Pat Goss
Automotive repair expert
Thursday, June 12, 2008
11:00 AM
Pat Goss has worked on cars for more than 40 years. He owns a car repair company that bears his name, has authored numerous books on auto maintenance, and makes weekly appearances on Motorweek, a PBS television program.
He visits right here once a month to answer questions about fixing your car.
For more auto advice and industry news, visit our
The transcript follows.
____________________
Arlington, Va.: Hi Pat,
Question about tire rotation. I took my Mazda3 into the shop to rotate, and when I got it back I realized that they had simply swapped right for left on each axle. This seemed like a very strange way to do it. Would this be standard for any reason? I always thought you switched front with back to even out the wear. But I wanted to make sure I should go back to them and make them redo it. Thanks.
Pat Goss: Ahh yes, more tire stupidity! The proper rotation for a front wheel drive car without directional tires or directional wheels is right front to right rear, left front to left rear, right rear to left front and finally left rear to right front. It's called a modified "X" and is the best rotation pattern for longer tire life and more even wear.
_______________________
Plymouth, UK: I have a Saab 9.5 1998 2.3 Turbo. When I start the car first thing in the morning it blows out white burning smelling smoke for about three minutes then its fine. It drives fine but its worrying me about the smoke.
Pat Goss: Begin by checking the valve stem seals and guides. This condition is often caused by oil seeping past the valve seals while the engine is sitting. This produces small oil deposits in the cylinders which are burned off when the engine is first started.
_______________________
Mt. Airy, Md.: Hi Pat,
Have you heard about Hydrogen Car Hybrid (HHO) conversion kits, which converts a car to run on water? If so, any thoughts on it? Thanks.
Pat Goss: What an absolute rip off --- there ought to be a law! These kits can not work it is impossible for them to work. It's a very differnet thing to try to run an engine on HHO than to light a torch with it. The volume needed to run a car engine is many hundreds if not thousands of times greater. For every gallon of gas you would need four gallons of water to produce the same amount of energy but the real problem is how to store sufficient amounts of the gas (by the way cars only run on liquid fuel not gaseous fuel which causes vapor lock) which would require a non-pressurized tank of about 10,000 gallons capacity. Anything else would mean compressing the gas which makes the volume smaller but requires a special tank and in the end the the tank is very dangerous to carry in your trunk. There is no miracle mileage improver except you!
_______________________
Fairfax, Va.: Pat,
Overall, we love our 2004 Chrysler Pacifica... it is a great road trip car, very comfortable and relatively low maintenance. I have recently noticed a problem, however, as I slow down for things like stop signs. The car seems to have an odd, harsh downshift, very noticeable, like the car gets stuck for a microsecond as it seems to hesitate. The car has roughly 55K miles and we have been having transmission flushes every 24 months.
Pat Goss: Begin by checking the throttle body for gum and varnish deposit buildup. This is natural and often causes the idle to be slightly higher which, in turn, causes a harsh downshift.
_______________________
Columbia, Mo.: I have a 1994 Honda Accord EX (4 door). One of the air-conditioner tubes (the "pipe, receiver," part number 80341-sv1-a11, which runs from the cooling unit [on the firewall on the passenger side] to the receiver dryer [located under the battery tray] ) needs to be replaced. I can get a replacement tube from the local salvage yard. How difficult would it be for me to do the replacement job myself?
(After replacing the tube, I would take the car to a local shop to have the refrigerant replaced. A local shop told me it would cost over $600 to replace the tube and fill the system. I can get the used replacement tube for $65 at the salvage yard.) Thanks!
Pat Goss: Normally replacing an AC line is relatively easy. If you can see and reach it the actual job should be simple. But be careful because the threaded parts are normally made of or connect to a part made of aluminum so do not over tighten the attachments. Also before you accept the used part check the threads for damage and corrosion.
_______________________
Washington, D.C.: Hi -- I have a fuel question. My car (VW EOS Turbo) needs 91 Octane fuel. In my area, however, all I can find is 87, 89, and 93 Octane. Can I use 89? Or can I blend the 89 and 93 (you know, fill up 1/2 the tank with each)? Thanks.
