94 3.0 replacing rear headgasket - replace front?

Opinions sought...
The rear bank of my 3.0 (1990 Taurus, 93,000 mi.) needs a new headgasket.
The front tests fine. Should I just leave it, or pull it and replace
the headgasket on it, as well?
Dave G.
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Dave G wrote:

How did you come to the conclusion that it was bad? Its unusual for a 3.0 to blow them. Common for a 3.8. If it is truly bad, you might have had a bad head bolt. Since you get two gaskets in the kit anyway, there is no reason not to change them both. And clean the gunk out of the heads and egr while your at it. And if you have not done it yet, change the water pump while your at it.
If your going to keep the car, i would take both heads off and take them to a machine shop and have the valve guides checked and the valves done.
Bob
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Thanks for the input - replies below.
wrote:

So I'm told. Last week, leaving my driveway, a few rounds of missing, followed by vast billows of white /blue smoke out the tailpipe. At least it was just as I was pulling out, so I didn't drive it.
When I pulled the back head, the cylinder marked X below had 1/2 to 1 cup of coolant in it.
firewall pass. 0 0 X side 0 0 0 radiator
The exhaust manifold was loose at that cylinder, perhaps contributing to the problem (smoke trails showed that exhaust gases were escaping big time, maybe heating up more of the head than cooling design could handle? maybe).

Well, sleeping dogs and all that.

Doing that - gosh, only 11 bolts to hold it on? You can always tell the design projects that went to the junior engineers. Of course, 2 broke coming off, and only 1 had been crossthreaded on original assembly.

Have a rebuilt/revalved head arriving tomorrow.
Dave G.
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Dave G wrote:

Are you rebuilding the head that came off or getting a replacement? I am kind of curious. When you get the bad head off, report back. Were all the head bolts tight and OK? Where did the gasket fail? Was the old head cracked?
Bob
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"Dave G" <dgayman(at)rcn(dot)com> wrote in message

the head gasket. That is a fairly common failure for the 3.0 and it appears most of the time on cylinder #3 as you describe.
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Oh BTW, while it is torn down, make sure the piston goes all the way to the top of the block, it is very common to bend the connecting rod ( as well as blow the cylinder wall out ) when that much coolant gets in the cylinder. Use a dial indicator and compare it to the other pistons. Even a small amount of bend will cause a engine miss. Take a double look at the cylinder with the piston at BDC look for anything that even resembles a crack. To find a damaged cylinder after you did all this work will surely make you pissed at your self.
>
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Bob first -- head is off, no obvious issues with head bolts (they all backed off with equal-ish wrenching.) No obvious crack.
Also no really obvious issue with the head gasket, so Thomas may be right about the manifold gasket.
I'm replacing the head, only because I got a good price on a remanned one ($100 including shipping, about $25 more than cleaning and planing in my area).
Thomas: Yes - will check piston travel and, yes, I'm worried about a cylinder crack, because there's no definitive leak around the head gasket and I don't know what I'm looking at re: the intake gasket.
*** LARGE GRAPHICS FILE ALERT **** I've put up a Web page, with HUGE picture files sorry to say, at http://users.rcn.com/dgayman/TaurHead.htm
If you have cable or DSM Web access, you might want to look at them -- it looks as though the manifold gasket might have been leaking. Or would the injector o-ring be steam-cleaned and the intake manifold inner surface be rusted if the head gasket was the problem? Would the rust stains on the intake manifold gasket for the affected cylinder be there (it's the only such rusty spot on the two intake manifold gaskets).
If you don't have fast access, I can re-do the pix to make them smaller, but don't have the time tonight.
Dave G.

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"Dave G" <dgayman(at)rcn(dot)com> wrote in message wrote:

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I'll have to study the pan idea -- the car is in the drive, not on a hoist... the y-pipe is still there and still has the exhaust manifolds hanging off it... and I'm running out of stamina and real, real tired of removing nuts and bolts and unplugging things... though if you tell me that crushing a bearing means I'll spin it, dang. A little knocking I can take, but spinning does things to the oil flow & pressure and too many chips will clog the oil intake.
The remanned head is minus rockers and gaskets, otherwise complete. I wont't see it until UPS shows up tomorrow, so I can't tell you more.
I'll have to study the old rockers and put them against the cost of the right thing, new rockers & pivots, but, hey, they're fairly easy to replace if the turn out to be too worn.
Dave

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That's kind of a myth about "spinning" bearings. The extra clearance may be enough to cause the bearing to fail over time due to the bearing not being able to do it's job in controlling oil flow ( letting too much run out of the bearing low lube damage ) and also because the extra clearance will cause excessive movement between the rod and crank ( the knock beating the bearing up ). I know it is a little more work, but it is not by any standard hard. It is a very easy pan to remove. Consider it very cheap insurance. Bearings are cheap, cranks are not and are a lot more work. "Dave G" <dgayman(at)rcn(dot)com> wrote in message wrote:

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[snip]
Seconded. For the amount of work and down time doing one head will take, doing both is a sensible precaution.
/------------------------------------------------------------\ | George Ruch | | "Is there life in Clovis after Clovis Man?" | \------------------------------------------------------------/
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