86.5 7MGE Problems
 

OK, so I'm starting to think that I have a BHG. My symptoms include...radiator fluid spraying out constantly from the purge port on the reserve and when I drive sometimes not all the time it will start hesitating while the accelarator is pressed. It seems that I have to fill up the radiator every two days or so because of all of the fluid being purged out. I had Pepboys do a pressure check on my coolant system and they said it was my radiator cap at fault. So, I replaced all of my coolant hoses and vaccum lines to include the radiator cap and thermostat...is there something else that I can try that I'm missing before I assume that it's a BHG??? I still seem to have great power and only powerloss when my radiator gets low on coolant or it starts to hesitate.

At the same time I see traces of black smoke on my rear bumper and I know that white steam/smoke is a sign of a BHG due to coolant mixing in the combustion chambers. Could this be also from worn out piston rings?

Ok Bill thanks for the imput I'll check on that. I have 244,000 miles give or take on it but before then when I purchased it the guy I bought it from said that the engine has been rebuilt, but couldn't find the paperwork on it. But I do see a placard on the engine from where it has been rebuit. The radiator looks worn I'll post pics asap. But not too sure about the water pump. Is there a way to test the water pump to see if it's operational or not?

I've often wondered about that myself, removing the cap and looking into the rad doesn’t tell you much. I guess you need some method of measuring coolant flow through the system. The reason I mentioned the water pump is I got caught out once; I had the usual over flowing expansion tank bottle, gurgling behind the dash noise and over heating. Did a BHG repair and drove it for about 10 miles down the road, opened the hood to find coolant overflowing from the expansion tank bottle. To cut a long story short, I removed the water pump to find the impellors had disintegrated due to the acidic condition of the coolant from previous BHG over the years. Combustion gases mixed with the coolant will start etching the metal parts such as water pump impellors. As you can imagine I'm a bit paranoid about water pump corrosion now.

Wow, I actually hear gurgling behind the dash when I start my car after it has set for a while. The overflow tank stays full to the brim and doesn't suck back into the radiator like you stated it's suppose to. It just purges as I drive. Oh yea I forgot to mention that when I went in to change out the thermostat it was placed in backwards. Do you think that would have caused even more chances of water pump failure?

Here are some pics that I took today of my expansion tank, radiator, and water pump.

And some more...

OK so this morning I when to check out my radiator again and to my surprise for the first time the radiator sucked up the coolant from the expansion tank it wasn't filled to the brim like it has been all week. So I start looking around and notice a drip coming from a hose above my water pump. Could this be the culpert or is it in combination with a faulty water pump?

Any leak in the cooling system will result in it not easily sucking the coolant back from the reservoir. As the coolant cools down, the pressure drops which creates a vacuum in the system. This is what draws the coolant back in. If there is a leak, the cooling system could draw in air (which is easier for it to do) instead of that coolant, leaving it all in the reservoir

Ok thanks btwilson86, I did find that there are two hoses that are adjacent to the water pump are swollen. I purchased a brand new water pump today just in case and it was the last one that they had in Denver out of all of their stores; and I'm going to change out the two hoses and see how that works. Would you change out the water pump just to be safe? I don't have any idea of all the parts on the engine; if I had all the money I needed I would replace everything with new parts just to save the headache for at least another 22yrs...lol

Well, water pump's are wear items, so IMO it's always good to replace it. I should change mine out, actually...

Swollen hoses also interfere with the cooling system purge, as it expands and contracts with pressure/vacuum.

Let us know what happens with the new parts

I am experiencing the exact same problem with the 86.5 7mge I just purchased. If you fix the problem please let me know what you did. I am going to start by replacing some vacuum lines.

Good luck to you too, and if you figure it out before I do let me know as well...thanx

Right as it sttarts to hesitate I start to smell a strong odor of gasoline I just recently started running 91 grade was running 89 grade or mid grade. I'm starting to think it may be the timing or bad injectors...maybe even both.

eh? upgrading the fuel could cause problems? I thought it was if you downgraded the fuel, you were more susceptible to problems?

No, I still have the stock fuel system set up for the N/A. I want to upgrade my system eventually when I get to that stage. But, I was saying that since my injectors are so old they are probably wearing or worn out already thus causing hesitation at times. Or my timing could be off and causing the problem too I have to look into that after fixing my current problems.

Bhg?
 

Check your plugs - if they look like coolant or have deposits its a BHG - Start with NO 6 as that is the most common - All plugs should be dry and light tan. Mine ran rough after sitting overnight and was burning coolant same on acceleration

I just got done with that same issue on my 87, I replaced the head gasket had all new hoses installed, put a new water pump on and fan clutch. All to find out my radiator wasn't cooling to specification so when the car stopped the pressure was still in the system as the coolant was too hot. I HIGHLY recommend taking out the radiator, take it to a radiator shop and have them flow test it. The average cost is around $15.00. It may save you hundreds in the long run and either way you know for certain if it is or isn't good enough at cooling. As the radiator heats up the fins are supposed to disperse the heat although a Toyota that is older sometimes has their radiators deteriorate. the money you spend on getting it tested will easily pay for your time and frustration in the long run.

