Eaton M90 and Lim swap questions

[Marshal]

I'm changing out my gen 3 for a gen 5 and just pulled the LIM. most of the bolts were damp with antifreeze, and I actually had a coolant leak from one of them I think because there was a small puddle in one of the lim valleys. Am I supposed to use rtv on those bolts to keep them from leaking?

 

I'm sure I will have more questions, but that's it for now.

[digitaloutsider]

Sounds like you had a failing LIM gasket.  There is no need to put RTV on the bolts. New gaskets, and torque it down properly and you're good to go.

[Marshal]

I do have new gaskets to put on, thanks for the input and a quick reply.

[scottydoggs]

you need pipe thread sealant, or the bolts leak, they live in the coolant jacket of the heads. 

[digitaloutsider]

I've personally never done it on any 3800 LIM job, and that's more than a few at this point.. I'm pretty sure that they don't go into the water jacket unless I'm having a serious mental lapse today. I seem to remember the bolt holes NOT going right into the water jacket and having their own independent bosses.

[bluegtp91]

https://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//N2131/large/16160023_ptx_80632_pri_larg.jpg

 

You are supposed to use a form of thread sealant.

 

When you remove the OEM bolts that is all the residue that is on the factory bolt to begin with.  Wire brush or chemical clean off...then apply paste.

[digitaloutsider]

Huh. Guess I've been doing it wrong all these years. Thread sealant next time it is!

[Marshal]

permatex thread sealant it is then

[scottydoggs]

they go right through the head and into coolant, just like the water pump and timing cover. all them bolts need sealant. 

 

ive also found that most oil pan leaks are the bolts, not so much the gasket, thos dumb bolts are clear into the bottom end and oil splashes on them,  then they seep and get that dot of oil on each of them,  i sealed mine and a few others did the one by one removal and seal and they dried up. 

[Imp558]

I'll be darned, guess I'm using sealant now. I've always done a little on oil pan bolts.I can picture another bolt that has a white sealant from the factory, front of the engine maybe?

[scottydoggs]

knock sensors need it too, also right into the coolant. 

 

rear cover bolts get a dot of loctite. 

[Imp558]

Knock sensors I knew, I use them as block drains, lol.

[Marshal]

got the lim back on and am calling it good for the night, used the thread lock with ptfe and tightened the bolts to good and tight.

[wstefan20]

Knock sensors I knew, I use them as block drains, lol.

Actually, according to the official service manual, this IS the official engine coolant drain plug! I read it one day and burst out laughing!

[Imp558]

Multitasking at it's finest. CKP sensors double as a huge pain in the ass and exhaust crossover pipes double as power robbing throttle body heaters. Honestly I really do hold the 3800 in high regard, despite the couple little things it's a tank.

[wstefan20]

Multitasking at it's finest. CKP sensors double as a huge pain in the ass and exhaust crossover pipes double as power robbing throttle body heaters. Honestly I really do hold the 3800 in high regard, despite the couple little things it's a tank.

Speaking of which, what success has anyone had with keeping engine bay temps down? I've been thinking about powder coating the headers inside and out and adding reflective shielding, and maybe a few hood vents. Any pros or cons?

[Marshal]

I put a custom hood scoop on and it made no difference. I had a set of ceramic coated headers at one point, but don't remember if they made any difference. I imagine they would, but for the cost it's probably not worth the effort. better to just intercool the supercharger.

[Imp558]

With my '96 it got so hot under the hood the strut towers were uncomfortable to touch. I took the rubber hood seal off the back of the engine bay and they were only warm after that. Of course it didn't smoke or anything that worried me coming in the cowl. Burning in new hot paint sucked for a few days though.

[scottydoggs]

the stink of even high temp paint is brutal, lasted months when i painted my new engine.  my ait temps hit 185 sometimes.  dead of summer heat type deal.

[wstefan20]

Wouldn't taking the hood seal off allow rain to get in though?

 

I'll have to look into ceramic coating though. Ever since I upgraded my headers, it's HOT under there...

[Imp558]

There's a lip, rain doesn't get in but it's a high pressure area so dirt sure did.

[digitaloutsider]

I must be the only person who doesn't have overheating/heat problems, no matter how hot it gets. Nothing special, just new coolant and a drilled 180.

[Imp558]

I must be the only person who doesn't have overheating/heat problems, no matter how hot it gets. Nothing special, just new coolant and a drilled 180.

 

What fan temp do you run? I liked 190* with my 180* stat, it stayed a pretty even temp on my scangauge.

[digitaloutsider]

Fan 1:

85 degrees C on

80 degrees C off

 

Fan 2:

91 degrees C on

86 degrees C off

[Marshal]

my car never overheated either