The most common but most unrecognized oil leak

[Dynomite]

The most common oil leak is an oil pan gasket leak which is often misdiagnosed. What is really leaking is the Oil Pressure Regulating Valve Cover Plate. It will appear as a drip of oil and oily surface on the right front of the oil pan. Often the tendency is to tighten the front oil pan bolts with no success on stopping the oil leak. The Oil Pressure Regulating Valve Cover leak can also be misdiagnosed as a Front Crankshaft Seal leak. The symptoms are a film of oil progressing rearward on bottom of oil pan or an actual drip of oil on the right front oil pan bolts.

1. Oil Pressure Regulating Valve Cover Plate (1990-1991 ZR-1).

The Oil Presure Regulating Valve is located on passenger side front of engine just above the oil pan. The two 6 mm bolts that hold the OPRV cover plate (and gasket) to the Engine sometimes come loose.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite/84b14ee2-b643-4c69-a2a9-de0d92b58a67.jpg

There is an OPRV Cover plate gasket but I just removed and cleaned the two 6 mm bolts (8 mm heads) one at a time and applied Blue Loctite (You could use Red Loctite as you like). I used Blue Loctite because I figured it was a temporary fix but appears to be a permanent fix. I reached in from the top front of the engine to get access to the two 6 mm bolts with an 8 mm hex flex head ratchet wrench. An easier method of access to the Oil Pressure Regulating Valve Cover Plate is from the bottom as described in item #2 below.

Since such a tight area to work in with engine in car I removed each 6 mm bolt one at a time so I did not drop the cover plate or gasket. So...no permatex on that gasket but both 6 mm bolts cleaned and Blue Loctite applied.

Since the bolts and plate were so loose I figured correctly just tightening the 6 mm bolts with Blue Loctite would solve the oil leak and loose bolt problem (The gasket was stuck to the engine block and not the cover plate). I tightened the bolts by feel as I could not get torque wrench even close to that area unless engine is out of car. No more oil leaks in that area at all.

The BEST fix, however, is to replace those two 6mm x 16mm bolts having 8mm heads with two 6mm x 16mm bolts with 10mm heads as described in item #3 below.

Torque for 6 mm bolts is about 89 in-lbs but in that area with no oil pressure to contend with less bolt torque with Blue Loctite or maybe Red Loctite is just fine :thumbsup:

2. Oil Pressure Regulating Valve Cover Plate (1995 ZR-1).

On the 1995 ZR-1 the Oil Pressure Valve Cover Plate is impossible to get to from above because of the EGR. But....one can get to that Cover Plate from below by removing the Passenger side strut that the Passenger Side Motor Mount is bolted to (no pressure on that strut from motor mount). Remove two 15mm bolts toward front and two 13mm bolts on frame rail passenger side. Remove 18mm Nut from Motor Mount Stud and drop the strut. The Oil Pressure Valve Cover Plate can be easily seen toward front where Strut was positioned. The bottom 6mm bolt is easy to unscrew and the top 6mm bolt required a vice grips gripping an 8mm open end to tighten. Both 6mm Bolts with 8mm Heads were replaced with 6mm Bolts with 10mm Heads.

3. The Trick to STOP oil leaks from the Oil Pressure Control Valve Cover plate.

I replace both top and bottom 6mm bolts with 6mm x 16mm Flange Bolts that have a 10mm head for a 10mm Box or ratchet Box wrench. It is a lot easier to tighten a 10mm bolt than an 8mm bolt which sometimes strips in the small 8mm box wrench. I used Red Loctite on the 6mm x 16mm Flange Bolts. No need to remove the Oil Pressure Valve Cover Plate or associated gasket.

https://cimg9.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-f874d5e1_9fa1_4006_8d20_705a8ce24d1c_1__448bec1bac cceecf1682fed82cd34554b63ec4ef.jpg

Two 6mm x 16mm Flange Bolts installed in Oil Pressure Regulator Valve Cover (10mm Heads)
replacing original 6mm x 16mm (8mm Heads) Bolts.
Top 6mm Bolt shown before tightening with 10mm Box Wrench

https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-386b82e6_ccc1_4b91_9c41_404ff4174d7a_1__dec2f738a0 265c7e32263b3c61f283ac22309009.jpg

See Potential Oil Leaks and the OPRV Cover Plate (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1581302471)

[mike100]

Now you tell me, lol. I replaced my oil pan gasket a few weeks ago. It was still wet on the front so I jacked up the engine, removed the middle wheel well plactic cover by the shock and got at it with a 1/4 drive swivel and a couple of feet of extensions. problem solved.


now if I could just figure out if the sub-block girdle seal wetness can be fixed.

