BooBsRGR8

Alright guys, I’ve got a few decisions to make and would like your help. My 97 Tahoe has 120,000 miles on it and Im starting to worry about it. I hate not having that piece of mind I used to have. Im moving back to Colorado soon and will be pulling a pretty good size trailer 1700 miles and cant afford to have anything happen during the trip. It would suck to have the truck break down 1000 miles from nowhere. With all that being said, what would yall do to either rebuild the motor or replace it. Im NOT looking for performance, I want reliability and piece of mind.

If I rebuild it, what are my options as far as complete kits? How labor intensive would it be? I don’t want to make a trip to the machine shop but would it be necessary? Would you feel comfortable running it for another 120k?

If I replace it, what are my options? I’ve found L31 crate motors for as cheap as $1,700 but of course I’d like to spend as little as possible. Could I go with a pre 97 TBI motor and save some bucks? Could I throw in a 5.3? I know a lot of you guys are tossing them so maybe I could come accross one pretty cheap. Would I need to replace all kinds of other things if I did this? Im even willing to go as far as just throwing in a carbed 350 crate. Would I need to replace all kinds of other things if I did this? Like I said before, Im NOT looking for performance, just reliability.

I was also thinking Im going to need to do something with the tranny just about at the same time. I don’t want to restore the motor back to like new condition and blow it with the power I’ve gained back. I’ve found tranny rebuild kits but are they worth it?

Any other suggestions? Im open to anything. I love my truck and would like to have it for another 8 years and 120k.

Thanks for your help guys!!!

99GMCsub

if you are not burning any oil and have good oil pressure and no piston slap or bearing rattle. pull the spark plugs and do a compression or leak down test. if that all checks out fine give it a tune up and service and run another 100k. i would trust your motor with 120k if every thing checks out more than i would trust a cheap remaned engine i have had some bad experiances with them

Nikon02

a friend of mine has a 99 yukon with a 350. he has 220,xxx miles on it and the only thing he has tuched besides regular maintenance, was his transmission at about 180,000 miles. i know people with that motor with well into the 300,000s and running just fine ( a few trannys later)

BooBsRGR8

I am leaking a little oil, not sure from where. I need to get some time to get in there and figure it out. Whats a good way to tell if Im having bearing rattle or piston slap other than just listening to it.

Would you at least suggest changing seals and gaskets if the compression is fine and no piston slap?

What do y'all think would be the most likely part to fail?? I really want to feel good about it but Im having a hard time.

Leroy_454

I agree with the others. I have personally seen many of these vortec 350's with well over 200,000 miles and still running fine. If you dont have any oil consumption or odd noises, I wouldn't worry about it. It would just be a complete waste to replace it simply because it has 120000 miles. One thing you should watch for is coolant loss with no apparent leaks. These engines have a common problem with intake manifold gaskets. Sometimes the coolant can leak through internally and contaminate the oil. Nothing to worry about unless you are losing coolant from the reservoir. If you do ever decide to replace the engine or transmission, I recommend GM/Goodwrench replacements (SDPC has them). They have great warranty and quality.

BooBsRGR8

I did have a coolant leak but it was from where the heater hose goes into the block and I corrected that quickly.

Should I be proactive and just replace the intake manifold gaskets now?

Any other problem areas I can/should attack now?

Thanks for all the input guys

Leroy_454

I wouldn't worry to much about it. Just keep your coolant in the reservoir to the full marks so you can easily notice if some is leaking. My 99 model just started loosing coolant, but it never would leak where I could see it. Replaced the gaskets and no more problems. Just keep an eye on the the reservoir every other fuel stop or so and you will be fine.

Bo185

I got 155,000 on my motor and trans! I run Mobile 1 oil and I had to change the intake gasket cause of a coolant leak. Other than that it's great. I trash on it everyday like I stole it and it keeps coming back for more.

I also have a '97 2500 with a vortec 350 as well and it has over 250,000 miles on it and runs like a top. I would not worry about a rebuild just change you plugs if you have not done so already. And like they said keep an eye on the coolant if it drops at all it's going some were more than likly into the motor!

hog

I have pulled down Vortec 350's with well over 300,000 miles on them and the ridge at the top of the cylinder bore from the piston ring is barely large enough to catch a fingernail, bearing look good and everything.

My Vortec 350 has over 300,000 kms, has 1000's of 0-60mph runs, over 300 1/4 mile passes and is daily driven.

That fitting that goes from the heater to the intake is best replaced with a conventional water nipple. The stock quick disconnect fitting is garbage and WILL break off. The only reason teh QD is used is to make assembly at the factory fast and easy, this fitting is made of a crappy material.

GM has improved intake manifold gaskets for these, the stockers are blue, the new 1's are black with metal tabs to help prevent the negative effect of overtorqueing. They only get 11 lb/ft of torque in the proper sequence in 2 or 3 steps of increasing torque. The new gaskets look much much more durable.

if I were to get a replacement, I would go to Skogin Dickey SDPC and order a Vortec L31 out of a 1996-2000 1 ton truck, it has different pn rods and 4 bolt mains. The LD l31 has 2 bolt mains.
The HD L31 is teh same price as the LD 350. Here it is, http://www.sdpc2000.com/catalog/123/...r-8500-GVW.htm

If you have good compression, doenst burn too much oil, if its noisy ONLY when cold out in the morning-but quiets down when the engine warms up, I wouldnt worry about the engine for a long time, at least 300,000 miles as long as you change the oil regularly. The Vortec engines just seem to last a lot longetr than the older engines do. I have pulled down quite a few early TPI 305's and 350's along with some TBI truck engines, these engines have much more of a cylinder bore ridge and tend to not get the same amount of mile from them.


if you buy an L31 Vortec 350 replacement, make sure the builder doesnt cheap out and install a flat tappet roller cam instead of the roller cam setup. The roller cam has benefits is reliability, power, and economy, I have heard of a few companies that do this. ALL L31's had rollercams from the factory, to not install 1 and still sell it as an L31 replacemet is simply wrong IMO.

peace
Hog

BooBsRGR8

Thanks for all the help guys. Im going to sleep VERY good tonight. I guess I was freaking out over nothing. Now I have to figure out what to do with the extra $$$$