erall0

so i purchased my sc400 recently its in immaculate condition an old couple owned it they had a few overheating issues with it and they replaced the thermostat and seemed to fix the issue for them.

after i purchased it i drove it home (550khm) 25 khm into the trip my temp gage moved up quickly 2 notches i puled over popped the bonnet steam everywhere bubbling and steam coming from the radiator waited 1 hr for it to cool and thought it was dead I've kiled it, i refiled it took heaps of water and noticed the hydraulic fan wasn't spinning much i put the ac on max cold fan kicked it full speed and continued and made it home the whole 550khm no issues.

so the next day i went on a trip 130khm each way i got there all fine picked up some parts left the car idling popped the bonnet and the motor was running cool enough to take the cap off i checked the coolant and proceeded home.

60k into the trip i overtook a truck 10k later my temp moved up 1 notch i pulled over and the radiator was bubbling and steaming but not as bad as the first time i took the cap off kept it running and slowly refilled the coolant and it drove home fine.

next morning i topped up the coolant and drove around town the whole day no issues.

next day same thing checked the coolant it was full drove 25k pulled up steam everywhere out the overflow temp remained normal on the gauge and overheated as bad as the first time.

now I've got constant bubbles in my coolant ( blown head gasket ) no water in oil or oil in water i put a bottle of sealer in it and it seems to have helped a little bit.

I'm worried as these are alloy head and block that the whole motor is stuffed just after other peoples experienced with overheating with this motor hoping i can get away with pulling the heads getting them machined and putting it back together but I'm not sure how the block will go any suggestions
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CatManD3W

iTrader: (18)

You may have air in your cooling system.....need to drain it all out and do a system flush...also check that your thermostat is working correctly

estomax

iTrader: (2)

first stop driving around after you are having steam coming from under the hood, you are damaging your engine potentially.

then, if there is air in the system, it is either coming from the head gasket or is there from the thermostat change. check your coolant for hydrocarbons to rule out head gasket.

are you losing coolant at all? when the car is cold is the coolant still full? the overflow will fill up as it warms up and if it gets hot it will push water out of the radiator cap as it has a pressure relief valve.

erall0

unfortunately the head gasket test comeback positive so definitely leaking gasses in the cooling system I'm worried the heads and block are stuffed from the severe overheating I'm guessing the factory gauge isn't very accurate lol if i let it idle once it warms up starts a volcano out the top of the radiator tank

estomax

iTrader: (2)

the previous owner probably knew it was going and tried to remedy it with the thermostat change, looks like you've got some work ahead of you now! are you going to do a 2jz swap or find another 1UZ to stuff in there? or rebuild this one?

Ramblerman

Krikey mate, sounds like your best bet would be to find a whole new engine to put in. Take a wee bit of luck to get away with just a head job, but that might be all you need. Inspect the block well to make sure of no damage and hope you didn't fubar the rings.

erall0

i don't think I've fubar anything yet still runs really smooth and has no blowby no smoke plenty of power I've just never had a alloy block car before and unsure if weather it can even be fixed i have no problem doing the job just not sure if the heads or block will even be salvageable after overheating anyone else overheated there car and managed to to a head gasket replacement?

isfvss

WHY did you keep driving it fix before you *****, maybe a good lessen

Htony

OP must be young person? If I had that kinda problem, pressure test cooling system, make sure water pump is in good working order, chem. clean the rad. and heater core.
Refill properly and make sure all is OK. Some cars are very finicky to fill cooling system properly. My son's old Subaru WRX STi was one of them. Also hook up OBD II scanner to see if there is any stored DTCs.

erall0

how are u meant to fix a intermittent issue like random overheating without driving it maybe you should keep your comments to yourself unless u have something to say worth reading i am not driving it anymore

eknine9

iTrader: (8)

If it overheats once, you should find the source of the problem before you drive it again, otherwise you can turn a cheaper problem into a much more expensive problem. Which is why everyone is now recommending you look for a new motor, instead of suggesting you have the headgasket replaced. Nothing happens randomly when it comes to cars, everything has a reason, hopefully with the cars you own in the future you'll learn from this and stop driving it after the first sign of trouble. Can't keep driving an overheated car without consequences.

Ramblerman

Aluminum is a wonderful metal, and has been refined greatly over the years. Lexus did a good job of design and building of the 1uz, but there is a reason most auto manufacturers don't use a aluminum block most of the time. It cannot take constant overheating, and will warp. You will need to dye check your heads, and gauge them for warpage, then they can only be decked so much or it will weaken the head.. Block can deform around the sleeves and rings can lose tension. You have about a 50/50 chance that you didn't damage or shorten the life of your engine. Good luck with your repairs and hope they don't cost to much. We will be here to advise as we can.