[Dynomite]

Well.......you got an oil change out of that deal........I wonder how many New Oil Pan Gaskets have been installed only to continue with the oil leak :D

But the best trick is the use of two 6mm x 16mm Flange bolts with 10mm Heads replacing the two bolts with 8mm Heads. Much easier using a 10mm Flex Head ratchet ;)


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[5ABI VT]

excellent will double check this thanks !:-D:cheers:

[Dynomite]

excellent will double check this thanks !:-D:cheers:

I actually removed both 18mm Nuts from the Motor Mount Studs (the Passenger Side Strut was removed) and jacked the engine up a couple inches to help reach the top 6mm x 16mm original Oil Pressure Regulator Plate Bolt. Once loosened from below, I then reached down from the front of the engine and was able to unscrew that bolt by hand. I then inserted and screwed in the 6mm x 16mm Flange bolt finger tight (with Red Loctite) and finished tightening that top 6mm Bolt from underneath as shown. It was Much easier using a 10mm box wrench to tighten the Flange Bolt. Absolutely NO oil underneath the engine anywhere to be seen :thumbsup::thumbsup:

If you have oil on the front passenger side of the oil pan where the 8mm bolts are located or that first 10mm Oil Pan bolt but the rest of the oil pan is relatively clean........you prolly have a loose Oil Pressure Regulator Valve Cover Bolt.

[5ABI VT]

Going to bump this thread .. still need to get to this but I was wondering .. can the egr system be removed ? Doesn't appear to be aluminum so am guessing it is not a part of the block. I'm wondering if removing the egr would give much more room to tighten the bolts.

[Dynomite]

Going to bump this thread .. still need to get to this but I was wondering .. can the egr system be removed ? Doesn't appear to be aluminum so am guessing it is not a part of the block. I'm wondering if removing the egr would give much more room to tighten the bolts.

I am thinking removing the EGR components would be a nightmare :p
For the 95'......just removing that Engine Mount Strut is very easy and gives you plenty of room.
You do need to do some reaching to get the front 8mm bolt on that Oil Pressure Regulator Valve however.

https://cimg9.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-f874d5e1_9fa1_4006_8d20_705a8ce24d1c_1__448bec1bac cceecf1682fed82cd34554b63ec4ef.jpg

https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-386b82e6_ccc1_4b91_9c41_404ff4174d7a_1__dec2f738a0 265c7e32263b3c61f283ac22309009.jpg

[Billy Mild]

How hard is this to get to with engine in place? Does the fender liner need to come out?

[Dynomite]

How hard is this to get to with engine in place? Does the fender liner need to come out?

See Item #2 in the first post of this thread :cheers:

[5ABI VT]

The pictures are excellent and accurate if a little confusing to figure out what you are looking at. I have a 94, and it is not visible because it is underneath the egr. I am trying to figure out how the egr bracket is removed, that would give line of sight otherwise the egr valve and its bracket/base that it bolts to is directly above.

I'm removing the egr valve now. Looks very easy. Looks like 2 10mm bolts. What it's bolted to however I'm going to try and figure out. I am taking pics and will post if anything is helpful

[Dynomite]

I went to The OPRV cover plate from under car after removing motor mount strut that takes no load from motor. Yes......take photos and describe your methods here :thumbsup:

Oh......I got 6mm x 16mm flange bolts with 10mm heads to replace the 6mm bolts with 8mm heads (lots easier to tighten).


