Weird Gel In Coolant
 

RE: my 1995 E320. I replaced the wrong coolant (2 years ago) with the correct MB coolant. The expansion tank was gross (I bought this car just 2 years ago) so I replaced that as well as the hoses and the water pump. The system works great. The entire system was drained (including at the block) at that same time. I just had to replace the coolant tank float sensor today which meant draining the tank. I noticed this amber-colored gel clinging to the sides of the expansion tank. It was as slippery as coolant, not sticky. What is that? I've never seen that before in a car with a rebuilt cooling system and the correct coolant. Any ideas?

It's possible that someone added some dex-cool at one point, caused the death-cool gel, and some of it is still making its way out of the system (just a guess).

Yeah, that sounds like the mark of Death-Cool!
I just cut open the side tanks of the radiator I took out of the Suburban and they were full of the stuff! I am talking six inches of gunk in the side tanks of the radiator!

In your case do a citrus acid flush and then use lots of water to get this stuff out of your engine. Then use distilled water to make the coolant mix with the proper MB coolant (or G05)

I don't think there's any Dex-Cool, I'm the only one working on the car. I either use Zerex G-05 or the MB coolant. This is weird.

Could the PO have used Dex??

Does this year have the silica bag in the expansion tank or did that come later?
Maybe that is what you are seeing...

I still say citric acid and distilled water to get rid of it.

The previous owner may have used something other than the correct stuff. I have yet to see a used, old MB with the correct type of coolant - amazing. What's interesting is that I also replaced the radiator 2 years ago too (forgot to mention that). The entire cooling system (component-wise) is new. I don't know where this stuff has been hiding. I don't believe these had the silica packet. I replaced the tank and don't remember hearing that moving around inside when I walked out of the dealership.

What are the instructions with that acid wash? I have the MB-brand bottle of that stuff but there aren't any instructions.

Your block holds a decent amount of water. Did you replace the hoses?

I've only seen 1 used benz for sale with the correct coolant in it. I bought it.

Careful make sure its not oil in the coolant. Head gasket issue maybe. Also is a possibility is water wetter. Sometimes it doesnt mix well but its pink and may become gel in the reservoir.

I changed all the coolant hoses, everything. It's not oil since there's no film nor emulsification nor discoloration going on. The headgasket was done about three-years ago with the updated reinforced metal tab gasket. The guy I bought it from was 90 years old. I don't think he was savvy enough to use water wetter - is that what water wetter looks like??

I've used water wetter in everything water cooled I have for years, never heard of it gelling in anything.

Water wetter (gas) is pink, diesel water wetter is blue.

Lots of posts on how to do it.

http://www.peachparts.com/shopforum/search.php?searchid=5146920

Basically you drain the system, rad and block, then fill with water and put in some Tide detergent, Run the car for a few minutes and then drain it again,. Flush it with running water - I made a back flushing gizmo with some 1/4" galvanized pipe, a ball valve, and a hose barb that I attached to the block drain. I also took out the thermostat and disconnected the wires to the mono-valve so it would stay open.

After about a 10 minute flush I let it drain and the poured in the acid mixture. I forget the ratio, but I think it is 2.5 pounds of powder mixed in hot water and poured into the tank. Fill the system with water and run the car for 1/2 hour or longer.

Then FLUSH FLUSH FLUSH FLUSH

Once it is clean and the water no longer feels slippery, flush it one more time and let it drain completely.
Then fill it with the right coolant mixture.

Hope that helps :D

Water Wetter is pink and can gel, its supposed to help in heat transfer to the metal parts to and from the coolant. But its just glycol so gelling seems like its pretty eveident, I stopped using it because of a rusty gel in my expansion tank (reservoir is in fender).

Odd that I've never had the issue in 20 years of use. Also, check your sources, Diesel Water Wetter is blue.

Might be in there intentionally, some tanks come from the factory with silica gel cartridges:
http://www.peachparts.com/shopforum/sitemap/t-142992.html

Good recommendation by LUVMB, but I would use the acid treatment first, then the detergent treatment. This would allow the detergent to neutralize residual acid.