TOPIC: 2002 Chevy CorvetteI ssue I'm trying to fix

I don't want to bother Ron so much anymore. I think I've done that enough. That's why I'm posting this on the forum.

My mother-in-law husband Rob. Got his Chevy Corvette grooved by Ron here in Utah on September 1st. He also capped the PCV valve. That same night he noticed oil leaking. Ron quickly called him and told him the seals are worn out. The front and rear seals.

Ron if you read this I think it's awesome that you are willing to call people and help out with any issues they have.

Anyways Rob contacted a mechanic he has known for several years.They lifted the corvette to inspect where the leak was coming from. The only place the oil was leaking was through the throttle body. The mechanic took off the capped PCV valve. Took it back to the way it was. Rob took it for a long drive and found no leaks when he came back to his house. Now he is a disgruntled because of all of this.He is assuming that the groove and capping the PCV Valve does not work on high compression engines like the corvette.

I wish to change his mind and I know Ron or anyone here can help out with this issue. I also wish to prove him wrong.

I don't know about anyone else here, but I don't know of any oil anywhere near the throttle body! And if the mechanic thinks the throttle body is the source of any oil leak just might want to go back to school.

Of course, if the blow-by was the cause of the leak (entering the intake) perhaps tightening the clamp would have taken care of it.

How about suggesting your friend take another look at it. Anyway, he told me it was coming from "the front and the rear" and made it sound rather severe! WAY more than could ever come from the breather tube.

Never trust an average mechanic when it comes to diagnosis when The Groove has been applied. If they could make them run better, they would be doing it. They have no interest in solving from our perspective, for they (for the most part) are conditioned beyond repair.

I wish more people were like us...

AS Ron said, there is no oil near the Throttlebody, it sounds like the intake vacuum was doing its job drawing the excess gases out of the crancase via the PCV line... sounds like he needs to replace the PCV valve for starters.

and if there is that much oil coming out of the engine via that hose, he may want to start checking his cylinder compression among other things.

Once that is all resolved, give it another try. If indeed the PCV line was the source of the oil, the mechanic obviously did not recognize the nature of the real problem that may exist.

Glad you put your post here.

Later

Karl Fortner
Tacoma, Washington

Hi Guys!

This Corvette has a 5.7 liter with electronic trottle body. Like Ron and Karl said, no oil goes through the TB. Check to make sure the PCV line from the drivers side valve cover and the vent hose from the pass side valve cover are "tee'd" together and then that "t" hose routed in front of the throttle body - passive side. This engine should be tight enough that rerouting the vent and pcv lines to the passive side of the throttle body will help the groove work AND keep the oil where it belongs.

Hope this info helps.

Scott Castleberg
Pellston, MI
Gadgetman Michigan

Hi everyone, I've got 2 cents to add to this. Just my opinion...

I've noticed a small amount of oil aspiration through the PCV re-route mod. On a few engines some oil does get drawn up through the tee'd hoses. If the hose diameters and legnths are increased it may reduce oil aspiration. A 3/8" I.D. fuel/PCV hose will fit pretty snug into a 5/8" I.D. heater hose, for example. A clamp over the hose joint keeps things snug, or use an adaptor.

I bought a Condensator and put it inline on PCV hose on my Slant Six years ago. The kit includes hose adaptor connectors and I think 3/4" I.D. hose, 4 feet of it. Idea is to slow down velocity of crankcase gas in hose, giving the Condensator more time to separate out heavy hydrocarbons and pass the light stuff.

My idea/theory here is with increased hose volume, the vacuum through the Tee'd hoses will be less, should reduce oil aspiration. Any crankcase gas pressure still can vent through the hoses OK.

Worth trying IMHO...

TracyG Gadgetman Reno

I 100% agree with you Ron. I wish everyone was like us. I will tell him to replace his PCV valve and tighten the clamps on his throttle body.

Can an auto parts store have the equipment to check cylinder compression or will he have to take it to a mechanic?

