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Discussion Starter · #1 · (Edited)
So I am driving to work today and all of a sudden both my security light and my parking brake light both come on, so im like WTF??? So I figure no big deal I'll just check the car out when I get home tonight. Then I notice my temp gauge is pegged past hot (this is normal though....the car always throws the temp gauge around eratically so at first I thought nothing of it). Then all of a sudden the CEL comes on as I am coming to a stop light. This has happened before to so I pull over and turn the car off for a few minutes thinking it is just acting funny today and decide to turn around and take it back home and make the wife drop me off at the train instead. So I restart the car and the temp gauge is back down and the CEL is off but the other 2 lights are still on and I notice that the car is really boggy while under boost, almost like it has a hesitation between 3k and 4k rpm and at the next light I come to the CEL comes on again and the temp gauge pegs itself. At the next light I notice white steam/smoke coming from under the hood and swear loudly. So I get the car home and pop the hood and the alternator belt is missing and the coolant in the over flow is boiling. I am hoping that the HG didnt blow on it, other wise replacement motor here I come. So who here thinks that the motor is toast? There was no coolant or anything near the motor itself, only upfront near the overflow bottle. I have my fingers crossed that I didn't kill the motor but I am thinking that it is a good possibility I did.

-Nick
 

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If you saw those plumes of white smoke with a good stock exhaust it's probably toast. If it's just the hood you might be okay. Depends how long it was overheating for. I'm sure someone else can chime in more knowledge.
 

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hmmm... why would it overheat from him snapping the belt?

doesn't make sense...
 

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Discussion Starter · #5 ·
Poodles said:
hmmm... why would it overheat from him snapping the belt?

doesn't make sense...
Because the alternator belt drives the fan and water pump. hence no cooling hence kaboom. it is basically a sure fire way to blow your HG.

-Nick
 

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lol, I forgot about that, I had it happen on my truck but it took it easily...but the headgaskets on the 7m's are bit weaker...
 

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Discussion Starter · #7 ·
Ok, I got the new belt on and the car fired right up. added some coolant and checked the the oil and she seems to be good. The only thing I am experiencing now is a hesitation under boost. does anyone have any ideas why it would be hesitating? The car excellerates good when not under boost and seems to build boost really good but then it feels like it bogs down and even though it is making boost it doesnt go anywhere. Anyone have any thoughts on that?
 

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I'd pull the plugs and look at them, make sure the electrodes aren't burnt off them or something. Higher cylinder pressures (boost) demand good spark.
I think you're very lucky your engine survived that. There would have been almost no coolant circulating, maybe a little circulation from convection, and temperatures in there would have gottened very high.
 

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Discussion Starter · #13 ·
lagged said:
what i am amazed at is how you are treating your car. you must have money to burn or something.
And that is supposed to mean what exactly?? I didnt have a choice in the belt breaking, the last time I looked at it it was fine. When i bought the car in april it was in far worse shape than it is now. Believe me I treat this car very well but there are always unforseen circumstances to everything that happens. I actually dont have money to burn which is why I am hoping the HG didnt blow out on me. Trust me when I say this that you are going to learn that shit breaks and half of the time there is no cause for it. The car is almost 20 years old, and on older cars you cant really prevent these types of things from happening. Sure I guess I could have replaced the belts sooner, but Why??? ever heard the phrase "dont fix it if it aint broke"? well it wasnt broke so i didnt spend the money to fix it. oh well shit happens life sucks. Can we get on with the technical help portion of the website now? Do you know what might be causing my hesitation? Got any Ideas of things I might be able to try to remedy the situation? No, then dont bother judging me if you dont even know me. Yeah Im glad your 20 and you have a SUPRA, now leave me alone kid.....ya bother me.
 

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NeedasupraMKIV said:
Yeah Im glad your 20 and you have a SUPRA, now leave me alone kid.....ya bother me.
It stops there.

As for your car problems... a compression test takes maybe 30 minutes to perform if you are new to these cars. I suggest you try it out and check the numbers. You can buy the gauge and attachment for ~$20.

Tim
 

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Discussion Starter · #15 ·
I didnt mean any disrespect towards anyone but lagged on that comment. and I understand that there may be people younger than me who know more about these cars than I do. Actually Im sure there are many pepole who know more about these cars than I do.

Selz202: Yeah the compression test is my next test, I checked the plugs and everything else and they looked fine. I am probably just in denial and trying to avoid that the HG probably is blown, I just dont want to deal with it. Compression test today probably then I will more than likely be ordering my MHG and head gasket kit.
 

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i know very well that things break and there is sometimes no way to anticipate it, but who would actually keep driving their car when a belt that drives an ESSENTIAL part of the motor, breaks?

make assumptions of me based on my age all you want, i have learned and accomplished more with my mkiii than you probably ever will.

also, in my eyes there is no reason to diagnose your "hesitation" problem because it is very likely that you blew the head gasket AND warped your head from running it without the water pump active.

its time to yank that motor out and tear it down, that is if you want to fix it the right way.
 

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The problem is the head is made of aluminum and it expands quicker than the block and warps allowing the coolant passages to get compression hot gases into it. Also if it warps bad enough, the cams can spool on the head which has happened to me. Sure symptoms of headgasket failure is can't keep level in radiator, a little oil film bubbling on water surface, white smoke and/or steam out the exhaust, possible misfiring, poor idling etc., oil cap showing moisture oil film under the cap.
You should have a block test and cylinder compression leakdown test to ensure no damage has occured. Replace the thermostat, and radiator cap and make sure the radiator is looked at and ensure the tubes aren't clogged with corrosion. So many times, the radiator holds water but if it has poor circulation through the tubes it will overheat.
The MKIII Supra's 7M series motors do not fair too well in the heat so keeping the cooling system 100% is a key factor to the life longevity of the engine.
 

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Discussion Starter · #18 ·
lagged said:
i know very well that things break and there is sometimes no way to anticipate it, but who would actually keep driving their car when a belt that drives an ESSENTIAL part of the motor, breaks?

make assumptions of me based on my age all you want, i have learned and accomplished more with my mkiii than you probably ever will.

also, in my eyes there is no reason to diagnose your "hesitation" problem because it is very likely that you blew the head gasket AND warped your head from running it without the water pump active.

its time to yank that motor out and tear it down, that is if you want to fix it the right way.
Congratulations on your accomplishments with your car I think it is great to have something to strive for. I have made some accomplishments of my own though that I felt were more important than getting a car that I knew could be potential trouble right off the bat. Maybe that is why I am just now learning about the MKIII. I dumped all my money into other things when I was younger which allowed me to get my car now and have just a little bit more money to play with as far as fixing things goes. As you can see in the original post I pretty much said that I thought I blew the HG, But I was trying to eliminate all other possible scenarios before I just replace the motor or have mine rebuilt. I wanted to know for a fact that the HG is actually blown, after working on the car all day and verifying everything I could I have verified that the HG did actually go on the car. So unfortunately some major consideration needs to follow.....do I find a low mileage engine and do it right or do I take mine apart and have it rebuilt.
 

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Id rebuild... never would i just get a jdm and drop it in... rebuilt engine is better than a new one, and jdm is getting some used one that probably has the same problems.

Rebuilding gives the piece of mind that it was done right and you learn alot more about your motor. Heh learning is one of the most important things in life, no matter how old you are. Theres alot to be learned on these 7Ms...

Tim
 
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