: peanut butter in coolant resevoir

06-08-10, 10:55 AM
Have a chance at a possibly good snag:

98 Z-rated STS with 111,000 km's. New engine from GM in 2007 or 2008. Its at a garage, the poor guy lost his keys. Dealer cut him a #2 key and no one can get it running. I tried to explain what was wrong but the mechanic says the guy has given up. Mechanic is the guy who installed the engine. Total bill when done was $14,000. His insurance covered it...

Mechanic insists he was told by GM that this engine is "updated from the old ones", mentioned they told him something about "longer head bolts" and "different block casting process".

The car has sat for 4 or 5 months. Coolant reservoir is dry, unfortunately i only took a quick look. I stuck my finger in there and on the center wall you can see in there i rubbed and pulled out a small bit of brown "goop". Maybe sludge, not sure. I didnt smell it, was in a hurry, not thinking.

My question is: did the owner (or someone who worked on the car) put something in the coolant? Is it possible the reservoir dried up from the car sitting? The engine obviously has low k's, and i would think it should be safely within the maintenance period. Was thinking maybe the goop is from before, not sure. Oh, it was brown. Rust brown maybe. I am trying to contact the owner directly but that is proving to be difficult....

Mark C
06-08-10, 11:00 AM
someone probably put the GM Sealant tabs in the reservoir instead of the lower radiator hose when the coolant was changed/filled. That will leave a brown goopy sludge inside the tank. Can't really fill the coolant system all the way up until the engine is running to purge the air out, so the level in the reservoir may go down as the air is either absorbed into the water in the block, or some of it naturally works its way out of the engine.

06-08-10, 11:29 AM
Thanks Mark, i wasnt sure what color those tabs were or what they would turn into. The shop guys are not cadillac or northstar experts, but it seems like they did a clean job of the swap from what i see on the outside. I'm a little disappointed at how much corrosion i see on a lot of the fasteners, and there is a lot of white powdery substance built up on some metal parts, could be coolant. The car was driven through a foot or so of water which got sucked up into the engine and it pretty much exploded so who knows how much of a mess was made when that happened. The guy is a local bar owner... sucks owning such a nice car when you bounce the drunks and they take it out on your car :( This one is keyed in at least 2 spots and the passenger seat looks like John Rambo went at it with his monster hunting knife.

06-08-10, 11:44 AM
As Mark said, that is most likely sealant tab residue. I'd almost bet on it.

there is a lot of white powdery substance built up on some metal parts, could be coolant.
That is dried Dex-Cool.