My 89' 7M-GTE Horror Story - HELP!

suprakc

New Member
Sep 29, 2013
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Salt Lake City
A little bit about my car: 1989 7m-gte, BPU (exhaust, intake, manual boost controller always @ 9-10 PSI). Over the past six months (I swear, ever since that 170,000 mile mark...) it has needed various repairs, new radiator, water pump, hoses... and this past month, it suddenly began overheating - notably after casual freeway drives, the auxiliary fans would come on, even in cold weather, and the temp gauge would be a little above normal OT.

Long story short, I noticed the coolant overflow was always... overflowing, and I was losing coolant. Progressively it got worse, and coolant began smelling of combustion, with small carbon particles in it. Despite not seeing any coolant into combustion (no white smoke at any time) I eventually ruled it as BHG. I am a working college student, so a full rebuild was not an option for me at this time. The plan: have the head sent out for complete overhaul and resurface, and slap on a fel-pro head gasket, along with the rest of the gasket kit - just to get me by.

So the project began, tearing that lovely 7m apart in the car (PITA). Luckily, no seized studs or bolts on exhaust side. Several days later, pulled the head and, sure enough, blown water jacket seal on the HG from cylinder 3, with other noticeable leakage from 2 - only it was external, having leaked down the block.

My car was purchased with 146,000 miles on it eight years ago - and had service records for a previous head gasket job. Whoever did it... really sucked. The head bolts were seemingly reused, and none of them came out with equal force upon removal. But nevermind that.

So the head was sent to a local machine shop here in SLC. Warpage in the head was only 0.002, so they lightly surfaced it even. Came back and looked great. We surface prepped the block with a 3M "cookie" rather than a razor blade. I figured that since we were using a composite fel-pro, this should suffice, as the coating and composite gasket should fill any minor surface flaws. Cleaned the pistons, and replaced the head with ARP Head bolts torqued to 90 ft. Lb. in four passes (one pass to tension, three passes 30-60-90) (as per recommended by ARP - despite my skepticism of being too much). Everything torqued smoothly, and we reassembled everything for the next several days.

OK- NOW THE GOOD PART: So after completing things, turned the key once for 3 sec.... twice for three sec...and - it fired! Great! Blew out some smoke and began running, but only on 4 cylinders, (and a coolant hose under the intake plenum began spewing coolant.... fixed that..) Turns out there was a crossed plug wire, so we fixed that... only now it was only running on 5 cylinders. Pulled injector wires, testing each one, and discovered that nothing happened when injector six wire was pulled. So we determined maybe a bad injector.. but it was still ticking - solenoid opening. After days of fiddling, we finally did some rewiring, timing adjustments (very minor), and it began running a little better, almost like it was firing on all six - but not quite.

All the while we were doing this, we noticed that the coolant overflow was spewing out the front... Uh Oh... We replaced the thermostat... still same problem. After a few days of the wiring things, it began blowing white smoke!

So... what could be going on? Could the machine shop have missed a crack in the head? Did the gasket not seal to the head? (no copper sealer used, either). Did I accidentally crack the head while torquing to 90 ft. lb.?

Any insight would be greatly appreciated. As for now, after 3 weeks of dedicated long, late evenings after work and school... I have decided to look for another car and make this a winter project. Just don't have the time.
I will post pictures of the process. Please let me know if you have any similar experiences, etc...
 

suprakc

New Member
Sep 29, 2013
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Salt Lake City
Photos
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supraguy@aol

Well-Known Member
Dec 30, 2005
4,236
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Atlanta
Hmm. really not sure where things might have gone wrong.
If the car was never really overheated, I don't see you warping the block surface at all. I would think that your recipe for repair was decent.
Do you have any pics of the head's mating surface after the headwork was done?
 

taymeller

New Member
Nov 6, 2012
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Orem, Utah
It sounds like your head gasket isn't sealing it could be due to a warp block or head I would check compression on each cylinder and then do a leak down test on all cylinders, and if you do have a cylinder leaking coolant, this will help you find it, and if you need to do the head gasket again pull the motor change the main and rod bearings, and get the block and head resurfaced with a metal head gasket with those ARP studs, I’m telling you from my experiences when I bought my MK3 I did just as you have done, minus the head gasket sealed for a short time but some coolant had gotten on my rod and main bearings and spun my main bearings, and had a rod knock in 3000 miles of doing the head gasket, and then I ended up rebuilding the whole motor after this,
 

suprakc

New Member
Sep 29, 2013
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Salt Lake City
Thank you for the responses. I don't have a pic of the head mating surface, sorry about that. I took pics of just about everything else, and wish I could go back.

I am currently working down to pulling the head again, should be off in a day or two. I agree about the bottom end bearing rebuild, for fear that fluids mixed this time (fresh royal purple down the drain :(

I'll post pics when available, hopefully portraying the culprit of all this.


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suprakc

New Member
Sep 29, 2013
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Salt Lake City
The head was pulled and returned to the machine shop. No visible cracks in head or block surface, looked like the gasket sealed fine, except for cylinder 1 near the firewall had coolant in it.

Machine shop pressure tested the head, no leaks were found.


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suprakc

New Member
Sep 29, 2013
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Salt Lake City
Update:

It looks like my ARP's bottomed out in the block prior to reaching true torque spec. Ordered bolts from Toyota for comparison, and they are about 1/4 inch shorter! Yikes what a nightmare.


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suprakc

New Member
Sep 29, 2013
10
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Salt Lake City
Car is up and running. Used all OEM parts this time (no fail-pro, no ARP). Runs flawless. If anybody else finds yourself in my situation, tell all the haters to stuff it with their advice and go OEM. (If your like me and enjoy the supra for what it is, and don't have 20+ years to work on it).

Cheers.


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MkIII FTW

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Aug 31, 2009
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Huntsville
I will agree that OEM Toyota gear is great. However, I've been building engines for years and not once has Fel-pro or ARP given me issues. The issues that come up most times with a failure is the execution, not necessarily the parts. One could very well have some type of failure even when using OEM. Not saying that is what happened in this particular case...I'm just saying keep that in mind.