2000 Tahoe/White smoke only when temp is up to normal

[Saint John]

I have a 2000 chevy tahoe Limited Z71 classic. It runs great, 5.7l but when ive driven it for a long period of time it begins to blow white smoke until I press accelerator. I put brand new spider injector system. New intake manifold gaskets and the plugs are all fine. I'm losing a small amount of coolant. Symptoms of a head gasket I know. Problem is the compression test dont show anything. I need help, I love this truck and I dont want to get rid of it.

 

[exp500]

Pressure test cooling system, Use stethoscope to determine head or intake. Sometimes have to pull plugs.

 

[Saint John]

Well I'm taking it to my shop and tearing the entire top end off over the next few weeks. I will not give up on this truck. Ive done alot of custom work to it. I do know it is on the left bank though because I have 3" true duals and it is only on the one side. But I was looking for recommendations for a new cam. Since im in there I figure I could play a bit and see if I can get more power out of this small block 350

 

[afpj]

How can you tell it's only one side? Is it blowing white smoke out the tailpipe or from the engine bay?

 

[OR VietVet]

How can you tell it's only one side? Is it blowing white smoke out the tailpipe or from the engine bay?

He has true dual exhaust. One pipe for each head.

 

[OR VietVet]

Welcome to the forum from Oregon.

Sure sounds like a head leak. Get it done before coolant damages bearings. Don't scrimp on parts quality.

When you said you "did not want to get rid of it", I was thinking, "Where is this truck?" Kind of want it. You never said how many miles on it.

There will be some cam aficionado's chiming in. Make sure to check distributor condition while out. Replace any hoses while apart. New thermostat. Etc...........

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

You are already receiving replies for the folks on this Forum.

 

[Saint John]

So my truck has 235,002 on it. So I'm opting for entire top end rebuild.if bottom end is even semi questionable it will get replaced too. This truck is flawless inside and out. The worst thing is I need to put on a rainguard fro pass window. It even has entire Youkon Denali interior. DVD monitors in headrest and double din dvd player. And 2 10" subs.... I couldn't price this truck because for me to sell it I'd have to be dead. Here are some more pics

 

[Rocket Man]

How can you tell it's only one side? Is it blowing white smoke out the tailpipe or from the engine bay?

He has 3” true duals...

 

[TollKeeper]

To me, it sounds like the typical valve guide seals are shot, which was a very common issue on the ol LT drivetrain. The way I read it, it sounds more like your small coolant leak isn't making it into the motor, but somewhere else, although I could be wrong.

But if your doing a top end rebuild, and it is coolant, you will get 2 birds with one stone in either case. So your on the right path.

 

[afpj]

He has true dual exhaust. One pipe for each head.

Doh!

 

[Fless]

He has 3” true duals...

How "flawless" is the rust?

 

[OR VietVet]

So my truck has 235,002 on it. So I'm opting for entire top end rebuild.if bottom end is even semi questionable it will get replaced too. This truck is flawless inside and out. The worst thing is I need to put on a rainguard fro pass window. It even has entire Youkon Denali interior. DVD monitors in headrest and double din dvd player. And 2 10" subs.... I couldn't price this truck because for me to sell it I'd have to be dead. Here are some more picsView attachment 280218 View attachment 280219 View attachment 280220 View attachment 280221

I remember those pull out/fold out cup holders in the center dash on my 1996. I would love to see this rig up close.

 

[OR VietVet]

To me, it sounds like the typical valve guide seals are shot, which was a very common issue on the ol LT drivetrain. The way I read it, it sounds more like your small coolant leak isn't making it into the motor, but somewhere else, although I could be wrong.

But if your doing a top end rebuild, and it is coolant, you will get 2 birds with one stone in either case. So your on the right path.

The way it happens does sound like a valve seal problem but not the color. The difference is the color. He said white so I tend to lean toward coolant instead of oil. I myself would dig deeper to check but his mind is made up on the entire top end and I am always looking for a reason to finally do something I have put off for a while, like @Saint John has likely been doing.

 

[Saint John]

So I just left my shop. I tore both heads off amd discovered the gasket has blown. On both sides. Not very pretty but the block looks intact and the heads look like they can be redone and put back on. Got some pictures of it. I'm not seeing any cracks so thats a plus. Now I'm deciding in whether I should just put new heads on.

 

[Saint John]

How "flawless" is the rust?

Literally the spot above the drivers exhaust. The doors on the back have been painted to match. Mind you this is a 21 year old chevy from Ohio.... Underneath still has factory black paint on it

 

[OR VietVet]

If you take a look at my Build Thread, in the Under Construction" section, you will see something like what your decision is. I am replacing items that at this time are working but have enough miles on them that I am going whole hog and replacing and upgrading.

If you plan to go deeper in the engine, now or later, get your heads done for that future work or put some new ones on but then you might as well just rip it all apart and go Hot Diggity!

I forgot to ask, what coolant are you running? Crusty looking in some spots there.

 

[TollKeeper]

Now I'm deciding in whether I should just put new heads on.

Thats a tuff call. Getting the heads decked, valves resealed, etc, new valves, springs, retainers, etc, can be expensive.

New heads, pull em out of the box, and set them on, and your off and running. And with new heads, you could get them customized for little extra money, honed, decked, etc.

At the end of the day, for me, it comes down to dollars and cents.

New heads can be had for refurbished - 300ish
New OEM style heads can be had for - 1000-1500
New performer style heads can be had for - 1000 to how much money you got?

With a stock lower end, unless you are going to drop in some new bearing, hone the liners, etc, I would stick to OEM or Refurb, or rebuild what you got.

 

[Saint John]

If you take a look at my Build Thread, in the Under Construction" section, you will see something like what your decision is. I am replacing items that at this time are working but have enough miles on them that I am going whole hog and replacing and upgrading.

If you plan to go deeper in the engine, now or later, get your heads done for that future work or put some new ones on but then you might as well just rip it all apart and go Hot Diggity!



The guy who owned it before me owned is since new. He owns the mechanic shop I work at. He used only prestone in this truck. It had blew an intake manifold gasket. Which led to my purchase of it a while back. But I do know that I'm seriously considering new heads instead. The rest I'll clean up and see how it works.

 

[TollKeeper]

Another alternative... Find a donor engine, and rebuild this one to the hilt in your spare time..