Need diagnosis - Headgasket
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
Need diagnosis - Headgasket
90 L98 150,000 miles. I've posted in the past about this problem, had it checked out and was told everything was fine. Now my coolant goes low about every 3 days but runs great. This past week after the car sits it doesnt seem to be running on all cylinders when you first start it. It slowly goes about after about a minute. I pulled all my plugs today and took pictures to hopefully get an idea of what is going on. I'm really leaning towards a headgasket and am waiting for my combustion tester to come to be sure. The car does not leak at all, or is the oil milky. If it is a headgasket, would a basic mechanic like myself be able to change them? How long do you figure it would take, and is there anything I should replace along the way or look for while I'm in there. I've never done anything like this before. I have been reading my FSM and it doesnt seem to hard. But that's just reading, I'm sure actually doing it is way harder. 
I don't know what all that crud is....
Thanks for any help everyone!
I don't know what all that crud is....
Thanks for any help everyone!
Last edited by jimmers; Aug 2, 2006 at 12:45 PM.
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Overall the plugs look pretty good. I'm not sure you could see a minor coolant leak on them anyway. The 2nd pic shows a little build-up from oil which wouldn't be too unusual, given your miles. Take note of whatever cylinder(s) any plugs that look like that came out of though. They are using the most oil. The head gasket change is not difficult. But the intake that you have to R&R to do it kinda' sucks on an L98! 
You'll get a good look at everything with the heads off and may just find that it would be a good time to do an overhaul.
You'll get a good look at everything with the heads off and may just find that it would be a good time to do an overhaul.
Race Director
Joined: May 2006
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From: Phoenix Arizona
Run a compression test to be sure, but it sounds like head gasket deteriation. VERY common with alluminum heads, and not that hard to do. There are threads here to show you how, and if you get in trouble, start a thread! If you're the type that wonders why things are, check this out...........http://www.babcox.com/editorial/us/us80222.htm
Thread Starter
Safety Car
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From: Winnipeg Manitoba, Canada
Originally Posted by bogus
did the plug in picture #1 come from the #8 cylinder (right side, last plug)?
If so, the head gasket is going.
If so, the head gasket is going.
Last edited by jimmers; Aug 2, 2006 at 03:18 PM.
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
Originally Posted by Corvette Kid
You'll get a good look at everything with the heads off and may just find that it would be a good time to do an overhaul.
Last edited by jimmers; Aug 2, 2006 at 03:28 PM.
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Team Owner
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From: San Pedro CA
on the head gaskets, at about 7 o'clock, the gasket has a weakness. I suspect yours has just started to find it.
The head gastet on bastet44s 87 did the exact same thing... a slow coolant loss, and zero other indications... then it blew.
The head gastet on bastet44s 87 did the exact same thing... a slow coolant loss, and zero other indications... then it blew.
Thread Starter
Safety Car
Joined: Mar 2005
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From: Winnipeg Manitoba, Canada
Originally Posted by bogus
on the head gaskets, at about 7 o'clock, the gasket has a weakness. I suspect yours has just started to find it.
The head gastet on bastet44s 87 did the exact same thing... a slow coolant loss, and zero other indications... then it blew.
The head gastet on bastet44s 87 did the exact same thing... a slow coolant loss, and zero other indications... then it blew.
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by jimmers
What exactly does an overhaul include? Can I do this myself or do I need to take the engine out of the car (which I can't). I really don't know anything about all this.
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by jimmers
Are there any performace parts I could get since I'm doing this. I would prefer not to spend a ton of money.
However if you rebuilt, slipping in a better cam would only be the price of the cam. And if you could afford it, porting your heads or upgrading to better ones would yield a nice increase too.
Race Director
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From: Phoenix Arizona
Now don't get excited, but have the heads checked for cracks, if they have any they can usually be welded. I think all you really need is a simple head gasket replacement, About $50 in parts. Your valves, rings , and bearings should be good for another 60-70k, barring any problems now. For more extensive work you should pull the engine. These engines don't really react well to simple mods, you usually have to do several things to get any improvement. The exhaust is probably the biggest restriction, as you will notice when you take the manifolds off. Oh, and check your compression before you do anything.
Last edited by zr1fred; Aug 2, 2006 at 05:39 PM.
Racer
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From: Alpine California
Originally Posted by zr1fred
I think all you really need is a simple head gasket replacement, About $50 in parts. Oh, and check your compression before you do anything.
Thread Starter
Safety Car
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From: Winnipeg Manitoba, Canada
Originally Posted by bogus
A lot will depend on if any coolant reaches the oil. If that happens, all bets are off.
Thread Starter
Safety Car
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From: Winnipeg Manitoba, Canada
Originally Posted by bogus
there is acutally an easier test... the combustion gasses test. It will tell if combustion gasses are reaching the coolant.
it's faster, easier, and very accurate. I think Lisle makes one.
it's faster, easier, and very accurate. I think Lisle makes one.