Skip to main content
you & your car

2011 Dodge Journey

When I had my Dodge Journey in for service the other day the mechanic told me to be sure to use high-test gas because I don't drive much and get "junk" fouling up my carburetor. Is that true? – Georges

Giving this mechanic the benefit of the doubt, I'm hoping he used the word carburetor to simplify his explanation. Otherwise, I'd dump him like a container of spoiled milk. Your Dodge does not have a carburetor, no Dodge has had one for three decades.

The next issue is one of gasoline fouling the system – here again, I highly doubt that is occurring. If it is, you might have obtained a bad batch of gasoline or perhaps are buying from a discounted place that uses base stock.

Gasoline comes from one of several refineries across the country. These refineries supply fuel to a variety of retailers whether it be Esso, Shell, Canadian Tire or other brands.

Each refinery produces what is called a base stock, to which a variety of additives are mixed in depending on the demands of the customer. Most of the majors have a strict set or parameters for the fuel they obtain from a refinery and almost all of them require detergent additives be mixed in the fuel they purchase. Shell, for example, has a major push on detergents for its fuel, claiming it has more than the others.

A few years back, once fuel injection became common practice along with increasingly strict exhaust emission requirements, many manufacturers were plagued with "junk" as your mechanic calls it, fouling their engines. Several car makers formed a consortium that demanded a certain level of detergent in their fuel – regardless of the source refinery. This fuel was termed "Top Tier" and has become all but standard for major gasoline retailers and sufficient to all but eliminate "junk" in an engine. But it is possible for discount gas retailers to purchase fuel from a refinery without these detergents at a lower price, allowing it to sell gas at a lower price.

Wheel chocks

I just purchased a RAV4. The owner's manual recommends using wheel chocks when changing a flat tire. Canadian Tire offers a set of folding steel chocks for less than $10. The problem is that they are for use with wheels up to 16 inches in diameter and my RAV4 has 17-inch wheels. Is the difference critical? I've posted a question on the Canadian Tire website a week ago, but so far I've not had a response.

These wheel chocks appeal to me because of the price, the material and the fact that they fold, which means they take up less space and can be tucked into a corner until needed. A quick search on the Internet didn't turn up any folding chocks; many are plastic or rubber and didn't seem to be restricted to a particular range of wheel sizes. Can I safely go with the Canadian Tire chocks? – Robert

You should be OK with the CTC chocks. The RAV4 comes with a variety of tire sizes ranging from 215/70 x 16 to 235/55 x 18 with overall diameters ranging from 707 to 739 mm. That slight variation should not make a difference as the chocks are meant for wheel sizes up to 16 inches without reference to the size of the tire on that rim.

The reason for the chocks is to prevent the vehicle from moving while you are working on it. To make extra sure that will not happen, in addition to the chocks, place a block of wood or other solid object both behind and ahead of any un-chocked wheel and make sure the transmission is in first or reverse if a manual, or Park if an automatic.

Send your automotive maintenance and repair questions to globedrive@globeandmail.com

*****

Top 50 New Cars of 2013

Grocery Getters: Little cars, lot of fun

Fast and Fun Rides: Get your heart racing

Green machines: Emission impossible

Big, beautiful boats: Smooth-sailing luxury machines

Practical People Haulers: Sensible, even when image matters

Practical people haulers: High-end SUVs

Mid-market machines: Popular picks

Starter Luxury: Moving on up

Interact with The Globe