How extensive is the motor damage?

are you losing any coolant? any bubbling in the rad or expansion tank when running?

Reply to
jim beam
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the description exactly matches the combustion product that builds up in open deck head leaks. hondas are famous for them. no oil leaks. no water int he oil. just brown slightly oily grunge in the coolant that then starts to bubble into the expansion bottle. don't know if the mitsu is open deck, but it's the first thing i'd check if trying to diagnose.

Reply to
jim beam

indeed. use solvent to clean the head, not scrapers or abrasives. do NOT use scotchbrite or anything like it!!!!

indeed.

uber-expensive. and you need some mighty good x-ray gear to get at the small ones in aluminum heads. largely pointless in this situation imo.

not on aluminum - which this almost certainly is.

what you say above it true, but i have to add that skimming/shaving an /aluminum/ head is much more of an issue than cast iron, which few shops will screw up too badly. aluminum heads get screwed up routinely - it's very much the norm in fact.

good junkyard engines are getting rarer and more expensive. thanks to the lack of zddp in oil. i have a cam showing flat tappet damage caused by the change in oil formulation and i'll try to post pics this weekend if i can make the time.

the op can try using one of the waterglass formulations which will effectively seal a head gasket leak for quite some time - "blue devil" or something like that is one of the brands.

Reply to
jim beam

I have a Mitsubishi that is 12 years old and has 80,000 miles on it. It's a V-6 engine and a five speed. It's been well maintained and has a brown greasy film in the radiator cap and in the reservoir. The oil dipstick is clean and doesn't show any signs of water contamination.

Seems to me that the cylinder head has failed and is leaking motor oil into the water jacket. Trouble is, I don't know how a mechanic goes about discovering where the trouble is--or if they just tear down the engine to the short block and machine the heads. Plus I'm trying to figure out how much the job will cost and how long the car is drivable until the work *must* be done.

Thanks in advance.

Reply to
geo pearl

If somebody put GM stop leak (maybe others too, think it's made by Bars) in it, that shows up as brown and "greasy" after some years. Might be the anti-freeze mixing with the organic stuff in the stop-leak causes it to be "greasy." Had that sludge in my Lumina 3.1 cap and reservoir a few years after using the GM stop-leak tabs as a "preventative." If you don't know whether that was used, you can flush the rad and see if it comes back. Once I cleaned it up and flushed, it didn't come back.

Reply to
Vic Smith

Sounds like you have a bad head gasket, a cracked head, or a cracked block.

If it was my car, I'd pull the head, look for obvious cracks, and if I didn't see any, I'd put a new gasket on and see what happens.

Machining the head is just asking for trouble and is apt to do more harm than good unless you have a shop that really knows what they are doing and will do more than just shave it.

You can have it x-rayed or magnafluxed to locate internal cracks, and you might find them if they are there or then again you might not.

If you put a new gasket on and it solves the problem, then you are good to go. If you put a new gasket on and it doesn't, then you know either the head or the block is cracked and you spent some money and effort for that diagnosis but less than if you'd had it taken apart and magnafluxed.

I have occasionally seen head and block damage repaired with epoxy glue and stuff like that, but for the most part if changing the gasket out doesn't fix it, or if you find clear signs of cracking, the cheap solution is a junkyard engine.

--scott

Reply to
Scott Dorsey

Now there's some REALLY BAD advice. Your issue may be related to something as simple as a bad pressure cap and oxalic acid based antifreeze. Vic Smith's advice was much more on target, but in any case, more testing is advisable prior to executing ANY major disassembly.

Reply to
None

Might be bubbling in radiator. More damage if coolant leaks into cylinders. Check if all plugs look ok and the same.

Greg

Reply to
gregz

Oxalic acid based antifreeze?

I've used ordinary green glycol antifreeze for decades and never seen any failure like that. I agree the original poster ought to just change his antifreeze and see if the problem comes back, but if it looks like oil, feels like oil, and smells like oil, what is it if not oil?

--scott

Reply to
Scott Dorsey

I've lived and traveled exclusively in the midwest for decades and have never once seen an iceberg or a hurricane.

Which is distinctly contrary to your previous advice.

But of course the OP never reported that "it looks like oil, feels like oil, and smells like oil", only that there was a "brown greasy film", a clean dispstick and an apparent assumption that it might be oil.

Reply to
None

The cooling system should stay pressurized when the engine is hot and off, whereas the oil system will not maintain pressure. If there was a crack, gasket, whatever, I would think that water would also get into the oil.

Reply to
Paul in Houston TX

that's not a given - it depends entirely on the design of the motor. open decks can lose pressure entirely between cylinder and the water jacket without coming anywhere near an oil circuit.

Reply to
jim beam

Tell me, then, about this oxalic-acid based antifreeze.

--scott

Reply to
Scott Dorsey

that pdf is is outrageous bullshit. yes, there is an oxalyic acid reaction, but it's perfectly natural and present from day one. to suggest that antifreeze manufacturers don't know about it and don't buffer/stabilize accordingly is ridiculous. and to suggest that egr valves are responsible in some way is preposterous.

Reply to
jim beam

May be a breakdown product of ethylene glycol?

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Reply to
AMuzi

Yep that's it:

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Reply to
AMuzi

when was the last time your system was flushed?

Reply to
m6onz5a

a V-6 engine and a five speed. It's been well maintained and has a brown g reasy film in the radiator cap and in the reservoir. The oil dipstick is cl ean and doesn't show any signs of water contamination. Seems to me that the cylinder head has failed and is leaking motor oil into the water jacket. T rouble is, I don't know how a mechanic goes about discovering where the tro uble is--or if they just tear down the engine to the short block and machin e the heads. Plus I'm trying to figure out how much the job will cost and h ow long the car is drivable until the work *must* be done. Thanks in advanc e.

System was flushed five months ago.

Reply to
geo pearl

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