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Oil in the antifreeze *NEED HELP*

fordeater

fordeater

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Ok, I've got a 1998 Chevy k1500 with a 5.7 Vortec. It only has 70,000 miles on it.

Just the other day I started smelling coolant really bad. So I check the radiator and it looked discolored. Its obviously normally orange, and it looked burnt orange, almost brownish. So I then checked my oil, and it barely registered on the dipstick. I just checked it a week or so ago and it was full.

I thought right away that it was head gaskets, but then the more I read on it, head gaskets caused antifreeze in the oil, not the other way around. So, i'm not sure what it is.

Can anybody get me going in the right direction in diagnosing this problem?
 
That orange Dexcool crap turns all sorts of nasty colors if you get air in the system. Check your oil and see if it is milky. That would be a better indication the two are mixing. Flush your coolant too. That stuff is a terible gunky mess once it gets contaminated.:mad:
 
There is no physical way to get engine oil into the cooling system unless you have an engine oil cooler that runs into the radiator tank and it went bad internally. You can however be mixing tranny fluid (assuming you have an auto) if the same said cooler in the radiator tank is internally bad.
 
Another good way to tell on those trucks is take the oil fill cap off and see if it has any coolant residue on the underside/threads. If it is orange then you need to do the intake gaskets.

Mine went at 66k miles on my 98, trust me its very common.
 
Same thing happened to my S-10. Thought it was oil, but found out the line running from the auto tranny cracked, causing it to leak into the radiator.
 
4X4HIGH said:
There is no physical way to get engine oil into the cooling system unless you have an engine oil cooler that runs into the radiator tank and it went bad internally. You can however be mixing tranny fluid (assuming you have an auto) if the same said cooler in the radiator tank is internally bad.
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That would make sense. I just don't understand how I lost that much oil that quickly. There are no obvious leaks. To be honest, I don't even know if I have an oil cooler. I'll have to look tomorrow.
 
98 chevy "should" have an oil cooler, the trans cooler is in the pass side, the engine oil cooler is in the drivers side.
 
Ok, just went outside and checked. It does have an oil cooler in the radiator. So, I think that is the problem.
 
it's a easy job to replace the intake manifold gaskets.
Will take you about 3 hours with hand tools.

I've never seen a oil cooler leak inside a radiator...
but that's just my opinion...
 
I've never seen a oil cooler leak inside a radiator...
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nor have i. do the oil cooler and radiator even have any tubes that touch? not sure why they'd do that. in any case, getting a hole in both in the same spot and having controlled fluid transfer instead of crazy spewing seems really unlikely to me.

i've been really lucky with my 94's intake manifold. after 14 years and nearly 133K miles, still no leaks.

i wouldn't bypass the cooler unless you plan to add a separate one. they put it there for a reason and it can really make a difference.
 
Oil coolers in the radiator can and do go bad. Usually it will start pushing coolant into the overflow tank and make a mess in the radiator.
Drain the coolant and see if it is oil fouled, it is pretty obvious if it is.
If you are unsure disconnect the cooler lines from the radiator, block one off and apply regulated shop air to a full radiator and see if any air bubbles are in the coolant.

If the radiator is oil fouled it will have to be flushed out. Do that by adding a bunch of Cascade dishwasher soap. Run the engine up to temp and drain.
Refill with plain water and repeat. Continue until the coolant runs clear.
Be sure to remove the block drains to fully flush it out.

The best mess makers are the extended life antifreeze and synthetic oil.
It fills the coolant system with a Vasiline like goo.
 
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