28th Feb 2003, 14:13

I have a '98 C2500HD, 5.7/5spd. Truck was flawless right up to 100k miles, now at 110k I'm replacing the intake manifold/heater hose nipple and intake manifold gasket. Replaced water pump at about 98k, didn't bother me.

One word of caution. I've heard of folks "fixing" their heater hose/intake manifold connector by using stainless steel parts. Don't do this! The problem in this case is galvanic corrosion, not DexCool or anything else. Galvanic corrosion causes the less noble of two dis-similar metals to corrode sacrificially, much like sacrificial zincs on sea-going vessels. It's caused by a low-voltage electrical current due to chemical reactions between the two metals. Like the charge you get when your silver filling bites down on a piece of tin-foil. Replacing the nipple with a more noble metal will cause the intake manifold to corrode from the inside out. Your best bet is to use the OEM part, and give it a good wiping down with Corrosion-X at every oil change. This won't completely stem the tide of galvanic corrosion, but will go a long way to helping that connector last as long as it can. As for the DexCool, its' problem is the additive used to keep gaskets conditioned. This is found in the green stuff as well, but in chemical form vs organic in the DexCool. While the ethyl glycol used in DexCool lasts seemingly forever, its' organic additive breaks down just like the chemical additive used in the green stuff. What does this mean? It means it should be changed just as often as the green stuff, or guess what, it eats gaskets. I hope all this helps.

13th Mar 2003, 20:38

I also have the coolant leak and couldn't find it. I just read where a guy with the same problem bought a tube of "Stop Leak" and hasn't had the problem since. He claims to have used only half the tube. I hope it really works... Three bucks beats the heck out of paying hundreds to have the manifold gaskets replaced!! I'll let you know how it works.

28th Mar 2003, 09:59

I have a 97 Z-71 and have experienced the intake leak and transmission problems. I have re torqued the intake at 60K and 105K to accommodate the coolant leakage with good results (no need to replace the gasket). The over sized TCC is the way to go with the transmission. A GM remanufactured transmission will just give the same problems again at 75-90K.

5th May 2003, 12:48

I have a 1996 Chevy Silverado with the problems with intake manifold gasket.

The beef I have is with my local GM dealer. After the sixth time this truck was in their shop, they found this problem. I was told that the condition of my truck's engine light being on was because of a code; I think it was code number (107) rich condition. My question is, is the problem with the intake gasket any relation to the engine light for the rich condition? After the repair of the intake gasket, the engine light has not come on. Cost of the repair was $522.00.

Note: I have bought four other trucks from this dealer.


14th May 2003, 11:34

Regards to changing the Dex Cool orange coolant to the old style green coolant. If you do this be sure to flush the entire cooling system with water and a flush product like Prestone. Do this several times to get all the old Dex Cool out. Be sure to flush the heater core and the engine block, not just the radiator. Then run the engine with htr on for a Short Time with clear water. If the water after 15 minutes or so looks clear, then drain and fill with 50/50% water and green coolant. This must be done because the Dex Cool and the green coolant are not compatible! They will form a brown sludge in the entire cooling system. I rec. using distilled water.

5th Jun 2003, 20:12

I have a 1997 silvarado and have replaced the water pump twice, changed all the hoses, and still had a coolant leak. I gave up and finally resorted to a radiator fix a leak product and it worked. When the truck has been driven at 55 mph for 45 min. or more the truck shifts extremely hard from 1st to 2nd and 2nd to 3rd with check engine light coming on. The dealer charged $700 to tell me that there was no transmission problem and changed plugs and wires and cleaned c20 intake throttle body. The truck was fine for maybe 500 miles and problem occurred again. Toyota will be my next truck.

7th Jun 2003, 10:41

I have 99 GMC safari AWD. The service AWD light has been coming on periodically so I took it to the trans shop. They told me the trans needed to be flushed, serviced and the speed sensor needed to be replaced. They performed the work and I paid. When I picked up the van the light was still on. They told me they don't know what it is except to bring it back and pay for a scan again.

28th Jun 2003, 09:08

Same Problem. 97 GMC with hard shifting trans. when hot and coolant leaks. I have always been a GM owner, but I cannot understand how a truck with 80,000k miles can have this many problems and the company will not stand behind their product? Do Fords or Dodges have these issues?

17th Jul 2003, 12:13

I have a 1997 Suburban 2500 with towing package. I rarely tow anything, when I do it is an 18 foot boat, not much of a load.

At 95,000 miles I have been told I need a $3000 Transmission overhaul. Mine is slipping had burnt transmission fluid when inspected.

Just recently had the head gasket replaced because I had a fluid leak. Cost $700, suspect it was a rip off and that I had the same mysterious leak mentioned in the other comments.

Now my dilemma is to fix it, or try to trade it in with this transmission problem. Was going to get another Chevy, but after reading all these comments, will not. May get a Ford or Toyota.

I agree that Chevrolet has a transmission problem they are not living up to. You should not need to replace the transmission at 80 or 90,000 miles unless you have abused it.

22nd Jul 2003, 22:12

Hey, where's the love? I own a '97 suburban, 5.7, 4x4. Love my truck. Have had to replace water pump, alternator, etc. Those are just wear items. Transmission shifts fine, no manifold leaks. Just turned 95,000 miles. I'm a mechanic by trade and will stand by GM trucks. I work on far more fords than chevy's.

3rd Aug 2003, 19:46

I have a 1998 Silverado and I have a steering problem. When you are making a right hand turn at a slow speed the steering seems to have tight spot or a catch in it. It only does this when turning to the right, and only at slow speeds. I have been told that chevy has a problem in the steering column causing this. The truck has 50k miles on it and it does a good job pulling my 30 ft. camper. Sure would like to hear some comments on this if anyone has any. THANKSBOB.

5th Aug 2003, 10:57

I have a 98 Silverado that also "dives" when negotiating a curve to the right at about 30-45 MPH. I have been told it is caused by a steering speed sensor on the steering column. It seems like this problem should be covered under a recall due to the unsafe condition it creates.