Pat Goss: That depends on the specific language in the owner's manual. If the manual says for best performance a fuel with a minimum octane rating of 91 is recommended you probably can use 87. When the higher octane fuel is recommended for best performance that is usually a legal rather than engineering statement.
But if the manual says fuel with a minimum octane of 91 is required you should stick with 93 to be safe. Although the number of cars that would sustain damage is probably very small if you're one of those drivers in that very small percentage you won't be happy!
_______________________
Washington, D.C.: Another tire question -- we're switching our '04 Passat Wagon from Continentals to Michelins (I believe Warren Brown recommended the Pilot tire). The front tires both need to be replaced this summer, the back tires will last through the fall. Is it best to make the move all at once? I hate to waste a few miles on the back tires, but my SO thinks it's horribly bad to have mis-matched tires. (If it matters, we will have a 1,000-mile road trip in August or Sept.) Thanks!
Pat Goss: Do all four. Risking personal safety to get a few hundred or even a couple thousand extra miles out of two tires is not smart. By the way I love my Michelin MXV4 Energy tires.
_______________________
Arlington, Va.: Do you know of any online caculators that estimate cost/benefit, true cost of ownership based on factors as miles driven per year, etc? I drive a car less about 8K miles per year. But I need to buy a newer vehicle. I'm trying to determine the tipping point between a larger (currently cheaper but uses more gas) vehicle vs. smaller eco-friendly (more expensive but less gas). Thanks.
Pat Goss: Unfortuantely no! But the math is very simple so you should have no problem doing the calculation. Unfortunately I don't have the time or space here to give the details but the calculations should not take more than 10 minutes.
_______________________
Fort Myers, Fla.: The clutch in my 2-year-old Kia has gotten stuck to the floor recently. Literally, the only way I could drive my car was to duct-tape my foot to the pedal to pull the clutch back up. Of course, I didn't do that -- I had the car towed to the dealership. The clutch was replaced a couple of months ago -- and now this. The shop tells me that there is nothing wrong with it because they can't replicate the problem. I can't drive this car with my 3 children -- and they can't (or wont) fix it. Do you have any suggestions on what I should tell them to look for or at?
Pat Goss: If the car is under manufacturer's warranty take it to another dealer that is more concerned with the safety of their customers. If the only warranty on the job is through the dealer that performed the work start climbing their corporate ladder until you speak to someone with authority. Be sure to stress the safty issues. If that doesn't get their attention contact your local consumer agency, then your state Attorney General and finally an attorney. Also keep good notes on all conversations --- times --- names etc.
_______________________
Courthouse, Va.: Do you have any general advice about the best brands in terms of quality, handling and wear for tires? These would be for a Ford Freestyle which had lousy OEM tires that need replacing at 25K miles.
Pat Goss: Tires are one giant trade-off! You have to decide what your absolute priorities are. If you want wet traction dry traction may suffer. If you want cornering ability wear will probably suffer. If you want extremely long wear traction and cornering may be slightly compromised. As I manntioned in my last tire answer I have Michelin MXV4 Energy tires on my Camry Hybrid and the run-flat version of the same tire on my Cadillac XLR and find them to be a very nice all around tire. But if you push the car to the limit they will not suit you.
_______________________
Pittsburgh, Pa.: I have a 1997 Civic hatchback, and when stopped on downward sloping ground, a grinding noise is heard. What could this be and what can I do about it? Thank you.
Pat Goss: Usually it is normal and relative to the brakes. But because it is a Honda you should check the engine mounts.
_______________________
Passat Cylinders: Hi, Pat -- I've (well, the VW dealer has) replaced two of the six injectors on my 2000 Passat (110K), with new CEL's immediately after. This last trip they found and replaced a vacuum line, which they believe was causing the cylinder failure. So far so good, but I'm still concerned about good money chasing bad. Is their diagnosis likely to be correct? Thanks!
Pat Goss: It would have been had they done the vacuum hose and vacuum leak check before they replaced the injectors.
_______________________
Fairfax, Va.: Hi Pat,
I always appreciate your advice and expertise. I'm looking to purchase an '08 Chevy Malibu. I've never owned a Chevy, much less an American made car, so I'm wondering what types of problems you usually see in Chevy's/GM's. I realize the redesigned Malibu is brand new for this model year. Anything in previous model years you think could continue to be a problem? Thanks again for your advice. Wish your garage was closer, you'd be my mechanic of choice!
