostat housing attaches to, coolant everywhere and what is left of the metal pipe still in the hose.
I think any steel pipes in hoses could be a problem, besides the turbo coolant line and the hose that attaches to the thermo housing, are there any others which I could check?

Those two drain plugs usually have fibre washers but some sealant on their threads works too.
Most unusual to have enough pressure rise in correctly operating cooling system to dislodge that pipe from it's housing. Have you pressure checked the cap yet ?
By the way. We commonly call that whole double housing "the coolant tree". It's not a thermostat housing. Thermostat is actually located in the inlet of the water pump ?

I knew it would have a name, but couldn't think of any suitable name at the time.
It appears that the steel section has corroded and when under (hopefully) normal pressure it just let go.
The temp guage sat at just under half the whole time, I was keeping a close eye on it and looking for leaks underneath. 
I did use a fibre washer on each of the screws, but no sealant, seems to have sealed well.

Still might be an idea to check the pressure that the cap opens.
Bit of sealant on those plugs now and you won't need to look at em again.
Original temperature gauge will sit at about the middle as dumb as an ox while the actual temp will climb to Gawd knows where before it will move. Hopeless for indicating an overheat situation. It will sometimes fluctuate wildly if there is a low coolant level causing air/gas to pass across the sensor. Way too late to be of any practical use.

Sorry for the late reply, I have a few irons in the fire atm.
I agree with testing or just replacing the cap.
I'm repairing and re-fitting the coolant tree tomorrow. Do you think having the car pointed downhill makes bleeding the cooling system easier?
The more I look at it, it seems to make sense for the purpose of eliminating air locks at the radiator and heater core, which I suspect could have been an issue last time I ran it.
 

Front of car down may have some benefit, maybe? Clear hoses on both radiator and heater core bleed points with both bleed valves open. SLOWLY trickle coolant in till it rises up in both clear hoses to the level of the filler cap. Close both valves. Remember that the air can only escape from behind the closed thermostat via the small jiggle valve and the coolant bypass hose. Hence the need to only fill very slowly allowing air to escape via the filler neck.
I suspect it is beneficial at this stage on Gen 2 engines to jack up the left hand side of the car as high as is safely possible. This sometimes produces a significant bubble of air to be emitted from the filler neck. Now just top up and install pressure cap. Overflow reservoir should be emptied and about half refilled with new clean coolant and it's hoses checked for blockages.
I now take the car for a short drive till it comes up to normal operating temp and pressure. I now carefully crack open the radiator bleed valve and make sure that solid coolant comes out under pressure proving the radiator is absolutely full. Same procedure is done to heater core bleed valve.
If the cooling system has no leaks it should draw coolant from the overflow reservoir when it cools right down overnight. So next morning is a good time to remove pressure cap and if necessary top up.