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[5ABI VT]

I went to The OPRV cover plate from under car after removing motor mount strut that takes no load from motor. Yes......take photos and describe your methods here :thumbsup:


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

I couldn't help but want to try :) egr is disabled in the time so I would imagine unplugging it shouldn't light up any codes ?!

[5ABI VT]

Well, managed to get to it from above. I also removed the EGR VALVE, as well as the bracket. All together maybe 7-8 lbs of savings :) the egr bracket is iron and heavy. I'll toss it on a scale later.

After pulling everything .. I looked from a different angle and realized i may not have even needed to remove the egr bracket from the block.. but regardless it opened up room to get a wrachet and my hand in there to easily pull the 2 8mm bolts out turn by turn and thread lock them and tighten them back up.

I did have a slight drip and under my pan I did see what was described in the original post of oil on the pan and in a wavy pattern. I'm not sure if it was coming from here.. the bolts weren't loose but I'll clean up the pan etc and check again tomorrow.

Pic showing the egr valve. Taken from passenger side near the corner of the radiator shroud looking down under the passenger side valve cover.
http://i1207.photobucket.com/albums/bb463/Emm3Speed/Header%20Install%20zr1/55467276-7C28-4F5A-9CB1-EC9679F7E44E_zpsi6ttqilm.jpg (http://s1207.photobucket.com/user/Emm3Speed/media/Header%20Install%20zr1/55467276-7C28-4F5A-9CB1-EC9679F7E44E_zpsi6ttqilm.jpg.html)

Egr valve out
http://i1207.photobucket.com/albums/bb463/Emm3Speed/Header%20Install%20zr1/3ECD72F3-2DD6-45D6-BEF0-DB97DEADEF9D_zps4jw1mrow.jpg (http://s1207.photobucket.com/user/Emm3Speed/media/Header%20Install%20zr1/3ECD72F3-2DD6-45D6-BEF0-DB97DEADEF9D_zps4jw1mrow.jpg.html)

Egr bracket out.
http://i1207.photobucket.com/albums/bb463/Emm3Speed/Header%20Install%20zr1/CD8C1170-0703-480C-AED7-74686E8CED85_zpskmfs4jy8.jpg (http://s1207.photobucket.com/user/Emm3Speed/media/Header%20Install%20zr1/CD8C1170-0703-480C-AED7-74686E8CED85_zpskmfs4jy8.jpg.html)

[5ABI VT]

The Oil Pressure Relief Valve Cover you are pointing to is actually the Passenger Side Chain Tensioner.

lol I looked back at the first page photos and realized my error :-D no wonder after I removed the egr I wondered why it was so easy !! Tried deleting the photo as not to confuse others! Will take another look from above shortly

[5ABI VT]

Pretty sure this is it . Short video showing its location

https://youtu.be/uQkQAuBtylo

That the one dynomite? Looks like 8mm bolts

Saved 4.5lbs too :)

http://i1207.photobucket.com/albums/bb463/Emm3Speed/Header%20Install%20zr1/ED39C702-F1BC-4E56-9EBD-D02327FB952B_zpsvlzcpsih.jpg (http://s1207.photobucket.com/user/Emm3Speed/media/Header%20Install%20zr1/ED39C702-F1BC-4E56-9EBD-D02327FB952B_zpsvlzcpsih.jpg.html)

Pretty sure that was the right cover.. the lower bolt was not even tight and hand loosened . The top was just barely snug. Cleaned the bolts and red loc-tite on both and retightened them. All done from above :)

[Dynomite]

Pretty sure this is it . Short video showing its location

https://youtu.be/uQkQAuBtylo

That the one dynomite? Looks like 8mm bolts

Saved 4.5lbs too :)



Difficult to tell....but seems very hard to get to from the top :D

This is the Oil Pressure Regulating Valve Cover near bottom front passenger side of Engine.

https://cimg9.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-f874d5e1_9fa1_4006_8d20_705a8ce24d1c_1__448bec1bac cceecf1682fed82cd34554b63ec4ef.jpg

[5ABI VT]

Difficult to tell....but seems very hard to get to from the top :D

This is the Oil Pressure Regulating Valve Cover near bottom front passenger side of Engine.


