Category Archives: maintenance

Codes and More Codes

Remember the good old days when you adjusted the carb or the vacuum break on the choke maybe bumped the timing up a toush. Now everything is electronic so you hook up a scanner or count light flashes to get a trouble code maybe use a lab scope to check burn time or KV of a plug wire if it has one or check a coil one for each cylinder.

I do think today’s engines run better with electronic controls. But getting a code is only the first step in repairing a problem. Code shows a bad MAP sensor so all you have to is replace the MAP sensor. WRONG it may be a leaking or plugged vacuum hose or a poor connection. When the counter guy says you need a MAP sensor to cure your problem remember it is his job to sell parts not to fix your problem.

Always use a trouble shooting tree to locate a problem and don’t skip a step because you kow it is OK or that never causes a problem. I have heard many a story from help lines that when they go there check list they find a skip was missed and that is the problem.


Coolant Flush

Every spring the subject of flushing the cooling system comes up. It is almost as if some DIY flush as a rite of spring. My opinion is that you should flush for 4 reasons.

  1. Coolant is over 5 years old.
  2. You have GM orange extended life coolant in you r system. If it is over 3 years old even if it is the original get it out. This coolant is affected by air infiltration into the cooling system and will turn to a gasket destroying sludge very quickly.
  3. You have anything more than a slight parasitic voltage across the coolant to ground.
  4. it is dirty cloudy or in any way not pristine looking.

Use a glass container to examine the coolant closely, or place some on a clean paper towel this also works with transmission fluid. The only test that requires any explanation is the voltage test. Place the negative on the negative battery cable and the positive in the coolant do not touch anything other than coolant, you should read .02 volts or less, if it is higher start the engine if the voltage increases you have a bad ground on a component. Start by turning all components on and off if the voltage jumps you have found the culprit. No problem found ground the heater core using a simple flat ground wire. Flush and recheck. With the many different metals and plastics used in the manufacture of a modern engine this is becoming prevalent on a regular basis. Owners of vehicles that have a problem bleeding out the air after a complete drain, mostly expensive European with oddly mounted engines. They will cheat the system by draining only the radiator and performing this twice as often. This will work if you never let the coolant deteriorate. When replacing the coolant stick to manufactures recommended fluids. Why we need a dozen different antifreezes I don’t know there should be a standard.Use caution when workings on a hot engine never remove the cap until cool. Dispose of your old coolant properly.

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Fall Check Up

It is that time of year again to check the little things we don’t do on a weekly or monthly basis. Most of us do a walk around of our vehicle on a regular basis, but there are things we miss.

  • Lube and check the door locks including the trunk. This is important on vehicles with remote functions as we never use the key and the locks can become inoperable, A major problem when the battery dies in the remote.
  • Check the license plate light, had a few too many and should not be driving, this is one of the major reasons law enforcement uses for stopping a vehicle.
  • Check the wiper blades and don’t just run your finger across them but clean them with a alcohol swab or something similar. I use either WD 40; hey it has to have some use besides cleaning gunk off.
  • Check the spare for air and yes the compact spares do take that much pressure.
  • Check your headlights for brightness, one of the problems with the modern bulb is they lose considerable lumens before they burn out. As it happens over a period of time we don’t notice it unless we are paying attention, often we tend to think they are dirty. Also are your lenses cloudy a simple fix.
  • Check the tranny fluid this is often not done on a regular basis as the engine has to be up to temp and running. Check your owner’s manual for the proper method to check the level as many are different.
  • One last one that may seem obvious but check where you park for fluid spots, often the vehicle is parked when we are close to it and this is often overlooked.

