2007 Suzuki Forenza 2.0, Rough Running Engine and Overheating Issues

This 2007 Suzuki Forenza with a 2.0 came into the shop a couple of months ago with a customer concern of a rough running engine and an overheating issue. We felt pretty confident we were looking at a blown cylinder head gasket at this point; but, we wanted to "test and not guess".

There are a couple of ways to check for a blown cylinder head gasket. One way is to pressurize the coolant system and, with the spark plug out of the missing cylinder (or all plugs removed), using a bore scope in the cylinders to check for seeping coolant. Another way is to use a 5-Gas Analyzer to check for combustion gases in the coolant system. The third option, similar to the second, is to do what is called a block test.

We opted for the third option. It is a method we have used often with great success.

Before this, however, we wanted to perform a visual inspection.

When the customer drove the vehicle up to the shop, we noticed the tell-tale white smoke out the tail pipe. It was quite pronounced and the smell of coolant in the exhaust was noticeable.

The next visual inspection was of the oil. As you can see in the pictures below, the milky look to the oil is a sure sign that coolant has entered the crankcase.

We let the vehicle sit and then took the cap off the coolant tank. We noticed when we started it, fumes coming out of the tank.

Per the instructions with the block test kit, we let the vehicle run for about ten minutes and then performed the test. The kit comes with a clear tube and a fluid. The fluid is added to the tube, then you place the tube over the coolant tank opening. You apply vacuum to the top of the tube, in this case we used a hand-held vacuum pump, and apply vacuum for a minute or two. If combustion gases are present in the coolant, which they should not be, then it confirms a problem. (If there is a problem, the fluid, which is blue out of the bottle, will turn green.) Of course, it could be a blown head gasket, a cracked head . . . etc., but you confirm there is a problem that calls for a top-end engine tear down.

In the picture below, you see the fluid just added to the tube. You can see it is a light blue color out of the bottle. If the test passes (meaning no combustion gases are detected in the coolant system; hence, no blown head gasket) the fluid will remain blue. However, if the test fails, (combustion gases detected) then it will turn green within a minute or two.

Here I am showing (minus the fluid) how the tube fits on the coolant tank. (It is minus fluid because I just took the picture to demonstrate how to do it.)

As I applied vacuum (via the vacuum pump) to the top of the tube, within seconds, the blue fluid changed to green. This confirmed a failure at the mating of the head and block. Now, it was time to remove the head, send it to the machine shop and replace the head gasket.

We replaced the head gasket, timing belt and water pump and other odds and ends. Put it all back together and the vehicle ran nice and smooth. We test drove it a few miles and shipped it to the customer.

2000 Chevy Astro, 4.3, Crank/No Start Condition (Fuel Pump Voltage Drop Testing)

This 2000 Chevrolet Astro 4.3 came into the shop with a customer concern of a crank but no start condition. The customer had been driving the vehicle, went to start it again and it would not start.

I determined the fuel pump was the culprit. It was an intermittent issue, the fuel pump would prime and function some of the time, but mostly it would not. I knew we would need to replace the fuel pump, but I wanted to do some checks before we did.

It is important to check the circuitry of the fuel pump to be sure everything is okay there. It is a common mistake for a person or shop to simply replace the pump without checking the circuits. Often times, this causes comebacks or a recurrence of the same issue not long down the road.

One of the tests I do, is to perform a voltage drop test on the power (feed) circuit and on the ground circuit. A voltage drop is an invaluable test to confirm the integrity of the circuitry.

To perform a voltage drop test on a fuel pump, you need jumper wires and a DVOM. You also need the circuit "loaded" to do a proper test. In this case, that means you want the fuel pump engaged or priming, and checking the values when the component is under a load.

First, I checked the power side of the circuit. I backprobed in at the power wire for the pump (you will need a wiring schematic to determine which wire this is) and attached my probe to the positive terminal at the battery. With key off and the fuel pump not primed we see battery voltage on this circuit. (The voltage was a bit low, due to cranking to get the intermittent problem to occur.)

When we turned the key on and the fuel pump primed we saw what our voltage drop was.

(Sorry for the glare.) The reading on the meter is .534 volts, or basically, half a volt. The general rule for a voltage drop test of this kind is you do not want it to exceed about .5v (1/2 a volt). Here with our reading, everything is okay. We don't want to be too dogmatic about the .5v rule. As long as it is relatively close, it is fine. Typically a bad reading will be overly excessive, say 3-4 volts.