That's definitely it then. Was raining yesterday when I started or I may have gone the under car route as I didn't want to pull the car outside. I will admit .. I am slim.. and it was fairly tight to get my arm all the way down there. Anyone that isn't skinny .. I would reccomend just doing it from below. Tomorrow I'll fire it up clean the pan etc and go for a spirited drive :-D

[dcarroll95]

On my 1990, took the inner fender liner out to be able to see it. Then I used vice grips to extend my 1/4 inch socket with an 8mm socket on it. See the pic below.

Tightened these two plus the the drain pan bolts (removed the frame supports and heat shields) and will see overnight if this was enough. I'm getting teaspoons of oil each night on the garage floor.

[Dynomite]

On my 1990, took the inner fender liner out to be able to see it. Then I used vice grips to extend my 1/4 inch socket with an 8mm socket on it. See the pic below.

Tightened these two plus the the drain pan bolts (removed the frame supports and heat shields) and will see overnight if this was enough. I'm getting teaspoons of oil each night on the garage floor.


Welcome to the Registry :handshak::handshak::cheers::cheers:

What you tightened is the passenger side chain tensioner bolts (not the Oil Pressure regulating valve cover bolts). If you still have a leak...….check the Oil Pressure Regulating Valve Cover.

Post 249 - Oil Pressure Regulating Valve Cover Plate (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505491)

See Also...……. Potential Oil Leaks and the OPRV Cover Plate (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1581302471)


I replace both top and bottom 6mm bolts with 6mm x 16mm Flange Bolts that have a 10mm head for a 10mm Box or ratchet Box wrench. It is a lot easier to tighten a 10mm bolt than an 8mm bolt which sometimes strips in the small 8mm box wrench. I used Red Loctite on the 6mm x 16mm Flange Bolts. No need to remove the Oil Pressure Valve Cover Plate or associated gasket.

https://cimg9.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-f874d5e1_9fa1_4006_8d20_705a8ce24d1c_1__448bec1bac cceecf1682fed82cd34554b63ec4ef.jpg

Two 6mm x 16mm Flange Bolts installed in Oil Pressure Regulator Valve Cover (10mm Heads)
replacing original 6mm x 16mm (8mm Heads) Bolts.
Top 6mm Bolt shown before tightening with 10mm Box Wrench

https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-386b82e6_ccc1_4b91_9c41_404ff4174d7a_1__dec2f738a0 265c7e32263b3c61f283ac22309009.jpg

[dcarroll95]

Thank you! Now I see it just in front of the oil pan front bolts. What a nightmare, but I was able to tighten them and they were each about 1/2 turn loose and leaking plenty right there. Lifted the engine as much as it would go and pulled the passenger side engine strut loose as suggested to get to it from the bottom. Didn't drip overnight but would have eventually so you saved me lots of time!

Thank you - great write up and pictures.

[Ccmano]

Thank you! Now I see it just in front of the oil pan front bolts. What a nightmare, but I was able to tighten them and they were each about 1/2 turn loose and leaking plenty right there. Lifted the engine as much as it would go and pulled the passenger side engine strut loose as suggested to get to it from the bottom. Didn't drip overnight but would have eventually so you saved me lots of time!

Thank you - great write up and pictures.

Yes, welcome! You will find that Cliff is usually (well ok, always) right. His “Solutions” stickies at the top of the the tech section have a wealth of invaluable information. They and a copy of the FSM will get you through 99% of the issues encountered. Good to have you aboard. We hope that you will find the forum informative enough to join us as a full member. Check out the registry site (if you haven’t already done so) for more information.
http://www.zr1netregistry.com

H
:cheers:

[Weeberone]

deleted

[Pete]

I found to be the easy from on top.
Remove Oil filter housing, remove right side motor mount nut, lift motor.
Plenty of room :)

Pete

[Dynomite]

I found to be the easy from on top.
Remove Oil filter housing, remove right side motor mount nut, lift motor.
Plenty of room :)

