My 305 TBI needs adult diapers...

[LEEVON]

I am on a mission to cure my '87 w/ 305 TBI of oil leaks. I hate them.

I started by replacing the oil pressure sending unit which was definitely spewing oil.

Still leaked.

Then I did the rear main seal (one piece) and the oil pan gasket.

Still leaked.

Thinking it might be the famous back-of-the-intake leak, I replaced the intake gaskets, and the valve cover gaskets too.

Still leaked.

Thinking I might have fouled up the intake install I did it again.

Still leaked.

Then I took it to the shop down the road to see if they could find the leak. He thought it was the rear main seal so I did it again. I found a piece of the old retainer gasket on the block, so I thought for sure I had found the problem.

Still leaked.

Then I found a bolt that was poorly sealed on the intake (there was oil pooled up) and fixed that. Thought for sure this was it.

Still leaked.

Then I replaced the distributor base gasket which had been done with the intake but it was discolored like oil was going out the back.

Still leaked.

Then I removed, cleaned, and sealed the dipstick tube.

Still leaked.

It only leaks after driving, and it's coming off of the starter. The back of the intake, sending unit, rear main, distributor, etc. are all clean. This engine is pretty clean and I should be able to see a leak.

I have had it on a lift, on stands, lights above and below, and the leak cannot be found but it's definitely on the back above the starter. To top it off, after driving it shortly today, when I parked it puked coolant. Could I have a bad head gasket, which is leaking oil down the back of the block, onto the starter, and now could be causing overheating?

Since everybody likes pics, here's the incontinent hunk of junk I'm talking about:

[gchemist]

In hot weather, my truck also pukes coolant. No problem. Refill it.

A leak over the starter is probably the valve cover. Use some silicon with the gasket.

[LEEVON]

I checked them again today, dry as a bone (I never undestood that phrase). But the valve cover is not leaking. I really am starting to wonder if I'm going nuts.

[Walts_restoration]

well since you think that trucks leaks pretty serious, ill just come over and take it off your hands. beautiful truck man, i love it, good luck on finding the leak. Think your headgasket has a leak?

[Rodms]

If it was head gasket you would know it and probably run like crap and you might have coolant in your oil too,not always,

[N2TRUX]

Don't know why it's leaking, but it sure is sweet looking. Do they make a u/v trace dye for oil?

[Square84]

Originally Posted by N2TRUX

Don't know why it's leaking, but it sure is sweet looking. Do they make a u/v trace dye for oil?

they have it at the parts house for about 10 a bottle and another 10 for the little flashlight and glasses.

[raiders3581]

my truck doenst leak ..... but it doesnt look like that either nice truck

[LEEVON]

thanks for the compliments. I'm about one more wasted trip to the parts store from trading for a non-leaking moped though.

[Rodms]

Are you sure you have the right oil pan gaskets?Sometimes where the rubber meets the cork they will leak and I have got two of the same before and had two front ones in a felpro kit

[85sqbdy]

Sounds Like Its Time To Pull That 305 And Go Ramjet 350.

[rss396]

Some of the early 1987 Chevrolet distributors did not have any grooves in the shaft of the dist to keep the oil from coming up. They would get oil inside of the distributor cap and make a mess leaking onto the intake and down the block. The replacement shaft had a spiral groove that kept the oil down. Check for oil inside the dist cap. If not there dry the dye and black light. It works.

[hotrodlover]

at least you don't have to worry about changing oil all you have to do is just add to it and change filter

[Slonaker]

I had a bad leak after replacing my pan gasket on my old 305. It was a one piece rear main engine like yours.

You know where there's a little dimple in the side of the pan and gasket where the dipstick goes? Mine had that dimple on both sides, but only the passenger side was actually drilled for a dipstick. The replacement gasket only had the dimple on one side. It LOOKED like it fit and sealed, but it didn't. The gasket was a dealer only item that cost me about $75 and a trip to the one dealer in San Antonio that had it in stock. It might be worth checking.

Slonaker

[spudz]

I bet that its still your intake....are you using a cork gasket for the front and back rails?? if so ditch in in favor or a large bead of quality silicone....