I changed the Water Pump on my 87 190D 2.5 and decided to go to Zerex from the PO's green Prestone. After about 3 days the radiator started to leak where the plastic meets the aluminum core.......OK, must be a its time......Replaced Rad, and it started leaking from Aux Pump and a couple of hose connections.......Hmmmmn, being the genius I am, I am begining to suspect that the New G05 fluid may me the cause......now, I am leaking Anti freeze into my drip pan I use to catch the oil from my leaky rear main seal (ANOTHER bad story). Question 1) Is there something about the Zerex product that can lead to this? 2) If my heater core is leaking, is there a drain that would dump the leaking fluid under the car as opposed to inside? What else could be leaking back there??? Damned puzzled and can't get under it until I am back in town........Any ideas? Thanks Scott

In my experience Dexcool is more prone to leak than IATs because Dexcool has no salts that can precipitate out to seal minor seeps.

There is no reason why G05 should immediately cause leaks if used to replace IAT.

Thus far I've replaced a leaking heater flow valve, leaky coolant level sensor, and a leaky aux. coolant pump. It just goes with the territory. So far my radiator is okay.

There is a plenun drain above the transmission where the coolant leaking from the heater flow valve dropped down, leaving residue on the transmission. A leaky heater core would probably drip from the same area.

Not too many have reported leaky heater cores, but the aux. coolant pump, heater flow valve, coolant level sensor, and snapped radiator nipples are relatively common. Sooner of later all these problems will happen to all of these cars.

Three down, one to go for me.

Duke

Perhaps that is why Zerex is nowhere to be found around here? I have been looking for it for my car to no avail. Maybe it was a good thing?

Just wondering - where did you even find it? Seems like it has vanished everywhere else.

Did you drain and flush before the changeover? Based on what i've read, mixing coolants would accelerate deterioration of those parts. It also explains why I have to replace the heater core, rad., and thermostat on my Volvo. The rad., and thermostat on my Mercedes. My coolant switch was from the green stuff to Dexcool.

These results are too much of a coincidence. Now, I've got Zerex and distilled water combo.

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joel

Prayers bring forth enlightenment.

Got mine from my local NAPA for $11.00.

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joel

Prayers bring forth enlightenment.

The volvo site has a sign up campaign for a class action suit against GM/DEXCOOL for similar problems discussed here. http://www.girardgibbs.com/dexcool.html

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joel

Prayers bring forth enlightenment.

I've never experienced any sludging with Dexcool and I've been using it in all my cars since '95, but am in the process of switching all but the MR2 to G-05.

GM claims in several TSBs that sludging and corrosion is the result of running with low coolant over extended time/mileage intervals. Apparently some of the components in Dexcool can oxidize if there is a lot of air in the system.

My opinion is that these Dexcool lawsuits have little merit.

Duke

I had the green stuff (Prestone) in my ol 450 sl 1977 for 5 years with no leaks same 5yr old green. No problems, just renewed with Prestone and again no problems! Still original radiator and water pump and heater core! I think that the propaganda on mercedes part to switch to their recommended product is over rated! I'll stick to green (with additives as needed). Just my opinion, Abe G

You probably had a lot of build up and crap in your system from the old coolant. Good thing everything is leaking now and not 500 miles from home on a trip.

If people just followed the two year changes MB recomends on these cars with the proper coolant a lot of these problems would be avoided. However for whatever reason they don't and ignore the cooling system for years until they start to have problems.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

There is no harm or danger in using Zerex G5 in a Mercedes product - IT IS THE SAME FORMULATION as found in what you buy from the dealer. Zerex has made the coolant for mercedes for many years!

Sorry, It isn't the G-5. Your car is 'experienced'. You wiggled, pulled, pried, twisted, and tightened on a lot of parts to get the water pump changed, and this, combined with age and heat, combined to jar a few leaks loose.
The electrical version: insulation in wires, solder connections, and plastic parts in an old electrical or electronic device get brittle with age and heat, and, when you disturb it during repairs, you get gremlins of all sorts.
Don't feel like the Lone Ranger.

The heater core started to leak almost immediately leaking as well..........I am not sure what the hell is going on but It is a more than just "wiggling" and age that caused the leaks after the Zerex change over. This is VERY odd........Something to think about for someone considering the same

..... well, probably. Nevertheless, I note that my daughter ran her Cavalier with low coolant quite often during the summer because of a tiny block leak (which btw a 'leak-stop tablet' fixed nicely) and wouldn't you know, I had to replace the leaking core in the fall. the car had about 150k km on it. Coincidence, possibly .... but maybe not

cheers

Aluma-Seal. 99 cents at AutoZone.

Doesn't hurt nothing. In fact, it helps keep the water pump happy...kinda like how lead used to keep valve seats happy!

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'01 SLK320, '79 450SL & '01 C320 -- What? 3 Mercedes? I am DEFINITELY crazy!!!

When air gets trapped in the cooling system, Dexcool has this habit of turning into mud/sludge looking mess - On GM cars, I have seen this firsthand; if you're looking to purchase a GM car that is running Dexcool, first thing to check BEFORE a testdrive is the radiator cap; open 'er up & look for mud on the cap seal... if you see any, run away! Soon you'll be replacing the radiator, hoses, heater core & flushing the mess out of the system. If you're lucky, you won't be changing the haed gaskets yet... Shops I used to call on would ditch the Dexcool & refill back with green coolant after doing engine/cooling system repairs on out of warranty cars.

I haven't had time to follow all the posts, but are some people switching their Benz cooling systems over to Dexcool? Why?

BNC