99 5.7 vortec w/ blown headgasket

**99vortec** · 09-07-2009, 05:30 PM

Hi,

I've got a 99 Suburban k1500 with a 5.7 vortec w/ 130k miles. Horrible miss, white exhaust, OBD should missfire on #6 with spurious O2 sensor issues. Did a compression and leakdown test.

Highest compression of 170 on 8,4,2,1. 160 on 7. 150 on 5. 140 on 3. 100 on 6. Leakdown test looked good on all but #6 which had air bubbling in the radiator and out the intake. Excepting #6 all the others are within 20% of the highest.

Pulled the passenger side head and sure enough, blown out gasket.

So, a) I want to keep the vehicle and b) since money is always an issue, do I lap the valves on #6 and change out the gasket and bolts or pull the other head, take em both to the machine shop and have them totally gone through. It did overheat couple times.

etc etc... Just looking for some pearls of wisdom! Any upgrades to consider that might be cheapish and bolt-on?

Thanks!

**tattooed4life** · 09-07-2009, 05:34 PM

I think I would knock down the other side and take them in and have the heads checked out. If the overheating did damage at least you'll catch it now and not after you put the motor back together. It will be cheaper in the long run.

**Poor Man** · 09-07-2009, 09:06 PM

Originally Posted by tattooed4life

I think I would knock down the other side and take them in and have the heads checked out. If the overheating did damage at least you'll catch it now and not after you put the motor back together. It will be cheaper in the long run.

I agree with this. Take both heads and have them magnafluxed and gone through. Costs about $120 at most shops. Then use FELPRO gaskets to reassemble. Anything less and you will eventually be doing this again. Good Luck.

Jim

**vncj96** · 09-07-2009, 09:49 PM

Do both heads at the same time, also get the upper intake gaskets done at the same time. I would also get new head bolts. it may cost a little more now but will be well worth it if you plan on keeping it for the long haul.

**99vortec** · 09-08-2009, 08:05 PM

Thanks for the input.

I did some scraping on the bank 2 head and found a crack by the #6 intake valve. So I pulled the other head and found a crack by the #3 intake AND what might be a crack in the #3 cylinder wall. When I pulled that spark plug I didn't think it was going to come out without bringing threads with it. The cylinder head surface was rusty but the gasket didn't look blown out, hence the guess that what feels like a score is a crack in the cylinder wall.

When it rains it pours.

Thanks again.

**vncj96** · 09-08-2009, 11:38 PM

Would be a good excuse to get a E383HT from GM for a replacement!! Or just a upgraded 350 from GMPP

**vms4evr** · 09-09-2009, 12:36 AM

I'm with Poor Man and vncj96. Get the Felpro kit. They have a lot of dry seal gaskets in their kit. Very easy to work with. Get the complete upper engine assembly kit. It contains head, intake, exhaust manifold, water pump, t-stat, egr, and any other required gaskets to do it right. It should also contain new head bolts. You absolutely need new head bolts. Most head bolts that I am aware of are a 1 time use. When you torque them you actually pre-stretch them using a torque down, loosen, re-torque sequence. After they take a set. That is it. If they get removed thrown them away. They have stretched and are no good.

**99vortec** · 09-09-2009, 09:50 AM

Originally Posted by vncj96

Would be a good excuse to get a E383HT from GM for a replacement!! Or just a upgraded 350 from GMPP

LOL. That'd be just the ticket!

http://www.jegs.com/i/GM-Performance...oductId=764049
Engine Hp/Tq: 340 Hp @ 4500 rpm / 435 Tq @ 4000 rpm

Aside from the fact that I have no way to pay that kind of coin, my wife would kill me!!

Actually I've been eyeing this one. (or the 4 bolt version)

http://www.jegs.com/i/GM-Performance...oductId=813788

Assuming the cylinder wall is cracked, if I track down heads, block, get a rebuild kit, gasket kit, pay for machine work, do the assembly myself etc I'll have say $1200-$1400 and a month of work in an engine with no warranty. For another $1k I can get one with a 3yr/100k warranty and be done in a day or two. And I could probably offset that a little with the scrap price of the junk parts and ebay sale of the rotating assembly.

(of course, the redneck in me is considering getting heads and a gasket set and JB Welding the cylinder wall then honing it out)

**vncj96** · 09-09-2009, 10:56 AM

I would go the route with a warranty chevy parts , while it is fun to tinker around and rebuild an engine, if your strapped it would be easier and smarter to do the comlete engine route incase something does go wrong. Either way give us some pics of the fun when you do start the work

**99vortec** · 07-05-2011, 09:14 AM

Update: It only took 1.5 years to come up with the $ for a new engine. I ended up going with a stock replacement from Engines Direct out of AZ. It had the same warranty as a Goodwrench engine and was about $800 cheaper.

The install went pretty well. The hardest part was remembering where all the extra parts went since it had been so long since I'd dismantled the top end. I didn't get any pic's but I can tell you, since I drive a keyboard for a living and don't get near as much exercise as I should the 4 days of yoga in an engine bay wore me out!

The engine purrs just fine. It seems a little sluggish and the fuel economy doesn't seem as good as it used to but the fuel guage is wonky anyway and I haven't actually measured mpg yet.

Now I gotta find a short in the lighter/door lock circuit, get some tires that are round, and fix the a/c. a/c was empty and the low pressure switch was bad. I just filled it up and replaced the switch. It gets down to 50 degrees at the vent when running down the highway but shoots up to 70 in traffic.