Pat Goss: There is very little carry over from the old car so that really doesn't count. I just interviewed one of the vice presidents of Chervrolet on my radio show last Saturday about this very car. I did this because the car received one of the highest awards that is issued with reagrd to customer satisfaction. It is an amazing car especially when you factor in it's very affordable price.
_______________________
Arlington, Va.: Hi Pat - there is an interesting article in the current Atlantic Monthly about the development of hybrid cars, including the Chevy Volt. One of the interesting points in the article is that hybrid cars are not only being developed by the name automakers but also other companies, including firms in Norway and Silicon Valley that I have never heard of. With respect to the Volt, the article suggests that it has the potential for being a tremendous technological breakthrough - it will go 40 miles on a charge without using the gas motor. But also the potential for being not-ready-for-primetime: they only have eight weeks to test the underbody (even though underbody testing can take up to a year) if they are to make the goal of releasing it in 2010.
So, I'm curious what you are hearing in the business about hybrids that we will see in the early part of the next decade.
Pat Goss: The Volt is not that new. I sat next to one to do a remote broadcast from the Washington Auto Show two years ago. So there has been plenty of testing and there will be lots more. I think you are about to see a huge change in available options as far as fuel efficient cars go. Everyone is working on better battery tecnology, many are actively testing and at least one company is getting ready to sell a fuel cell car. There are various types of hybrid systems being developed such as gas or diesel hybrids that solely drive generators that charge batteries that drive electric motors at the vehicle wheels and on and on. It is going to be utterly amazing over the next 10 or so years.
_______________________
Bethesda, Md.: Another tire question -- out in Arizona they're starting to fill up tires with nitrogen instead of air. Supposedly it'll keep better tire pressure and won't be as "leaky." Do you think it's a gimmick or fact? (By the way, I did switch just to do something different.) Thanks, Pat.
Pat Goss: Arizona??? I guess someone has moved my shop from Maryland to Arizona! I use nitrogen in all my cars and my motorcycle. It is not a miracle product but it does keep tires at-pressure longer because it doesn't leak as fast. It also is absolutely dry which protects against oil and moisture damage to tire pressure sensors in all new cars and many older models. Nitrogen is becoming widely available.
_______________________
Washington, D.C.: Pat, Thanks for these chats. Question about CVT transmissions. Do they require the same maintenance as an automatic transmission? I swear I don't remember transmission fluid changes referenced in my owner's manual (maybe I overlooked it). Thanks.
Pat Goss: That depends on the CVT most do need fluid changes or flushes for absolute longest life. Anything that has fluid should have periodic fluid replacement for best service. There is no fluid in an automobile that gives like-new protection forever.
_______________________
Bethesda, Md.: Pat,
I have a 2000 Honda Civic with 170k miles. It's a stick shift. When driving slowly, and shifting into or out of first gear, it frequently makes a clunking noise accompanied by a shudder or bucking when depressing the clutch pedal. I also notice that if I shift into first, let out the clutch, and do not give it any gas, that this clunk noise and bucking will happen several times. I'm thinking maybe it's a bad engine or transmission mount? Thoughts on how to inspect & ease of replacement? Thanks.
Pat Goss: Sounds like you're on the right track --- check the engine and tranny mounts.
_______________________
Washington, D.C.: Is a podcast available for your radio show? If so, how does one obtain it?
Pat Goss: Not at the moment but I have been sending the substantial number of requests to station management and hopefully!
_______________________
Arlington, Va.: Edmunds has a cost of ownership calculator at http://www.edmunds.com/apps/cto/intro.do
Pat Goss: Yes, they do, and I forgot about it but be careful about some of the results which may require an additional step. Thanks for reminding me!
_______________________
Alexandria, Va.: Hi Pat,
I have a 2005 Ford Focus and have noticed that when I stop at red lights there is a loud vibrating noise coming from the rear of the car. Do you have any idea what could be causing that? I have checked the trunk for any non car related culprits. I just like to have some idea of what is happening before going into the garage.
