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Questions and Answers

Nissan Pickup Getting Coolant In The Oil

Q. Hello how are you doing? I have a question regarding my 1991 Nissan Pickup. Here is the info on it first:

  • 1991 Nissan Pickup
  • 2.4 liter KA24E engine 2WD
  • Manual 5 speed transmission
  • 90,000 miles
Nissan Pickup Getting Coolant In The Oil

Okay, here’s the problem, I bought this truck from my uncle with the understanding it was getting water in the oil. Well seeing this on several other cars I thought it was an easy fix by replacing the head gasket. Well I did that and I was still getting water in the oil. So I then tore it back apart and had the head shaved and checked for cracks.

The machine shop told me it was good to go so I replaced all the gaskets again and no go, I still was getting water in the oil. Well I talked to some friends and they told me to replace all the gaskets on the front of the engine, the timing cover gasket and all. So I tore in to that project with a smile figuring it would fix it.

I replaced the timing cover gasket, water pump and gasket, oil pump gasket, oil pan gasket, fan clutch, thermostat and gasket, and alternator. Well it is all back together and it is still over heating and getting water in the oil and I am out of options.

I was told it could be the block but I think the head would crack before the block will because the heads are aluminum and the block is cast iron. So can you help me figure out why I am getting water in the oil?

Thank you,
Chris

A. As my Grand Father used to say, "When you have eliminated the obvious, whatever is left, no matter how improbable, must be the answer".

There's not too many ways for coolant to get into the oil. A blown head gasket, cracked head or cracked block are just about it. In all the years I have worked on Nissans I have never seen one crack a block. That's not to say it can't happen, just that I have never seen it. I have, however, seen plenty of cracked heads.

Before condemning the block, I would like to see the head retested for cracks at a different machine shop. This will eliminate the possibility of a mistake being made at the first machine shop. Then when you put it back on, make sure the head gasket is on the right way. I have seen head gaskets on the KA24E engine get put on backwards.

When you put it back together, fill the bolt holes with carburetor cleaner and let it soak. Then blow the holes out with compressed air. Make sure you wear goggles. I have seen guys tighten head bolts with oil in the holes. The bolts can't compress the oil and even though the head bolt torque is correct, the head is still "loose".

Nissan Pickup Getting Coolant In The Oil

Use this procedure and tighten the head bolts in this order.

Tightening procedure:

  1. Tighten all bolts to 22 foot pounds.
  2. Tighten all bolts to 58 pounds.
  3. Loosen all bolts completely.
  4. Tighten all bolts to 22 pounds.
  5. Turn all bolts 80° to 85° clockwise with an angle wrench, or if an angle wrench is not available, tighten all bolts to 54 to 61 pounds.

I would also get new head bolts from the Nissan dealer. These are "stretch" bolts that could be stretched out. This is everything you can do to be absolutely certain the head and head gasket are good and on properly.

If you still get coolant in the oil, the next thing to do is drop the oil pan. Use a flat blade scraper to break the oil pan loose from the block. A screwdriver will damage the sealing surfaces.

Pressurize the cooling system and look inside the block. You maybe able to see if coolant is coming in and where.

Additional Information provided courtesy of AllDATA

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