I am working on replacing the UIM with a new Kenco unit. Have everything taken apart ready to install. Noticed dirty oil sitting in the two odd shaped rectangle recessed areas of the LIM. Specifically located at the most right of the bottom row and most left of the upper row. There was about 4oz of oil in each location. I cleaned it out with a rag. Car has 94.5K and I'm original owner. Would like to know if this condition is normal.

Also, this car never uses a drop of oil between 3k oil changes, nor does it use any coolant. The LIM gasket was done at 59k.

After reading the archives, I see two possibilities. Either wicking up the threads or a faulty PCV valve. Looking back on my records, I can't recall ever replacing the PCV valve. In any event, I don't think this is anything to be alarmed about after all.

Thanks

Yes, it is normal. It is oil from the PCV system that condenses and drips down. Makes it even harder for first timers to find the hidden LIM bolts.

Thanks.

Anyway, I'm going against the tide here a BC and not changing my LIM gasket to the new aluminum design. Like I stated, it was done at 59k (about 35k miles ago) and never loose any coolant. Using the Prestone Orange DEX-Cool compatible coolant aka ethyl glycol. Same as the green stuff, just orange in color.

I disagree. I have studied this carefully and have concluded that Prestone Orange Dex Compatible is Dex. Others disagree, but I can't understand why anyone would take a chance on this stuff when they can use "mixes with any color" coolant and take no chance for early gasket problems.

And...generally speaking, green stuff is phospated EG, Dex and Dex compatible are organic acid technology, and yellow is mixes with any.

I read the ingrediants label on all currently available Prestone coolant products before buying. The compatible with any coolant extended life(mixes with any color), and Dex-Cool approved extended life.

Ingredients are identical .

Ethylene glycol
diethylene glycol
sodium 2- ethyl hexanote
sodium neodecanoate

I feel very confident in my purchase.

Please note that the "Prestone Yellow-mixes with any" is an organic acid based coolant. The organic ingrediant is called 2-EHA short for 2-ethyl hexanoate.

So you are correct that the original green formula is a non organic acid based. However, it appears that the orange dex-compatible and yellow mixes with anything are both organic acid based formulas.

Please re-think using any orange or yellow coolant that may become acidic over time. You won't have that problem with the green stuff, and all your other gaskets will last longer.

I have not heard that the yellow "mixes with any" coolants cause problems. The additive pack may be organic. I don't know. But, I would not condemn their use on that basis. It may be organic, but it is clearly not Dex. If it were, it would not mix with phosphated coolants.

What I am referring to specifically here are the G05 class of coolants that were developed and used by Mercedes since the mid-eighties. Although the "mixes with any" coolants I have used have been a lighter yellow, I think it is likely that there are other G05 spec coolants with different color dyes.

The color orange is the one that I stay away from.

The original formula for Havoline Dex Cool is:

http://www.havoline.com/images/produ...nti_exlife.pdf

Ethylene Glycol
Diethylene Glycol
Potassium 2- Ethylhexanoate

The Prestone formula for Dex-Compatible/yellow mixes with any is not the same. I trust that Prestone tweaked the formula to make is safe.

Just to be clear. Prestone markets an orange colored product called Dex compatible that will NOT mix with any antifreeze, only Dex. They also market a "Mixes with any" coolant that is yellow in color. I have been advocating the use of "mixes with any" no matter who makes it. I do not recommend the orange colored stuff, because I believe it to be Dex. The bottle on the left, below is the Dex compatible and is orange in color. The bottle on the right is the mixes with any that is yellow. In this image the "mixes with any" is already diluted, although Prestone markets this undiluted, too.