Classic/Antique Car Repair: 1977 Thunderbird, Electrical Diagnosis


Question
QUESTION: I have a 1977 Thunderbird that has started making a clicking noise coming from the engine. It isn't constant, it sort of comes and goes. But it is always there when I first start it in the mornings.

ANSWER: Hello John,

I always start with the simplest thing when diagnosing engines. It sounds like you've got sticky valve lifters. Valve lifters on your car are hydraulic devices that translate the motion from the camshaft to a pushrod and thence to the valves to make the car run.

Valve lifters are pressurized with oil. If the oil is either restricted or not retained properly due to dirt or wear, that's when you get the clicking noise, particularly on cold startup.

Not knowing how many miles are on the engine or how dirty the engine is inside makes  me unable to give you more specific advice other than to start by draining the oil and refilling with a good 10W40 weight oil. The thicker viscosity than the stock 10W30 should slow down drainback from the lifter and help pressurize it quicker when it's cold. If when draining the oil, there's a lot of gunk found, you may want to flush the engine with a special solvant based oil to clean out as much gunk as possible, THEN refill with the new oil and filter. Unless you're a good mechanic or are careful, I'd leave this step to the pros as the flushing lubricant is just made for cleaning and doesn't provide proper oil pressure so it shouldn't stay inside your engine long and is certainly not for driving the car.

If this doesn't do the trick, there are hydraulic valve lifter cleaning additives that you CAN add to and leave in the oil.

Next step if the preceding doesn't work, there is hydraulic lifter cleaner that comes in a spray can that you can spray directly down the pushrods if you remove the valve covers.

Failing the above, valve lifters can be replaced but you will need to remove both the pushrods, rocker arms and the intake manifold to get at them. And at this step, if lifters are worn enough to replace, chances are that other major engine components are worn also so you really need to evaluate the condition of the entire engine before making the lifter investment.

Nontheless, these are steps you take, from easy to harder, and hopefully, at some intermediate point, you'll solve or greatly improve the noise.

One other suggestion I have for the top end of your valve train is Marvel Mystery Oil. Available at Walmart and similar places, the name sounds hokey but the product really works. It's called a "top oil" for lubricating the valve rocker arms and pushrods. As the clicking you hear may also be due to upper valve train wear, adjustment (though lifters auto-adjust the valves when they're working right) or sticking, put this stuff in your gas tank and you've covered another base inexpensively.

Hope one of these solutions works for you and that you'll soon be driving a much quieter car. The 302 or 351 engines originally installed in your car are known as reliable workhorses that can take a lot of abuse and wear and come back for more!

I love that era T-bird--it was my favorite car after the Trans Am when it was new!

Good luck,

Bob          


---------- FOLLOW-UP ----------

QUESTION: Hello again Bob,

I've been working on that lifter noise, and I've put in Power Punch and STP motor treatment, after giving it an oil change.

The ticking noise is lighter, but still there. I've been recommended to use Sea Foam, but I've read some scary reviews for it on Amazon.
what do you think about me using this on a car of this age? I should have mentioned, I have a '99 rebuilt motor in it.

ANSWER: Hello John,

Thanks for writing back. Sounds like you're making progress but your lifters are still sticky. I think part of your issues are due to using general purpose engine treatments instead of single purpose cleaners made specifically for the problem you're trying to solve. Yes, they may claim to clean lifters on the can along with a myrid of other things but the concentration of the lifter cleaner is too low to help much. Rather, Try the following fixes individually with a fresh change of oil so you know what works and what doesn't:

1) Wynns makes a good brand of hydraulic lifer cleaner that seems to have a good reputation. You'll find it in the better repair shops and tire stores.

2) This isn't an approved method. But I've used it several times and it works. BUT, you have to be aware of the risks. You can actually dislodge a clump of dirt and clog an oil gallery.

First, fill with fresh oil and a MAXIMUM of 1 PINT of ATF (that's IN ADDITION to a full fill of oil). Yes, I know you're overfilling. But a pint will not cause problems. Never add a full quart of ATF. Yes you can drive on it. Keep it in until the tick goes away. Then change oil and filter. (always)

If your engine is still filled with sludge, this won't fix it. You can do a complete engine flush on a motor but, unless you're prepared to buy a new one, be extremely cautious. Very tricky. Better to pull apart and clean if extremely dirty.


3) Ask any Dealer service counter what they think of the preceding plan. You're not going to like what they they will say although if done carefully, it does work because ATF transmission fluid is a high detergent oil, perfect for cleaning out any further residual dirt and sludge you may have down there!

4) A final idea that goes with any of the preceding. Change the oil and filter and this time try Mobil One full sythetic or synthetic blend, high mileage 5W-30 which has a very strong detergent package and just might free-up the stuck hydraulic valve lifter. We're going in the opposite direction from what I recommended last time but given your stubborn case, an oil that flows faster on start-up might just cure your start up blues.

Any of these are worth a try before going to the trouble of tearing off the intake and valve covers to change just one lifter. There is a method to more directly spray lifter cleaner on the pushrods and lifters by taking off only the valve covers, but let's try the preceding first.

Good luck,

Bob


---------- FOLLOW-UP ----------

QUESTION: Hello Bob,
I've taken care of that ticking noise. Would you believe it turned out to be only a lifter tapping on the underside of the valve cover because it was torqued too tight? Sometimes it's the simplest thing, I guess.

I have another question. My back-up lights stopped working some time ago. I've checked the bulbs, sockets, fuses. All good. I've heard it could be the back-up ligh switch, located on the steering column. I wanted to see what you thought before I put the time and effort into this.

Thanks, John

Answer
Hi John,

That's great news!!  You just illustrated one of the first rules of a good mechanic, something that even the pros sometimes forget: Always check the most basic and simplest causes of a fault first! Sometimes we (including me) tend to jump the conclusions of the worst cause possible. Anybody can guess and parts change but I was taught that the true mechanic diagnoses the root cause of a problem first.

Using this same simplest first reasoning, check the fuses and the grounds for each of the lights (they should be fused into a single circuit, however). Just like you did with the light sockets, remove and check the fuse for continuity and corrosion. The light should have a ground somewhere, either by single wire or by case to body contact. After doing these things and then pursuing any another cause you may find (like broken wires, etc.), then I agree with you, the most likely next cause would be the switch.

Good luck in your detective work!!

Bob