SC300 Possible Head Gasket
10-14-14, 07:45 PM
#1
Driver School Candidate
Thread Starter
SC300 Possible Head Gasket
Alright,
I'm new so I'm dumb.
I tried using the search option but since I keep getting results from throughout all of CL and I couldn't find anything specific or close to my problem I figured I would make a thread. This is my issue...
Got a 92 SC300 from my grandmother back in July... Drove it home (Arkansas) from Florida with no [major] issues. (with the exception of the window regulator on the drivers side going out.... and the turn signal relay working intermittently.. I digress.) This car was seldom driven throughout the years and it is pretty clean. It only has 88k miles and everything is original with the exception of the retro fitted R134a air conditioning system. Looks awesome too, you can see a pic of it in my pictures as well as on the "introduce yourself here page". While driving home from work one day I noticed it began to overheat. No big deal, I'll just pull over and its probably a thermostat, its been sitting. Surprise Surprise, when I check the coolant, it looks Milky. My initial thought is head gasket. I check the oil on the dipstick and there is no water from what I can tell.
I let her cool down and then I Decide to limp her home. She Doesn't overheat on the short trip home which surprised me because I figured the oil in the system would not let the oil circulate properly but oddly enough, I didn't have any issues. Its been sitting for a couple weeks and I haven't had the time to mess with it. Other people have told me it COULD be the transmission lines that go into the radiator but I'm pretty sure this model doesn't have an integrated system like that. Another guy I work with said its possible the water pump may have oil passages in it that could leak into the coolant system. I feel this is far fetched but worth bringing up. I don't know much about the systems of this car because this is my first Lexus and I feel confident that I can do a HG job myself but I just want someone elses opinion before I just go tear it apart and find out that the head gasket is fine. I really feel terrible that its sitting and I have to look at it every day when I go to work 
so I want to get it back on the road ASAP. Any help would be awesome.
Thank you guys!
I'm new so I'm dumb.
I tried using the search option but since I keep getting results from throughout all of CL and I couldn't find anything specific or close to my problem I figured I would make a thread. This is my issue... Got a 92 SC300 from my grandmother back in July... Drove it home (Arkansas) from Florida with no [major] issues. (with the exception of the window regulator on the drivers side going out.... and the turn signal relay working intermittently.. I digress.) This car was seldom driven throughout the years and it is pretty clean. It only has 88k miles and everything is original with the exception of the retro fitted R134a air conditioning system. Looks awesome too, you can see a pic of it in my pictures as well as on the "introduce yourself here page". While driving home from work one day I noticed it began to overheat. No big deal, I'll just pull over and its probably a thermostat, its been sitting. Surprise Surprise, when I check the coolant, it looks Milky. My initial thought is head gasket. I check the oil on the dipstick and there is no water from what I can tell.
I let her cool down and then I Decide to limp her home. She Doesn't overheat on the short trip home which surprised me because I figured the oil in the system would not let the oil circulate properly but oddly enough, I didn't have any issues. Its been sitting for a couple weeks and I haven't had the time to mess with it. Other people have told me it COULD be the transmission lines that go into the radiator but I'm pretty sure this model doesn't have an integrated system like that. Another guy I work with said its possible the water pump may have oil passages in it that could leak into the coolant system. I feel this is far fetched but worth bringing up. I don't know much about the systems of this car because this is my first Lexus and I feel confident that I can do a HG job myself but I just want someone elses opinion before I just go tear it apart and find out that the head gasket is fine. I really feel terrible that its sitting and I have to look at it every day when I go to work so I want to get it back on the road ASAP. Any help would be awesome. Thank you guys!
10-15-14, 04:04 PM
#2
Check your ATF fluid.
The SC300 auto radiator does have lines flowing thru it to cool atf fluid. If the car sat for years, it is very possible the lines could've corroded inside the radiator (since that fluid has been sitting for years).
If you can rule that out, then the next culprit would be headgasket.
The SC300 auto radiator does have lines flowing thru it to cool atf fluid. If the car sat for years, it is very possible the lines could've corroded inside the radiator (since that fluid has been sitting for years).
If you can rule that out, then the next culprit would be headgasket.
10-17-14, 12:54 AM
#4
Driver School Candidate
Thread Starter
Check your ATF fluid.
The SC300 auto radiator does have lines flowing thru it to cool atf fluid. If the car sat for years, it is very possible the lines could've corroded inside the radiator (since that fluid has been sitting for years).
If you can rule that out, then the next culprit would be headgasket.
The SC300 auto radiator does have lines flowing thru it to cool atf fluid. If the car sat for years, it is very possible the lines could've corroded inside the radiator (since that fluid has been sitting for years).
If you can rule that out, then the next culprit would be headgasket.
10-17-14, 11:41 AM
#6
Driver School Candidate
Thread Starter
No the coolant was green. I haven't gotten the time to replace anything except the oil because I just got the car. The radiator does look kind of red, but the coolant reservoir looks brown like oil. I just want to see what you guys thought before I tore it apart.
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10-17-14, 02:14 PM
#9
I am not seeing the "milkshake". the oil and the coolant wouldn't mix so well like that, it would be all lumpy (I have seen it a few times to say the least) sort of looks like you had original toyota red coolant and someone topped it off with the wrong green stuff. probably got hot from an air pocket the first time or maybe air in the heater core the first time it burped out.
