Oil In My Radiator


I have a 2002 Honda Accord LX with 145000 miles. My problem is that I am getting blobs of oil in my radiator. Its driving me to the poor house because my mechanic thinks I have a bottomless pit of cash. He changed the heads,head gasket,thermostat,applied leak protection,changed my radiator and the problem is still there. There is no water/coolant in the engine tho (thats the consolation he gave me). HELP.

Sounds like the automatic transmission cooler is leaking or has otherwise failed

I concur as a first guess of the problem.

If your car has an automatic transmission it has a transmission cooler built into the radiator. You can see the connections if you look under the hood. If the transmission cooler leaks you get transmission fluid (oil) in the radiator. Your mechanic should know this. If your car has a manual transmission, your mechanic will have to keep looking, but I’ll bet your car is an automatic.

You may also have a bad water pump / gasket. Some cars require sealant on one or two water pump bolts because they go into the crank case. And the transmission cooler is another possibility. Did you mean that the coolant has disappeared or that there is none mixing with the oil? You have to clear writely.

I agreed with the others and then noted that the radiator has been changed.
Maybe what’s happening (if this is an automatic car) is that your previous transmission fluid cooler was leaking and what you’re seeing now is residual transmission fluid from inside the engine water jacket and hoses.

If this is the case, maybe simply flushing the cooling system out will eliminate any residual oil lingering around in there.

Also if this is the case, I would advise checking the transmission fluid and make sure it’s not contaminated by coolant as this can destroy a transmission.

This is a long shot. Does your engine have an engine oil cooler? Is this Accord a I4 or V6? I believe the I4 may have an engine oil cooler that may be leaking. The leak would be from the engine into the coolant as the pressure gradient is that direction.

If you discover the problem, post back the solution.

At what point could oil get into the coolant?? That is if it was the oil cooler??
And Rainier, is either the engine or transmission losing oil?

I saw your question about oil in the radiator. As I have the same car,same engine and same problem with 137000 miles on it, I thought I would tell you what Honda told me. They said it was high pressure oil from the engine oil gallery passing througe a porus engine block into the water jacket and into the radiator. They told me to replace the block or the entire engine. As of now I have done neither. If you come up with a fix please let me know.

Did they explain exactly how they determined the engine block is porous?
Have they by chance actually seen this problem before and pointed it out to the parent company, Honda Motor Co.?

Some of these things should be taken with a grain of salt. One would think if someone is given a diagnosis like this, the shop should consider adding some dye to the engine oil and actually verifying that dye can be seen in the radiator shortly afterwards before going all doom and gloom.

I was shown the milky oil in the overflow resevoir and the low oil dipstick. The head mechanic said he had encontered this before. What I found suspecious was if the engine is down at least four quarts and the overflow tank is only half full where is the rest of the oil. I had them change the oil and flush the cooling system and we will see what happens.

If your engine was down 4 quarts of oil then you probably have some serious trouble looming in the future and any alleged crack is irrelevant.

When an engine gets that low on oil that means the oil pump is inhaling some air as most of the oil is in suspension (meaning it’s filling oil passages, pooling, being thrown around, etc.) and there is not enough oil in the oil pan to maintain a steady supply.
This means damaged engine internals to some degree.

If your car has an automatic transmission I would advise checking the transmission fluid level on the offchance the cooling system mess could be caused by transmission fluid mixing with the coolant. Even a small amount of trans fluid can make a huge mess when mixed with anti-freeze.

Thought about this as there was no engine oil lite and the car has been running fine for a week I am just watching. Transmission oil is fine so it did not get into the radiator through the trans oil cooler at bottom of radiator. The engine does not leak and I have the oil changed every 4000 miles. The coolant is bluish in colorand I was thinking of mixing small amounts of oil an coolant in cup and trans fluid and coolant in anothe and compare. If it happens again I will have the trans lines disconnect and the radiater trans coil pressure checked.

I was wondering if the fluid in your radiator looks like silly puddy? Our radiator fluid turned to sticky , stringy Silly Puddy. The mechanic said it was Transmission fluid in the radiator that caused it but our Trans. fluid is full. ? We feel it was a bad mix of two different coolants. (we had the coolant exchange done less than a week before the problem happened)