Pete

Maybe...….unless you have EGR on later Zs.
I do not like to remove oil filter housing (another oil mess) and having to replace that gasket also. Unless Oil Filter housing is leaking :p

https://cimg9.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-f874d5e1_9fa1_4006_8d20_705a8ce24d1c_1__448bec1bac cceecf1682fed82cd34554b63ec4ef.jpg

From the bottom...….
Two 6mm x 16mm Flange Bolts installed in Oil Pressure Regulator Valve Cover (10mm Heads)
replacing original 6mm x 16mm (8mm Heads) Bolts.
Top 6mm Bolt shown before tightening with 10mm Box Wrench

https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-386b82e6_ccc1_4b91_9c41_404ff4174d7a_1__dec2f738a0 265c7e32263b3c61f283ac22309009.jpg

Post 249 - Oil Pressure Regulating Valve Cover Plate (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505491)

See Also...……. Potential Oil Leaks and the OPRV Cover Plate (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1581302471)

[billschroeder5842]

Hey all, I think I too have this issue. I noticed that I have a bunch of oil gathering under the passenger side of the engine and is slowly seeping.

I've read this post a couple of times, but am left pretty confused as there seems to be a couple of ways to fix this. I appreciate all the different and creative way that we all tackled this one.

Is there a consensus on the best, easiest most effective way ?

[TX '90 ZR1]

Hey all, I think I too have this issue. I noticed that I have a bunch of oil gathering under the passenger side of the engine and is slowly seeping.

I've read this post a couple of times, but am left pretty confused as there seems to be a couple of ways to fix this. I appreciate all the different and creative way that we all tackled this one.

Is there a consensus on the best, easiest most effective way ?

Bill,
As far as I can tell there is no easy way to get these tightened up. It was the most challenging leak I had on my '90, but am proud to say it is bone dry now. (Fingers crossed!!).
I could never bend the correct way to get on the bolts from the top. Finally got the car up and removed the frame braces so I could see the area where the cover was. Took the longest ratcheting box end wrench I had, hooked another box end to it and tightened the bolts. The bottom one was quite loose. The top not so much.
I did not attempt to change the bolts as my body does not contort as it used to. Just tightening mine made it dry and it has remained that way for nearly a year.
Good Luck!!
:cheers:

[billschroeder5842]

Thanks- I'm going to tackle (again) tonight and see what I can get accomplished.

[Ccmano]

Bill, what also helps for access is to undo the lower engine mount nuts and lift the engine by and inch or two. If your removing the “K” members (frame supports) you’ll be undoing the engine mount lower nut anyway.
Have fun,
H
:cheers:

[billschroeder5842]

Oh, Jeeeeez.... not looking forward to that one.

I am able to get my fingers on it, by contorting my body and right hand. I can feel the bolt heads but that is about it. I'm wondering what is "better" doing the "k" frame or removing the oil pump. Sure the oil pump is messy but I have a mess going already.

I looked through the FSM last night and found no reference to this fix. Marc Haibeck mentioned this problem in one of his posts. He said he raised the engine a bit and did the repair by feel. Not much more information than that.

I did remove the inner fender well plastic and was able to put some light "down there" I'm going to try (pray?) fishing a long socket extension with some universals through the "gap" and the "feed" with my right hand the 8mm onto the bolt and twist with my left hand. That's the plan from my work desk at the moment.......

I'm blessed with big hands and PopEye forearms so repairs like this are miserable.

[Ccmano]

I found to be the easy from on top.
Remove Oil filter housing, remove right side motor mount nut, lift motor.
Plenty of room :)

Pete

Sounds like a combination of the two. Doesn’t even require removing the “K” member, just the nut. I did one while installing headers and another while the engine was out. I suspect Pete’s got the right idea.
H
:cheers:

[billschroeder5842]

*UPDATE*

I "think" I may have got it, but the true test will be tomorrow when I drive it..

I did a "hybrid" of some of the past efforts. I took a series of extensions about 22" long and put a U joint at the bottom with 8mm socket. I stood on the inside of the tires between the tires and the inner fenders- damn near vertical from the problem area.

