I recently purchased a 1989 C4 L98, was running hot so I changed the Thermostat to a 160...... But while doing the work, I noticed the lines are damaged. How would you repair? The are broke right at the connection. I cannot find these lines anywhere.

 

Looks like you will need find something to fit into the control mechanism.'
Then you could use rubber tubing to fit over the plastic line and the "patch" extension.

 

I replaced all with standard vacuum tube.

 

this EGR relay does not have the vacuum attachment nipples like newer EGR relays, so this I would have to replace the relay as well, correct?

 

I would try to drill out the broken pipe with a drill bit turned by hand. Reinsert the pipe after covering the tube with JB Weld. Dan

 

Welcome to the Corvette Forum pcmou94!

The EGR valve should be checked to see if it is still able to move. Using a handheld vacuum pump you can connect to the EGR valve and test while running. While you apply a vacuum to the EGR valve the idle should change a little as the diaphragm moves. If the diaphragm does not move then it is time to replace the valve. When my EGR vacuum solenoid was found disconnected I learned that I had a bad EGR valve. It took many hours of cleaning the hard carbon out of the block and intake manifold. I used a wire brush and carburetor cleaner to get the passageways open again. It was not easy to do But I am glad I did it.

I ended up removing most of the intake system but I replaced a lot of parts. 8 Fuel injectors, 1 cold start injector, 1 fuel pressure regulator diaphragm, 1 EGR valve, a new ignition coil, 8 spark plugs and new wires. The hardest part was clearing the carbon out of the passageways, it was work as the carbon was hard. I painted the intake and re-assembled the whole mess.

After getting your EGR valve to work normally the engine's operating temperature will drop back to normal. The EGR is important to a smooth cooler running L98. The functional EGR keeps the L98 out of the detonation zone and is good for the engine.

 

Think they all have, the entire rubber connector (with the two tubes) needs to be removed.

 

took the option - JB Weld option in the short run until I had time to replace the whole system...... and it seems to be working perfectly. Car runs much better with no hiccups/knocks. Thanks!!

 

Were you able to drill out the broken piece of tube?

 

yes, not perfectly though. used a scalpel as well to gently get out what I could and make the end of the hose flat.