Pat Goss: Check the exhaust system for broken or mispositioned hangers and rattling heat shields. Other than that and looking for items that may be mispositioned I'm afraid not.
_______________________
Arlington, Va.: I'm taking a road trip out to the Midwest later this summer, and before I go, I was planning to get an oil change on my vehicle (mileage notwithstanding). Is there any other general maintenance you would recommend?
Pat Goss: Check everything and I do mean everything and fix all that is questionable. When I check a car for a long trip my list includes up to 240 different items on the car.
_______________________
More on tires: How often do tires typically need to be changed? I have a 2005 Passat and 3 out of 4 blew out in a 2-week period 5 months after I bought the car in July 07. It had 35k miles. I'm just wondering how long I could expect the new replacement tires to last -- I've had them 7 months.
Pat Goss: No way to predict. The life of a tire depends on it's profile (low profile high performance tires wear much fatser than less agressive tire and are more prone to blowout), the quality of the tire, how frequently the tires are rotated, the type of driving the car is subjected to, how well tire pressure is maintianed, and numerous other factors. We find worn tires on some very high perfomance cars at 10,000 to 12,000 miles. We see other tires that last well over 100,000 miles and everything in between.
_______________________
Ellicott City, Md.: Hi Pat,
1996 Nissan P/U 4 Cyl 5 Spd 114,000 Mi. Truck continues to get only 11 MPG AFTER: New fuel injectors, plugs, cap, rotor, MAF sensor, NO CHECK ENGINE light comes on. Why such poor mileage? Faulty fuel pump? Thanks.
Pat Goss: Sounds as if you're replacing everything except the things that control mileage on fuel injected cars. Check the coolant temperature sensor, check the inlet air temperature sensor, check the thermostat and then evaluate the readings in the computer's datastream.
_______________________
Annapolis, Md.: Hi Pat, my 1995 Toyota Corolla is having difficulty starting. Specifically, when I turn the key, I hear a click and then nothing. After 4-5 turns of the key, the car starts up just fine. Is this a likely starter issue, distributer, spark plug, or what?
Pat Goss: Check the battery first, then the battery cables and battery cable connections, followed by the starter. Toyotas have a huge problem with battery cables so make sure you select a technician that knows how to perform a votage drop test.
_______________________
Rockville, Md.: Mr. Goss, can a burned out catalytic converter on my 1996 Nissan Pickup 4 cyl 4WD be causing me to get around 12 mpg? Mechanic who charged me $1800+ for fuel injectors + MAP Sensor to fix problem (which didn't) says yes.
Pat Goss: Only if it will barely accelerate. If it isn't absolutely lacking in its ability to accelerate the converter probably isn't the issue.
_______________________
Richmond, Va.: Good morning. Great info here. I'm driving an 08 Mercury Mariner V6 and have noticed tons of knocking and pinging when I'm moving down the highway without load and not on a hill... just when I touch the gas. The manual says it required 87 octane gas which is what I use. Any ideas what's going on? The dealer suggested I try some dry gas which had no effect. Any thoughts? Thanks.
Pat Goss: The dealer needs to pay attention. The problem is most likely caused by an emissions component such as the EGR system (if equipped) or a faulty computer program.
_______________________
Laurel, Md.: I have a 1991 Honda Accord LX. How often should I get an alignment? Last one was done 5 years ago.
Pat Goss: Only when needed and many cars (if properly aligned) will never need an alignment.
_______________________
Wellsville, Pa.: Thanks for answering questions today, Pat. Is there much difference using a Goodyear Tripple Tread all season tire or a Yokohama AVID TRZ touring all season tire? I think the Tripple Tread tire is 6 pounds more than the Yokohama.
Pat Goss: Unsprug weight (heavier tire or wheel) can significantly change the way a car rides and handles. But that goes both ways heavier or lighter. If you liked the way the car responded when new buy repalcement tires with similar weight.
_______________________
Washington, D.C.: Passat tires again. I recall using the Energy tires on my Golf -- are those ok for the larger and heavier wagon? (Clearly I'm clueless on this!) We need an all-season tire that is good in the snow (the long road trips are typically to Vermont).
