LIM corrosion/pitting

**vertebrate** · 08-09-2012

I got my LIM off of my 2000 GTP and was cleaning it up and noticed that I have some pitting in the square section against the gasket between cylinders 2 and 4. When I removed it, it had a layer of coolant sludge just sitting on it. The port on the head that it sits against likewise had a nice thick layer of sludge.

All of the other surfaces seem have some discoloration, but are smooth. Should I ignore it, or am I going to have to get a new LIM?

Thanks,
Steve

**dsmuts** · 08-09-2012

pics would help a lot.

**vertebrate** · 08-09-2012

I figured it would, but I was out, and couldn't attach at that time. Here are a couple pics.

lim_corrosion_2.jpg

lim_corrosion_1.jpg

**Fivefingerdeathpunch** · 08-09-2012

It seems that some coolants over time eat away at the aluminum.

A guy on here had the 2 coolant ports on his blower and on the LIM have pitting. Not to say its common, but it does happen.

**DanGTP** · 08-09-2012

A lack of cooling system maintenance can cause pitting in aluminum parts like that. Also, mixing Dex Cool and conventional green drastically reduces the anti-corrosive properties of the mixture. Make sure the system is flushed and always use the same type of coolant - no matter which one you choose to go with.

**vertebrate** · 08-09-2012

So what about the manifold though? Should I be good to put it back on given where the pitting is?

**BillBoost37** · 08-10-2012

It's normal. Clean it better and put it back together like I would.

I wouldn't even look at that twice.

**vertebrate** · 08-10-2012

Somewhat off topic, but I decided on short notice that since I was in there, I was going to do the lifters as well to get rid of the ticking. I forgot to get the bolts for the rocker arms, and pretty much no dealer around can get them until Monday.

They're torque to yield bolts, so they have to be replaced, correct? Is there another option? I've seen some mention in other places of using non torque to yield bolts, that get torqued to 25ft/lbs, but I don't know where to get those.

**BillBoost37** · 08-10-2012

Those would be like a Fastenall or McMaster type buy. All you need is the right thread, length in a non stretching bolt or recessed hex hed (most reusable bolts).

Some have reused the rocker bolts w/o problem..a few have had them break. Honestly..it's likely not worth the issue, replace them. Maybe check with the parts places to see if anyone has them.

**vertebrate** · 08-10-2012

I haven't pulled the bolts yet. Do you know the specs for them?

**BillBoost37** · 08-10-2012

If I knew..I'd have quoted them for you. I like to look like a know it all on Fridays. Sorry dude.. I don't have them. Check the bolt and bolt spec thread..I think it's in there.

**vertebrate** · 08-10-2012

I found the torque ratings, but nothing on the size. I'm just going to pull a bolt and take it to the Fastenal near me. Red loctite or blue when putting them back on?

**BillBoost37** · 08-10-2012

None if you torque them to 25ft lbs like non stretching bolts.

**vertebrate** · 08-10-2012

3/8" head. 5/16" coarse X 2" o f course the fastenal near me didnt have any.

**FordMan77** · 08-10-2012

How about a Lowe's or Home Depot? They usually have one of those thread matching guides near the bolt isle that you can use to thread your old bolt into to verify you have the right one.

**vertebrate** · 08-10-2012

Home Depot was a no go for the right size. Might try ACE later. The dealer can have them tomorrow morning though. Was hoping to get it all done tonight, but might just have to wait.

**SMazza** · 08-10-2012

Originally Posted by vertebrate

3/8" head. 5/16" coarse X 2" o f course the fastenal near me didnt have any.

Are you sure it wasn't M8x1.25, with 10mm bolt heads, 50mm long? If you get it wrong, they are very close, but
won't thread all the way in.

**vertebrate** · 08-10-2012

If that's what it's supposed to be officially, then I would go with that, and will delete my post above so that noone gets misinformed. What I had above is what they measured them as at the Fastenal store. I do know that the heads on mine are 3/8, as the 10mm socket had too much play.

**vertebrate** · 08-12-2012

I'm putting it all back together now, and looking at this Felpro kit that I got I have the runners that have the hard black plastic that sit on the edges of the block, but I also have two light blue grooved rubber pieces that are about the same length. I didn't take off anything that looked like them, and am wondering where exactly they are supposed to go?

Are they for a different version of GP, or...?

Thanks for all the help guys.