good report with this modification .

 

I forgot the follow up. So when my son came home from school in December last year (95 9C1), we pulled off his oil cooler adapter to check to see if we had used the "square" ring in his rebuild (we couldn't remember). We had. Oops.

We looked at the paper gasket very closely. You should be able to see the lines from the adapter pressed into the paper like a crease. Nope, no marks. The paper gasket easily slipped right out ... looked brand new.

Now two points:

1) If you torque the adapter bolts down beyond their torque spec ... you might be able to compress the paper gasket if you used the square o-ring. I wouldn't. I think you'd have to be way over the spec. I didn't test that.

2) People say the square o-ring doesn't leak ... indeed, it does not. Wrong measure, wrong issue ... read the thread again. The oil is slipping past the paper gasket between clean and dirty oil ... that's the issue. It's slim, but at 60psi ... it's a basic bypass.

 

Wanted to say thanks, clear as rain. Sticky-worthy.

 

I wonder if this would also cause the oil pressure to read low. I may need to pull mine apart and check this out too.

Back when I did my cooler install I used the square gasket, but I have noticed a steady drop in pressure recently and was thinking of following his advice anyhow just for shyts and gigs. It could just be that I got an engine getting tired or hopefully it's just a sensor or this gasket deal. .

 

Got the Gasket swapped out tonight and pressure is 10+ PSI higher. . The old Felpro paper gasket wasn't stuck to the block at all and pretty much just peeled off the Adapter except for one area around just one of the bolt holes. To be fair I think I installed this setup about 10 years ago and maybe 40-50k. I kinda remember that it took a good bit of scraping to clean the Block when swapping out the L99 Adapter for the Oil Cooler Adapter and this was the original GM install on that engine.

Instead of the Felpro kit I got GM #88893990 (only $3.50 with discount ) and the local Dealer had it in stock. The GM gasket for between the Block and the Adapter is not just paper, it's a metal shim with a paper like coating on it.

Dealer didn't have any gaskets for the 2 cooler lines that connect to the Adapter. Just got 2 Premium Assortment Kits #653306 ($2.99 each) from Autozone to replace those while things were apart. It is the same rubber oring type gasket used on the Drain Plug.

 

Good deal. That was exactly my observation ... the boss end gasket was not even under compression (at the proper torque spec). Definitely use the O-ring. Too boot, O-rings are designed for pressure situations. As the pressure builds, the oil force causes the O-ring to get tighter (expanding its diameter). This naturally seals the connection even better.
Dorman has a kit for the oil filter that also comes with that steel ring with paper over it. The shim just takes up space in the calculations (earlier post above). As long as the steel and paper hit the .035 range ... good to go. If it is too thick, the O-ring will not seal properly.
I have no facts on this, just thinking out-loud. I think the steel shim was part of a follow-up mod to address folks "flattening" the O-ring too much. Once the O-ring resembles a square ring ... it stops sealing as designed. I think they came up with the shim idea to address the lesser of two evils. A simple bulletin would have been nice.

10 psi. Awesome. Good stuff.

 

So I found this thread... and I went ahead and replaced my gaskets, mostly because I am pretty sure that was the source of my engine oil leak. And not a China wall leak. So all went well, and it seemed obvious that the oring was gone. But I lost the washer to one of the Allen head bolts and for some reason that has really pissed me off. I'm still frikin mad as all hell about it. Anyway. If anyone has the exact replacement just sitting around I'll buy it. How hard is it to not lose a frikin washer ya ditz? I'm sure it's some where.. I'll clean the garage this weekend I guess.

Followed your advice because, yeah the obvious answer is that the oil filter gasket is way to big to be compressed to get into the gasket well enough. And when you open the thing up, this is obvious.

Good work on the thread! Really helped me put on mine.

Oh and BTW 4door, the reason your oil pressure went up is because you are now flowing less oil. Pressure is a measure of restriction, not flow. But obviously better to filter the oil than not filter it. Durrrrr!!!!

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Good stuff. I just did this job yesterday on my '95 9C1 and was very perplexed by the metal "gasket" that came with the NAPA kit 601-1363. But with NAPA being closed by the time I opened the kit, I assumed somebody knew what they were doing and installed it. Their kit also comes with the round oring (not the square one). I have not used the car yet but I did start it afterwards for a minute or so with no oil on the floor. I'll check the oil pressure later today when I use it.

I was disappointed that the kit did not come with the gaskets for the tubing and had to reuse my old ones. Thank you 4doorSS for that part #.

Looking at all the gaskets and O-rings taking it apart, it appears that this was not the source of my oil leak so I took apart something perfectly fine and made it questionable. Grrrrrr...

I do plan to get new hoses made so I will do this job again at that time with more knowledge, patience, and measuring.

 

I suspect China wall leak for you Mr. Fun 9C1!! No shame in that..

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You can get generic sealing washers at your favorite auto parts store. Usually with the oil drain plugs and fuel filters. Just get the right size. Don't over tighten, this is a flat on flat seal. Snug plus a bit is sufficient. Good luck.

 

I am deleting my oil coolant lines and replacing with the "L99" Adapter in my "B4U" as I am not racing at this time. Excellent thread !!!

 

... deleting my oil coolant lines and replacing with the "L99" Adapter in my "B4U" as I am not racing ...

