Coryvette1

Alright, so I've had this problem for about a year now, but never really bothered to fix it. I have a small oil leak coming from a line somewhere behind the intake manifold on top of the engine. It really isn't that big of a deal to fix, since it is a small amount of oil, but I still want to get around to fixing it. Problem is, I'm not particularly familiar with this engine as most of the work I do has been on Ford engine and truck engines. Should I get a service manual for this and how hard is it to remove the intake and fix the leak?

Coryvette1

I should mention it is an 87 coupe.

jan-erik

Hi. Be aware of this leakage as it may be a reason for engine crash.
On the top of the engine behind the distributor is the oil pressure switch. This is the switch for the fuelpump. As the oil pressure reaches a certain level it closes and parallells the fuelpump relay. If the switch is bad it may empty the engine oil.
I had a breakdown starting with a slight leak and on a trip far away from home I registered smoke behind the car and stopped. there was oil the ground behind the car and the reason for the smoke was oil splashing ver the exhaust.
The oil spray out of the top (connector) of the switch and run down the engine by the oilfilter.
Its difficult to come to and unscrew it as the place is narrow and to ease the unscrewing and installation its needed a special tool.
Just take care and at least check it. Yoou have to remove the aluminium part of the plenum over the distributor.

Hope you find the leakage
jan-erik

floridamale

You should get a FSM when ever you own a Corvette they will save you a ton of $ash. If you have to remove the intake it looks worse then it really is. A couple thing to check before you do the job, is your EGR, injectors & FPR. Now is the time to replece those if they test out bad. Also check the oil sending unit and pressure switch.
Good Luck its also a good time to clean the top end.

Coryvette1

Where can I get an FSM? Also, is the oil pressure switch actually hidden behind the air intake? When I look at the car, I can definitely that it is coming from behind the intake, but am not exactly sure what is back there.

easyrider41@q.com

The switch in question is under the distributor on the left side==it is a black plastic tube sticking up from the block under the distributor and has two pieces--tip piece usually cracks and leaks oil sometimes a lot quickly. good luck

floridamale

Both the sending unit and the oil pressure switch are back on driver’s side of dizzy. They can be accessed by removing the rear cover on the plenum. That is all that is really back there except for the wiring loom and the tach filter bolted to the bellhousing.
The switches attach to the china wall via a threaded housing

WW7

It could be the distributor gasket is either not there or has torn and is leaking.. It could be the oil sender leaking, or it could be the intake manifold is leaking at the rear, which is common for these engines.. When mine leaked it was the intake manifold..If you pull the distributor you should be able to tell which one is leaking...WW

coupeguy2001

yup, pull the distributor. it's the only way to see what's leaking..........except without the distributor, you have to use a priming tool to generate oil pressure with a drill. Unless it's obvious what's leaking.

cv67

First time around is a pain in the rear after that its easy.
FSM for sure.
TPI is like a puzzle it must be put back together in the SAME order taken apart or you may find yourself doing it twice if you forgot a detail or two.

Calderone

mcsports965

Same problem with my 94'. It started off as a small oil leak from passenger side back of the intake manifold, checked oil pressure switch but it wasnt that. About a yr later the leak got pretty bad and was going through about a qt of oil a few weeks so I finally decided to fix it myself.
I was pretty intimidated about doing it myself and wanted to take it in to get done but figured I would save about $600-$700 doing it myself.
It was actually not that hard at all, a pretty straight forward job. my first time doing it and it took me about 8hrs to do. Now no oil leaks at all and im glad i did it myself!
there are a lot of forum posts giving step by step instructions to change out the manifold gasket, Id recommend doing it soon before it gets worse.

Coryvette1

What was leaking in your car?

mcsports965

oil leak, from the rear of the intake manifold.

floridamale

Great you fixed it your self but in my opinion there is a world of difference between doing the intake on a LT1 & doing one on a 87/ TPI.

mcsports965

good point... didnt take that into consideration!

Coryvette1

I take it a TPI is much harder to do than a LT1?

Kubs

I wouldnt say the TPI is harder, there are just more parts to remove so it takes longer. Take your time and pay attention to where things go and its not that hard of a job at all. When you replace the intake gasket, I prefer using RTV along the front and back instead of the rubber gaskets that come with an intake kit. The rubber ones tend to leak.

floridamale

I always use The Right Stuff on the china walls, have never had one leak afterwards. with Kubs just take your time label things some take photos as a guide whatever it takes to get it right. After you do one you can do them in your sleep.

RLDaily

Oh fiddle, get some tools and fix it.

You think a little old L98 is hard? Try working on helicopters...those are a challenge.

Go by your local O'Reillys or whatever, get the special socket for the pressure switch/sensor, pull everything out of the way and go for it.