The Color of Trouble

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Red means stop and green means go – but what are the colors under the hood of your car trying to tell you?

* Engine oil –

Fresh oil is usually light to dark amber and translucent. Like honey. This is how the oil should appear on the dipstick immediately after an oil change. If you paid someone else to do this job, pull the dipstick and check before you drive off. If the oil on the dipstick is not light to dark amber, the color of honey, they may not have changed it.oil-pic

Over time, oil will turn darker (brownish)  in color due to contaminants being held in suspension. This is normal. The oil is doing what it’s supposed to be doing. When the oil has turned black, it is probably time for an oil change – or getting close to it.

Watch out for:  Milky or cloudy-looking oil. This is a clue that water (engine coolant) is getting into the oil, possibly from a leaking intake manifold gasket or more serious problem such as a failing head gasket.

Get the car to a shop ASAP.

* Automatic transmission fluid –

Most, though not all, automatic transmission fluid is reddish in color when fresh and like engine oil, gets darker over time. But unlike engine oil, it should never look brown or (worse) black. If it does, it is likely the transmission overheated at some point. This is your cue to have the car checked out. A running-hot transmission will usually be a short-lived

Watch out for:  Burnt smell or small metallic shavings held in suspension in the fluid or present on the dipstick. Wipe the (cool) dipstick between your thumb and index finger. If you feel any grit, it is very likely the transmission will need work – possible a major overhaul – in the near future. A burnt smell is a clue the transmission is running hot. Get it checked as soon as possible.

*Engine coolant –

Coolant (anti-freeze) used to be neon green in color but many late-model cars also use so-called “long-life” coolant that can be orange in color. What you want to be wary of is coolant that is brown or oily-looking. If the coolant just looks dirty, all the system may need is a thorough flush and refill with fresh coolant. If there’s oil in the coolant, it could be a more serious problem that might involve major work to the engine as well as the cooling system. Look out for air bubbles in the coolant, which you can check for by removing the radiator cap (engine cold!) and then running the engine for a few minutes while you watch the filler neck. Bubbles in the coolant are a clue that an intake manifold or head gasket may be leaking.coolant-images

Watch for: The manufacturer’s recommendations about which type of coolant to use. If your car came from the factory with the orange-red colored long-life coolant, it may not be ok to top off or refill the system with standard green coolant. If it’s an emergency and nothing else is available, use straight water – ideally distilled water.

Have the car serviced as soon as possible.

* Crankcase breather element –pvc-system

In addition to the air filter, inside the air cleaner assembly in most late-model cars you will find a small, replaceable breather element. It filters the air that’s normally sucked into the engine’s crankcase as part of the Positive Crankcase Ventilation (PVC) system. It’s normal for this small filter element to look dusty and dirty – and when it does, it’s probably time to replace it. What’s not normal is for the breather element to look black and be sopping wet with oil. If it is, there may be a problem with the PCV system (minor and easily fixed) or the engine might be getting tired; oil is leaking past piston rings up into the air cleaner assembly.

Many owners forget to service this small but important little  filter. Check its condition at least once a year and replace the breather element when indicated.

* Brake fluid –

Like engine oil, brake fluid looks clear to honey-colored when fresh and gets darker over time, as contaminants build up. Unlike engine oil, the contaminants in brake fluid don’t get caught by a filter.brake-fluid

Brake fluid also tends to attract water, which can rust out the lines (and master cylinder, if it’s metal) from the inside. This is why it is especially important to keep track of the condition of the brake fluid and have it changed out as necessary (usually, once every 3-4 years at least). Otherwise, you risk damaging expensive components. Braking performance will also be reduced, especially if any air has gotten into the system.

Be certain to use only the correct type of fluid for your vehicle (e.g., DOT 3, 4 or 5) as specified on the master cylinder cap. Use of incorrect/incompatible fluid can cause problems you don’t want.

Watch for: Spongy or soft pedal feel. This indicates low brake fluid level, or air in the system – either of which are potentially dangerous. Reduce your speed and leave extra stopping room between your car and  other vehicles, just in case. Have the car looked at a soon as possible. depends on you to keep the wheels turning! Clovers hate us!

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  1. Since my vehicles are still within the 5-year drivetrain warranty I have the oil changed at dealerships, for proof of maintenance.

    There have been mishaps such as the wrong oil being used for my engine and overfilling. So, I insist that I watch the oil pour into the engine and the only oil to be used is the manufacturer’s own brand (Toyota) from bottles. No problems since.

  2. Ah, memories of the Dexcool sludge, and the silicone head gasket it destroyed. But GM says Dexcool is good stuff, so no recall for you!

