Do you have oil in your radiator? If you do, we recommend you bringing your vehicle to J-Mac Car Care right away. However, if you would like to troubleshoot the problem and be able to tell us what’s wrong, there’s nothing wrong with that. Troubleshooting oil in your radiator is a difficult process and it’s not for the novice mechanic. So please be very careful troubleshooting on your own.
You’ll need several tools to troubleshoot having oil in your radiator. Here’s what you’ll need: your repair manual; a compression gauge; a vacuum gauge; a radiator pressure tester; a spark-plug socket and wrench; and an assistant. If you don’t have all of these items, then you need to skip the self-diagnosis and go ahead and take your vehicle to the helpful staff at J-Mac.
To determine if you even HAVE oil in your radiator, you first need to start your vehicle. Then immediately after start up remove the radiator cap and examine the condition of the coolant contained in your radiator and overflow reservoir. If there is oil in the coolant, it will look muddy brown and “frothy” with the consistency of a milkshake. Then you need to drive your vehicle for an extended period of time, so the engine heats to its normal operating temperature. After awhile, park the vehicle and read the temperature gauge. If the temperature gauge needle is reading “above normal” temperature limits and you saw muddy brown contamination during your inspection, you’ll also need to check your engine.
To inspect your engine, you need to use the following steps:
Step 1: Make sure your vehicle is turned OFF with your vehicle in park or neutral AND set the emergency break.
Step 2: Using the spark-plug socket and wrench, remove the spark plugs. Screw in the compression tester or use a hand pressure tester into the spark plug hole. Remove the high-tension coil or coil pack wire.
Step 3: Your assistant is now needed! Have your assistant turn the engine over (with the key) seven or eight times then stop. Each time read the pounds per square inch (PSI) on the gauge as well as for each cylinder. Record the numbers and note any deviations with your results.
NOTE: Any cylinder that reads less than 30 pounds will have a problem and could point to a blown head gasket.
Step 4: Hook up a vacuum gauge to a vacuum source on your engine. The best vacuum sources on your engine will come from a hose that leads from the intake manifold, carburetor or throttle body.
Step 5: Idle the engine. While the engine is idling, read the gauge and record the number. Use your owner’s manual has a guidebook for the correct vacuum reading. It will be measured in inches of mercury.
NOTE: Any number that is less than the manufacturer’s specification will indicate excessive vacuum entering the combustion chamber. A warped or cracked cylinder head or a defective head gasket could cause this problem.
Step 6: Turn off your engine and check your oil. Look for any light brown coloring or foamy substance on the tip of the dipstick.
NOTE: If you see any light brown coloring or foamy substance on the tip of the dipstick, this indicates that that a cylinder passage in the head or block has crossed an oil passage with a water passage. A warped or cracked cylinder head or a blown head gasket could cause this problem.
Step 7: Hook up a radiator pressure tester to your radiator cap inlet. Manually pump the tester to the pressure that is listed for your radiator (it will be written on the radiator cap). You can exceed the pressure, but only by a few pounds, without damaging your radiator system. So please be VERY careful.
Step 8: Wait for approximately five (5) minutes and see if the pressure slowly drops. Listen for any hissing noises coming from the area near or around the cylinder head.
NOTE: If you can hear hissing noises coming from around the cylinder head or the pressure is slowly dropping in your radiator, your vehicle may have a defective gasket seal and potentially an exterior crack in the cylinder head.