Questions as I work through LIM job...

**ayeb** · 04-13-2015

OK the reason I asked is because I seen a lot of threads from various forums saying that they replaced the o rings with ac delcos because the dormant ones leaked over time or they applied rtv to the o rings

**bobc455** · 04-13-2015

I've heard that too, but never done it. As long as the o-ring is lubricated and the holes are cleaned out, I haven't had a problem yet (knock on wood).

**RegalEagle** · 04-13-2015

Well, if the elbow o-rings give out on me, I will be sure to post back in this thread to update yall.

Nobody mentioned if the trans seal is a must-replace item when doing cv axles?

**ayeb** · 04-13-2015

I didn't replace mine and I've been good for almost a month now

**REDCRAPGP** · 04-13-2015

Don't use rtv.. It's unnecessary and makes for a hassle if you have to remove them. Just use a little oil or whatever you have easily available to lube them up a bit and slide them in.

My originals lasted awhile only reason I ever replaced them was when I did the lim.. The replacement dorman plastic ones lasted years and again no leaks but went ahead and replaced them when I was swapping the tensioner.

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**ayeb** · 04-14-2015

Does anyone know if the stock plastic lim gaskets had rtv bulging from the corners. I'm asking because I'm not really sure if I have to change my lim gaskets or not. Maybe they have been changed already.

**Scottydoggs** · 04-14-2015

if you see a black gasket, just take the top off and replace them, it dont matter if they have been done already, plastic is not good.

and yes, the factory used a dab of rtv too.

**RegalEagle** · 04-14-2015

Originally Posted by Scottydoggs

and yes, the factory used a dab of rtv too.

I will second this. My plastic/factory gaskets had RTV in corners when I pulled them. You can see the blob of it in this pic, to the left of the text.

And in this pic, in the four corners (ignore the colored ovals):

**BillBoost37** · 04-14-2015

The RTV is considered the seal in the corner where the heads meet the block.

**ayeb** · 04-14-2015

Thought I might have been lucky guess I'll tackle the job thursday

**RegalEagle** · 04-21-2015

Ok folks... both CV axles done. Thanks for that write-up, Bill.

Another question now: as I'm keeping an eye on coolant level since the LIM gasket job, I'm noticing some residue build-up on the radiator cap.

The dex was flushed about 12K miles ago and also came out very clean when I drained it for the LIM gasket replacement. I opted to keep it dex and given that I replaced so much of it, I was expecting it to be pretty clean throughout the system. Any ideas on why the buildup at the cap? Is that just normal for a car with 115K that I should see some residue whenever I check the cap? Is it possibly residual from when the LIM gaskets were bad? Or, is this the nature of the beast with a dex car?

**BillBoost37** · 04-21-2015

Wipe cap and repeat, there's still a little goop in there and it'll clean up over time. Try not to be OCD about it and you'll live a longer happier life.

**RegalEagle** · 04-21-2015

Right on, thanks.

**ayeb** · 04-22-2015

Actually that's for the FTP on the fuel pump sending unit

Originally Posted by 02NavyBlue

It looks like the seal for the MAP sensor.

And at least on the newer 3800's, they just use the rubber thermostat gasket. Won't hurt to use both I suppose. It will only leak with just the rubber one if you don't get all the corrosion out of the groove.

**02NavyBlue** · 04-22-2015

No it's the map sensor.

**ayeb** · 04-22-2015

For what year? And where is it located?
I got the map sensor mixed up with the purge valve

**02NavyBlue** · 04-22-2015

It's on top of the pcv housing on the upper intake, passenger side. N/A engines only.

**ayeb** · 04-22-2015

Oh ok. Because mine is totally different. Was confused

**RegalEagle** · 07-15-2015

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

Since I did this work, I've been keeping an eye on mpg and wanted to follow up with an update. I recently took a long road trip with my family and the car was LOADED to the brim with stuff and people. Pure highway driving I was seeing average 26-27gpm. Given that factory estimated highway mpg is 28 and that my 14 year old motor pulling a completely full car was getting that kind of efficiency, I think that the MPG concern may not be very pertinent in this case. I can't speak to the burning off of volatiles, however, as you pointed out.

I did get to add a new item to my to-do list. The light to the odometer and gear indicator area of the dash seems to have a connection loosened or perhaps getting weak/burned up. It was going in-out for some time during and after the trip, but now is completely out. With some convincing tapping on the dash, it can sometimes flutter back on, but it doesn't stay on. Anyone tackled one of these before?