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My dad found the car working on a lady's roof. Her sister died and left the car to her, it was sitting for two years. I took it on a long test drive and paid $2300. It is perfectly clean and has only 55000 miles on it. All of the service was done and documented at the local dealer under a service contract. I took it home and my friend who is a Buick Caddy GMC dealer told me about the intake manifold issues. I did some research and found this site with the wonderful instructions and install guides.

I read Bill's post four times and gathered all of the parts. This is the first time I did a repair without having to run to the parts store several times. Everything went fine when replacing the LIM gasket. Even though the car is a 99, it needed the 3/4 inch stove pipe. When reinstalling everything I noticed the APN intake didn't correctly match the bolt holes when I layed in on the manifold; I needed to force the intake to the right then run a bolt in to keep it in place. I decided to not do the cleaning steps because the car has so few miles. I did clean the back of the throttle body, it was covered in carbon. I accidentally sprayed the sensor in there with carb cleaner, probably not a good idea. I forgot to install the alternator bracket until after the UIM was installed, which made things difficult. I forgot about the PVC and spring when installing the UIM. I actually had no left overs when everything went back together!

In the end, the gaskets and UIM were fine, the car didn't need the procedure at all. Hopefully now it never will. I flushed the engine, radiator and heater core and used the coolant fill procedure. The factory thermostat has a bleed on it. I drove the car for a couple hours, everything seems fine so far. The guides are awesome, thanks a lot.

Glad you did it, because the car DID need it. The OEM design WILL fail. Good peace of mind, and many happy miles ahead.

First off, welcome!! Glad to see we could help you out. The car may have not needed it now, but it will have failed eventually. An ounce of prevention is worth a pound of cure. Now your Olds is good for many more miles of trouble free driving.

Glad to help. If you haven't thrown out the old UIM, take a big needle held in vise-grips or an awl and push hard on the plastic in the EGR passage. See if the point penetrates. Using this method, compare the condition of the plastic in the EGR passage to the plastic on the outside top of the UIM. We usually find a big difference.

Even if the OEM parts were still okay, the aluminum-frame LIM gaskets, APN upper, and no Dex will make your L36 as bullet-proof as we know how. It should provide many years of trouble-free service now.

My 88 has 282,000 miles now. The APN upper just started to leak!

Now that is dedication. Comes back 12 years later to update.

Is it the upper itself or just the gasket?

I just got off the phone with APN customer service. I told them how unhappy I was that their part failed with only 220,000 miles on it. In all seriousness, I read somewhere on here that the intake should be replaced every 100,000 miles. I should have listened!

The coolant is seeping out around the throttle body. I didn't take it apart yet. It isn't getting into the oil or combustion chambers yet.

All anyone really needs to do is fill the coolant ports in the UIM with JB weld. Throttle body icing is very unlikely. Lots of people have done it and I ran that way for years.

I finally got around to fixing my Olds. My goal is to get it to 300,000 miles. The body is very rusty and it might fail before the engine and transmission. Here are some observations on a high mile 3.8.

The plastic elbows were the main problem. I had the metal elbows but I never bothered to install them. The plastic elbows disintegrated after 200,000 miles.

When I first did this repair, the car only had 60,000 miles so the procedure was a breeze. Everything was corroded and stuck this time around. I had to use a long bolt to pry loose the broken bits of plastic coolant elbow. I replaced the belt tensioner. The new tensioner came with metal elbows. I replaced the original belt at 200,000 miles, the belt I replaced it with was splitting apart with about 100,000 on it. I bought two metal coolant parts that fit on top of the tensioner that connects with he heater hoses. One rock auto part fit perfectly but the other wasn't right. I cleaned up the original part with a wire wheel then replaced the o-ring. I replaced all of the hoses at 200,000 miles so I didn't replace the heater hoses.

The original alternator is still good with 296,000 miles but I did have to replace the starter. I'm still running the aluminum LIM gaskets that I replaced at 60,000 miles.

The fuel injector spacers and o-rings from the APN kit fit my car. The redesigned APN UIM was still good for the most part except for the coolant passages into the throttle body. The leak there was minor and I think filling it with JB Weld would have fixed the issue. If I notice any more leaks at the throttle body, I will fill those passages with JB Weld in the future.

I never replaced my PVC once. The LIM pockets were filled with oil. I installed a new PVC but I had to use the original spring and housing because the APN kit parts wouldn't fit.

I used the procedures Bill wrote up to keep my Olds running. The belt replacement, APN intake kit and coolant refill procedures were very helpful again. Thank you everyone who read my posts and helped keep my car going.

Awesome. You're certainly getting your moneys worth out of that car.

Good to see someone with a similar experience with their 3800. Sitting around 245k now on mine. Original LIM gaskets done around 60k. Original UIM failure around the same time. Second Dorman UIM failure a few years later, but lasted nearly twice as long as original. If it fails again, I'll just do another. Job is quick.

Swapped to metal coolant elbows when doing VC gaskets, they were fine otherwise but finally disintegrated during removal.

Other than the AC compressor, all other accessories and starter are original. Original driver side CV axle.

Rust will likely kill mine before 300k though. Hard to beat these cars for a cheap and comfy way to get around with no car payment or stress about whether a shopping cart hits it lol

95naSTA wrote:You're certainly getting your moneys worth out of that car.

...and this thread.