Thanks for the input I'll look into that, I was wanting to get an aluminum radiator any ways now I might have a reason to get it earlier than anticipated :D

Alright, so I finally changed out my water pump and two more short hoses that had a crack in them and were swollen. I noticed that there is some pitting or scraping inside the chamber where the water pump sat, hopefully it's nothing to be concerned about. The water pump didn't didn't look too bad, but I changed it out anyways to keep from doing it later on down the road. In the process of it all I ended up with a broken temp fuel control sensor I think that's what it's called and now have to wait until Thursday or Friday for the part to come in from Toyota. So, now I won't be able to test out my work until then. But on the positive side it forces me to wait to make sure I have a good seal formed before I put antifreeze in and start putting pressure back on the system, should be good since I used high temp RTV in place of the gasket cause the gasket it came with was destroyed to begin with.

Before you re-assemble everything, how is your clutch for your fan? it should be very tight. It should not spin super easy and if you spin it with your hand there should be a lot of resistance. Otherwise if its easy to spin, you wont have your fan cooling as well as it should be. The clutches are around $40 if you need to get one replaced.

Sweet how it pays to read threads not yet related to issues I'm having... that's good to know, ty :D

also remember to look between your radiator and ac condenser that no animal has made a nest there to help for cooling, its hard to see sometimes, the back of your radiator looks like its deteriorating.

Trust me upgrading to the aluminum radiator is great. I would recommend getting a 3 row radiator with some electric fans to cool it. Thats what I did when I bought the car because the radiator was messed up. That thing cools down so fucking fast.

I'm looking to do this fix too, since I live in vegas and w/o a fan shroud on the crank fan, I'm at high risk for over heating next summer. Luckily that means I have time to save and do homework on the project. However, I still have come across some questions I'm hoping someone can answer for me rather than me asking the manufacturer themselves.

I have a 7mge that was manual, is now automatic... Looking into:
Aluminum Radiator and Aluminum Dual Fan Shroud

However, I noticed that the radiator says 86-92 manual. Why's the transmission type make a difference? Are the radiators different specs/sizes? Since I can't find any aluminum radiators for an automatic, I have to think it doesn't matter... but if it didn't matter, why do they specify manual? Same applies to the fan shroud since that's the radiator it'd best mount up to...

Am I SOL cause I have an automatic? maybe stuck with using Elec. fan mounted to radiator? or can I do this upgrade on the auto? Further more, if I mount the single fan to my existing radiator or upgrade the radiator and throw in the dual elec. fan shroud assembly, do I pull the fan off the crank? or does that stay for weight balance?

First of all you definitely want to pull the manual fan off if you put electric ones on because that's going to more problems than solutions and plus I don't think you could get the dual fans on without pulling the clutch fan off. The difference between the auto and manual radiators is that the automatic radiator has transmission coolant line connections which you need versus the manual which doesn't have any use for them.

I didn't find coolant but I did find oil...I have already replaced my No 3 valve cover with O Ring Gaskets covered in RTV, and they are not leaking so that means it's coming from inside. All 6 of my plugs were covered completely in oil :(
And on top of all of this my car won't even start now that I got the water pump back on and coolant back in and new plugs. I'm thinking it's possible that I might have messed up my timing since the pulleys were spinning while I was trying to get the fan off.

Also, I found black residue in my intake manifold when I was changing out my plugs.

You don't get WET oil on spark plugs unless it's coming from outside the engine... in the 7M's case, valve cover seals and the three galley cover bolts are the only place it'll come from.

The oil inside the plenum is a side effect of a functional PCV system. Excessive amounts may point to a problem with blowby due to worn rings, a leak down test would tell you what shape the rings are in.



Automatic radiators had a small oil cooler for the transmission fluid. http://www.cygnusx1.net/Supra/Librar...spx?F=1603&P=3



Pitting around water jackets is the result of the wrong type of coolant being used... it's due to a dielectric reaction. Thoroughly fluch your cooling system and switch to Toyota's red coolant to prevent further damage. Supposedly, the newer green coolant formulas are better at preventing this type of corrosion, but if you're already seen signs of damage I'd switch coolant soon.

NOTE: You MUST thoroughly flush the coolant system out before changing from one type of coolant to another. Failure to do so could result in emulsification.

Ah, I was wondering that... and that actually concerns me... since the car was a manual and an auto was thrown in... I'd have to guess that I have no transmission fluid cooling going on... :\ Also, you confirmed my suspicion about the crank fan coming off... didn't look like there would be enough clearance anyways... I'm just wondering if it can come off at the crank, or if I need to leave the clutch assembly attached to balance weight somewhere along the lines.. granted it's not much weight to be balanced, but spinning that fast, the smallest offset could throw the thing into a sloppy rotation.. much like a washing machine with an uneven load? Eh, that's my logic... which is why I ask questions, I know I'm not a mechanic, but I want to get used to my mk3 rather than being concerned about what every pop and ping I hear might be. Also hoping this concern will subside the longer I drive the car in good running condition... having it die after two weeks of owning it doesn't exactly support a positive confidence in reliability..

