C4in mesa

I have a oi leak. I installed the sensor going behind the manifold rather than removing it. I could barely get my finger tips on it to start it back in the hole. I felt confident it was good and put the socket on it. Used the ratchet and tightened it down. The first time I drove it it started smoking real bad after 3 or 4 miles. I pulled over and towed it home. Got a wrench on it and gave it one full rotation on the sensor. Felt all was good and took it out again. This time I thought the smoke was left over from the first leak. I left a oil trail into my driveway after I pulled in and checked the surface before driving all the way in. I looked after parking it and saw oil drips front the street to where it's parked now. I got underneath it and a small puddle had formed after I shut it off. I will remove the intake manifold and inspect the damage. I suspect the sensor was cross threaded from the start. Until I am able to actually look at it I can't say for certain.
If it is whether or not it can be used again is another question. If not I will get it welded and relocate the sensor to make changing it in the future easier.

johnson-rod

Take the intake manifold off and the sensor is right in front of you. Perhaps you can get a new sensor and carefully thread it correctly. Try some plumber's tape on it. Be careful as these engines are made of aluminum.
You could try running a thread chaser covered in grease down the hole. Crank the engine over to push the grease and metal chips out. Wipe everything down carefully. Clean everything with brake cleaner. Vacuum if possible.
Do not over tighten the sensor. It causes them to fail very soon. And you have the extra problem of the bum threads.
Good luck.

C4in mesa

I just got home from work and immediately jumped on this project. Hoping to get it off by tomorrow night after work. I think I will just move the fuel rails out of the way after I get them disconnected from the intake manifold.
I am ready to remove the 10 bolts and pull the intake manifold off. Before stopping tonight I vacuumed the manifold and then hit it with the garden hose. Afterwards put my tools away and closed the hood. I will wipe it down the best I can tomorrow.

Vetteman Jack

Good luck - hope you can get this fixed without too much problem or expense.

jimcork1

It is possible you just cracked the plastic cap if you tightened too much. If you put Teflon tape on threads It won't allow current to ground properly and indicate. I have replaced 2 sensors by pulling the manifold. I found one of the causes of failure to be the chassy is too short putting a lot of tension on the wire and with engine vibration causes it to fail. I also found a quick easy to install the vacuum line that MUST attach to the manifold if you want the a/c to work properly.

C4in mesa

The AC Delco part has tape on it already to seal it and prevent a leak. The tip has a hole and there is a washer for contact. Until I get the manifold off I am not sure the extent of the damage ? I went through the small opening and didn't have anything in my way except for my hands not being able to get in there left me using tools like a surgeon. I was able to get my finger tips on the end of the sensor and get it started. This is where I think the threads were crossed. I screwed it down and took it for a drive. Until I was about 3 miles away everything worked fine. Then I saw smoke coming out of the hood. I just pulled over and got towed home. I put the 1 1/16 socket back on the sensor turned it once then reconnected the plug. I took it to the store and noticed smoke again but figured it was from the initial leak and paid it no mind. The total distance driven was 4 miles round trip. By the time I pulled in to the driveway it was clear that oil was leaking bad. I had oil from the street to the parking spot. I stopped before pulling in and checked out the space where the car was going. After parking I got under the car and saw a small puddle of oil collected. I can't believe how much oil came out of the sensor ? Man I thought I had a main seal going bad. After calming down and going through the events I am counting on the sensor being the oil leak source.

jimcork1

Your avatar is C4.. Is it C4 or C5 you are working ON? Pic of engines LS1.

C4in mesa

This is a 2004 Z06 LS6 engine.





Filthy ! I have my work cut out to clean this mess up.





The sensor was not damaged by my instalation neither was the hole in the block. I must assume the sensor was not tightened correctly. I did see some goop in the hole along the threads. I must have gotten that in the hole when I was prodding around trying to get it in the hole. I will buy a tap put grease on it and run it down the hole to clean the threads up.

C4in mesa

I have to replace the gaskets on the intake manifold they look worn.

dadaroo

Help me:

I installed the sensor going behind the manifold rather than removing it?


Mr. Sam

johnson-rod

Glad you didn't screw up the threads. If you can clean them up with brake cleaner then I wouldn't mess with the tap.

Normally you don't have to replace the intake gaskets but those look toasted.

Isn't it so much easier to see what you are doing with the manifold off? Don't forget to re-connect that vacuum line on the back of the manifold or you'll be doing this again.

While you have the manifold off you could clean the throttle body and pretend that's what you had planned all along.

C4in mesa

I am replacing several hoses and the intake manifold gaskets plus cleaning absolutely everything. I will put it back together slowly so I don't forget to reconnect anything !

jimcork1

The vac hose to the AC is a !@#$% to install. I found that If you buy emission tubing at autozone same size/type as on the car you can make an extension. I read the chevy book on repairing emission tubing and it is basically a splice with normal vac tubing. I connected the tubing I bought and added about 12" don't remember exact length. Then I put a nice loop coil in the tubing and plugged it into the manifold BEFORE it was seated. The loop was behind manifold and didn't have a kink. This made quick work of connecting and saving all the words that may spring forward if you just installed as the factory did when before the engine was installed.

C4in mesa

Excellent suggestion. I will definitely do this too.

C4in mesa

My intake manifold has oil up inside the ports. As I am wiping it clean using carb cleaner I noticed that oil is up inside each port. Since everything sticks to oil I now have a problem. Tiny particulates inside the intake manifold. How do I clean it short of soaking it in a large pan of carb cleaner ? Even if I could do that inside the manifold is a concern.

zachaeous

I used brake cleaner to spray mine clean. I stood it on it end, front side down with the throttle assy removed and washed it from the top down. It did come fairly clean and I noticed no ill effects from job after reinstall. It did take a lot of brake cleaner though. After the cleaner dried up the inside of the manifold was very clean.

C4in mesa

Here is a picture of my ports now. I used carb cleaner and a rag. Sprayed the rag then stuck my finger up inside and wiped each one clean.

C4in mesa

This is one of my clean intake manifold ports. I used brake cleaner. I held it upright and let the black cleaner drain out. The brake cleaner is strong stuff and did a great job.

C4in mesa

The old gaskets were flush with the intake manifold. The new Fel Pro gasket kit came with the two foam pads. I used a finger dab of Mobil 1 and placed each gasket in the groove.





I'm surprised that the engine ran fine with the gaskets being in such poor condition. The kit was $22.62 off ebay.





This picture clearly shows the raised gasket.

C4in mesa

Done cleaning it. There is still oil residue in the back but it is not caked up like it was before I cleaned this mess.