I snaked my right hand down to the (it helps if you coat your arm with car soap) down to the fittings and "found" the bolt heads strictly by feel. I then snaked the extension down with my left hand in the area in between the oil filter and the valve cover, dropping it until it fell into my right hand. I "cupped" the u-joint fitting and fiddled around until it mated with the bolt head. I held the extension/u joint pretty firm to bolt to help with seating and void stripping.

I was able to turn the top bolt about 1/3 of a turn and the bottom about 1/2 turn. It was pretty hard to turn the nut but that could have been part of the angle of the u joint and extension.

I'm not sure if I did any good or not, but I'll take it out in the next couple of days. I spent about 30 minutes on it not counting me messing with a rag to soak up any oil residue.

Fingers crossed!

[Dynomite]

I did a "hybrid" of some of the past efforts. I took a series of extensions about 22" long and put a U joint at the bottom with 8mm socket. I stood on the inside of the tires between the tires and the inner fenders- damn near vertical from the problem area.

I was able to turn the top bolt about 1/3 of a turn and the bottom about 1/2 turn. It was pretty hard to turn the nut but that could have been part of the angle of the u joint and extension.



https://cimg0.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/600x500-1/80-386b82e6_ccc1_4b91_9c41_404ff4174d7a_1__dec2f738a0 265c7e32263b3c61f283ac22309009.jpg

If you can see them, you can get a wrench on them.....
just takes the right wrench/wrenches (I REPLACED the two 8mm head bolts with 10mm head bolts) :p

And you have to get the Z off the ground so you have elbow room :D


Post 249 - Oil Pressure Regulating Valve Cover Plate (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-13.html#post1592505491)

See Also...……. Potential Oil Leaks and the OPRV Cover Plate (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1581302471)

[billschroeder5842]

*progress report*

I drove the car about 35 miles today (I do love this car) on my round trip commute to work.

I checked for oil in the cradle to verify my "fix" and found that the area was mostly dry- WAY less oil than before about a 90% reduction. I'm not sure if the remaining oil was left overs that gravity finally pulled down, my poor cleaning job or fresh oil but from a much smaller leak.

I'll do another (but better) clean job and have an opportunity to drive the car about 75 miles tomorrow. That will be a more definitive test.

[TX '90 ZR1]

Bill, have you checked the front oil pan bolts? You need to remove the frame braces to get to them. All of the ones on my car were loose except for the one that was totally missing!
Good luck and thanks for keeping your progress updated.

[wutanec]

Sorry to revive this post, this is probably old news to a lot of people.

I am trying to do this by method #2 originally posted by Dynomite.

So by dropping the "strut", it means the diagonal chassis brace that motor mount is bolted correct? Can I really remove this brace without putting a support on the engine? I am going to do this on a 4-post lift and do not want the motor to drop on my head!

[dcarroll95]

Yes you can unbolt that cross brace and engine won’t drop. You can even pull both when you need access to various things.

[Ccmano]

Yes you can unbolt that cross brace and engine won’t drop. You can even pull both when you need access to various things.

Correct, you’ll find that the engine mounts sit above the “K” member on their own platform. This is also a good time to check the engine mount for damage. Due to age (~30yrs) and heat cycles these oil filled rubber mounts tend to crack and break. If they have never been changed chances are good they are broken. Looks like this when they go.
H
:cheers:

http://a67.tinypic.com/30uflg2.jpg

[wutanec]

Thanks guys, I leased a lift next Monday so I can do a thorough oil leak proofing. Fingers crossed!

[MuRCieLaGo]

This job is a major pain. I discovered oil pretty much all over the place on the ground this morning (especially from passenger side). I tried to access the 2 bolts from above, underneath, from the side... A big hour later, no luck. I had to remove my headers to tighten them with my (left!!) hand. I've got no clue how you do this without removing your exhaust manifold.

Now the car is out of order until I get a new exhaust manifold gasket.

[1991 Corvette ZR-1]

I run the OBX headers but I can get to the bolt closest to me on that cover. On the one furthest away, I happen to have my rack out for service anyway so I was able to reach in through the front to tighten it.