Leave the mechanical fan and forget the electric... for some ungodly reason it seems no one ever manages to install them properly and I'm sick of all the "my fans caught fire and my wire harness is f@#%ed" sob stories... besides, there are virtually no gains to be had from it. The more electrical drain you put on the alternator the harder the alternator become to move... you lose what you gain.

If you feel you need something which imposes less resistance the best solution is a flexible fan... they're lightweight and they flatten out the faster they move causing a drastic decrease in resistance while maintaining a *reliable* source of airflow.

Yea, I have been finding myself replacing my plugs like every 4 to 6 months because I can feel a restriction in my plugs and usually they are fouled out. I have replaced my No 3 trash gasket with some O Ring washers so maybe they are not holding up like I thought they would I'll recheck them to make sure didn't feel any oil leaking from them the last time I checked two days ago. This guy that worked at a parts store told me that I might want to switch from using synthetic oil to high mileage or regular oil and that should fix my plugs being covered in oil problem. The way he described it as it is so thin that it's blowing right past my rings in my pistons. He said that should fix it, just a guess of course cause that was supposedly his problem with his 88 corvette.

I'm going to be disgustingly blunt here... if you don't like it, I'll apologize in advance... I'm sorry.

The parts store guy is a F@#$ing idiot and you really need to find a mentor to help you out while you learn your way around the engine bay.


There is NO WAY a running engine will get WET oil on the plugs much less soak the THREADS which happen to be outside of the combustion chamber! NONE! The parts guy is an idiot and you've got leaking valve covers or the bolts which hold down the No3 gasket.

Wet oil around the plug wires can cause shorts to ground and a heavy miss... the fact that replacing them makes it feel better for a while is because each time you pull them you're dumping all the oil that was surrounding them into the cylinder and thus eliminating the real problem for a little while.

A plug which has seen burning oil is black, but it's dry.

No worries CRE, you seem like you know way more about the Supra then them and I'm not calling you wrong on this, because what you said makes more since than anything any of these parts guys has been telling me. I still consider myself quite new to the Supra, it's become a headache at times, but I still love the Supra it's an awesome machine. Hey, since your in Denver also would you care to be my mentor?

I'm not up for mentoring... I haven't the patience for it. I may be persuaded into coming over and having a look and helping you figure out where to start though. PM me your email address or phone number.

If you haven't already, order new valve cover gaskets. They're not that expensive and I'm positive that's where your oil is coming from (it's VERY common). Even if the gaskets are still soft they compress over the years and will fail to seal no matter how hard the covers are tightened (NEVER over tighten the valve cover bolts! The covers warp easily enough and then you're screwed.). The valve covers are supposed to be tightened at 22 INCH lbs... NOT ft.lbs. If you don't have a torque wrench capable of such fine measurement then use a screwdriver and only tighten them hand tight. Some people like to switch out the phillips head screws for bolts; that's fine, but you still need to make sure you're not over tightening them.

Ok sounds great I'll PM you right now. I replaced my value cover gaskets in Oct last yr that's one of the first things I did to the car is a tune up to include replacing the value cover gaskets. I think that when I went to replace my No 3 gaskets I used the wrong gaskets all together so I'm going to redo them with the part number I got from IHATEHACKS thread just in case so there will be no more second guessing on it.

Personally, if you've still got the No3 gasket I'd use it. Just clean off the dried up rubber around there the big bolts go through so it's bare metal and then put some RTV on both sides and reinstall. Those plugs don't really see any pressure worth mentioning so if you don't want to keep the gasket then you could just put RTV on the plugs and be done with it. I'd keep the gasket though, it still serves to keep larger debris out.

I do understand why IHATEHACKS didn't replace it with a new gasket though.. they're damned expensive. The thing is that they're supposed to seal along the sides too. I keep thinking that sometime I'm going to build a template and cast a silicone piece to laminate to the old gasket.. I could do that for half of what Toyota wants for it and get the same seal and... COLORS!!!! ;)

No I threw that thing away to the trash when I put in some plastic gaskets from Napa but they weren't as snug as I would have liked them to be.

Tisk, tisk... well, if they're not sealing they'll leak a bit and it will also cause a vacuum leak. Double them up if need be. Me, I'd toss them, take one of the plugs to A & A Tradin' Post on Broadway and buy a few nice fat O-rings which fit the plug just firmly enough.

Ok, here's the update I was down for about two weeks or so because of several problems that happened at once and waiting for parts from the Toyota Stealership. First my timing was out bad where it wouldn't start, had to wait for a connector from my wiring harness that was broken, and on top of that my starter went out. I proceeded by replacing the plugs, rotor, and cap. So I had to take off the throttle body and the intake manifold to reach the starter. I swapped out the starter and the positive terminal cable. On top of that I changed out some more hoses that were old and had heat damage; replaced the factory hose clamps with some better ones. Also, had to replace the intake manifold gaskets, because they became damaged upon removal. Then I put it all back together and connected the coolant lines together that ran from the throttle body and adjusted the timing with some great advice from CRE, by the way thanks for the help and for stopping by :D Now she sounds GREAT and runs better than before!!!