i checked my radiator fluid the yesterday and it is a sort of grey sludge-like looking stuff, did't look too good, but i had to drive to work, i drove slow and kept an eye on the temp gauge, it didn't get out of it's normal spot, but the engine smelled hot, what do you guys think?
thanks for any help

 

Oil in the wrong place, crack head, block or head gasket!

 

how long can i go before i have to fix this?

 

Most of the time not very long

 

Does it appear to be motor oil? Try flushing the cooling system thoroughly and fill with new coolant and see if it comes back. What vehicle and motor is this?

Marty

 

the fluid is sort of a nasty gray color, earlier i noticed a puddle of green fluid under the truck, looked like it had come out of the motor somewhere from where the puddle was, this is in a 94 f-350 4x4 351w the previous owner told me he had put a new radiator in because it had gotten some oil in it, when i bought the truck the radiator in it had a defect or something ( bad o-ring i think) so the radiator i have in it now is under warranty.

 

My girlfriend's car has a similar problem. I went to change the fluid and the stuff that came out was the color of mud; very thick too. I tried to flush it all out, but it kept coming back. I don't see any oil leaks on the engine or ground and it's not running hot at all, but it does smell like burnt oil. Sound bad? What do you think?

 

If your heads/gaskets/block are in good shape:

Have you ever put any galvanized metal in the cooling system? Many aftermarket lower radiator hoses have galvanized springs in them to keep the hose from collapsing when the system pressure goes negative. Coolant and zinc are not compatible, and the system will sludge up just as you have described. Check your thermostat housing bolts, etc. for anything with zinc.

 

thanks, i'll try that if i don't catch it will this sludge stuff hurt my radiator over time?

 

It'll hurt your waterpump most, but the entire cooling system can also be compromised if you let it go too long.