Drip - oil temp sensor - picture

[froggy47]

I've been getting a drip on the garage floor - I thought tranny because of the place where it drips - but it could be this too. It's the pass side of the block. The oil collects on that cable wrap & clip holding the cable wrap.

 

[vettered91]

Welcome to the club!

My 91 started dripping that way few weeks before I sold it (last May), my brother's 91 and 92 did have the same kind of leak a few weeks ago . In all the cases we changed the oil pressure sensor and everything went to normal.

And just this afternoon I was telling him that my LT1 started to leak a few weeks ago, and today it is leaving a path of drops! :duh

The dilemma is that I'm not sure if the cause is the oil pressure or the oil temp and I'm a little low on $ and don´t want to buy both!

Of course there's always the chance of bad intake manifold gasket (RTV sealant) or a tranny leak!

 

[froggy47]

Thanks. Do you need to drain the oil to replace the temp sender?

 

[vettered91]

No, you don't need to drain it but I guess you already know there's not much room to work on it (like everything else in the LT1s & LT4s)

How do you know it is the temp and not the pressure unit the one leaking? (in my past experiences you could see they where broken) (oil pressure sensors)

 

[froggy47]

I don't know, are they both in one unit? See my pic at the top of the post. It's down low on the pass side of the block, all I know.

There's seepage at the rear of the intake manifold, could be that. Dealer's putting the flourescent dye in, I'll drive a couple hundred miles & he'll put a black light on it.

Ext warr work. Shoot, glad I bought it (the warranty).

 

[scorp508]

Is it oil or coolant on your floor? That is your knock sensor above the small shield and it goes into a cooling passage.

 

[vettered91]

The one in the pic is one of two knock sensors. There's another one in the other side of the engine behind another shield but both only could leak coolant.

In my case the oil is leaking somewhere at the left rear side (pilot)
of the intake manifold there's a little base where both sensors oil pressure (vertical) and oil temp (horizontal) are located.

I just took a closer look and the oil temp sensor it's all cover with oil so maybe that's the one!

In my past own experience with four C4s (2 L98 & 2 LT1) that's a very good spot to start looking for oil leaks.

I hope you solve it soon and keep us posted!

 

[scorp508]

In my case the oil is leaking somewhere at the left rear side (pilot)
of the intake manifold there's a little base where both sensors oil pressure (vertical) and oil temp (horizontal) are located.

I just took a closer look and the oil temp sensor it's all cover with oil so maybe that's the one!

On my L98 that is the oil pressure sending unit and you are correct that the can leak major amounts of oil when failing. I think yours may be the same. The oil temp sending unit on my car is a located just above where the oil filter spins onto the block. I would change it ASAP as when they REALLY fail oil can shoot straight out of them killing your oil pressure totally.

 

[froggy47]

vettered91: If that's a knock sensor (not questioning you) & can only leak coolant, then it's not leaking there, because, I truly know the difference between the orange coolaid stuff (coolant) and oil.

My guess now is that it's seepage from the intake manny finding it's way down there.

I'm new to Vette engines & thought it was an oil temp or press sensor. Oh well.

 

[froggy47]

scorp, dude, which is it? You said oil sensor in one post & knock sensor in the other?

 

[froggy47]

Course the three of us have 3 different engines, so that doesn't help.

 

[scorp508]

scorp, dude, which is it? You said oil sensor in one post & knock sensor in the other?

I was replying to what vettered91 was talking about on his engine. Your picture is without a doubt a knock sensor.

 

[vettered91]

froggy47,

The LT4 engine and the LT1 are mostly the same engine with minor changes, most of them internal. I'm almost certain that you have both oil sensors (pressure & temp) located same place than mine.

When one of them start leaking, they do it drop by drop. (mine started last February) It's very difficult to see the oil there at the beginning because it rolls down the engine at many places near the spot in your pic and drops to the floor.

Give it a try and take a look!

Anyway it's good to know it's under warranty.

And scorp508: I really miss my L98! (less complicated engine to work with)

 

[froggy47]

Let's say it's just dripping down onto the knock sensor, where do I look for the oil thing?

Same side of the engine, I assume, where is it, what's it look like, can you post a pic?

Thanks.

 

[scorp508]

Its on the very back/left of your block screwed into a little "tree" sorta thing with 2 sensors on it. It is pretty much where a distributor would be if an LT1/4 had one.

 

[froggy47]

Thanks S!

 

[froggy47]

This must be them, don't look leaky at all, the I manifold rear seal is "sweating" some oil, maybe enough to get down to pass side of block?

 

[vettered91]

They look very clean to me in the pic, I don't know about the intake manifold rear seal but it may be the cause if you can see oil there!

Tomorrow it's a non work day here (today) and I'll try to fix my vette. I really hope my problem stays in the sensor or in the "tree" area because there's lot of oil in the manifold rear seal too.

I'll let you know how it ends! (if it ends) :L

 

[froggy47]

Yup, manny rear seal is gonna leak sooner or later I guess. There's an "off road" intake gasket (bigger holes) to stick in if you do the job.
Part # is posted somewhere, supposed to be that GM detuned the LT4 with a restricted manny gasket so as not to po the lt5 & ls1 guys.

 

[keefyboy]

I hate to threadjack, but here goes...

It was mentioned about manifold leaking oil... I think I have this problem. My question is, how the heck does the intake manifold leak oil?

Now, I've had my muffler bearings replaced and the Knuter valve adjusted, :gap but I didn't know the intake air needed lubricating!!!

There's oil ALL OVER the bottom of my engine, and I know the intake gaskets on the driver's side have been replaced at least once in this Vette's life (thank you to the original owner for keeping receipts!), but how does this develop into a major oil drip?

We're talking enough to give the oil pan a nice oily sheen all over, but not enough to warrant adding any oil at all between 3k mile changes... It's not dangerous (I think) for the engine, but it's annoying to needlessly stain the garage floor all the time... Makes me feel like Beverly Hillbillies moved in! :gap
-keith