GM Truck Club Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
671 Posts
Discussion Starter · #1 ·
I bought a 99 tahoe back in February (ebay special) was nice as hell so i had no problems driving from Nashville to PA to pick it up. I noticed that the at different times on the way home (usually shortly after i got in it really well) I smelled coolant.

The coolant bottle was kind of full so i assumed that it was just coolant over flowing the bottle but I also noticed it smelled like the coolant was burning off on something. I was kind of baffeled because I looked but didn't see any thing leaking from any where.

Fast forward to two weeks ago. I left the house mad one day and of course took off like an idiot rooster tailing dirt and gravel the whole way out of the driveway and to the auto parts store to get some mobil 1 oil as it was time for an oil change in it (I have had great success running strictly mobil 1 in anything with more than 100,000 miles on it). When i pulled in at the auto parts store i got out and heard a faint hissing and realized it was coming from my truck. I was bound and determined to find the source thinking i would be lucky and it would be something simple like a hose or clamp or something that needed replaced.
Not so lucky on that count, the leak was coming from between the intake and the head on the drivers side front of the engine, a tiny little spot right under where the AC compressor hangs over the front of the motor on that side.

I was told that the Vortec motors all have problems with the intake gaskets not holding up very well anyone have any coroboration of that statement from thier mechanics ?

The truck still runs like a raped ape but I noticed when trying to diagnose the problem a little further at home the upper hose vacuumed almost completely closed when the engine RPM's were up around 2500 - 3000. I don't know how to begin with the repair on this one there are too many electronic gadgets in the way and I really don't look forward to recharging the front and rear ac in this thing because i had to take the compressor off to change out the gasket .

Any feedback at all would be greatly appreciated

Jim
 

·
Super Moderator
Joined
·
1,567 Posts
Yep, that vintage Vortec engine has intake gasket issues. It seems they like to go about 100k miles. I've replaced the intake gasket on my '98 5.7 (Is yours a 5.7?). I didn't have to evacuate and recharge the AC, just hang the compressor out of the way. Beyond that, it was a bit of work, but doable. A good manual, and there's at least one good write-up on the net that helped me do mine. Most say the new Fel-pro gasket set is the best replacement.
 

·
Registered
Joined
·
671 Posts
Discussion Starter · #3 ·
yes mine is a 5.7 litre , nothing else would move this big beast as well. was considering a hydrogen hybrid conversion on it too, may look into that a little further after i get this situation straightened out. my wifes suburban may have the same issues soon as hers is a 98 5.7 vortec also. I love the 350 v8 you can't beat those things. the right mix of lower back pressure (Flow Master) and intake (K&N air filter) combined with a good Synthetic motor oil (mobil 1 10w30) and usually you have one hell of a good running vehicle , ( I still have an 89 silverado sport 5.7 (pre vortec) that has 272,000 on it and it never had to have a wrench turned on it till now. It needs the upper end gone through now though as it is floating a valve after 45 minutes at highway speed. Hadn't anticipated the heart ache of having to work on this thing already.
did yours start leaking in the same place?
 

·
Super Moderator
Joined
·
1,567 Posts
When I had the pressure tester on mine, it appeared to be leaking from just below the thermostat housing. Others have reported the leak coming from the rear of the intake manifold.
 

·
Registered
Joined
·
671 Posts
Discussion Starter · #5 ·
getting it repaired

When I had the pressure tester on mine, it appeared to be leaking from just below the thermostat housing. Others have reported the leak coming from the rear of the intake manifold.

Finally found a GM mechanic that will fix it on the side for a reasonable fee. all the dealers were wanting close to $1000.00 for putting in the new gaskets and i have learned from many other tahoe and suburban owners that this is a common thing to go wrong with the vortec motor which worries me because most of our vehichles are vortech's (Chevy family) we have an 89 silverado sport (pre-vortec), a 98 suburban SLT, my 99 Tahoe LT, and a 2000 Astro AWD with a 4.3 vortec. all but one of them has the vortec branding, thinking about reinvesting in swapping out the tahoe vortec for a 9c1 interceptor motor so i won't have these issues any longer,

What are your thoughts on this idea?
 
1 - 5 of 5 Posts
Top