mr mojo

70 olds delta 88 custom 455 - 68,000 miles

Ok here goes:
1.Oil looks good, no sign of coolant in there. good n' black
2.exhaust doesn't smell like coolant and seems to be clear. no steam
3. slight coolant loss which appears to be from visible pinhole leaks
ok here comes the strange parts
4. I have seen oil in the coolant before on other cars that have had head gasket leaks. The excessive foam , the tan coolant, the overheating . This is more like a thin black sooty layer that floats on top of the coolant . Maybe three or four bubbles trapped (that i can see) just under the sooty layer also but not all the time when i check . i can dip a white paper towel into the coolant with the radiator cap off and this allows me to kind of blot it up and see the color of the soot. The coolant underneath after i blot it looks pretty green and normal, but not quite as clear and pristine as out of the bottle.The car is 40 years old . Oh did i mention that sometimes i take off the radiator cap to check and i don't see any sooty film ????

My biggest worry is some type of engine crack. What causes in the soot???? Exhaust in the coolant? impending breakdown of the water pump? Oil in there?? combustion byproducts? Ideas on how to proceed?

greenslade

soot? oil, could be from trans cooler?

mr mojo

perhaps. Could this come from the trans cooler in the radiator? i haven't checked the trans yet. I just had the trans serviced a few hundred miles ago, and didn't hear anything about any contamination of the trans fluid then. But that was before the soot showed up. The soot is black. not sure how the trans cooler would leak this floaty black soot.

mr mojo

soot is the best way i can describe it. It is a very fine black material that seems to be hydrophobic. like something you would see in an exhaust pipe. it floats on top of the coolant in a very thin film

svnt442

If it were a trans issue I have a feeling he'd know it by now with a blown trans.
You could have a bad head gasket or even an intake gasket giving you issues. What I'd suggest is get some dye and dump it in the oil and then run the car. If it shows up in the coolant you know you have an issue that MOST LIKELY will have to do with the head gasket, but not a certainty.
Just something you have to deal with when you have a 40 year old engine.

mr mojo

i like the idea of using the dye. thanks for the idea! if it WAS a cracked block, would these symptoms still occur (meaning the seemingly one way leaking of oil into the coolant)? just trying to calm myself down a little! i really don't want a cracked block . any other ideas out there?????

jeffreyalman

yes. I had it happen too.

when and how thorough was the cooling system completely flushed? and by how thorough, my experience has been that I needed a few complete and thorough flushes before this stopped for me.

I just think this is residual from 40 years of age.

mr mojo

hmm... this is getting interesting. i too thought it might be residue that was just getting stirred up. I bought the car four months ago and i have been driving it everyday since the weather improved. around town and on occasional trips to the big "city". I am in maine so this is really tongue in cheek From what i could gather this is the most use this car has had in a really long time. Since i got the car i always check the coolant levels before every drive. The "soot' just showed up a few weeks ago. I know that there haven't been any overheats or even stop and go driving which could possibly inflict temperature stress which makes me a little less worried about an engine crack. Talked to my mechanic today about the UV dye in the oil . will hopefully narrow things down a bit.

where is this stuff coming from????? I did have the heater core replaced around the time this stuff showed up, but i can't be certain that this has any real relevance. didn't have a full flush done though.

jeffreyalman

full full flush it then do it again I don't know how to accomplish it since there are no drains in the block but that's all it is

svnt442

Actually there are. There is a plug at the bottom of each cylinder bank that just un-screws for block draining. It MAY be hidden by the motor mount.

EDIT: You can see them here, but it looks like these have been modified for easy draining as it should be just a plug.

jeffreyalman

I have never had one removed so I flush then run then flush again every few years x 3 ! but I am in S Fl and loathe cooling syst issues

Axeni

Could it be someone put in Rad Leak 10 years ago??
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LuxuryStarXXX

Warhead

No overheating, no excessive pressure in the system?
Heater cores will burp first when there is excessive pressure.
Screw the dye, you need to have a shop put compressed air into each cylinder, 1 at a time, and with a FULL radiator, check for champaine bubbles. This will help locate a leak if present.
If this has never been apart before, I would be concerned with the steel manifold gasket, and the steel shim head gaskets. THESE corrode, that is how I got my 65 post...
Jim

mr mojo

no overheating, everything seems fine. compression test is a definite thing that will be happening soon. i am just waiting for some steering parts to come in then its off to the mechanic. i know for a fact that one of the manifold gaskets is leaking . you can smell some exhaust in the engine compartment, sometimes with the windows cracked it gets drawn in the passenger compartment.

as to any excessive pressure issues there don't seem to be any that i can see ( i know this doesn't mean much). the heater core was replaced because it had a leak in it. the previous owner never used the heat and all the levers were set to off. Maybe now that i am turning them on, and actuating the vacuum lines that control that valve thingamabob (i can't remember the name of it) to allow coolant to pass through the core , this is the source of the residue?????

Lady72nRob71

...or by accumulated grease and grime. It took a while to find mine...