It just sounds like there is something else wrong. Never heard of oil passing through the throttle body.....

Something to keep in mind with any kind of vapor, after awhile there will be accumulations that will eventually make themselves known. That is why they want to keep it contained in the engine. With a high performance engine... and a lead foot there is no telling what kind of accumulations may occur.

Karl Fortner
Tacoma, Washington

I just wanted to give an update. Rob the corvette owner after the leak happened. Had it checked out from a mechanic he trusts. The mechanic looked it over and everything seems fine. Nothing is loose.

I told Rob it's most likely his PCV Valve that needs to be replaced. I called up a Chevy dealer and it's a cheap part only $8.22 at the dealership.

But Rob was skeptical. It shouldn't be the PCV Valve because it's capped!! Why would it be that? I could not answer his question. Hopefully someone here can help me with this. I will ask him if his PCV Valve has ever been replaced.

So now he is driving his corvette back to stock. He is only getting half of the benefits of the Gadgetman Groove. He also thinks that the Gadgetman Groove does not work on high compression engines like his corvette.

Ok, here's two cents more. Here's a link to a forum for Corvette and other GM car fans:
LS1 PCV system to a LS3/7 style....how to route it????? - LS1TECH - Camaro and Firebird Forum Discussion

So here are some good pics of and discussion of the PCV system in these cars. Anyone here tech-savvy enough should already understand what the whole re-route thing is about. Same principle applies to any engine, it's just figuring out the hardware, routing and execution of this mod.

I did a Groove w/ re-route mod on an 06 Chevy Avalance 5.3 ( I think it was, it was the small-block flex fuel one). It had a conventional PCV on top of the intake man. towards driver side. So that one the pcv is direct to manifold vac--so it was capped and the hoses re-routed.

If these pics on this GM enthusiast forum show the type setup owned by the 'Vette owner mentioned--well then here is a great visual explanation of this system. Note these guys are also talking of re-working their PCV systems and one of their issues is controlling oil/oil vapor going to intake.

The Groove will work regardless of higher/lower compression ratio. Remember despite the Pride we take in our respective rides--the engine doesn't KNOW it's in a Corvette, or a Mustang, a BMW, a Charger, a Dodge Dart, or whatever!

TracyG Gadgetman Reno

Basically, all he is doing is putting the hose back where he can't see the oil vapor that comes out of the engine.

The EPA's whole purpose in this is to contain the product that is exiting the engine block and reburning it.

For it to be relocated to the intake side of the TB changes nothing but the visual.

Karl Fortner
Tacoma, Washington

Ok, my 2 cents are basically I could guess here but to be more sure I would need data. If the pcv and hose doesn't fix it (re-routed to a connection in the tube before the throttle body) you have other issues with excess crankcase pressure.

What is the compression tests on all cylinders with the throttle body wide open and no air tube? (A leak down test would be better than compression if you know how to do that). This needs to be when the engine is hot. Also hook up a vacuum gauge to it and tell us the vacuum at idle - again with the engine hot.

Sounds like the piston rings are getting tired and has a little blowby or intake gaskets are leaking a little. The compression test and vacuum test can rule that out. It may take inclusion of a catch can between the pcv and intake to keep oil out of the TB.

I looked at this video on youtube and there were some good comments that might help:
ls1 oil leak - YouTube

Also read this post (see page 1 for stock pcv routing diagram with catch can). I will ASSUME that getting a catch can with pcv and then hooking up the vacuum side of the catch can in the airstream in front of the throttle body would help. Hard to say though as it is hard to fix it not being in front of it. The vacuum lines from both valve covers would need to be in a T or Y and plumbed into the catch can together. See my revision of the diagram posted of the stock routing for more clarity.

Stock routing with catch can (not optimal with gadgetman groove):


Help with oil leak, PCV, RevXtreme catch can - Page 2 - LS1TECH - Camaro and Firebird Forum Discussion