Thread: Questions as I work through LIM job...

Hi all, I'm new to this forum and was directed over here by a good dude from a Buick Regal forum who said this forum is super helpful, active, and knowledgeable. I have an 01 Buick Regal LS (naturally aspirated) with the 3.8L V6.

To start, the car had a bunch of leaks when I got it. I am tackling these slowly but surely. I started with the oil pan gasket and changing the out the motor mount, both of which had failed and were leaking (one oil, the other hydraulic fluid of course). This is where my first question arises. During the oil pan gasket change, I had to remove the oil pickup tube to install the windage tray for fear of damaging it. I encountered an extremely difficult/baked on gasket at the oil pickup tube. I was tired, and it was late, and I unfortunately made the call to leave some of the gasket on that I could just not get off. So, I put the new gasket over a non-perfect mating surface. This was dumb, I agree. I still regret it. Next time I will call it a day and start fresh another time because it's not worth it. Given all of that, I've been concerned about possible oil starvation and decided to test the oil pressure. I took a couple short videos and here they are:

Video @ idle: https://youtu.be/GNe2CgEhYAc
Video @ 3K: https://youtu.be/VctvaU8hgsM

My questions are: is the bounciness normal at idle? Is this pressure normal for a car with around 114K miles? Is it odd that the bounciness of needle goes away at 3K rpm? The gauge was brand new. It seems as though it had good pressure and I'd like to stop worrying about the oil pickup seal if there is any chance that these results can confirm the seal is ok.


Currently, I'm working through the LIM gasket and valve cover gaskets due to other leaks. Once winter temps warmed up, I noticed steam out the exhaust pipe and fairly recently, a slowly decreasing amount of coolant. This led me to believe some sort of upper or lower intake manifold gasket failure. The valve cover gaskets were pretty obvious - oil seeping slowly right beneath them. This is my first time doing a job like this and I've snapped some pictures along the way with some questions. As far as parts are concerned, I am going to replace the upper intake manifold/plenum with the Dorman kit. Using Felpro LIM gasket kit, aluminum coolant elbows, new stant 180 degree thermostat, Felpro VC gaskets and grommets, new autolite iridium plugs and new delco wires (I took the advice of a DIY article on another forum which said that if someone suspects coolant getting into combustion process, it is best to drain oil and coolant, pull all plugs, rotate crank bolt manually to purge coolant out of motor, add oil, run starter several times to lubricate bearings and get additional coolant out, then drain oil. I figure might as well put new plugs in since I had the old ones out and don't know when the previous owner last replaced them. I've had car for about 10K miles total).


Pic of old plugs for reference. Any red flags?


Other DIY articles did not show this line and I'm unable to find what it is in my Hayne's manual. It seems either EGR or vacuum related. Any ideas? The line appears to go down toward the front driver side fender/bumper area into a canister. The other direction, it heads toward firewall and into a canister with a vacuum line and another line that appears to connect to a mini manifold and then to back of block. Just curious what it is and what it does.


TB before and after.


Injectors - what is the preferred cleaning method and solvent for these? I have mineral spirits, carb cleaner, brake cleaner, MAF cleaner, acetone, rubbing alcohol... some people say soak, some don't? I plan on replacing lower o-rings and leaving the upper portion of them alone.


Shot of UIM, removed. Next shot is of a failure point, glad I bought a new nylon manifold.


Was checking out new TB gasket from Dorman and noticed the crack. Is it worth sourcing another? I'm leaning toward yes.


Top of LIM, note oil in corners. Will plan to use a thread sealer when reinstalling the bolts. Is the white permatex thread sealer ideal for this application or is something like blue loctite better? Should it be used on all LIM bolts, or just the two hidden ones? What about on UIM bolts?


For reference / red flag review only. Rear VC removed


Front VC removed


LIM removed


Question: Should I remove the temp sensor and reinstall with new thread locker or RTV of some sort for good measure? What is the other thing in yellow oval - is it some sort of coolant passage? Should it be removed? If so, I don't know that I have a new gasket for it.