Dex Cool Problems

Having to replace the intake manifold gasket at 43K in my wife’s 2005 Bonneville I decided some research was necessary on Dex cool. What I found is the best example of planned obsolescence I have ever witnessed. Introduced in 1996 it has changed very little if any since then. As a coolant it works until it is introduced to air, according to GM, IE you have a slight coolant leak and the system runs low, it causes the coolant to deteriorate rapidly. The coolant does not have to be that low but just a slight loss of volume in the radiator can cause problems. The intake and manifold gaskets are also unchanged to prevent the coolant from causing a problem. There was a change in the gaskets a few years ago but it had nothing to do with coolant contamination. Dex cool is a organic acid technology and when it breaks down tends to drop out inside the engine in the low spots. Dex cool can turn to a gooey, muddy, orange corrosive gel that will attack the plastic surfaces and the gaskets causing leaks. In severe cases it can clog the heater core, radiator and in some cases the water pump. . In severe cases this can harden and actually push the gaskets out of place. If air was in fact the cause of the problem why doesn’t the coolant in the overflow container turn to sludge? Basically all 27 brands of coolant start out the same it is the additives that are added for corrosion protection that cause the problems. For years this protection came from silicates. Recently more of the brands are using OAT and a few are using both. The actually cause of this problem is unknown and the only cure is to replace the Dex cool with a good quality green antifreeze and replace it every 2 years. Why it happens to some vehicles and not others is the question that is unanswered. GM says that the radiator cap may be the answer a cheap form of prevention and I do recommend replacing the cap with an aftermarket when doing the first flush. Even if your coolant looks fine it may be carrying a small electrical charge which will cause corrosion. Check the parasitic voltage with a volt meter, positive lead in the coolant and the other to ground you should have very little if any voltage. If voltage is present replace the coolant and check the engine grounds. I install a ground wire from the radiator to the body, a little anal perhaps but remember the radiator has very little if any metal to metal contact. Rubber hoses and mounted in bushings. There is a class action suit for this problem but that is for a later date.Before I get a ton of Emails, yes I did say aftermarket radiator cap if there is a problem with the GM cap why use another when a aftermarket will work, perhaps better.

Expensive To Repair

Just was posting about a 1964 Mercury Comet with 576K on it. I think that high mileage vehicles are going to become rarer as time passes. What are you going to do with a 5 year old Focus and it needs one of the several computers that it has for a horrendous cost, could be as much as half the worth of the car. The constant transmission goes out on your rice burner and again the cost is prohibitive, you have to go borrow money at the bank to repair might just as well buy a new car, same payments just for a longer period. Body shops have been seeing this for a while now, blow a couple air bags and a little body damage and your car is headed for the salvage yard. This may be a blessing in disguise as more used parts will be available. Have you ever noticed where most computers are located, where are are likely to be destroyed in an accident, there are a few under the dash which is a little safer. Mounted on the inner fender is not a good choice however in the event of an accident. ABS and HVAC controllers are the same story, expensive and poorly placed. We fight to keep home computers cool and the manufactures place them in the engine compartment. As engine compartments become more cramped and hotter I believe we are going to start seeing heat problems on several components as the current day cars get some miles on them. It is going to cause some difficult decision making if we should repair or replace, of course if the price of cars keep going up this may not be that large of a problem.

Charged Engine Service

With the introduction of V-6 engines that are either super or turbo charged, a word of advice on oil change procedures. Most charged engines use engine oil to lubricate the moving assemblies. These move at a very high RPM and need constant lubrication and if certain precautions are not taken when the oil is drained you will cause problems. The most critical of these procedures is to fill the filter with oil before it is installed this prevents oil starvation on start-up while the filter fills with oil, true this is a very short period but it is enough to damage a device with the high RPM of a super charger. When I did my own servicing I always filled the filter before installation, no reason just seemed like the proper thing to do. A quality filter is also important as the charger, more a super then a turbo can be damaged by minute particles not removed by a cheaper filter. Brand and type of oil is also important, stick to the type of oil that the owner’s manual calls for and if possible use a quality synthetic. Contrary to popular belief there is a difference in synthetic oils they are not all manufactured the same. Most formulas are a highly guarded secret so it is hard to say which is which. Mobil one is in its own world as to how it is manufactured, it has been rumored for years they use ethanol. Any quality brand will suffice. A synthetic blend will not work in place of synthetic. True synthetic such as Amzoil the jury is still out on. If your charger is not lubricated by engine oil follow the recommended service to the letter, checking the oil level in some is a pain but it must be done. Asked the service writer where I get my oil change and he showed me a check list they go through when servicing the new Eco-Boost engine, it is a Ford dealership, they of course recommend only Ford synthetic and I am sure GM is doing the same for their new oil.

100 MIllion V8’s

General Motors will build its 100-millionth small-block engine on Nov 29, a milestone for the company. It is headed for GM’s historic museum.Introduced in 1955, remember the tri colored 555 Chevy with the continental kit on the rear, it has been used to power everything from passenger cars, boats and industrial machines. Currently Chevy, Cadillac and GMC use it in the United States while Vauxhall and Holden use it overseas.Chief engineer Ed Cole transferred from Cadillac to Chevrolet, and started to save the design, deceasing weight and adding power. It was a way build engines that took advantage of current production techniques.I wonder how many 3.8 GM has built, I am sure it will, if it hasn’t already hit a milestone. It doesn’t have the industrial applications like the V8 however an Ii don’t think it is used overseas.Speaking of engines it looks like the Eco-Boost by Ford is not working out like planned as it has numerous complains of low power. These have mostly been towing problems. When will the engineers learn power or mileage you can’t have both.