97 Maxima, just bought. No idea of whether the coolant has ever been changed. I dumped out half on Sunday and replaced it. Everything I drained out is great. However, in the reservoir I found some floaty things. Their pictures are below. I think that since they floated, and coolant goes in and out of the rervoir a little bit, it served as a sort of trash can, which would explain why the only gunk I found was in there. There wasn't much of it. In the second picture the "glob" thing was a ball, and it's squishy as you can see. It feels like a little ball of glue or sealant or something like that. Thanks for any ideas! Car otherwise is great.

 

Looks like some StopLeak or a similar product. People dump that stuff in the radiator when a leak occurs.

It stops the leak for a while, but if you don't change your coolant shortly after adding it you end up with sludge.

 

Hmm, interesting. There is no leak that I"m aware of the. Thermostat has been bad for a long time, and I diagnosed that on the test-drive. I fixed that on sunday, and I wonder if this sludge somewhat gummed up the original one...

There was VERY slight film on the top of the coolant (checked the tub that had my gallon of coolant in it), when I checked it this morning. It did not look like oil, but more just like a very slight film of miniscule little white thingies.

Don't leaks almost always occur either in a radiator or hoses? If this is stop leak and a leak comes back I can replace either of those.

 

If there was a leak, and they used stopleak, it will hold for quite a while. Leaks can occur anywhere: radiator; seal on the thermostat housing; head/head gasket; hoses.

People generally only use stopleak if the radiator springs a leak. It's not very good for anything else. Of course, if you ask me, it's not very good period.

What you describe is exactly what I experienced on my girlfriends Subaru. The stopleak finally gave out and spat that white **** all over the place.

 

Let's hope it's not the head or head gasket It's definitely not the thermostat housing, so hoses/radiator no worries, as long as the thing doesn't burst and overheat before I notice it Thanks, sryth!

 

I had that when I accidently put the orange coolant in the RAD. It started showing up a couple weeks later.

 

I got that same looking gunk on the sid of the bell housing of the trans.....I have always wondered what it is or where it came from. Mine looks to be a bit more fluid like.

 

I would change the coolant asap. Looks like it went bad acidic, I've seen that only once on my friends dads beater chevy wagon, coolant that never was changed. Change it out when you can the coolant isn't doing your engine,radiator,waterpump any good.Acid eats metal aluminum..etc.

 

Interesting...I have good records from the car, and looking through them - unless some are missing, which I doubt - it seems that the coolant has never been changed. Nissan should cover with the 60k right? I know that was done, but I didn't specifically see a coolant flush on it I don't think.

I did the "quick" change, as per motorvate.ca's instructions (undoing the engine block plugs is insanely ridiculous, so I only dumped out half of this stuff). I suppose I could do it again - just radiator and I'd end up with about 75% of the coolant changed from both radiator swaps.

 

hope not but that is exactly how the coolant looked in my 3rd gen when I had a blown head gasket...are you having to add coolant as well???especially since you said the thermostat was bad.. could lead to that from the overheats...when mine got really bad you could find that stuff in my coolant and under the oil cap...do you know how long it has been since the oil was changed??? might want to check that too..

 

Oil changes are documented, and were all frequent (3000 miles or more often). She drove very infrequently, so sometimes it was several months between changes, but never was running on oil with too many miles. I've not had to add any coolant in the last 150 miles that I've been checking since doing the thermostat. There are no problems with the oil or under its cap or anything either!

BTW the thermostat was locked open, not having problems staying closed, so the engine was underheated for a long period, but I doubt it has ever overheated.

 

I just replaced my rad fuild today and I found similar gunk in my tank. However, it wasn't floating, it sank to the bottom. I had to shake the tank with water in it to remove it. I dunno what it is tho. Hope it's not serious...

 

I was just saying that if it had been a while since the oil change and you didn't see any of the gunk in there that would point towards something else, and the thermostat seems to back that up as well..

 

looks like oil residue but in that case your oil must have like a grey or brown gunk as well you may not see looking at the dipstick, change your oil a let it settle for a while when the oil is gets cold water separates from oil