    In other news, I got the offer letter from VW/Audi yesterday. Now I need to find a notary public and get a date to sell the A3 back to them. Just for fun I drove it the other day. I don’t remember so much road noise and odd squeaks out of the rear suspension. And it has developed a rattle too. Might be time to move on anyway. Still can chirp the tires though, and hugs the corners like your girlfriend when you get home from hunting camp.

    • iirc it was normally the (silicone) intake gaskets that let go, don’t think I’ve ever seen a silicone head gasket.
      best part was GM knew going in that there was a material compatability problem but decided to ignore it.

      • They touted a “limp-home mode” on W-body/3800 Series 2 vehicles (probably others too). The vehicle would be able to safely drive at a low speed, should the engine coolant suddenly be depleted. I always thought, gee, it’s like they knew.

  3. Eric,

    Nice article, a little racist (LOL), but informative. I didn’t know any of the signs of manifold gasket failure. Would this “new” (to me) phenomena be due to the use of plastic manifolds?

    I would add one VERY important caveat to those who have their vehicle taken in for service by Y chromosome deficient individuals.

    You say,”Fresh oil is usually light to dark amber and translucent. Like honey. This is how the oil should appear on the dipstick immediately after an oil change. If you paid someone else to do this job, pull the dipstick and check before you drive off. If the oil on the dipstick is not light to dark amber, the color of honey, they may not have changed it.”

    If there is NO OIL on the dipstick, DON’T START THE CAR or attempt to drive it.

    My ex managed to ignore that simple rule a couple of times. The first time I had a bit of a temper tantrum, as she had gone to the oil change place before driving to work, lunch, shopping, and then coming home.

    The second time it happened, I told her not to worry, that red light was just the replace engine light.

    After about ten days of sticking to my guns and repeating “Honey, that’s the replace engine light”, I came home and she told me to look in the garage. Much to my delight, I found a new crate motor and a brand new six wheel four ton convertible cherry picker.

    Figuring that I was way ahead of the game this second time around, I sprung for a new starter, battery, and cable (seems she continued to try and start it several times a day until the insulation cooked off), and swapped it out the next weekend.

    All I said to her was, “Your car is fixed, make sure you check the oil before you start it.”

    • Well-said, T!

      This has happened to me, also… well, to a Y chromosome deficient individual related to me (mom). After “service” at a Jiffy Lube. The “wrench” cross-threaded the drain plug but did not cop to it (much less heli-coil or repair the damage). He just let her drive away with the loose/barely in oil plug riding in stripped threads. Mom got home, parked and later noticed a large puddle under her car, called me to ask about it. I came over and got under the car. Lucky for her, the plug was still dangling, like a loose tooth. Not all the oil had drained. No engine damage. Just a big mess – and a PITAS.

      I told her to bring the car here next time it needs an oil change. I might not be able to do it “right now” (her big complaint) but I am a good enough wrench to not ruin a thread – and if I did, I’d fix the bugger! 🙂

      • eric, my parents always got their oil changed and car serviced by a guy in town who had a station and would go over the car and check coolant, battery, etc. and grease it.
        Once he retired they began taking it to a damned Jiffy Lube 60 miles away. They’d go out to eat(Golden Corral, yuk) and shop. I think getting the lube done was the excuse to go out and eat. They had plenty money and didn’t need to justify going out to anybody or for any other excuse but this was their MO. I told them countless times to bring their vehicles to me and I’d take care of them and not only do it right but use better oil and filters. I buy oil from a jobber or used to so I generally had 2-3 types for different engines and plenty of it, a stack of cases of oil in the corner of the barn….24 can cases.

        One evening they show up and when they stop to open the gate the oil light came on. They were just back from you know where with a fresh oil change. After their pickup sat a while I checked the oil, nothing on the stick. I poured in a quart, nada, zilch. I poured in another quart and it was on the stick. I had gotten low on that type of oil I didn’t use much of so I poured in my last quart and brought it up just to the add line. I was amazed the engine had survived. So I chewed on them a while and reiterated bring the damn cars to me and I’ll do it right. They never did. But I bought some filters that would fit their vehicles and now and then when they were out I’d ask when their oil was last changed and they’d always say, “Oh, not that long ago”. I’d check it and it would look like crap so I’d do an oil change and grease the car, check the fluids, etc. They always seemed to think it was somehow making me work too hard or adding to my load. It was so easy for me to do I never considered it ‘work’.

        You, like me, have probably never cross-threaded a plug in your life. Hell, if it won’t screw in pretty tight just with your fingers anyone with half a brain knows it isn’t going in correctly.

        Those fools at the fast change place aren’t checking the oil obviously. They often have a nozzle with a quart setting on it and just stick it in and let it run assuming it’s getting the correct amount, never figuring that drum it comes from may be out. They don’t use oil to my specs anyway. If they advertise Pennzoil, that’s enough to keep me away.