Oil in Radiator

Hello Sir

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Make: Toyota
Model: Corolla
Engine Size: L4-107.5 1762cc 1.8L DOHC(7A-FE) Sedan (not DX).
Transmission: Automatic

Some amount of oil was found in the Radiator two weeks ago. Besides vibration was observed while stopping at the light in Drive postion. Vibration lessens if in Neutral. Rear Shifting the gear introduces the vibration. The vibration seemed to be coming from the passenger side dash/engine part.

The following was done.

Engine vibration check out results- Scanned the code for codes and found none. Scoped the engine and the ignition was checked to spec. Did not find any misfires. Timing was correct, the starting and charging system checked to spec, the fuel and emissions systems along with the cylinder balance test came out good. A coolant hose leaking at the back of the water pump. Found oil in the radiator. Did not see coolant in the oil or in the transmission fluid.

Replaced the hose at the back of the water pump and block tested the engine. No head gasket leak was found. The colour of the liquid did not change.

I showed to another shop and they did the following:

The Radiator was pressure tested and was found alright. The upper hose was replaced since it was not in good shape. Radiator Coolant Flush under recommendation was done and by the 4th day I am finding oil in the coolant and radiator again.

The good thing is the Engine is not overheating.
But I am not driving more than 18 miles at a stretch and have not used this vehicle for long distance driving for several months.

While checking the engine oil, I am finding water bubbles along with the oil.

I would appreciate if you can advise me on the the course of action. Thank you.
Do you
have the same problem?
Saturday, April 21st, 2007 AT 11:29 AM

1 Reply

I've reviewed everything possible to cause this problem. My conclusion came up with a minute crack on the gasket-if it was me I will retorque the heads as per its special intructions and recheck for leakage. Or if you wish run a therma gasket thru the cooling system.

Did they attempt to sniff for hydrocarbons thru the radiator fill neck with a gas analyzer. If hydrocarbons shows up you have a combustion leakage.


Heat makes aluminum swell almost three times faster than cast iron. The resulting stress can distort the head and make it swell in areas that are hottest like those between exhaust valves in adjoining cylinders, and areas that have restricted coolant flow like the narrow area that separates the cylinders. The typical aluminum head swells most in the middle, which can crush the head gasket if the head gets hot enough. This will cause a loss of torque in the gasket allowing coolant and combustion leaks to occur when the head cools and you probably think its leaking in while its hot.

You're thinking am not overheating-remember if the idiot gauge is out of calibration it will lie to you, and won't even notice that there's something is going on with the cooling system.

I've been in a similar situation like yours-what I did was pour in liquid copper in the cooling system and that fixed my problem.

HTH-Good LUck
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Sunday, April 22nd, 2007 AT 3:35 AM

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