Next, I wanted to do the same test, but this time on the ground circuit. I backprobed the ground wire for the fuel pump and but my lead to the negative battery terminal. With key off, pump not primed we are reading 0v., which is what we expect for a ground.

We then turned the key on, with the fuel pump primed and read the voltage drop reading.

(Again, sorry for the glare.) You can see we are well under our .5v limit. We are below .1v, so no problem on this circuit either.

At this point, there was nothing left to do but to replace the pump. We inspected the gas tank for any contaminants and made sure the gas and tank were nice and clean. After replacement, we tested it and drove the vehicle. Everything was now fine.

We also changed the fuel filter, which was extremely clogged. It  probably contributed to the failing of the pump. We also put some good injector cleaner through as well.

2003 Ford Explorer XLT 4.0, Clicking Noise in the Dash When Operating the HVAC System

This 2003 Ford Explorer XLT 4.0 came into the shop with a customer concern of a clicking noise in the center o,f the dash when he attempted to change the temperature from cold to hot. This vehicle has a manual HVAC control system. If he just barely moved the temperature knob, the noise would start. If he had the vehicle running and had the temp knob all the way to heat, the noise became louder.

This post is not so much a "how to", but rather a "why" post. It is not necessary to remove the entire dash to do this job; though, the service manuals call for that. I have found the job can be done by removing he center console and the cover beneath the steering column.

The issue is a common one on the Explorers around this year model. The culprit is a faulty temperature blend door actuator. Below is a picture of the actuator.

Internally, this actuator is made up of two small plastic gears. The piece that fails the majority of the time, causing this customer concern, is the smaller, black gear. If you take the actuator apart to see inside, you will see that this black gear has anywhere from two to three teeth sheered off of it. Below you will see the inside of the actuator and the black, plastic gear with the missing teeth.

Below is the small gear by itself. It may be hard to see, but in the pictures below, the two sheered teeth are at approximately the one o'clock position.

These missing teeth cause the gears to slip, not allowing the actuator to move the blend door to its proper location. When the gears hit this bare spot (the spot of the sheered off teeth) it cannot catch and so slips, causing the clicking noise in the dash.

We removed the faulty actuator and replaced it with a new OE actuator. We then tested the system, moving the temp knob from cold to warm and back several times. The noise was now gone and the blend door was operating properly.

2004 Honda Civic LX 1.7 Replacing the Cabin Air Filter

This 2004 Honda Civic LX with the 1.7 engine, came into the shop for a couple of issues.  One thing that we did while we had it was to change the cabin air filter/pollen filter. (It goes by different names depending on manufacturer.)

On this make and model, the cabin air filter is located behind the glove box. The purpose of this filter is to remove odor from the HVAC system, allowing good, fresh air to come into the passenger department.

First, access the glove box. Open the glove box. In order to get to the filter, you will need to drop the glove box down out of the way.

Below, you will see that Honda did a good job making the process much easier than it is on some other makes. You will notice the tabs on the inside of the glove box on the inside. I have my flashlight shining on these tabs.

Next, pop these tabs out and pull them out of the glove box.  The next picture shows the tab popped out of place.

Next, simply push the tab out of position and pull it out.  Below, is what the tab looks like removed.

Now that the glove box will drop down out of the way, the filter housing is easily accessible.

Next, pop the cover off the housing to access the filter.  Below, is the cover removed.

With the cover removed, you can now see the filter in the housing.  Pull the old filter out.  As you can see below, this filter was very dirty and in dire need of replacing.

In the next pic is the new filter.

Now, place it inside the housing.

Then replace the cover over the filter in the housing.

Reattach the tabs in the glove box. This can be a little tricky.  You have to make sure the glove box is partially closed, so the tabs are on the other side of the stoppers.  Once they are in place, close the glove box.

And that's it.  These filters should be changed regularly according to the maintenance schedule.  Check your make and model's info for details.  (Note: not all vehicles come equipped with a cabin air filter. There are some others that did not come installed with one from the factory, but can be added if you want one . . . a Nissan Xterra comes to mind as one of these.)

Cabin air filters should also be replaced if you are constantly getting odor out of your HVAC registers/vents. Or if your HVAC system is not blowing air out as strongly as it once did, this filter could be the cause.

