2jzge overheating?

[Aston2jz]

hiya guys, I recently bought my first supra (93 NA SZ Jap import) and have ran into some problems which I was hoping you could help me out with. The car was running fine for the first 2 weeks then on a hot day when I had been running the car all day, I saw steam coming out of the engine (note the temparture guage was reading as normal), a few days later it happened again and I discovered the coolant hose at the back of the engine which connects to the heater core had split, the engine had then started misfiring and running rough, so I removed the house and reconnected the other one so that it bypasses the heater matrix. I had noticed a lot of water had leaked from the hose to the engine, so checked the spark plugs which were drenched in water, so dried it out and replaced the plugs, the engine was no longer misfiring but still overheating (but this time the temp guage was high) so I flushed the coolant system and eplaced the thermo stat and compression tested the cylinders which read lowest 174psi highest 184psi cold engine, I also checked for signs of gasket failure in the oil and coolant. Yet it continues to overheat with the coolant resovior boiling and spraying water out, and light steam at the back coolant hose. Thanks for anyone that took the time to read this and offer any suggestions as I'm all out, and I'm ssorry for the use of paragraphs and grammar as I'm on my phone that freezes.

[Benjy]

Were the electrodes at the bottom of the plug wet? Or just where water had been splashed over the engine?

 

It does sound a little head gasket failure like. You may not get a difference in compression until it's failed big time. Best bet is to do a block test mate to determine early signs of h/gasket failure.

[-Welsh-Stealth-]

Possible overheating due to lack of coolant from split hose. Could cause the head to warp, especially if running all day dry...

If you do the head gasket it would well be worth getting the head checked out imo.

Possible head warp/head gasket.

[Alex]

If water is being pushed out of the overflow tank then it's usually the £10 rad cap that's failed - common fault with age, simple fix. It'll fire all the coolant out in short order so I would replace this straight away, as it's not exactly pricey of it proves to not be the fault.

 

I would also do a careful test of the rad core. Get the engine up to temp and shut it off, reach inside the rad cowl through the fan blades - carefully test the temp with your hand - a simple can I feel heat or not test. If you find an area that's cold it's likely that the rad is blocked and become far less efficient, the only fix for this is to replace the radiator - again this is an age related issue.