And a few pics to show some of the likely failure points on the notorious plastic LIM gaskets.


I know this is an absurdly long thread, especially for a first post, but I'm grateful for anyone that has stuck with it and might be able to answer some of the questions I've posed above. If I've asked anything that is blatantly ignorant, you can trust that I'm trying to learn by asking.

Thanks!

Other than being champion plugs, they look okay. Those new Iridium plugs are going to perform alot better.

That hose is for the the cali emissions, that thingy that it run too is for an air pump.


Seafoam in the gas or just regular fuel injector cleaner works great. I've never clean them with a machine as that would mean I'd have to send them somewhere.

TB gasket is up in the air, I'd just slap it together myself. It will smoosh enough and seal just fine if you ask me, or just dab some rtv in that spot and call it good. Otherwise a new gasket is cheap.

Oil in the corners of the LIM is 100% normal, the PCV system does that and you can't stop it.

i use this kind of thread sealant on the lim bolts only.



dab of red rtv in the 4 corners, then put the metal gaskets in place, then the side rubber pieces then another dab of rtv in the 4 corners. then i put the elbow in the alt bracket, then put the lim on the elbow and line it up over the engine. and bolt it down snugging the bolts in a X pattern each time around the bolts will need to be snugged up more till its pulled in place.


if your temp sensor worked before hand, leave it alone. new ones are known to fail new in the box.

and mod your lim too. that way it never leaks coolant on you again.

I don't know what that is called but I know there is a new gasket in most LIM/UIM kits. It doesnt really serve a purpose on our cars other than a block off plate really.


And the oil pressure looks great to me, there is a spring in the housing that controls the pressure. These motors arent super smooth at idle anyway so it will bounce a tad.

A really hot idle it would be down more around 40-45 psi.

no idea the part number for the coolant passage gasket, but you see it in most lim gasket kits.

that thread sealant should do the trick.

I think the Delco LIM kit comes with that coolant passage gasket from what I've seen in pics. Don't see it in my felpro lim kit, which is this one. http://www.amazon.com/Felpro-MS-9801...ntake+manifold

Think this is it right here... Coolant bypass gasket : ACDELCO 24505049
http://www.amazon.com/gp/aw/d/B00HFL...DELCO+24505049

Here is a pic of the bypass area on the LIM for anyone who is interested...


It has injector orings, thermostat seal, gasket for thermostat housing, and a couple other orings and a little blue piece that I've not yet identified where they go. Any ideas on those orings in top right of picture and the blue piece?

Lastly - how clean does the mating surface of LIM need to be? I've gone over it thoroughly with a razor blade and solvent but there is still staining. The surface is smooth when running a finger over it. Do you generally hit it with a scotch brite pad? Some people say that's risky due to the potential for creating low spots. Here is a pic after the razor blade pass. Clean enough or do the scotch brite? Ignore the intake ports, still need to clean those.

Look good enough to me, if it's smooth when you drag your finger over it you should be just fine.

in this pic you got injector o rings, the t stat gasket, the t stat rubber ring, the two coolant port o rings that you wont need if you plug the holes, and the other tow look to be new o rings for the coolant elbow. buy new elbows, the metals ones are at most part stores now for like 12 bucks iirc. the light blue ones are for the n/a engine, the dark blue are for a sc engine. they are the side pieces.

Personally..I'd block the coolant ports and open up the turn around area. There's no need for a new manifold once you know what causes it.,

Search on my name and "UIM Failure", then "Modding a LIM" if what I said interests you.

FWIW GM changed the torque spec on the lim over the revisions
11ft lbs nylon gasket only
13ft lbs nylon gasket with metal sleeves
I personally use 15 ft lbs on the metal gaskets. And with the number that I've done.. it's a safe bet to say it's about the right number.

