Suspected blown head (gasket)

I'm asking here cause this forum's the best. The engine is a toyota 3sgte (turbo, iron block, alloy head) in an engine bay with almost no room to work with.

the symptoms are that it gets hot if you really thrash it, it's underpowered (when boosting, it only has power from 3000-5000rpm), it would lose water, also, letting the motor idle away at normal operating temperature with the radiator cap off, after a few minutes, it randomly shot a good amount of coolant out of the radiator with a fair bit of pressure, it only done that once. That's what made us suspect a blown head gasket. Other than that, the motor still runs good

I started pulling the motor apart and found a small coolant hose from the TB wasn't connected to where it should've been, heaps of brown marks where its been losing water in its surrounding area. also the exhaust has been leaking around 2 manifold ports

I guess the exhaust leak is why it would be lacking in the power department?? (never worked with turbo issues before, so this is new to me). The losing coolant issue I would think is the hose that was never connected. The 'getting hot when thrashed' thing I guess could be related to that hose too, or an incorrect thermostat? (someone's been doing shoddy work on this car before I got it, so that wouldn't surprise me). Only thing that worried me was when the radiator randomly shot water out while the motor was running. but it only did that ONCE, I couldn't get it to do that again. That's the only thing I couldn't figure out why it would happen once but not do it again.

anyways I haven't pulled it all to pieces yet, the head is still bolted on to the motor. I'll do a compression test when I find my tester. I can't do a leak down test though cause I don't have an air compressor or tester

Basically I don't want to pull the head off if I don't have to

In the meantime, what are your thoughts or what would you recommend doing in this situation?

A cooling system won't cool unless it can build pressure and keep the water from boiling away from hot spots. An exhaust leak will also cause the turbo not to spool up as it should.

You can fix those two issues and see if that cures the symptoms, but if it doesn't, I'd pull the head. If the engine were out, I'd pull the head anyway, like I do with every engine I swap.

ill put money on the head gasket being fucked from someone overheating it from the water pipe missing. with the exhaust leak, you would have to be able to hear it for it to affect the turbo spooling?

You say it runs good otherwise I can see why you are reluctant to split it.
The gushing water could be a lazy thermostat or simply gushed from being low on coolant when it opened. Clogged radiator would mimick that too.
Compression check should help you decide.

does that ECU hold back until the ECT says the engine is warmed up?

I might get a new exhaust gasket & put it back together to see how it goes.

I forgot to mention that all but 1 of the exhaust manifold bolts where only a bit more than finger tight (the only tight one was the stud/nut) I'm surprised I couldn't hear it leaking. must only be under load or something???

Oh yeah, as for the radiator, it appears to have a brand new one in it. which basically tells me the car was already someone elses problems before it was offloaded onto us haha

not sure how the ECU works on these cars. Only reason I'm reluctant to pull the head off is cause it's a shitty job to do with the motor in the car :P

done a compression test, from cyl 1 - 4, in psi it was about 110, 100, 90, 125. poo

no good, should be 180 at best

well the manual says between 128 & 164psi, with no more than a 14 psi difference between cylinders. on the bright side, there's 2 possible 3s-gtes i may be able to get, so hope all goes well.