Also, I'm guessing the services VW suggests, such as the various line flushes, are unnecessary & just money makers for the service shops? Thanks again!
Pat Goss: You would be wrong about flush services and other preventive maintenance procedures. They can double or triple the life of the car. For your type of winter driving it sounds like a good tire for the summer and four winter tires on seperate wheels for winter would make sense.
_______________________
Saturn fuel pump: My 1997 Saturn has a delayed start when the engine is warm. The repair shop says the fuel pump is loosing pressure when I turn the engine off. Do I need to replace the entire fuel pump or just the check valve?
Pat Goss: The symptoms are not really right as the check valve leak down usually occurs while the car is sitting ovenight. For warm leakdown they need to check the fuel injectors and fuel pressure regulator. The check valve is normally part of the fuel pump.
_______________________
Arlington, Va.: Following up on the tire question: How important is it to go with the original tire model when replacing all 4 tires? Is it okay to go with the lesser known (and cheaper) brand as long as all 4 tires are matched? Thanks.
Pat Goss: Brand isn't important as long as the quality is still present.
_______________________
Tyson's Corner, Va.: A local dealer wanted to charge me almost $150 to "cleanse the intake tract" on my car as part of an engine sensor replacement. I declined. This same dealer also did an unrequested oil change, and tried to charge for 5 quarts of oil in a car that only holds 4. Just a warning to others out there: the days of muffler bearings and turnsignal fluid are far from over. Read your bill carefully people.
Pat Goss: Thanks for the info. Unfortunately things like this happen but they are very rare today. The intake cleaning is a vital servie on many cars and on cars with dual intake runner and butterfly control valves failure to clean the intake can cause damage up to $2,000.
_______________________
Washington, D.C.: Pat, I believe that I've seen you say that it is not worth switching to synthetic oil in an older car. Do I remember that right?
If so, is there a general guideline as to when switching to synthetic oil is not cost-effective (e.g., 100,000+ or something similar)?
Pat Goss: No that is not right. It depends on how long you plan on keeping the car. If it going to be in service for many thousands more miles sysnthetic will help meet that goal.
_______________________
Falls Church, Va.: I am looking at a 2005 Acura TL to buy used with 36K miles. Any thoughts or advice?
Pat Goss: Nice car, fun car, relaible car, not particularly economical though if that's an issue. And make sure you get good warranty coverage on its automatic transmission.
_______________________
Rockville: Pat, I've hit the mileage (105,000 miles) on my Nissan Frontier V-6 where I need to replace my platinum spark plugs. Is changing out the plugs a DIY job like it used to be or do I really need to take it to a dealer or repair shop?
Pat Goss: If you have basic skills it should be do-it-yourself.
_______________________
Arlington, Va.: I have a 1997 Ford Explorer with 97,000 miles. I'd like to figure out what kind of shape the car is in and how long I can realistically expect it to last based on its current condition. How much would such an inspection typically cost (ballpark) and how do I go about finding a good mechanic to do it? Thanks!
Pat Goss: I don't know how you find the shop but the price can vary from about $65 all the way up to $200 in some shops. I don't license anyone to use my procedures in the Washington, D.C., metro area so I really don't have a recommendation.
_______________________
Fairfax, Va.: So if the car's manual says Minimum 91 Octane REQUIRED (as opposed to RECOMMENDED) -- what kind of potential damage are we talking about? I know that using lower-octane fuel in a high-compression/turbo-charged engine can cause engine knock, but what is the potential for long-term damage to the vehicle if I consistently put lower octane fuel in it?
Pat Goss: Burnt valves and destroyed pistons or piston rings. Again only on a very small percentage of vehicles but it happens to you!
_______________________
Alexandria, Va.: Hi there! I have a timing belt question. I have a 2000 Honda Civic and want to drive it into the ground. It only has 50k on it, but it has been out in the world since 1999 (I got it used). I'm doing the timing belt and water pump, but feel a little sheepish about the low mileage. I figure I can do it now or a year from now, wither way it doesn't matter. Better to do it when I've got the dough. Thoughts? Does time or mileage matter more for a timing belt? I'm assuming mileage...