Originally Posted by bobc455

My personal preference is to stick with the hottest possible thermostat. If you are modifying the engine to be racier, or maybe you have some temperature-related detonation/knock (and are using sufficient octane), then maybe go with a cooler thermostat. But a 195 degree thermostat will give you better MPG (and more heat in the wintertime). Plus your oil life will be longer (burns off volatiles better).
[I'm sure many people will say "My 180 degree thermostat works fine" and I'm sure it does, but unless you have a reason for the colder t-stat, I stick with the hottest possible]
I figured heat is the enemy usually and since our winters aren't very cold in Texas but the summers are hot, perhaps this would help things like the nylon upper intake manifold not warp as quickly. Is this flawed thinking?

The oil pressure looks fine. I'm guessing the engine is cold because the pressure seems like it is high to me. What viscosity oil are you running?
The oil was warmed up to operating temp, I showed this in the 2nd video. I'm using conventional 10w30.

I wouldn't disturb anything that doesn't have a reason to be disturbed - so I wouldn't touch the temp sensor.
Check.

One other note. Water vapor is a normal by-product of combustion, so there will always be vapor coming out of your tailpipes - it's just more visible during certain (colder) conditions. And another note- since the exhaust system is hot when you shut off, this vapor will tend to condense on the inside of your exhaust system as it cools. Therefore after startup, you are getting all of this extra condensation vapor out your tailpipe as well. Every car does it, and don't be alarmed unless you are fogging up the whole neighborhood. Simple high school chemistry stuff.
Right. The reason for concern with water vapor in my case was that it was significant and I waited until after winter/cold temps to verify that there shouldn't be that much visible steam. Combining that with the fact that I was losing coolant and that my LIM gaskets had multiple failures, then I'm pretty confident it should be reduced. Per your advice though, I will try to not be alarmed if there is a little vapor going forward.

Also, consider a complete cooling system flush and changing to green stuff. It's a good time to do it. Dexcool (and the lack of changing it) is probably the reason for your LIM gasket failure.
I've sometimes heard about water pump concerns when flushing. Do we need to worry about damaging water pump internals when flushing? I was going to keep the dex and just drain/fill on a more frequent basis but perhaps that plan isn't a good one. Would it be worth it to just just fill with "mixes with any color" coolant from here on out? And as I perform drain/fills in the future, dex will get more and more diluted?

Your plugs look fine to me. Are you going to re-use them? (Why did you remove them?)
I'm putting in new plugs - Autolite Iridiums and also new wires (AC Delco). I removed them so that after draining coolant and oil, I could cycle motor by hand at crank bolt to help remove additional fluid. Then added oil and ran motor via starter. This advice was gleaned from this DIY page: http://www.pontiacbonnevilleclub.com...hp?f=53&t=3591

I would use thread sealer but not loctite (unless you never want them to come out again).
Check.

As a side-note, I believe the torque specification for the LIM bolts is for a dry bolt. I think that should be changed when using thread sealant (since it acts as a lubricant) but I've never seen an appropriate spec for that. In general I tighten about 15%-20% more than specification when using lubricated fasteners.
Check.

I also agree on plugging the passeges to the throttle body. No need unless you are in upper alaska.
I don't have the tools for this, unfortunately.

I'm surprised at the cracked gasket. I would also be worried about that, and if time permits I would source another one. Hate to have to re-do...
Getting a new TB gasket and also sourced a new coolant bypass gasket. New gaskets for all!

I'm a big fan of cleanliness - and it looks like you are too! Worth taking the time as you do the job.

-BC

BC - thanks for the reply and info! I have added answers inside you quote, in red.

The issue though..isn't Dexcool and it's not mileage. The issue is heat from the EGR stovepipe and a crack from heat cycles.

the 2 yellow o rings would be for the lim to sc only i guess.

the other two black o rings next to the yellow ones look to be for the coolant elbow. but its best to just replace the whole elbow. and they come with new o rings.

the t stat, ive heard of people just using the black t stat ring and it seals. i used both, the ring and a paper gasket. no leaks so why not use it.