Jesse Asked
The workers at Jiffy Lube suggested that my '95 Grand Caravan (193,000 miles) needs a transmission flush. I've heard both good and bad about these. What exactly is involved in a "flush" and would you recommend it?
Leon (Transmision Exchange) Replied
I would need to know more before you could give you the best answer. If all they do is disconnect a cooler line and hook up a machine and pump out the old fluid and pump in new fluid, then no. The problem with this is that it doesn't change the transmission filter which is probably partially plugged already. The new fluid, which is highly detergent, loosens up the old debris in the transmission and then it gets sucked into the filter and plugs it off and burns up the transmission. If that is the original transmission with 195,000 miles it just might hasten it's failure. Pulling the pan and cleaning it out and changeing the filter and the fluid is the safest proceedure. It is also wise to cut the filter apart and inspect the inside of it and the pan and magnet, this will be helpful in understanding the condition of your transmission.
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Love the idea of this blog.
Question: The "ABS" light just came on in our 1999 Volkswagen Jetta. I checked the brake fluid level, and it was full. The brakes don't seem soft, what do you think could be causing the light to be on?
Each wheel has a sensor that tell the computer what that wheel is doing. The sensor is connected with wire to the computer. In this kind of weather with the snow and the slush it can get to that wire and sensor. Sometimes the the snow can break a weak wire or if the insulation comes off the wire and the snow can short the signal to ground it will set the ABS light. The system is such that even if the ABS systems fails the brakes still will work, only you won't have the added protection that the ABS gives.
I'd love your opinion on a couple of matters:
1. I've heard that higher octane gas isn't necessary and isn't worth the additional cost. Is it?
2. What's your opinion of bottled additives that are sold in some gas stations? Are they a gimmick, or is there some value in using them for my car's system? And if so, how often?
1. Photo by Alexander Koellner High octane gas is expensive - Is it worth the money?
In my post Is Cheap Gas Bad for Your Car, I discovered that in the U.S., gas is gas. The only significant difference between cheap gas and brand name gas is the price. But what about octane rating?
•Does using a higher octane gas improve mileage or fuel economy?
•Does higher octane gas give my car more power?
The answers may surprise you.
High Octane - Simple Definition
Technically, an octane rating measures the proportion of isooctane to heptane in a fuel. But as a practical matter, a fuel's octane rating relates to how much energy it takes to ignite that fuel.
The higher the octane number, the more energy it takes to ignite the gas.
Does High Octane Gas Improve Gas Mileage?
No. Unless your car is explicitly designed to run on high octane gas1 (it's rare, read your car's manual), using a high octane gas will NOT give your car better mileage. That's because the rating refers to how much energy it takes to ignite the gas, not directly to how much energy the gas puts out.
Does High Octane Gas Give More Power?
No. Unless your car is explicitly designed for high octane gas (see your car's manual), using a high octane gas will NOT improve the power output of your engine. Again, the octane rating relates to how much energy it takes to ignite the gas, but NOT directly to how much energy the gas puts out.
Exception 1 - By Design
One exception is with engines or cars designed for high octane gas. In that case, using high octane gas WILL improve performance and mileage. The reason has to do with the compression and ignition timing characteristics of the engine. Those specially designed engines will only perform efficiently with higher octane gas. Most engines are not designed this way.
Exception 2 - Engine Knocking
The second exception is if your car has a lot of engine knocking or pinging. This is a sign that the gas is not igniting when it should. This reduces the power and efficiency of the engine. Assuming your car's manual says it's okay, using a high octane gas can help. Does High Octane Gas Reduce Engine Knocking?
Yes! If anything, high octane gas will help reduce engine knocking in most cars (assuming your car's manual says it's okay to use such a gas). The reason follows from the fact that octane is related to how much energy is needed to ignite the gas. If the gas ignites too easily, it can ignite before it's suppose to, which causes the engine knocking or pinging sound. Using high octane gas can reduce and even eliminate that knocking, and help your engine run more efficiently.
Conclusion
In most cases there is no reason to use and pay for expensive high octane gas. Unless your car was designed for such gas:
•High octane gas does NOT improve gas mileage
•High octane gas does NOT improve power output
Exceptions: If your car is explicitly designed for high octane gas, use it. If your car has engine knocking problems (and your car manual says it's okay), using high octane gas may reduce the knocking.
2. Chevron and Texaco add Techron to their gas and it does help clean your fuel injectors. I pick up a car real cheap because it wasn't running very well and bought a bottle of Techron fuel additive and put in the tank and then filled it up with Chevron gas and by the end of the tank of gas it was puring like a kitten. Occasionaly a hard excelleration is good for cleaning out the engine of some carbon deposits.
(Leon) Transmission Exchange SLC
HOW MUCH WOUKD IT COST TO FLUSH THE TRANSMISSION IN MY 1990 DODGE CARAVAN? I LIVE IN SALT LAKE CITY, UTAH.
Sounds like you need a transmission flush. Great article, and continuous comments would be great. Take care of some transmission maintenance in calgary just to make sure everything runs fine. Check your oil pressure and level as well. Make sure it gets changed regularly. Thanks for the posts.
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