Top the reservoir off and keep an eye on the level. if it doesn't overheat again you will have ruled out the head gasket. if it sucks the reservoir dry and overheats some you may have a pinhole leak in the HG. since you don't have the stuff mixing anywhere else and that doesn't look like a BHG milkshake to me, I doubt its the HG , normally something causes overheating that blows the headgasket, not just one day the headgasket goes and causes it to overheat. likely you just had some air in the system and need a new thermostat.
Or as said above you could have atf mixing with green fluid. I have a manual so I am not sure what that looks like. this could reduce the ability of both systems to operate correctly, IE the radiator and the auto trans eventually. the leak is internal so you prob wouldn't see it.
you can get a new auto radiator if thats the problem, or get a manual radiator and run a separate trans cooler so it never happens again.
Top the reservoir off and keep an eye on the level. if it doesn't overheat again you will have ruled out the head gasket. if it sucks the reservoir dry and overheats some you may have a pinhole leak in the HG. since you don't have the stuff mixing anywhere else and that doesn't look like a BHG milkshake to me, I doubt its the HG , normally something causes overheating that blows the headgasket, not just one day the headgasket goes and causes it to overheat. likely you just had some air in the system and need a new thermostat.
Or as said above you could have atf mixing with green fluid. I have a manual so I am not sure what that looks like. this could reduce the ability of both systems to operate correctly, IE the radiator and the auto trans eventually. the leak is internal so you prob wouldn't see it.
you can get a new auto radiator if thats the problem, or get a manual radiator and run a separate trans cooler so it never happens again.
Last edited by Ali SC3; 10-17-14 at 02:28 PM.
10-17-14, 02:49 PM
#10
Driver School Candidate
Thread Starter
I am not seeing the "milkshake". the oil and the coolant wouldn't mix so well like that, it would be all lumpy (I have seen it a few times to say the least) sort of looks like you had original toyota red coolant and someone topped it off with the wrong green stuff. probably got hot from an air pocket the first time or maybe air in the heater core the first time it burped out.
Top the reservoir off and keep an eye on the level. if it doesn't overheat again you will have ruled out the head gasket. if it sucks the reservoir dry and overheats some you may have a pinhole leak in the HG. since you don't have the stuff mixing anywhere else and that doesn't look like a BHG milkshake to me, I doubt its the HG , normally something causes overheating that blows the headgasket, not just one day the headgasket goes and causes it to overheat. likely you just had some air in the system and need a new thermostat.
Or as said above you could have atf mixing with green fluid. I have a manual so I am not sure what that looks like. this could reduce the ability of both systems to operate correctly, IE the radiator and the auto trans eventually. the leak is internal so you prob wouldn't see it.
you can get a new auto radiator if thats the problem, or get a manual radiator and run a separate trans cooler so it never happens again.
Top the reservoir off and keep an eye on the level. if it doesn't overheat again you will have ruled out the head gasket. if it sucks the reservoir dry and overheats some you may have a pinhole leak in the HG. since you don't have the stuff mixing anywhere else and that doesn't look like a BHG milkshake to me, I doubt its the HG , normally something causes overheating that blows the headgasket, not just one day the headgasket goes and causes it to overheat. likely you just had some air in the system and need a new thermostat.
Or as said above you could have atf mixing with green fluid. I have a manual so I am not sure what that looks like. this could reduce the ability of both systems to operate correctly, IE the radiator and the auto trans eventually. the leak is internal so you prob wouldn't see it.
you can get a new auto radiator if thats the problem, or get a manual radiator and run a separate trans cooler so it never happens again.
10-17-14, 03:13 PM
#12
sc400 has the same setup that goes through a separate part of the radiator. the radiators are not the same though its on the other side or something. I searched and am not seeing anyone with that same problem , but doesn't mean it can't happen.
yeah when you drain the coolant you may have a better idea. the oil in the coolant will tend to blob together like islands of oil floating around in the coolant, or it will become a thick foamy milkshake if enough mixes.
a BHG usually looks more like this, like a foamy paste.
yeah when you drain the coolant you may have a better idea. the oil in the coolant will tend to blob together like islands of oil floating around in the coolant, or it will become a thick foamy milkshake if enough mixes.
a BHG usually looks more like this, like a foamy paste.
10-17-14, 03:17 PM
#13
Driver School Candidate
Thread Starter
Yeah I looked as well, didn't find anything. But this car has been garage kept for 20 years and hardly driven, There aren't many SC's out there that are that way I'm assuming. But thanks for the info! I really appreciate everyone's input. I'm new to CL and so for everybody has been super cool and helpful.
10-17-14, 03:23 PM
#14
check this out, 4 runners have the exact same setup and basically transmissions as in our cars.
they are saying if you catch it in time then you can save the transmisison, since it just happened to you you may be able to save the trans.
http://www.toyota-4runner.org/3rd-ge...-mixing-2.html
I would do replacement radiator, separate trans cooler, and try and drain the trans out and put new fluid in it as a precaution and hope there isn't much coolant in there (since you will be putting the cooler on you might as well drain and refill once or twice, maybe once with regular fluid and then again with the good stuff). even a little bit of coolant is not good. don't let them power flush, just do the drain and refill a few times if needed.
they are saying if you catch it in time then you can save the transmisison, since it just happened to you you may be able to save the trans.
http://www.toyota-4runner.org/3rd-ge...-mixing-2.html
I would do replacement radiator, separate trans cooler, and try and drain the trans out and put new fluid in it as a precaution and hope there isn't much coolant in there (since you will be putting the cooler on you might as well drain and refill once or twice, maybe once with regular fluid and then again with the good stuff). even a little bit of coolant is not good. don't let them power flush, just do the drain and refill a few times if needed.