I Shine

When I check the coolant level in the radiator I can see a little bit of oil floating on top of the coolant. After further inspection the under side of the radiator cap has a thick black grease film. The inside of the filler neck has this same film. There is no signs of water in the oil and the engine runs strong. The engine appears to have been well taken care of. I'm thinking maybe it previously had a blown head gasket and the radiator was not properly flushed. Can this grease be flushed out of the radiator ? Should I just take the radiator out, fill it full of a de-greaser, and give a good flush. Or maybe just buy a new radiator.

BIGCAT7274

more than likely oil cooler failed if it has one.

dawn will get the oil out. just have flush it a few times.

I Shine

It does have an oil cooler. I think my oil cooler is also leaking from the adapter above the oil filter. There is always a bead of oil dripping from the filter.

Paul Bell

iTrader: (9)

The F-Body factory oil coolers rarely leak. The oil does NOT circulate to the radiator.

Head gaskets are a much more likely cause of oil in the coolant.

SS RRR

iTrader: (2)

How is that?

speed_demon24

iTrader: (6)

So oil leaking into the coolant system from a faulty oil cooler won't circulate to the radiator?

Murche

iTrader: (1)

The coolant flows to the oil cooler mounted above the oil filter, and I have seen several leak allowing oil to eventually get to the radiator. The cooler can be removed and the coolant lines bypassed.

Paul Bell

iTrader: (9)

I posted that the oil cooler rarely leaks and that blown head gaskets are much more common in these engines.

I did NOT state that it was NOT the oil cooler and that it HAD TO BE a blown head gasket. This will be determined by further diagnosis of the vehicle.

I've simply stated what would be the most likely cause of the problem.

The oil that flows through the cooler/adapter in under pressure from the oil pump. If there's a leak between the oil side and the coolant side of the cooler, it'll eventually pump all the oil into the coolant side. This is because the oil is normally at a higher pressure than the coolant. Shut off the engine and the oil pressure goes to zero and as the coolant side is under some pressure during operation, it'll then cause coolant into the oil system.

During a quick search of the LT1/4 section, there's zero results for "bad oil cooler" yet a good handful or results when searching for "blown head gasket".

Paul Bell

iTrader: (9)

I Shine, you say you think the car had a blown head gasket and you suspect the oil in the coolant is left over from that. This is a possibility-if in fact the engine has had a blown head gasket. Do you know that a head gasket was replaced?

If you want to totally rule out the oil cooler as the culprit, you can remove the oil cooler completely (many consider the stock cooler as little help and prone to leaking oil onto the ground), completely flush the cooling system (engine, heater core, overflow bottle) and do an oil change. Drive the car for some weeks and see if the oil contamination returns.

It would be great for you if it was the oil cooler-it's considerably less work than head gaskets.

SS RRR

iTrader: (2)

Still don't see how a blown head gasket could yield oil in the coolant?

saltwaterreefguy

iTrader: (1)

When a head gasket goes south oil and coolant mix MOST of the time. in rare cases if the head gasket has a pin hole you wont see it.

SS RRR

iTrader: (2)

Sometimes they do indeed mix, in the bottom of the oil pan. There are times the gasket may only give and coolant will escape into the cylinder only. My question is, how does oil get into the cooling system where you can notice it from the radiator fill, if the oil cooler is not at fault?

Paul Bell

iTrader: (9)

Aside from the good number of posts here on LS1tech discussing oil in the radiator and head gaskets, there's the usual internet searches:

http://www.chacha.com/question/what-...n-the-radiator

http://www.yotatech.com/f120/oil-my-...s-mean-242717/

http://answers.yahoo.com/question/in...5225125AA1Vlyw

http://cars.blurtit.com/180652/oil-i...s-the-problem-

http://wiki.answers.com/Q/Why_is_the...in_my_radiator

http://www.fixya.com/cars/t5287257-o...flow_tank_mean

http://wiki.answers.com/Q/Oil_and_an...wn_head_gasket

SS RRR

iTrader: (2)

I really haven't seen any threads here or any f-body forum for that matter regarding oil in coolant due a to blown head gasket(s). Some of those links you've provided are completely inadequate. There are no oil ports between the heads and the block on the LT1 engine. It reads more like some of the descriptions are for OHC engines. The only part of the gasket that is exposed to oil is within the lifter valley. Because coolant is under more pressure than oil vapors w/in the lifter valley, coolant will always find its way into the engine rather than oil finding its way into the cooling system barring no oil cooler.

Paul Bell

iTrader: (9)

Regardless of how the oil gets into the radiator, it's usually a sign of a bad head gasket. This is somewhat common with SBC engines. Even my 1999 Savana blew a head gasket-at 200K.

SS RRR

iTrader: (2)

Not on a LT1 SBC it isn't, unless somehow oil can defy the laws of physics.

BIGCAT7274

the oil cooler is the only place oil is in proximity to coolant in a pressure condition. Remove the cooler and bench test it in a 5 gal bucket of water.

93Euphoria

ok correct me if im wrong but I thought no oil what so ever passes through the heads gaskets on a small block?!

BIGCAT7274

There are no pressurized oil passages that go through the head gasket on sbc or lt1. The only place oil goes through the gasket is the corner drain holes.

SS RRR

iTrader: (2)

Exactly. Only time oil is pressurized to the heads is through the pushrods and into the rockers. After that, gravity takes over.