Rogue
Well-known member
I need to know what is really going on with my Corvette.
In 2008 my '91 L98 Corvette began idling rough a day after a long drive. It felt like the car had a vacuum leak at idle. It would also surge at small throttle openings. At 35k miles, back in 2003 I had the car tuned up by the dealership which included new spark plug wires, new spark plugs, etc. In 2008 the car had 51k miles on it. I know....I don't drive the car that much! I ride a motorcycle to work that's why.
I replaced the EGR valve thinking it was a stuck valve. The problem persisted. So I broke down and took the car to a trusted garage and took their mechanic for a test drive so that I could demonstrate to him what the issue was. After a day at the garage, the mechanic called me up and told me I had coolant in my cylinders and that's why it was idling rough and surging. I asked the mechanic how he found this out. He said he pulled two spark plugs from the left side of the engine and they were wet with coolant! The repair bill would be $1,500 to R&R the cylinder heads as it could be a cracked head or a defective cylinder head gasket.
At first I went off the roof. Then I sat down and had coffee and thought about it. When I regained my senses, I picked up my Corvette and decided to see for myself. I began to get speptical when I remembered the coolant level had NOT gone down in the car for a while. I also checked the oil and it was clean. The car did not blow smoke out the tailpipes either. So I proceeded to replace the spark plugs just to see what would happen. What's $30 worth of plugs and a bit of time at that point? I was able to replace 7 spark plugs except for the one on the passenger's side closest to the headlight. WTF! I simply could not get to that plug without dismantling the AC and some other bracket! Every single spark plug I removed had some moisture on the threads. Although the spark plug heads themselves (the part where the electrode is located) all came out dry and had the correct discoloration on them.
After I replaced the 7 plugs, I drove the car and holy moses!! The rough idle was gone and the so was the surging! I have since put about 3k miles on the car over the past 11 months and it is still running very good. In fact it is purring like a kitten so far.
However, I'm not so sure.....what about the moisture on the threads of the spark plugs?
Is my L98 truly leaking coolant into the cylinder heads?
How on Earth do I replace the spark plug on the passenger side, closest to the headlight? What do I need to remove to get to it?
Thanks all!
In 2008 my '91 L98 Corvette began idling rough a day after a long drive. It felt like the car had a vacuum leak at idle. It would also surge at small throttle openings. At 35k miles, back in 2003 I had the car tuned up by the dealership which included new spark plug wires, new spark plugs, etc. In 2008 the car had 51k miles on it. I know....I don't drive the car that much! I ride a motorcycle to work that's why.
I replaced the EGR valve thinking it was a stuck valve. The problem persisted. So I broke down and took the car to a trusted garage and took their mechanic for a test drive so that I could demonstrate to him what the issue was. After a day at the garage, the mechanic called me up and told me I had coolant in my cylinders and that's why it was idling rough and surging. I asked the mechanic how he found this out. He said he pulled two spark plugs from the left side of the engine and they were wet with coolant! The repair bill would be $1,500 to R&R the cylinder heads as it could be a cracked head or a defective cylinder head gasket.
At first I went off the roof. Then I sat down and had coffee and thought about it. When I regained my senses, I picked up my Corvette and decided to see for myself. I began to get speptical when I remembered the coolant level had NOT gone down in the car for a while. I also checked the oil and it was clean. The car did not blow smoke out the tailpipes either. So I proceeded to replace the spark plugs just to see what would happen. What's $30 worth of plugs and a bit of time at that point? I was able to replace 7 spark plugs except for the one on the passenger's side closest to the headlight. WTF! I simply could not get to that plug without dismantling the AC and some other bracket! Every single spark plug I removed had some moisture on the threads. Although the spark plug heads themselves (the part where the electrode is located) all came out dry and had the correct discoloration on them.
After I replaced the 7 plugs, I drove the car and holy moses!! The rough idle was gone and the so was the surging! I have since put about 3k miles on the car over the past 11 months and it is still running very good. In fact it is purring like a kitten so far.
However, I'm not so sure.....what about the moisture on the threads of the spark plugs?
Is my L98 truly leaking coolant into the cylinder heads?
How on Earth do I replace the spark plug on the passenger side, closest to the headlight? What do I need to remove to get to it?
Thanks all!