Finding the cause of leaking coolant
Q . I have a 1998 Ford Crown Victoria that is losing coolant. I have checked the system for leaks and haven’t found any. Even after being parked for a few days, there are no wet spots on the ground. The oil is clean with no signs of no moisture in it. I am adding about a quart of coolant a week. What is the issue? A . The problem is most likely a leaking cylinder head gasket. The standard procedure is to pressure test the cooling system and if the system holds pressure, then the next step is to look for an internal leak. You can purchase a kit that uses a special chemical to look for exhaust gases in the cooling system. These kits are $35-$50 and are easy to use and quite accurate. Q . My daughter has a 2007 Toyota Camry Hybrid. Lately, the car has started to vibrate/slide as she brakes, as if the ABS system is engaging even though the road is clear and dry. The light with the squiggly lines will appear briefly. No other lights activate. Our mechanic has been able to experience the issue but has not been able to fix the issue. Any advice?
A
. The anti-lock brake system uses sensors at each wheel that monitor wheel rotation. What you describe as a phantom ABS application can usually be traced to a rusted or cracked ABS tone wheel. A careful inspection and some testing should be able to pinpoint the problem. Q . My Mazda 2014 CX-9 has about 55,000 miles on it. During a couple of four-hour drives on the highway, I noticed a hum coming from the car. After some novice detective work, I figured the right rear wheel bearing/ hub was the problem. I removed the assembly and replaced it with a “sorry to say” economy brand part I purchased online. I roadtested it and for about 300 miles of highway driving, no sounds. Unfortunately, after a few hundred more miles, the same “hum” is back, although less intense. I did more internet research, and some comments were that this brand failed prematurely. And other sites mentioned a bit of a sophisticated install process. The replacement of this bearing hub is straightforward: remove the defective part and install a replacement. Four bolts hold the assembly to the rear axle assembly, and you just remove and reinstall the axel nut. Mixed recommendations on the torque specs for the axel nut: 200ftlbs/258ftlbs. Do you think I just got a lemon part? Did I install it incorrectly? Not like the old days when you’d repack the wheel bearings and “set” them with rotating the wheel and tightening and backing off the holding nut. A . I suspect you may have gotten an inferior part. You are correct the replacement of the bearing is fairly simple. According to AllData, the technical database I use, the attachment bolts should be tightened to 58—75-foot pounds and the axle nut is tightened to 175-202 foot pounds of torque. Q . I have three simple questions that I can’t get an answer for, so I’m coming to you. What window washing fluid do you recommend, especially in the cold Northeast states? Are there any window treatment products do you recommend that shed water or prevent fogging and are gas additives worth the money? My car is a 2015 Kia Soul, but I’m sure the advice applies to most cars.
A
. When choosing windshield washer fluid (which is basically soap, water and alcohol) look for fluid that will protect against freezing to at least 20 degrees below zero. Some fluids will have additives that do a better job of removing bugs and other debris and some will bead water. Whatever fluid you choose, the best results come from a clean windshield. Clean the windshield inside and out with a good quality window cleaner and then go over the windshield with a clean microfiber cloth. Regarding window treatments, I have tried some and had mixed results, so I tend to stay away from
them. If you are trying to prevent fogging, first make sure your defroster is set to fresh air. Fogging happens when there is a temperature differential of the inside and outside of the windshield. A do-it-yourself method to prevent fogging is to clean the window with shaving foam. I haven’t tried it on my car but it works on my bathroom mirror. Regarding fuel additives, adding a fuel injector cleaner periodically and using a gas line antifreeze just before cold winter temperatures can’t hurt, although typically not necessary if you use quality fuel and keep the fuel tak at least half full to prevent moisture.
Q . My daughter’s 2010 Honda Accord has a very slow leak in the front passenger side tire. Last winter it would lose about seven pounds of air every month but all other tires remain full. In summer it would lose the same over a six-week period. I had the tire remounted but with the recent cold nights it’s losing pressure again. All the other tires still remain full. Should I try nitrogen, or have it remounted again?
A . Nitrogen is a cleaner, drier, fatter (not scientific) air. In fact, regular air contains 78 percent nitrogen, so using nitrogen on a tire with a leak won’t fix the problem. I suspect the tire is leaking around the rim. Have the tire removed, the rim inspected cleaned and sealed with a commercial bead sealer and that should fix the problem.
Q . My 2008 Suzuki XL7, runs great but the RPM (idle speed) will dip or hesitate. Again, it runs great on the highway. I think it’s the timing belt or serpentine belt is off. What do you think?
A . A worn timing or serpentine won’t cause an engine to idle poorly. I suspect there is a fuel issue. This could be a clogged/ dirty fuel injector, vacuum leak or even a sticking exhaust gas recirculation (EGR) valve.
Q . Let me first say that I enjoy the insight that comes from you on both your radio show and Newsday. My question is about thread sealant. When doing routine repairs on my vehicles (brakes, suspension etc.) is it advisable to use thread sealant as an additional measure of safety or is it OK to just tighten nuts and bolts according to the manufacturer’s specification?
A . Topically use a thread locker (Loctite is one) when that bolt is under extreme stress or instructed to by the vehicle manufacturer. If the fasteners are something that are removed periodically, I wouldn’t use a thread locker just tighten to the manufacturer’s specifications.
Got a car question?
Email the Car Doctor for a personal response at jpaul@aaanortheast.com. John Paul is an automotive consumer advocate with AAA.