2003 Chevrolet Silverado 5.3, Brake Lights Illuminated and Blower Motor is Inoperative.

This 2003 Chevrolet Silverado 5.3 came into the shop with several customer concerns.  The major concern was that the AC was inoperative.  He mentioned the AC had stopped working within the last two weeks or so and (another concern he had) his brake lights (both the ABS and red brake light) had come on at the same, or about the same time.

First things first, I confirmed the customer's concern.  With the AC on (the control panel lights were on and showing the AC was on), going down the road, cold air would blow in.  When you stopped the vehicle, no air at all.  The brake lights also were illuminated in the panel as the customer said.

Next thing, pull out a wiring schematic and do some checking on the circuit.  It was obvious from driving the vehicle down the road (and observing it visually) the AC clutch was working and the compressor was cycling.

Since the blower motor resistor was fairly easy to access, I started there.  With a test light I checked for power on the respective wires to the resistor.  The Power Probe showed no power on any wire at any speed.  The feed wire also showed no power.

(This is why it is important to "test and not guess".  I have seen a lot of people just throw a resistor in there, because they "go out all the time" only to have it not work.  Make sure you know the cause of the problem before you start removing and replacing parts.  R&R of parts can cost you a lot of time and money.  The best solution is to take it to a professional and get it done right the first time.)

Next, I went to the fuse panel in the left side of the dash.

No power at the fuses.

The brake fuse and HVAC fuse are supplied power by the ignition switch.  An orange wire supplies voltage to these fuses.  Probing this wire, as expected, I found no voltage.

It was time to replace the ignition switch.  The ignition switch is an electrical component.  It is not the part you put the key in to start the vehicle . . . that part is the key and cylinder or tumbler.  Some ignition switches will come with a wiring harness.  This one did not.

To access the switch, remove the steering covers and the tilt handle.  To remove the handle pull outward.  Sometimes a pry bar or long screwdriver may be necessary.  Just be sure not to break any of the plastic surrounding it.

The switch is located on the bottom of the steering column.  It is located just below the lock cylinder.

Disconnect the holding tabs (2 white tabs, one on each side) and gently pull down.  Next remove the wiring harness.  The switch by itself is shown from a couple of angles below.

Once the switch was replaced and installation was completed, it was time to try out the AC and see if the brake lights were now off in the dash.  Sure enough, the brake lights were no longer illuminated and the blower motor was now operational.

The high speed was inoperative, but the customer said it had been so for several years and declined to have it repaired.

2000 Chevrolet C3500 5.7, Wipers and AC Inoperative

This 2000 Chevrolet 3500 came into the shop with a couple of complaints by the customer. He said that a few days before both his AC and windshield wipers stopped operating.  He had checked a couple of fuses, but was unable to find a problem.

First things first, I confirmed the customer's concern.  The AC and the wipers were inoperable.  Next thing to do was to pull up a wiring diagram and start checking the circuit.

I first checked out the two fuses in the fuse block on the left-hand side of the dash.  The wiper and AC fuse are next to one another.  At first, I wondered if something might be going on with the terminals.  When I checked the fuses (Fuse 11 Wiper 25A and Fuse 12 HTR-AC 25A) with KOEO (Key On Engine Off) and the AC and wipers in the on position, I got ground.  No power was coming to the fuses.

Now that I knew there was no power to these two fuses, it was time to find out what their power source was.  Again, consulting the wiring diagram, I saw power was supplied to these circuits by the IGN B 50A fuse.  I saw the radio was also powered on this circuit, and when I checked the radio, as expected, it did not work either.  The IGN B 50A fuse is located in the Power Distribution Box under the hood, on the left (driver's) side of the engine compartment.

The fuse I'm pointing out is the IGN B fuse.  When I checked it with the Power Probe it showed one side with power and the other side without.  This meant we had a blown (melted) fuse.  I replaced the fuse, turned the key to KOEO and tried the problem circuits.  They all now worked.

Of course, fuses don't just blow for the fun of it.  When I reported my findings to the customer, telling him we would need to do further diagnostics to determine the cause of the blown fuse, he opted to pick it up and run it until he has any more trouble out of it.

I advised him on the potential problems and inconveniences that could result from this; but, he decided to pick the truck up as is anyway.

I just hope it doesn't decide to blow when it's raining!