The radiator sidetank(s) are meant to warm up the motor oil (and/or ATF) to minimum operating temp more quickly in winter-cold situations, but are superfluous / redundant the rest of the year.
Once the thermostat fully opens, the radiator sidetanks barely function as coolers for (either) the motor oil (and/or the ATF) once the thermostat fully opens, even with non-OE cooler fan-on thresholds.

If one does not race, tow heavy, idle for extended lengths of time, or otherwise subject the engine (transmission) to unusually strenuous loads, the radiator sidetanks can be bypassed / deleted if so desired for the spring, summer, fall (and even warm winters - provided the powertrain is treated gently until after minimum operating temp is reached.

If on the other hand, one DOES race, tow heavy, idle for extended lengths, or otherwise work or play with the powertrain harder than 'normal', one should very seriously consider upgrading to external cooling upgrades for the motor oil, ATF, power steering fluid, and brake fluid, exceeding the 9C1-specs for best results.

(Every winter, I'd typically cover & insulate my 9C1's external motor oil ATF and power steering coolers.
I'd also temporarily remove the airdams every winter to protect them from snow damage.)

 

GM felt fleet use cars (cabs & police) that saw a lot of idle time and long periods of use that an external "air" oil cooler was necessary. This would include high RPM engine use (racing). Additionally automatic B bodys had the external "air" cooler for trans which was also plumbed into the radiator side tank.

GM would not spend $.02 on anything they felt they could do without so IMHO I would not delete the oil cooler to radiator side tank UNLESS you replace that set up to the external air cooler aka 9C1 oil cooler

 

... I would not delete the oil cooler to radiator side tank UNLESS you replace that set up to the external air cooler aka 9C1 oil cooler.

If you'll pardon my paraphrasing?
You'd not delete the 'internal' motor oil 'cooling' provision (which doesn't cool all that much once the coolant hits 195F), EXCEPT to upgrade to an external motor oil cooler?
OK, makes sense to me. I'd apply the same logic to the ATF cooling provision.

That said, a growing number of us here at the ISSF who ... drive more like Aunt Cester or Aunt Tique than we used to.
For the conservative drivers, in my experienced opinion, the so-called 'cooling provisions' which use the radiator sidetanks are more like warming provisions, especially in winter.
As for the rest of the year, once minimum operating temps are reached, they cool nothing.
If anything, the motor oil and ATF radiator sidetanks add heat to the coolant.

...1992-1996 Corvettes do not have oil coolers due to clearance issues when the catalytic converters were moved close to the oil filter.

The only reason Impalas had an oil cooler is because they did not come from the factory with Mobil 1 synthetic. Hence why Corvettes of the same vintage don't have an oil cooler.

Again, to paraphrase:
Since '92-'96 'vettes do not have enough room for any motor oil cooling provisions, it's a good thing that the intentional use of Mobil1 GroupIV synthetic motor oil makes motor oil cooling provisions a moot point.

 

The only reason Impalas had an oil cooler is because they did not come from the factory with Mobil 1 synthetic. Hence why Corvettes of the same vintage don't have an oil cooler.

 

Note: sarcasm

Corvettes had no oil cooler and this was not a problem as they used a oil temperature gauge to tell the corvette driver that the oil was too hot and stop driving. The oil temperature sensor also sent a redundant (one sensor with two separate outputs) signal to the PCM so the warning lights would come on to tell the corvette driver to shut down the engine when it got too hot.

So much easier to down load the problem to the car owner than to add coolers.

In the real world the corvette forums are full of adding oil and transmission coolers just like this forum.

On the plus side a corvette steering cooler seems very large.

 

No, Vettes did not have coolers because:

1992-1996 Corvettes do not have oil coolers due to clearance issues when the catalytic converters were moved close to the oil filter.

 

B body's built with the external oil cooler, aka 9C1 oil cooler, did not have the radiator side tank cooler, just external. Trans had both side tank and external cooler which it desperately needed

Y body cars had a space issue preventing external oil coolers but as mentioned above did have Oil Temp gauge for the reasons stated and synthetic oil which could endure higher oil temp operation

and yes, many Y body enthusiasts added aftermarket external coolers

In my case, 96 SS, I swapped to the external oil cooler and since the T56 swap the external trans cooler is now plumbed as a power steering cooler. My radiator, FSR, has no side tank provisions

 

Yeah the space constraint is absolutely not why they removed oil coolers, if the car needed an oil cooler it would have one.

Richard Newton in Project 101 states: “In 1992, Chevrolet did away with the optional Corvette oil cooler and switched to Mobil 1 as the factory oil. The cooler was eliminated to reduce manufacturing costs, and the synthetic oil could function very well it the high heat. If you have a 1992-1996 Corvette, you should continue to use synthetic oil.”

Synthetic removes the oil cooler need for 95% of drivers. Just the truth. Mobil 1 synthetic flash point is 491 degrees.

For us enthusiasts an oil cooler may be more of a requirement.

 

For us enthusiasts an external oil cooler may be more of a requirement.

I'd gently amend to:
For enthusiasts, and those whose vehicles work hard, EXTERNAL motor oil cooling may be more of a requirement, even if we also already use a genuine GroupIV synthetic motor oil.