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Troubleshooting an oil leak

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  • Troubleshooting an oil leak

    Hi all, I'm almost finished with my Caterham build (Roadsport 175 w/ Duratec 2L) and had my first drive around the block last week. After the maiden voyage I let it idle in the garage for a bit so I could check the coolant level, make sure the fans came on, check the lights, etc. and noticed a bit of oil underneath the engine. It wasn't a horrible gushing amount, maybe 1/4 qt had built up, and is coming from the driver's side. The largest bit of oil was near the blue drain plug and under the oil filter adapter where the oil pan meets the block. The oil filter itself and the oil cooler sandwich plate (Modine oil cooler) had no oil around their seams so don't believe its coming from there.

    After the discovery, I shutdown and cleaned off the engine, cleaned up the oil from under the car, and let it sit most of the week. I've identified the blue plug in the oil pan as seeping a bit, based on the paper towels I left under the engine, so know it needs to be tightened down more, but it's on pretty damn tight now. The oil filter housing which attaches between the oil cooler sandwich plate and the engine is torqued to 25nm per the Ford Haynes manual. I don't think the oil was coming from there, but there was definitely a lot of oil underneath it - which I'm assuming was sprayed or had run from the blue plug. So... the questions:

    1) The blue plug, as I've got it on now, has a rubber O ring, then an aluminum washer that came with the pan, on it. I found some other posts on here mentioning the aluminum washer being on there but didn't see anyone mention the rubber O ring. Should that be on and if so before or after the washer?

    2) If I need to take off the blue plug to swap the O ring / washer, any tips on getting it out without oil everywhere? I was thinking of just putting the front end on jack stands and trying to get the plug in out with as little mess as possible.

    3) When we put the pan on, we were really careful to make sure our RTV followed the Ford diagram for the gasket routing. Any tips on testing to see if the oil is really coming from the gasket instead? I was thinking of just running the motor and watching it but not sure if it needs to be under load or something to leak.

    Thanks all for any advice.


  • #2
    Is it a Raceline wet sump? If so, as I recall, that is about a 30mm aluminum washer. The o-ring is probably easy to find (maybe go a bit thicker?) I have a torque value from Peter at Raceline that I will pass on when I get home on Sunday.
    Wide-body Birkin, 2.3l Duratec


    • #3
      I have a Zetec with Raceline sump and had major spills on 2 occasions: one time when I did not notice that the oil filter gasket stuck to the mounting plate and the next oil filter with new gasket folded it up. The other time when I forgot to reinstall the little plug for the crankshaft TDC tool after an engine rebuild (not sure if the Duratec has that). I also had a slow oil seep out of the valve cover gasket for a long time due to smallish crankshaft and valve cover vent hoses and resulting internal pressurization at high rpm.

      After a few oil changes I got fed up with the Raceline blue aluminum plug (thread seizing and hex rounding) and installed an Aeroquip oil drain quick disconnect. Quite nice...push on the drain hose and no mess. For that matter, I don't remember that plug having an o-ring but maybe I forgot.
      Last edited by slomove; June 19, 2015, 06:55 PM.


      • #4
        You can get a UV dye and light kit from the local auto parts store. It will help you locate the leak. Easier to see if you do it in a darkened garage.

        The blue plug should be tight but not overly so as it is aluminum and you can strip the threads.

        Mine have the crush washer but no O ring. Get new crush washers for when you remove it. They are usually a BSP size. British Standard Pipe I think. Call or email Raceline or find from Summit or Pegasus. Buy several.

        Use a small amount of Hylomar or Yamabond sealant on the crush washer. Couldn't hurt.

        Safety wire the plug or plugs in place. I will attache some photos of drilling mine for the wires, if I can find them.