Head Gasket Replacement
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FIrst off, maybye youd like to provide a bit more information....like what your talking about.
Secondly, you bump this thread 2 and change hours later, at night no less....please, be patient....answeres do not come instantly!
As for your issue...(and after checking your profile for a hint as yto the vehicle you are talking about) most likley the coolant bypass recalll was not done, causing that cyl to overheat...could be a good many thinks that could be wrong. Plugs, head gasket, etc.
Not too farmiliar witht he problem, so hole up, im sure someone will help
Brad
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2,090 Posts
the coolant bypass is easy:
you have a tube going from the water pump to the firewall (heater core inlet).
you have a tube going from the fire wll to the engine block (heater core outlet).
you cut both lines put "t's" in them and use a piece of 3/4 hose inbetween.
As explained to me, the heater core over time gets pluged up, as a reult the coolant flow is impeded, causing the cooling of the rear head to drop, resulting in burnt plugs and what not. This allows a bit of coolant to bypass the core, coolign the heads, but not afecting heat output.
Brad
This diagram shoud help (BOB, dont laugh to hard, ill kick your ass if you do!)
you have a tube going from the water pump to the firewall (heater core inlet).
you have a tube going from the fire wll to the engine block (heater core outlet).
you cut both lines put "t's" in them and use a piece of 3/4 hose inbetween.
As explained to me, the heater core over time gets pluged up, as a reult the coolant flow is impeded, causing the cooling of the rear head to drop, resulting in burnt plugs and what not. This allows a bit of coolant to bypass the core, coolign the heads, but not afecting heat output.
Brad
This diagram shoud help (BOB, dont laugh to hard, ill kick your ass if you do!)
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Bob Gervais
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OMFG Emma can use paint better than that! You gotta get better at this Brad, we're starting to look way too retahded! 
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Bob Gervais
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To answer the original question, and possibly make us look more intelligent after that fine display of imaging, here's my answer about the head gaskets, along with some diagnostic advice.
First the diagnostics:
-check the plug after letting the car run for about 30 seconds. Is it wet with coolant? If yes, it's a defenite bad head gasket.
-check the compression on all cylinders. PSI should be around 150-160, however you're more interested in the change amongst the cylinders. They should all be within 10% of each other.
-does the coolant reservoir bubble when the car's running? Does it puke fluid out when capped? If so, it's another sign of head gasket failure.
-Does the car overheat, or use up coolant? Another classic sign.
For the replacement, it's fairly simple, and doable by a backyard mechanic with a decent set of tools. A torque wrench is required, however those can be rented at Autozone if you don't have one.
I'll go over some basic things you'll defenitely want to do, however the Haynes manual covers the replacement pretty well. There's simply too much info to type it all out here, you'd be best off to spend the $15 or so and get the manual.
-After removing the heads, take them to your local machine shop and have them pressure checked for cracks or leaks. Have them resurfaced too. Around here, I can get all that done for around $130. It's money well spent, you don't want to have to do this job twice.
-Do not re-use the old head bolts. They are torque to yield, and stretch upon installation. Re-using them will result in improper torquing, and eventually failure. They're only about $30 for 16 of them.
-If the car is going to sit for any length of time, drain the oil and refill with fresh oil. Ethelyne Glycol (the major ingredient in anti freeze) will erode the surface of the rod bearings and eventually cause failure of those as well. No need to create more work!
Now is also a good time to paint your intake, etc. while you have it off. It'll kill some time while waiting for the heads to be done at the machine shop.
If you need anything else, ask away or PM me.
First the diagnostics:
-check the plug after letting the car run for about 30 seconds. Is it wet with coolant? If yes, it's a defenite bad head gasket.
-check the compression on all cylinders. PSI should be around 150-160, however you're more interested in the change amongst the cylinders. They should all be within 10% of each other.
-does the coolant reservoir bubble when the car's running? Does it puke fluid out when capped? If so, it's another sign of head gasket failure.
-Does the car overheat, or use up coolant? Another classic sign.
For the replacement, it's fairly simple, and doable by a backyard mechanic with a decent set of tools. A torque wrench is required, however those can be rented at Autozone if you don't have one.
I'll go over some basic things you'll defenitely want to do, however the Haynes manual covers the replacement pretty well. There's simply too much info to type it all out here, you'd be best off to spend the $15 or so and get the manual.
-After removing the heads, take them to your local machine shop and have them pressure checked for cracks or leaks. Have them resurfaced too. Around here, I can get all that done for around $130. It's money well spent, you don't want to have to do this job twice.
-Do not re-use the old head bolts. They are torque to yield, and stretch upon installation. Re-using them will result in improper torquing, and eventually failure. They're only about $30 for 16 of them.
