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Old 10-29-2020, 09:59 AM   #26
esmth
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I replaced my head gasket for the same issue. Kept leaking externally on the exhaust side and it was neither the valve cover nor the cam seals. As far as I could tell it was an original HG. (~260k miles at the time)

My exhaust studs were the main thing I was worried about, and I ended up snapping 3 of them off. 2 were recoverable and the last was too low below the surface. Still running with 7 (well now 6 ) without an exhaust leak.

About the valve cover gasket, I used RTV in the corners where it bends over the humps. Both top and bottom of the cheap gasket with no-leak & no-seep success.
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Old 10-29-2020, 11:35 AM   #27
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PB blaster the exhaust nuts every day for a few days before trying to loosen them. Also try to tighten just slightly before loosening.
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Old 10-29-2020, 12:03 PM   #28
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Quote:
Originally Posted by Toybox View Post
Errr... isn't a non-flat head one of the primary reasons the HG would fail in the first place?
Head gaskets can leak coolant and oil from corrosion. Caused by long oil change intervals, never changing the coolant, and age.

All of the head gaskets I have replaced started leaking from corrosion, not from overheating and the head warping.
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Old 10-29-2020, 12:18 PM   #29
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1 quart every 5k miles is what I would consider an acceptable leakage. Probably doesnt even leave a spot on the driveway.

Regarding VC Gaskets, I usually put a skim coat of Permatex "The Right Stuff" Black Flavor on the gasket and a dollop in the corners where it bends. Toight like a Toiger.
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Old 10-29-2020, 12:40 PM   #30
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Quote:
Originally Posted by culberro View Post
All of the head gaskets I have replaced started leaking from corrosion, not from overheating and the head warping.
Good data point to know. I was taught that Aluminum heads warp not just with overheating, but also very, very slowly due to combustion pressure and time. Whenever I have removed one (typ 250+k miles and 25+ years), it has always needed a very small cleanup cut. Maybe I've been doing overkill, maybe a few thousandths doesn't matter, but I figure why bother with the HG replacement if I don't give it the best chances of survival? In comparison, cast iron blocks have never failed a straightedge test, for me.
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Old 10-29-2020, 04:02 PM   #31
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It's the oil feed to the cly head valve train. You will need a new head gasket.
I had this happen on my 92 245. I ended up redoing the head gasket. Mine started leaking pretty badly.
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Old 10-29-2020, 09:55 PM   #32
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The leak in question is oil under pressure from the oil pump to the cyl head, goop,sealer's etc won't work.
A. Leave it alone and let it leak if you do not want to change the head gasket.
B. Leave it alone, let it leak oil, run out of oil, blow up motor.
C. Leave it alone, let it leak oil, catch on fire, burn the car to the ground. [happened to a customer of mine, was too cheap to fix the problem].
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Old 10-30-2020, 01:09 PM   #33
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Thanks everyone. I figured goop wasn’t going to help. I’m just going to monitor it for now and see the outcome. If it worsens, I’ll post back with questions on how to go about doing the job.
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Old 10-30-2020, 03:22 PM   #34
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I timed myself when I pulled the head on my 1991 740 Turbo with 300K+ miles. It took me ONE HOUR. That is with professional tools, equipment, and skill level. Putting it back together has been taking quite a while to "do it right". With new studs, engine bay cleaning, block cleaning, replacing blown rubbers, etc.
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Old 10-30-2020, 11:27 PM   #35
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Originally Posted by 240-FAN View Post
Eeeek. I was afraid of this.
Hate to admit it, but the car is probably not worth fixing because Iím pretty sure those exhaust manifold nuts are not going to come out without a 3 feet breaker bar.
A large breaker bar on a rusted exhaust stud, sounds like a disaster(I've seen the studs break with a regular racket handle). If you do decide to go the route of doing the HG, maybe check in with some of the folks on here. Personally I've never used a torch on manifold nuts, but seen plenty who did with success(careful not to damage the head!). My technique was to do something like VB242 mentioned by adding penetrating oil over several days, and that has so far worked for me.

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Old 10-31-2020, 11:11 AM   #36
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Quote:
Originally Posted by ZVOLV View Post
I timed myself when I pulled the head on my 1991 740 Turbo with 300K+ miles. It took me ONE HOUR. That is with professional tools, equipment, and skill level. Putting it back together has been taking quite a while to "do it right". With new studs, engine bay cleaning, block cleaning, replacing blown rubbers, etc.
Thatís mighty impressive. When the time comes, my plan is to get started on a Friday afternoon and hopefully have it back together by Sunday night.

Quote:
Originally Posted by Otto Mattik View Post
A large breaker bar on a rusted exhaust stud, sounds like a disaster(I've seen the studs break with a regular racket handle). If you do decide to go the route of doing the HG, maybe check in with some of the folks on here. Personally I've never used a torch on manifold nuts, but seen plenty who did with success(careful not to damage the head!). My technique was to do something like VB242 mentioned by adding penetrating oil over several days, and that has so far worked for me.

Thatís a good idea. Dousing it with some PB Blaster every few days for a couple of months isnít going to hurt anything I suppose. The car wonít be driven more than a few weeks now until April.
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Old 10-31-2020, 01:44 PM   #37
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Get all new studs, washers, and nuts. New headbolts. A headgasket kit. A good 14mm 1/2" drive impact socket and 6" extension. A good breaker bar, and a pipe to slide over it. Get a 24mm impact socket for the crank pulley bolt.

PCV box oring, dipstick oring, heater hoses, pcv hose stuff, 15 feet of vacuum line, air filter, coolant, oil and filter!
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