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Discussion Starter · #1 ·
Having some issues with the 5.3 in my 2000 GMC 1/2 ton Around 90,000 miles and never any trouble till now. - Looks to be water in the oil. A couple of weeks I noticed this and did a complete oil change with Mobil one (this is what I always use) and everything was fine and I checked it again today and it has a milky brown substance on the dipstick and it reads over a quart high.
The coolant level in the tank is at the proper level but I don't remember exactly where it was before. I am asumeing a head gasket. Any way to tell what side it is? I have not noticed any white smoke but it's been so cold it's hart to tell. How much of a job am I in for? Any suggestions?

Thx.
LK
 

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I second the intake gaskets, quite common on GM engines. I bought my 98 2500 with leaking intake gaskets, (7.4) coolant running right out of it in the front.
 

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lk,
I have heard of several instances of cracked heads and at least one block :( I don't think there is any water in the intake, so that should rule that out. The heads that have been cracked are across the top, near the center bolt hole. You need to put some die in the coolant, run it a while, then put a radiator pressure tester on the radiator and pull the valve covers. You should be able to see it bubbling if its the head. Could be the head gaslket too, if it is and you have the heads surfaced ... make sure your machine shop is capable of putting the correct finish on them for the MLS gaskets that they use. It needs a very smooth, almost like a mirror, finish, 30 RA or better.
 

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Well that's not good news. Mine sure had coolant running through it, out it, and all over it.
 

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T-man's motor is different. The ~1995 to 1999 Vortec motors are notorious for the leaking intake gaskets. I just swapped mine on my 97 Tahoe this weekend. I could never see coolant in the oil, but I was getting some sludge oozing from the filter. I then noticed coolant presipitation on the inside of the oil filler-cap.

A compression test on the cylinders will tell you which head it is. But honestly, it'll be another $40 and 2 hours of labor to do BOTH heads while your in there.

May I suggest cleaning out the device(s) that are involved with pulling vaccum from the valve covers. Be it a PCV or not, mine was clogged up with the goey white sludge. So was the bottom of my valve cover, but the PCV system should be fairly easy to get to and clean out. This could help buy time on a slow coolant leak. but 1 quart of 5 being total coolant! yikes, I'd just as soon not drive the car for fear of total bearing failure. cut open that filter if you still have it. See what kind of metal is in there.

It took my three days, about 6 hours each day to replace the intake gaskets on my 97 Tahoe with the two-piece intake manifold. I was totally flying blind!
 

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BB Mike is exactly correct. The intake gasket problems that are so common heard of with GM trucks are commonly associated with the 5.7 motors that were used up to 2000. The newer LS style engines are not nearly as notorious for intake gaskets as the previous engines are.
 

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Discussion Starter · #14 ·
Is there a distributer to worry about on the top end like the old motors? I have not even looked at it yet I as I am not looking forward to this project.

LK
 

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Discussion Starter · #17 ·
Any special tools needed for this job? The exhaust manifold bolts look TINY - Hope I can get them loose.

LK
 

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There is no distributor, new distributorless ignition. It does have a seperate coil for each cylinder though. Remember fellas, these engines are a completely different beast than all previous chevy engines. There is pretty much nothing the same as previous small blocks. I think the only parts that are identical are the cam bearings.
 
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