-If the car is going to sit for any length of time, drain the oil and refill with fresh oil. Ethelyne Glycol (the major ingredient in anti freeze) will erode the surface of the rod bearings and eventually cause failure of those as well. No need to create more work!
Now is also a good time to paint your intake, etc. while you have it off. It'll kill some time while waiting for the heads to be done at the machine shop.
If you need anything else, ask away or PM me.
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Now I read this. :homer:
Here's want went and is going down.
Sell/ give bro-in-law my '95 3.8, drives it about 4 months, a lifter collapses.
He and my other B-i-l replace it without me because i'm too busy.
1 month later main bearings fail.
we don't know that because we think it is another lifter so we replace all the lifters and reassemble.
Went back together nicely. Still making awful noise and get professional opinion that the bearings are bad.
We pull the motor and this weekend I pulled the heads and wouldn't you know the front head (which was removed to change the lifters but shouldn't have been) gasket is the one that failed and caused the death of yet another 3.8L. He also didn't replace the bolts which probably didn't help the situation.
Moral of the story. If you remove a head you MUST have it milled before you reinstall it. Because we/ he didn't because he's an idiot and doesn't do things the right way, he now has to rebuild the bottom end of the motor which none of us has ever done. And for those don't know, the bottom end means everything is disassembled except the pistons and rods, which will be left in.
So... in another thread I'll be asking for advice in the reassembly although I hope I can get a neighbor to do it for us. Anyone know what a fair price to pay for the assembly of the bottom end (Main, and rod bearings)? All the other stuff will be done by us.
-Jeff
good things to look out for guys...
Brad...for your wonderful etch-a-sketch I may have to penalize you for that...that means you'll have to help Bob replace my subframe...lol...
I'm going a whole flush this weekend so I'll be sure to have all the pics we need for a TOTAL write up
Brad...for your wonderful etch-a-sketch I may have to penalize you for that...that means you'll have to help Bob replace my subframe...lol...
I'm going a whole flush this weekend so I'll be sure to have all the pics we need for a TOTAL write up
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2 things..HAVE YOUR HEADS CHECKED!! I replaced gaskets, didnt have them checked..guess what..got to spend another $100 on gaskets and bolts cause the heads were of .08 and .06", so they wouldnt seal. So off they came, to the machine shop, and $280 later they are BRAND NEW!! Got hot tanked, magnafluxed, vacume tested, milled, dis-assembled, exhaust valves shot.ground, 6 new intake exhausts, new valve guide seals, assembled, painted..not a bad deal!!
Also..this link is your FRIEND!!
http://www1.autozone.com/servlet/UiBroker?...23d801af122.jsp
that is WAY better than the Hayes Manual..I use the AutoZone fixer site ALLOT for all kinds of cars!!
Also..this link is your FRIEND!!
http://www1.autozone.com/servlet/UiBroker?...23d801af122.jsp
that is WAY better than the Hayes Manual..I use the AutoZone fixer site ALLOT for all kinds of cars!!
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Bob Gervais
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Two reasons. It takes out any warpage that may have occured, and also gives the surface a nice sealing finish.
Not sure of any in Bridgeport, but I know a great one in Providence if you need a hookup and don't mind the distance thing.
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Doc
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The shops will mill the heads just enough to clear up the warpage unless you specify something different. I don't have the specs but they can only go to a certain point after which a new head will be required. Some are too far gone. If this turns out to be the case with yours, drop me an email I may still have 10 or 12 sets of heads laying around. I have to go root around in the garage to see if Jo got rid of them while I was gone.
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Bob Gervais
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Here's what the shop I use will do for $130:
Clean the heads in a hot tank
Pressure check for cracks, and/or leaking valve seats
Resurface the gasket surface
Usually that's all that's needed, even on a 130k Vulcan. The valve seats are hardened steel, and the valves are hardened as well. There's not much wear in there, even after a lot of mileage.
Depending on the results of the pressure test, the shop may recommend a valve job, which usually includes new valves, valve seats, valve stem seals, and assembly of these items using your old valvesprings. Like I said though, the cases of these engines needing this are rare.
Also, your heads are cast iron, and shouldn't be warped badly enough that they can't clean them up with a couple passes on the resurfacer.
Clean the heads in a hot tank
Pressure check for cracks, and/or leaking valve seats
Resurface the gasket surface
Usually that's all that's needed, even on a 130k Vulcan. The valve seats are hardened steel, and the valves are hardened as well. There's not much wear in there, even after a lot of mileage.
Depending on the results of the pressure test, the shop may recommend a valve job, which usually includes new valves, valve seats, valve stem seals, and assembly of these items using your old valvesprings. Like I said though, the cases of these engines needing this are rare.
Also, your heads are cast iron, and shouldn't be warped badly enough that they can't clean them up with a couple passes on the resurfacer.
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