My friends 1994 SE, anti-freeze now looks like chocolate milk :? . I am assuming it is a LIM gasket failure but I am not 100% on that. Input is appreciated.


P.*. I wasted post 500 on him I hope he'* happy.

LOL...Post 500 to help a friend...

Brown ugly coolant coloration is typically caused by mising red and green coolants together.

First thing to try if the car is running well would be a full flush of the cooling system and refilling after probably 2-3 good flushes with green coolant as that was the expected color in 94

I bet you it was that Fel pro gasket I put in when we changed the thermostat. It had a red rim to it and a week later some brown color substance started to seep out of the thermostat housing. I am going to flush the system and change that gasket.


edited as per request.

Thermostat gaskets don't turn coolant into muck. Something is mixing in there. Either two types of coolant as mentioned, or coolant and oil.

Have you checked his oil filler cap and the dipstick for anything odd there?

nope nothing odd there.

I believe that red rim you've referred to is a thin, roundish strip of gasket sealer usually located on the top side of that FelPro gasket. I know that GM also uses a similar strip of sealer on their brand of T-stat housing gaskets as well - at least the GM gaskets I've used over the years in my '92 Bonneville SE did. For the '92 SE (and probably a few other year models with the 3800 engine) the GM part number is 25535214 while I believe FelPro lists their replacement gasket as 35534.

he hasent by chance put and coolent system stop leak in has he?...when i tryed that once it made my coolent look like that

If you are referring to the coolant that is in the overflow bottle, it could be normal buildup of crud.
Remove the rad cap and inspect the coolant inside the rad. If it is the same then you may have trouble.
If not, just empty and clean the overflow bottle then fill with fresh coolant. When was the last time he flushed? Should do every three years even with extended orange type. If he uses normal green coolant, the chocolate milk is corrosion product....rust from the cast iron block. Change and flush it.

Saw this type of thing this w/e. Bandit had dark choc milk for coolant.

He tested it and it did fine for antifreeze properties, however I suggested a good flush.

Will this one be getting a flush and refill as well?