Pat Goss: Oh, but it does matter. I matters a lot! Timing belts have to be changed based on time or miles --- whichever occurs first. In the case of your Honda it is 90,000 miles or five years. You are courting disaster because the belt is really stale at this point.
_______________________
Fuel Question: Really, the difference between 87 and 93 is about $3 for a 15 gallon fillup. If you can afford the Eos, you can afford the $3. It's not worth the risk.
Pat Goss: Agreed. In my world the risk doesn't warrant the savings.
_______________________
Vienna, Va.: Hi Pat,
There is so much conflicting information out there about what grade of gasoline to use. We have an Acura MDX and TSX, both of which say "Premium only". But I have heard that we don't need to use the highest grade if we have knock-sensors. What is your suggestion? I switched to 87 in the TSX, and have not really noticed a difference. I went down to 89 in the MDX and notice a slight difference in power, but not much. Am I harming the engine(s)? Thanks!
Pat Goss: Did you hear all that conflicting information from Honda Motor Company? I didn't think so! Information from individuals without real names or faces on the Internet really shouldn't be trusted more than the people who designed and built the car. Just a common sense obsevation.
_______________________
Washington, D.C.: Given the superior fuel economy of diesel, especially at highway speeds, it would seem natural to integrate it with hybrid technology, for overall maximum fuel economy, and yet diesel-hybrids don't appear to be on the market. Do you know why that is the case? Is it an engineering problem? Thanks!
Pat Goss: The government has strangled diesel sales in the U.S. but you should see a big change in the next few years due to clean diesel technology.
_______________________
D.C.: Can you visually tell when a distributor cap and spark plug wires need to be replaced. Someone remarked to me about white residue on the insulation as an indicator.
Pat Goss: Not a good indicator as white residue is caused by static charge as well as problems, so in a word, no. At least not unless there are more serious visual cues.
_______________________
Vienna, Va.: I have an '01 Toyota Avalon that just hit 100,000 miles. The service schedule recommends replacement of the timing belt at 90,000 miles, but this has not been done yet. I know the timing belt should be replaced, but should I pay the extra to have the water pump, cam and crank seals replaced? Replacing the pump and seals seems to add $450-$500 to the job, and I'm not sure it's worth the cost if I only plan to drive the car another 50,000 miles. What are your thoughts?
Pat Goss: Water pump yes seals if there is any indication of leakage.
_______________________
$75 and climbing...: ...for a fill-up! Hey Pat, can you, once and for all, explain to people why you need to put premium gas in a car? I drive a turbo-charged Audi A4 1.8L convertible and my friends say I'm crazy to keep filling it with premium when prices are so high... I say I'm keeping engine knock and the resulting eventual expensive repairs at bay. The manual and the sticker inside the fuel-filler door both say "Minimum 91 Octane (i.e. premium) Required." Can you tell us which types of cars/engines NEED premium and which types are OK with regular?
Pat Goss: Engines that are specifically designed for premium. There is no particular class as even some so called economy cars require premium fuel. The differences are how much the pistons compress the fuel before igniting it and how early in the piston's upward travel the spark is delivered to the spark plugs. The effects of not using premium in a premium requred engine can be quite varied. If the spark occurs too early for the type of fuel being burned (premium burns and expand more slowly) the fuel will start expanding as the piston is still moving upward. The ping you hear is the power intended to propel the car expanding early and hammering the tops of the pistons. The computer can compensate right up to the point where it reaches its limit and then --- LOOK OUT!
_______________________
Pat Goss: Well the clock has caught me again. I'm sorry I couldn't get to everyone's questions but it has been a busy day. Just remember that modern cars burn roughly 97 percent of all the fuel that goes into their engines so when you hear claims of 10 percent to 20 percent or more improvements in fuel economy with a pill, a can, or a gadget it ain't gonna happen! Thank you for participating, I'll see you next time -- until then please remember and support our troops and please drive gently.
Pat
_______________________
Editor's Note: washingtonpost.com moderators retain editorial control over Discussions and choose the most relevant questions for guests and hosts; guests and hosts can decline to answer questions. washingtonpost.com is not responsible for any content posted by third parties.
View all comments that have been posted about this article.