1994 Buick Century - 3.1L Coolant Mud

[Tim Martin]

This 94 Century with a 3.1L power plant came in from another shop for me to replace lower intake manifold gaskets. This evening I brought it in to get started on it and I saw signs of brown goo around the radiator and right side of the engine. When I opened the radiator cap, the coolant is in the form and consistency of brown muddy water that has plenty of thick stuff with it. Obviously this stuff is not going back in after I drain it but i am wondering how can I get most, if not all of this junky stuff out? And, not only that, how will I keep it out? Car runs great, is in nice shape, only had 94,000 miles on it.

[steven kiser]

May i suggest doing just what you're doing. Drain and refill only. I can promise you that flushing and cleaning it out will cause a headache. Once you clean out the system you'll more than likely open up a flood of leaks. The muck may be acting as a "plug". I remember years before Oldsmobile had a similar situation where a Cutlass would come into the shop with a water pump leaking, two week later the heater core would start leaking, two weeks after the radiator, two weeks after the intake would go, then the freeze plugs would start up. Once the crappy sludge was removed it started leaking from everywhere.

' This is a situation where repairing a problem isn't in the best interest of the shop or vehicle owner. Just adding new coolant to this when you're done can clean it enough so it starts leaking. I had a disclaimer that i would add to orders when these sludge buckets started showing up in my shop. They seemed to barely make it through the warranty period and the dealer even shied away from these.

[Pauls Automotive]

I agree with Steve. This could very well cause more problem that they will want you to fix for free. Just top it off and do a disclaimer. CYA

[JBUTITTA]

The mud comes from the cooling system having air in it and breaking down the coolant. Most causes of this was a bad radiator cap from the factory (GM wont admit this to the public through). In a cases like this I inform the customer of his options. My recommendation is always to repair the leaks, r/r radiator and clean, and flush cooling system with chemicals and replace radiator cap. Customer is also informed of possible future leaks and possibly having to flush cooling system several times within a year to get the desired results of a clean optimal cooling system heat transfer. On occasion Ive had to pop a frost plug out of each side of the block to get the sludge out of the engine block. Without getting the system clean the mud acts like and abrasive coumpound inside the cooling system attacting all components and causing premature failure. Make sure you give the customer the option of a clean system. Jerry